Secondary Intraocular Lens Implantation and Stabilization

Cataract Surgery, 3rd Edition

PART VI – Intraocular Lenses

Chapter 41 – Secondary Intraocular Lens Implantation and Stabilization

Roger F. Steinert, MD,
Martin S. Arkin, MD, PhD

Contents

	•	Surgical Procedure
	•	Studies of Secondary Intraocular Lenses
	•	Complications
	•	Comparison of Sutured Posterior-Chamber Intraocular Lenses with Open-Loop Flexible Anterior-Chamber Intraocular Lenses
	•	Conclusions

CHAPTER HIGHLIGHTS

	≫	Pros and cons of different fixation sites
	≫	Detailed surgical method of iris and scleral suture techniques
	≫	Results
	≫	Avoiding complications

The approach to the repair of a subluxating intraocular lens (IOL) or the secondary implantation of an IOL involves similar choices. In both cases, the dominant issue is the desired location of new IOL placement and the method of fixation in that location.

The surgeon has four principal alternatives for fixation of secondary IOLs:

	1.	Standard capsular bag-fixated or sulcus-fixated posterior-chamber (PC) lenses
	2.	Transscleral suture-fixated PC lenses
	3.	Peripheral iris suture-fixated PC IOLs
	4.	Anterior chamber (AC) lenses.

If capsular support is available standard PC lenses placed in the ciliary sulcus or, preferably, in the capsular bag are the standard of care. If capsular support is absent, the decision is more controversial. Sutured PC IOLs have become increasingly popular over the past decade, but audience surveys in multiple major meetings indicate that many surgeons will select an open-loop flexible AC IOL in the absence of a specific contraindication. Extensive debate persists between these options because of the limited number of studies that are available and the lack of controlled studies with long-term follow-up.

The first suture-fixated IOL was implanted a half century ago by Parry.^[1] Worst was a pioneer in the use of iris pupil-fixated lenses in the mid-1970s.^[1] McCannel reported the use of midperipheral iris fixation sutures to stabilize dislocated pupil-fixated IOLs in 1976.^[1] Since then, numerous techniques using sutures to secure PC lenses to the iris or sclera have been described. Although many studies report on relatively small numbers of patients with short-term follow-up and fairly good results, few large prospective controlled studies exist. Most of the studies involve concomitant corneal transplantation to treat pseudophakic bullous keratopathy (PBK). This makes the analysis more difficult because these eyes often have a high degree of existing pathologic conditions, and corneal transplants have their own complications, including astigmatism, glaucoma, cystoid macular edema (CME), and graft rejection.

It is rare to find an aphakic patient with an intact posterior capsule. Most aphakic patients have had a complicated phacoemulsification or extracapsular cataract extraction. Aphakic patients with residual capsule often have synechiae between the anterior capsule and posterior iris or between the anterior capsule and posterior capsule. The surgeon has the option of placing a PC IOL in the ciliary sulcus after lysing iridocapsular adhesions or attempting capsular bag placement after reopening the bag. In the rare case where secondary IOL implantation can be achieved using an intact capsular bag in a healthy eye, stability and complication rates are believed to be similar to those of primary PC IOL placement in the sulcus.

Three primary options exist for IOL fixation in the absence of capsular support: transscleral-sutured PC IOLs, peripheral iris-sutured PC IOLs, and flexible open-loop AC IOLs. If both the posterior capsule and the iris are disrupted or absent, then sutured transscleral PC IOLs are the only IOL option. Tables 41-1 to 41-4 review the advantages and disadvantages of each of these IOL styles and those of nonsutured standard PC IOLs.^[2–5]

Table 41-5 lists the principal indications for secondary IOL implantation. Clinical scenarios include rupture of the posterior capsule at the time of cataract surgery or a patient with a threatened expulsive hemorrhage in whom the cataract surgery was aborted without IOL placement. Some patients with closed-loop AC IOLs who have been followed closely and have not yet developed generalized corneal edema have been found to have decreasing endothelial cell counts, increasing corneal thickness, localized peripheral corneal edema, or CME. These patients may be candidates for IOL exchange. AC IOLs and sutured PC IOLs are also used to replace malpositioned lenses that are decentered, subluxated into the vitreous, or dislocated near the endothelium. Panton et al.^[6] described the use of iris sutures and IOL exchange for scleral-sutured PC IOLs to manage subluxed primary PC IOLs. Price et al.^[7] believe that capsulorrhexis should help decrease the incidence of this complication. Finally, cataract surgery complications that can lead to IOL exchange include the uveitis-glaucoma-hyphema (UGH) syndrome or chronic pain from closed-loop AC lenses without corneal edema. Doren, Stern, and Driebe^[8] found that the UGH syndrome was usually associated with a relatively poor outcome, even with lens exchange. See Chapters 44, 46, and 49 for further discussion of corneal decompensation and the technique of removing closed-loop AC IOLs.

Table 41-1 -- Theoretical properties—nonsutured standard PC IOLs

Advantages

Disadvantages

Low incidence of CME, pupillary block, UGH, PBK

Requires intact posterior capsule and zonules

Less endothelial loss*

		Mechanical barrier against vitreous movement or diffusion of vasoactive substances that could lead to CME or retinal detachment
		Positioned at nodal point of the eye
		Distant from trabecular meshwork

Increased risk of dislocation

CME, Cystoid macular edema; UGH, uveitis-glaucoma-hyphema;

PBK, pseudophakic bullous keratopathy.

^*	Soong HK, Meyer RF, Sugar A: Techniques of posterior chamber lens implantation without capsular support during penetrating keratoplasty: a review, J Refract Corneal Surg 5:249–255, 1989.

Table 41-2 -- Theoretical properties—scleral-sutured standard PC IOLs

Advantages

Disadvantages

? Share advantages of nonsutured PC IOLs

Technically difficult to insert

Can be used with limbal wound or penetrating keratoplasty

Increased operating time

Not dependent on presence of iris tissue

Often requires extensive vitrectomy

Vitreous supported by lens

Suture-related endophthalmitis

Limited pseudophacodonesis

? Risk of epithelial downgrowth from suture path

Minimizes uveal contact

		Risk of retinal detachment from vitrectomy and manipulation near the vitreous base
		Risk of hemorrhage from suture passage through ciliary body
		Long-term dependence on fixation of IOL by a suture

Ciliary body erosion from haptics*

PC IOL, Posterior chamber intraocular lens.

^*	Duffey RJ, Holland EJ, Agapitos PJ et al: Anatomic study of transsclerally sutured intraocular lens implantation, Am J Ophthalmol 108:300–309, 1989.

Table 41-3 -- Theoretical properties—iris-sutured PC-IOLs

Advantages	Disadvantages
? Share advantages of nonsutured	? CME from uveal irritation
PC IOLs	Pigment dispersion
	Technically difficult to insert
	Technique easier to use with penetrating keratoplasty; challenging in closed chamber
	Limited pupillary dilation*
	Pseudophacodonesis
	Requires sufficient iris tissue

PC IOL, Posterior chamber intraocular lens.

^*	Spigelman AV, Lindstrom RL, Nichols BD et al: Implantation of a posterior chamber lens without capsular support during penetrating keratoplasty or as a secondary lens implant, Ophthalmic Surg 19:396–398, 1988.

Table 41-4 -- Theoretical properties—flexible open-loop AC IOLs

Advantages	Disadvantages
Easier insertion and sizing	Difficult to insert properly—iris tuck
Less operating time including uveiitis, glaucoma, hyphema, CME, PBK	? Lower but persistent risks of older-style AC IOLs,

AC IOL, Anterior chamber intraocular lens; CME, cystoid macular edema; PBK, pseudophakic bullous keratopathy.

Table 41-5 -- Indications for surgery—secondary IOL or IOL exchange

Corneal edema

PBK (usually with IOL exchange)

Closed-loop AC IOLs

Iris-supported IOLs

Modern open-loop AC IOLs

ABK

		Aphakia
		Prior intracapsular cataract extraction
		Contact lens intolerance
		IOL complications
		Complications during planned extracapsular cataract extraction
		IOL exchange of closed-loop AC IOL
		Decreased endothelial cell counts
		Cystoid macular edema
		Malpositioned IOL
		UGH syndrome
		Pain
		IOL power error

ABK, Aphakic bullous keratopathy; AC IOL, anterior chamber intraocular lens; PBK, pseudophakic bullous keratopathy; UGH; uveitis-glaucoma-hyphema.

Surgical procedure

Few patients have an intact posterior capsule and no IOL present. Occasionally, PC IOLs dislocate without extensive capsular bag disruption, and an IOL exchange or repositioning is necessary. Some patients with an old-style rigid AC IOL and PBK may have some capsular support evident at the time of penetrating keratoplasty and IOL exchange. For the few patients in whom secondary placement of a nonsutured standard PC IOL is possible, the two options are capsular bag or ciliary sulcus placement. In patients with an intact posterior capsule, a significant surgical obstacle is reopening the capsular bag. Nevertheless, in cases without extensive fibrosis, the anterior and posterior capsules can be separated. The key is to locate one area in which the anterior capsule edge is not strongly adherent to the posterior capsule. Using this entry point, viscoelastic agents can be very helpful in the separation of the capsular layers. If adhesions are very dense, blunt dissection with cannulas or other instruments can be attempted. In some cases, the adhesions can be left intact focally by creating an extension of an anterior capsulotomy peripheral to the adhesion, using either capsulorrhexis-like tearing techniques or scissors cutting of the anterior capsule. A final alternative is sharp dissection between the anterior and posterior capsules, but this carries greater risk of penetrating the posterior capsule.

If reopening of the capsular bag is not feasible, ciliary sulcus fixation of the IOL is a reasonable alternative. This requires at least peripheral capsular support and intact zonular support. A frequent situation is a posterior capsular rent with an intact anterior capsulorrhexis. It is often necessary to lyse adhesions between capsular remnants and the posterior iris to reconstruct the ciliary sulcus before IOL placement. It is important to visually confirm that the haptics are not inadvertently directed under the anterior capsule during insertion to ensure proper support and avoid vitreous entanglement. If capsular support is focally uncertain, suturing one of the IOL haptics to the iris or sclera is advisable.

It is commonly stated that AC IOLs are easy to insert but difficult to insert correctly. The three most common mistakes made during insertion are incorrect sizing, not taking sufficient steps to avoid iris tuck, and insufficient attention to location of iridectomies and the capacity of haptics to rotate through them. Table 41-6 lists the most important steps in AC IOL placement.

Table 41-6 -- Surgical procedure for AC IOL placement

Correct sizing—length 1mm greater than horizontal white–white distance (limbal diameter)

If feasible, orient incision on steep meridian to reduce postoperative astigmatism

Orient incision to place haptics away from peripheral iridectomies, or rotate IOL away from iridectomies after insertion

Construct pupil preoperatively (e.g. pilocarpine 2% drops, 30min before operation)

Use viscoelastic substance to maintain anterior chamber

Vitrectomy to clear anterior chamber and wound of vitreous if necessary

Avoid iris tuck, dialysis; some surgeons prefer the use of a Sheets guide

Haptics should rest securely at level of ciliary body band—perform “bounce” test to evaluate both stable fixation and absence of iris tuck

AC IOL, Anterior chamber intraocular lens.

Peripheral iris suture fixation

Peripheral iris suture fixation of the haptics of a PC IOL is commonly referred to as “McCannel suturing,” which is in recognition of the contribution of Malcom McCannel, who first described the technique for passing sutures through the iris to stabilize an IOL that had dislocated postoperatively. McCannel's description was in the context of a pupil-fixated IOL, an IOL style abandoned long ago. However, the basic maneuvers that McCannel described, using long needles to pass sutures through the iris and around elements of the IOL, remain highly useful for the stabilization or secondary implantation of a PC IOL in the absence of adequate capsular support.

Some surgeons advocate these techniques over transscleral suturing in all cases. Others reserve peripheral iris suture fixation for particular indications. These include glaucoma patients for whom an AC IOL is thought inadvisable or anatomically impossible and patients in whom the conjunctiva needs to be preserved for possible future filtration surgery or where a filtering bleb is already present and must be protected. The technique is also attractive in the setting of phacoemulsification under topical anesthesia when capsular support is inadequate. Most patients can be comfortable with intracameral anesthetic, such as 1% nonpreserved lidocaine, while the surgeon places and sutures the IOL to the peripheral iris, whereas taking down conjunctival flaps and passing sutures through the ciliary sulcus and sclera may be unacceptably painful under topical anesthesia.

The basic technique for peripheral iris suturing of a PC IOL begins with constricting the pupil adequately to temporarily capture the PC IOL optic in the pupil anterior to the iris plane, while the haptics remain in the posterior chamber. The technique is illustrated in Figure 41-1. A key in obtaining a round central pupil is to keep the length of the iris suture pass as short as possible and as peripheral as possible. Long suture passes bunch up iris tissue. Nonperipheral suture passes inhibit free movement of the pupil. Both errors result in distorted, nonreactive pupils. The repair of a subluxating PC IOL that is not located in the capsular bag is fundamentally the same as a secondary implant with the McCannel technique. The surgeon manipulates the IOL optic anterior to the iris plane while the haptics remain posterior. The pupil is pharmacologically constricted, capturing the optic. The haptics are then suture fixated. In the final step, the optic is then prolapsed posteriorly back into the posterior chamber.



Figure 41-1 McCannel iris suture fixation of a PC IOL. A, Kuglen hook in the surgeon's left hand and an Osher Y-hook in the surgeon's right hand are introduced through two paracentesis openings and used to elevate the optic above the iris plane, capturing the optic in the pupil while the haptics remain in the posterior chamber. B, A 10-0 polypropylene suture on a fine long needle (Ethicon CTC-6) is passed through the paracentesis, penetrates the iris in the periphery just in front of the haptic, which is indenting the iris stroma, exits the iris as soon as possible after the haptic, and then is driven up through the peripheral clear cornea. C, Same maneuver is performed under the opposite haptic. D, With both needles remaining in place behind the haptics, the successful capture of the haptics and acceptable location of the IOL in the pupil are verified. E, Sutures are tied and cut inside the eye using the “slip knot” technique illustrated for iris suturing in Figure 31-1. Kuglen hook presses the intraocular lens (IOL) optic posteriorly. F, Pupil is round, and the IOL is well centered.

Soong et al.^[9] describe both two-point and four-point iris fixation for PC lenses at the time of penetrating keratoplasty.

Transscleral suturing

Many different alternatives have been presented in the literature for placement of transscleral-sutured PC lenses. Scleral-sutured lenses can be sutured from the inside out (ab interno) or by passing the needles from the outside of the eye inward (ab externo). A combination of scleral and iris sutures has also been described.^[10] Transscleral sutures can be oriented vertically, obliquely, or horizontally, except that direct 3 and 9 o'clock horizontal fixation is inadvisable because of the danger of suturing through the long ciliary arteries and nerves in these locations.^[11] It is important to do an extensive anterior vitrectomy in most cases before placement of a sutured PC lens to avoid vitreous incarceration and subsequent retinal traction and detachment.^{[9,][11,][12]}

Many of the early surgeries performed with scleral-sutured PC IOLs placed the haptics too far posteriorly. The goal is to have the haptics resting in the ciliary sulcus. Anatomic studies have shown that the ciliary sulcus is only 0.83mm posterior to the limbus in the vertical meridian and only 0.46mm posterior to the limbus in the horizontal meridian.^[4] Duffey et al.^[4]passed needles perpendicular to the sclera at 1, 2, and 3mm posterior to the limbus and found that the needles exited internally at the ciliary sulcus, pars plicata, and pars plana, respectively. These anatomic studies emphasize the importance of keeping transscleral needle penetration sites anteriorly. The surgeon can detect that a needle is being passed too anteriorly by iris movement as the needle penetrates the peripheral iris stroma near the angle. In determining the correct location, the surgeon must be mindful that the anatomic studies are based on a strict perpendicularity of the needle relative to the scleral wall. If the surgeon passes the needle through the scleral wall at an oblique angle (usually tilted toward the iris plane), then the external scleral point will need to be more posterior for the interior scleral point to be at the level of the ciliary sulcus.^[13]

The surgeon has the option of creating scleral flaps so that the polypropylene (Prolene) suture knot is buried, avoiding exposed suture ends. Cautery is recommended to retract exposed barbs, should they occur postoperatively, to avoid a possibly entry tract for microorganisms or epithelium. If the suture knot is rotated, as in the technique of Stephen Lane shown in Figure 41-2, then no scleral flap is needed.



Figure 41-2 Lane technique to avoid scleral flaps. A, Double-armed polypropylene suture is passed through the haptic positioning hole. B, Suture is passed ab interno through the ciliary sulcus, as in Figures 41-3 and 41-4, except that no scleral flap is required. The sutures should be spaced 1.5–2mm apart. C, Suture is tightened and tied with a small 1-1-1-1 knot. D, Knot is rotated internally. Conjunctiva is then closed over the smooth suture loop.

PC IOLs made specifically for suturing to the sclera have eyelets on the haptic to aid suture fixation and large-diameter optics (7mm) to compensate for possible decentration. A commonly used model of scleral-sutured IOL is the Alcon CZ70BD.

The ab interno technique for transscleral suture fixation of a PC IOL typically uses polypropylene (Prolene) suture material. A long needle is required for the pass across the anterior chamber: the Ethicon CIF-4 and Ethicon STC-6 and CTC-6 needles are commonly employed^[14] (Figures 41-3 and 41-4). The CIF-4 is thicker and affords more control to the surgeon. The needles are passed under the iris, aiming for the ciliary sulcus. A girth hitch can be used to attach the polypropylene suture loop to the IOL haptic (Figure 41-5). Alternatively, sutures can be tied to the haptic, to the haptic eyelets, or proximal to a haptic eyelet.^[15] The needles exit the eye under the previously dissected scleral flaps, and the sutures are tied (Figure 41-6). Alternatively, to avoid dissecting scleral flaps and the potential for later erosion of the flap and conjunctiva, with exposure of the suture ends, the suture is passed through the positioning hole in the haptic, and the knot is rotated below the scleral surface (see Figure 41-2). The ab interno technique is adaptable to foldable IOL implantation as well, allowing suture fixation of the IOL while retaining a small incision, which is particularly important if capsule support is lost during primary cataract surgery through a small, clear corneal incision.^[16]



Figure 41-3 Technique for the ab interno approach (also see Figures 41-4 to 41-6). First the long needles are passed under the iris, aiming for the inferior ciliary sulcus. Two needle passes are made for each haptic if four-point fixation is desired. Needles exit under previously dissected scleral flaps.



Figure 41-4 A second pair of short needle passes is made under the superior iris for the suture to be tied to the second haptic.



Figure 41-5 Girth hitch can be used to attach the polypropylene suture loop to the intraocular lens (IOL) haptic. This technique is more rapid than tying the suture to the haptic. Alternately, the suture can be attached to the IOL haptics before the transscleral needle passes, but the surgeon must avoid tangling the long sutures.



Figure 41-6 After exiting the eye under the previously dissected scleral flaps, the sutures are tied, securing the intraocular lens (IOL) into position. Appropriate suture tension is important to avoid lens decentration. The inset shows the cross-sectional view of the eye with the IOL correctly positioned in the ciliary sulcus.

The principal advantages of the ab interno (inside-to-outside) approach are that it is more straightforward and possibly faster than the ab externo (outside-to-inside) technique. It is also easier with penetrating keratoplasty. The disadvantages include the fact that the needle is passed under the iris without direct visualization, and the surgeon has to rely on indentation of the iris with the needle from behind to ensure correct placement in the ciliary sulcus.

Lewis^[17] first described the ab externo technique of passing the scleral needles from the outside inward. The sutures used for the procedure are 10-0 polypropylene with a long straight needle, such as Ethicon STC-6. Alcon produces Pair Pack Fixation Suture, which is a hybrid combining an SC-5 straight needle on one end and an AUM-5 corneal needle on the other. This is specifically made for the outside-to-inside technique of scleral-sutured PC IOLs. The long straight needle is passed perpendicularly through the sclera (usually under partial-thickness scleral flaps) approximately 0.75mm posterior to the limbus (Figure 41-7). Inside the eye, the needle should penetrate at the ciliary sulcus. The needle is then “docked” inside the tip of a 25-, 27-, or 28-gauge hollow needle, which has been passed through the ciliary sulcus on the opposite side, also with an outside-to-inside technique (Figure 41-8). After the long straight needle with the 10-0 polypropylene is docked within the hollow needle, the hollow needle is withdrawn with the solid needle inside of it. In this way, the polypropylene suture is pulled across the eye. A hook is used to then pull the suture out through a superior limbal wound (Figure 41-9). The suture is cut, and each end is tied to a haptic of the IOL (Figure 41-10). After the IOL is placed into position, the scleral sutures are secured to the sclera.



Figure 41-7 Technique for the ab externo approach (also see Figures 41-8 to 41-10). The long, straight solid needle is passed through the sclera (usually under partial-thickness scleral flaps) approximately 0.75mm posterior to the limbus. Inside the eye, the needle should exit at the ciliary sulcus. A second hollow needle is passed from the opposite side of the eye. A pair of sutures can be used if four-point fixation is desired.



Figure 41-8 Solid needle is “docked” inside the tip of the hollow needle, which has been passed through ciliary sulcus on the opposite side. After docking, the pair of needles are withdrawn together from the eye, with the solid needle inside the hallow needle.



Figure 41-9 A hook is used to pull the suture out through a superior limbal wound so that it can be tied to the intraocular lens.



Figure 41-10 Suture is cut, and each end is tied to a haptic of the intraocular lens (IOL). After the IOL is placed into position, the scleral sutures must be anchored to the sclera. Either a “blind pass” in the sclera is made so that the suture is tied to itself, or the transscleral suture is tied to a second suture that has been tied to the sclera with a short partial-thickness pass within the bed of the scleral flap.

This procedure can be performed with two sutures per haptic if the surgeon desires four-point fixation to ensure stability (Figure 41-11). The surgeon ties the sutures to the haptics and buries the external knot under a scleral flap (Figure 41-12). The alternative procedure, illustrated in Figure 41-13, allows rotation of the knot to avoid the necessity for scleral flaps and the potential of late exposure of the suture ends, but the antirotational stability of true four-point fixation is not achieved.^[15–18]



Figure 41-11 A, Double-suture variant of the Lewis ab externo technique begins similar to the single-suture technique, except that the suture entry point under the scleral flap is displaced to one side. B, Second suture is passed parallel to the first, with 1–1.5mm between the two sutures. C, Care must be taken to keep the sutures taut to avoid crossing them or confusing which suture originates from each scleral site, while a Kuglen hook or similar instrument withdraws the suture loop through the previously prepared principal incision.



Figure 41-12 A, To achieve four-point stable fixation, the cut sutures are tied to the haptic on either side of the eyelet. B, Intraocular lens is then placed in the posterior chamber, keeping the sutures taut to avoid entanglement. The ends are then tied under the scleral flaps, and the conjunctiva closed over the flaps.



Figure 41-13 In this variant of the double-suture ab externo technique, the goal is to achieve a loop of suture where the knot can be rotated beneath the sclera, avoiding the necessity of a scleral flap and the potential for late erosion of the knot or suture ends. A, Cut ends of each suture are passed through the haptic positioning hole and tied. B, As the intraocular lens is positioned in the posterior chamber, one end of the suture on each side is pulled so that the knot passes through the sclera to the external eye, where it is cut off. Remaining suture ends are then tied together, and the knot is rotated beneath the sclera (inset), achieving the same end result as illustrated in Figure 41-2.

The advantage of the outside-to-inside approach is greater assurance of the location of internal scleral penetration at the ciliary sulcus. Bleeding may be minimized by using precise measurements and avoiding the highly vascularized pars plicata. In addition, the anterior chamber remains closed during the needle passes, decreasing the duration of ocular hypotony. The disadvantage of the ab externo approach is that it takes longer and it is not applicable with the open-sky situation of penetrating keratoplasty. In addition, if more than one suture pass is performed, it may be hard to keep track of the origin and course of the various suture ends.

If a double-suture technique with knot rotation is selected (see Figures 41-2 and 41-13), the surgeon must be meticulous in achieving a suture orientation that permits easy rotation of the knot (Figures 41-14A and B) and avoiding suture configurations that will resist rotation of the knot (Figures 41-14C–H). Furthermore, the surgeon should orient the suture pass through the opposite haptics in a direction that will resist rotation of the IOL out of the iris plane (Figure 41-14I) rather than allow rotation (Figure 41-14J).



Figure 41-14 Suture passed through the positioning hole may wrap around the haptic in eight basic configurations. Only A and B illustrate appropriate pathways. In C through H, the ability to rotate the suture will be impaired or fully prevented by the circuitous route taken by the suture. Because there are two haptics, a total of 16 configurations are, therefore, possible. I, Surgeon should take care to use configuration A on one haptic and the opposite configuration B on the other haptic. In that manner, torque of the intraocular lens (IOL) is resisted; as one haptic starts to rotate in the direction not resisted by the suture loop, the other haptic meets more resistance (arrows). J, When both suture loops have the same configuration, the suture does not resist torque of the IOL (arrows).

“Lasso” suture fixation of the capsule/intraocular lens complex

A posterior chamber IOL may be properly placed within the capsular bag at the time of initial cataract surgery, and then the entire IOL-capsule complex become unstable and dislocate months or years after surgery. This scenario most commonly occurs after trauma to the globe or in the setting of pseudoexfoliation, where the zonules lose integrity over time. Because the haptics and optic are encapsulated, a standard McCannel suture approach is impossible. To deal with the constraints of this scenario, Steinert devised a technique of trans-scleral “lasso” suture fixation. Trans-scleral sutures are passed through the peripheral capsule so that a loop of suture is created around each haptic.

Copyright © 2010 Elsevier Inc. All rights reserved. Read our Terms and Conditions of Use and our Privacy Policy.
For problems or suggestions concerning this service, please contact: online.help@elsevier.com

Studies of secondary intraocular lenses

In studies in conjunction with penetrating keratoplasty, there does not appear to be a major difference in short-term overall results among scleral-sutured PC IOLs, iris-sutured PC IOLs, and modern AC IOLs. Kornmehl et al.^[19] reported good results with flexible Kelman Omnifit AC IOLs compared with previous reports of sutured PC IOLs in penetrating keratoplasty. Lindquist et al.,^[12] studying scleral-sutured PC IOLs without penetrating keratoplasty, also found results comparable to those in published reports using AC IOLs. Although the difference in complication rate is not striking in any series, some authors have found more complications with the scleral-sutured PC IOLs, compared with either iris-sutured PC IOLs or modern, flexible open-loop AC IOLs. In the setting of penetrating keratoplasty, Schein et al.^[20] reported that iris-sutured PC IOLs had the lowest rate of early complications. This may have been a result of the increased complexity of the scleral-suturing techniques, which were relatively new at the time of that study.

Overall results of secondary IOL surgery are better if the initial cataract surgery had been uncomplicated.^[8] Eyes with previous cataract surgery complicated by vitreous loss have worse results regardless of the type of IOL used at the second surgery. Vitrectomy at the time of placement of a scleral-sutured IOL does not seem to relate to the final visual acuity.^{[19,][21,][22]} However, there is at least one report in the literature that contradicts this conclusion; Wong, Koch, and Emery^[23] found a 28% incidence of retinal complications if vitrectomy was done at the time of secondary IOL placement.

Visual acuity results with scleral-sutured PC IOLs during penetrating keratoplasty have been similar, for the most part, to those achieved with other modern lens types.

Eighty-two percent of patients had better vision postoperatively compared with the preoperative vision if a combined corneal transplant and scleral-sutured PC IOL was performed.^[24]Only 4–10% of patients had worse vision postoperatively, compared with preoperative vision, after scleral-sutured PC IOLs with or without corneal transplantation.^[24,][25] Several studies agree that approximately 30% of patients have vision of 20/40 or better after penetrating keratoplasty with scleral-sutured PC IOLs.^{[14,][24,][26,][35]} Lass et al.^[26] included a control group of patients who had corneal transplants with modern AC IOLs and found that 25% of the AC IOL group had a final vision of 20/40 or better. Thirty-five percent of patients after penetrating keratoplasty with scleral-sutured PC IOLs had a vision of 20/200 or worse.^[24] For iris-sutured PC IOLs with corneal transplantation, the final vision was 20/40 or better in approximately 45% of patients.^[21] Most authors conclude that modern AC IOLs, scleral-sutured PC IOLs, and iris-sutured PC IOLs all achieve similar short-term results if used with penetrating keratoplasty. There are fewer studies of visual results of sutured lenses alone, without corneal transplantation, and they typically report on smaller numbers of patients. Nonetheless, visual results are reasonable. Patients with good preoperative corrected visual acuity and secondary sutured PC IOL placement usually maintained their preoperative vision.

Wagoner and colleagues reviewed the world literature on IOL implantation in the absence of capsular support, an Ophthalmic Technology Assessment Report on behalf of the American Academy of Ophthalmology, published in 2003, covering the period of 1980 to 2001.^[27] Of 189 citations, they found 43 suitable case series or higher level studies, but only six publications suitable for comparative statistical analysis. In a report by Hennig of 2002 cases randomized between an AC IOL and no IOL after intracapsular cataract extraction, the only significant difference was in the rate of glaucoma escalation of treatment, at 1.3% for the AC IOL group vs. 0.2% for the aphakic control group (P = 0.05).^[28] In the previously cited Schein et al study of 176 patients randomized at PKP, the only significant difference was in the rate of postoperative CME (iris-sutured: 20%; AC IOL: 38%; sclaeral sutured 41%;P = 0.02).^[20] Note that all of these rates are high, perhaps reflective of many of the PKPs being done for corneal edema due to closed loop AC IOLs. In a study of PKP patients, Sugar et al found lower endothelial cell loss rates with flexible open loop AC IOLs than iris-sutured or trans-scleral sutured IOLs, but the difference did not reach statistical significance.^[29]Davis found no statistically significant differences between AC IOLs and sutured PC IOLs at PKP.^[30] In a non-randomized case series of secondary implants, Lyle and Jin found minimal differences between AC IOLs and sutured PC IOLs.^[31] In the sixth comparative series, Belluci et al compared 35 eyes with AC IOLs to 33 eyes with scleral sutured PC IOLs.^[32] No statistically significant differences were found in mean visual acuity, corneal edema, glaucoma escalation, CME, lens tilt or decentration, retinal detachment, or endophthalmitis.

Collins and coworkers looked at the outcomes in Veterans Administration patients after complicated cataract surgery.^[33] Four-hundred and thirty-eight eyes had adequate peripheral capsule after anterior vitrectomy and randomly received either an AC IOL or a sulcus fixated PC IOL. A significant difference occurred in visual acuity after 1 year, with 79% of AC IOL vs. 91% of sulcus fixated (unsutured) PC IOL patients achieving 20/40 or better best-corrected visual acuity (BCVA) (P = 0.003). In a second arm of that study, looking at 143 eyes with inadequate capsular support for sulcus fixation of a PC IOL, and without randomization, 125 eyes received an AC IOL (87.4%), only two eyes received a sutured PC IOL (1.4%), 11 eyes received no IOL (7.7%), and the implant status was unknown in five eyes (3.5%).^[34] Only 66.7% of the inadequate capsule total group achieved BCVA of 20/40 or better, significantly less than either arm of the earlier study (P = 0.04). This finding emphasizes that extensive vitrectomy and loss of capsular support is associated with poorer outcomes, independent of the IOL implant.

Complications

Although overall visual acuity rates are similar among IOL groups, there may be a tendency toward an increased risk of unusual but serious complications with scleral-sutured PC IOLs. These serious complications include retinal detachment, hemorrhagic choroidal detachment, and later lens dislocation.^[14] Sundmacher et al.^[25] found that there was a 12% rate of severe complications with scleral-sutured PC IOLs. However, they pointed out that many of these eyes had preoperative disease, and half the complications were unrelated to the surgical method. These researchers believed that vascular risk factors predisposed patients to complications from scleral-sutured IOLs. Schein et al.^[20] found a greater overall rate of complications with scleral-sutured PC IOLs compared with iris-sutured PC IOLs or modern AC IOLs. However, Heidemann and Dunn^[14] reported that the incidences of glaucoma, CME, and graft failure with scleral-sutured PC IOLs were comparable to those with iris-sutured PC IOLs and modern AC IOLs used with penetrating keratoplasty. Table 41-7 compares the relative rates of various complications among the different lens options. This table extrapolates from data derived from initial studies and should be only considered a rough approximation of true relative complication rates.

Table 41-7 -- Relative frequency of complications associated with secondary IOLs

	Capsular-Supported		Scleral- Sutured	Iris-Sutured
Complication	PC IOL	AC IOL	PC IOL	PC IOL
Acute CME	+	++	++	++
Chronic CME	–	+	+	+
Glaucoma	–	++	+	+
Lens tilt or decentration	–	+	++	++
Polypropylene knot erosion	NA	NA	++	NA
Suture-related endophthalmitis	NA	NA		NA
Endophthalmitis (unrelated to polypropylene suture)	+	+	+	+
Corneal edema	+	++	+	+
Intraoperative bleeding	+	+	++	++
Synechiae	–	++	–	+
Retinal detachment	–	+	++	+
Choroidal detachment	–	+	++	+
Uveitis/iritis	–	++	–	+
Long-term corneal graft failure	–	+	–	–
Risk of polypropylene suture failure	NA	NA	+	+

* −, not associated; +, mild association; ++, strong association; NA, not applicable.

AC, Anterior chamber; CME, cystoid macular edema; IOL, intraocular lens; PC, posterior chamber.

The most common postoperative complication after scleral-sutured PC IOL implantation is persistent CME.^[9] A range of 9–36% of patients with scleral-sutured lenses and penetrating keratoplasty had this complication.^[9,][36] Schein et al.^[20] reported that slightly less macular edema was clinically observed if iris-sutured PC IOLs were used, compared with scleral-sutured PC IOLs or flexible open-loop AC IOLs. Although CME was a relatively frequent acute postoperative complication of scleral-sutured lenses, some patients who had a long-standing decrease in vision preoperatively because of CME improved greatly after AC IOL exchange for a scleral-sutured lens.^[9,][12] Thirty-two percent of patients with preoperative CME had a vision of 20/40 or better postoperatively with penetrating keratoplasty combined with a scleral-sutured PC IOL.^[14]

Glaucoma is the second most common complication with scleral-sutured PC IOLs implanted at the same time as a penetrating keratoplasty.^[14] It is difficult to determine the cause of this glaucoma because keratoplasty alone is associated with a 5–65% incidence of new onset of glaucoma.^[3] Lass et al.^[26] found that the mean intraocular pressure was significantly higher with scleral-sutured PC IOLs when compared with penetrating keratoplasty with flexible open-loop AC lenses. However, they recognized that their study may have been somewhat biased by case selection because patients with extensive peripheral synechiae preoperatively did not receive AC IOLs. Holland et al.^[35] suspected that scleral-sutured lenses were associated with glaucoma; they found new-onset ocular hypertension in 30.3% of patients after a penetrating keratoplasty with a scleral-sutured PC IOL. Heidemann and Dunn^[14] found that 59% of their patients with corneal transplant and scleral-sutured lenses required additional glaucoma medication postoperatively. Therefore, although sutured PC IOLs were not expected on theoretical grounds to be associated with glaucoma, initial studies suggest a possible correlation above that found with corneal transplant alone. Bias resulting from case selection may be responsible for most, or all, of this trend, however.

Lens tilt or decentration is found in 5–10% of patients after scleral-sutured PC lens implantation.^[25,][36] IOLs with large optics are recommended, so a small degree of decentration is not usually clinically significant. Proper polypropylene suture placement and tension are important in avoiding this complication.

Initially, scleral-sutured lenses were tied under conjunctival flaps alone. However, the high incidence of erosion of the sutures through the conjunctiva prompted surgeons to place these knots under scleral flaps. Solomon et al.^[37] found that polypropylene suture erosion was the most common complication of scleral-sutured PC IOLs. Even with scleral flaps, up to 17% of patients have sutures that erode through the conjunctiva.^[35,][37] This rate greatly exceeds the experience of most surgeons, however. Without scleral flaps, 23.8% of patients have sutures erode through the conjunctiva. Because suture-related endophthalmitis has been reported,^[38] it is recommended that all exposed sutures be treated either with cautery or with free scleral grafts.^[16] Some have recommended leaving the polypropylene suture ends long so that they lie flatter on the globe, thus avoiding exposure.^[12]

PBK has not been a frequently reported complication of scleral-sutured PC IOLs, perhaps partially because of the relatively short follow-up in these early studies of a new technique. If endothelial cell counts are measured after corneal transplantation with scleral-sutured lenses and compared with the results from corneal transplantation with modern AC IOLs, there is no significant difference in endothelial cell loss.^[26] Soong et al.^[9] found a 19% endothelial cell loss after 1 year with iris-sutured PC IOLs, compared with 28% with closed-loop AC IOLs.

Although bleeding in the form of vitreous hemorrhage or hyphema would be anticipated to be a frequent problem with scleral-sutured lenses because of the proximity of the needle path to the ciliary body, this has not turned out to be the case, and hemorrhages are relatively infrequent.^[15]

Heidemann and Dunn^[14] reported an 11% incidence of hyphema or vitreous hemorrhage in association with scleral-sutured PC IOLs. Holland et al.,^[35] however, reported no hyphemas in 115 cases. The highest reported incidence of bleeding was 22%, reported by Kora, Fukado, and Yaguchi.^[39] However, their experience was atypical. Proper passage of the needles through the ciliary sulcus rather than the pars plicata may help prevent this complication. Vitreous hemorrhage, if it occurs, is usually self-limited and spontaneously clears. Massive suprachoroidal hemorrhage is rare.

Although few studies address the question of synechial progression, at least one early report seems to contradict theoretical expectations. Schein et al.^[20] found less synechial progression with modern AC IOLs compared with scleral- or iris-sutured PC IOLs. This may, however, result from the fact that AC lenses were oriented in the same meridian as the closed-loop AC lenses that they replaced. New synechiae formation may be limited by the synechiae already present from the older AC lens.

There appears to be a slightly greater risk of retinal detachment with sutured PC IOLs. Soong et al.^[9] reported a 2.3% risk of retinal detachment with corneal transplant combined with iris-sutured PC IOL implantation. Three studies with corneal transplantation and scleral-sutured PC lenses reported a 2.7–5.4% risk of retinal detachment after this combined procedure.^{[14,][24,][35]} Several retinal detachments have been reported with a retinal hole in the meridian of one of the transscleral sutures.^[40] Not all studies have identified transscleral suture fixation of PC IOLs as a risk factor for retinal detachment, however.^[41] Pathology studies examining eyes that have had sutured PC lenses implanted have found that haptics are usually posterior to the ciliary body adjacent to the pars plana rather than in the ciliary sulcus.^[1,][4,][42] This may increase the risk of retinal detachment. The location of the haptics at the pars plana was found in pathology specimens from both iris- and scleral-sutured PC lenses. The authors explain this finding by the fact that the iris often sags when the globe is fluid filled, making the ciliary sulcus inaccessible internally.^[4] They recommend the use of an air bubble to help pull the iris away from the ciliary sulcus. One surgeon used an endoscope to locate the ciliary sulcus intraoperatively.^[39] A second explanation for the poor positioning of the haptics with sutured PC lenses is incorrect measurements used in placing the scleral sutures. A surgeon may easily overestimate the distance between the limbus and the ciliary sulcus.

Theoretically, the risk of choroidal detachment ought to increase with the length of operative hypotony. Also, transscleral sutures ought to increase the risk of choroidal hemorrhage or effusion.^[14] Early studies seem to bear out this expectation to a small degree. Holland et al.^[35] found that choroidal detachments, if they occurred, were often located alongside the site of a transscleral suture. Heidemann and Dunn^[24] found that 3.6% of scleral-sutured PC IOLs were associated with a choroidal detachment, although these were nonexpulsive.

Uveitis does not seem to be frequently associated with sutured PC lenses. In a series of 105 penetrating keratoplasties with scleral-sutured PC lenses, there were no reported cases of chronic uveitis.^[35] Theoretically, iris-sutured lenses may cause more inflammation as a result of irritation of uveal tissue because of suspension of the relatively heavy IOL from the iris. Pathology specimens from iris-sutured PC lenses show mild-to-moderate local inflammation, but this has not been shown to be clinically significant.

A disturbing late complication is the report of spontaneous polypropylene suture breakage leading to displaced PC IOLs. Price et al.^[43] reported five such cases of late breakage of previously stable iris-supported PC IOLs. It appears that the polypropylene suture was cut by persistent rubbing at the optic hole of the IOL over time. This occurred on average 9 years after the initial surgery. Pathology studies have shown that sutures are the primary fixation point for both iris- and scleral-sutured PC IOLs.^[1,][42] There is no postoperative fibrosis^[14] and no inflammatory reaction around the polypropylene suture.^[42]

Accidental cutting of the polypropylene suture is sometimes associated with dislocation of the IOL into the vitreous cavity.^[42] This dislocation often is delayed after the cutting of the polypropylene suture, suggesting that the haptic may be embedded into tissue over time, but this fixation is not necessarily adequate to support the IOL long term in the absence of the suture.

Several visual complications are unrelated to the sutured PC IOL procedure. Often age-related macular degeneration was discovered after lens implantation. Vision was found to be limited by this condition in 5.7% of cases after penetrating keratoplasty with scleral-sutured PC IOL.^[35] Maculopathy from other causes, such as vascular causes, was found in a minority of cases.

Comparison of sutured posterior-chamber intraocular lenses with open-loop flexible anterior-chamber intraocular lenses

In most cases of secondary IOLs, the management decision is between a scleral-sutured PC IOL and AC IOL. There has been no convincing study implicating the modern, flexible open-loop AC IOLs with the many problems associated with the older, rigid closed-loop designs. Modern AC lenses have a greatly decreased incidence of postoperative pain and a decreased incidence of UGH syndrome.^[44] Many studies have shown that there is a low rate of overall complications with these newer designs. Apple et al.^[1] found that, although 75% of AC IOLs inserted now are of modern, flexible open-loop design, fewer than 15% of complicated AC IOL cases involved flexible open-loop AC IOLs. Mamalis et al.^[45] found a favorable outcome in 86% of IOL exchanges to a flexible open-loop design, compared with 90% with exchanges to a standard, nonsutured, in-the-bag PC IOL. The similarity in the results between even standard nonsutured PC IOLs and AC IOLs supports the assertion that both are very stable in the eye. Uveitis is rare with the newer open-loop flexible AC IOLs.^[45]

Soong et al.^[9] found similar results after penetrating keratoplasty with IOL exchange whether the new lens was an iris-sutured PC lens or a modern AC IOL. Visual results showed that 57–63% of patients after penetrating keratoplasty and modern AC lens placement achieved 20/40 vision or better.^[19,][46] Endothelial cell counts were also similar with AC and PC lens types. Soong et al.^[9] stated that not only were the endothelial cell counts as low with modern AC lenses as with unsutured standard PC IOLs, but they were lower than counts seen with iris-sutured PC lenses: 11.2 vs. 19% loss. The rate of new glaucoma with AC lenses and penetrating keratoplasty is similar to that with penetrating keratoplasty alone.^[46]Although persistent CME is a frequent postoperative problem after penetrating keratoplasty and IOL exchange with any lens type, modern AC lenses perform similarly to other lens types in terms of the incidence of CME. Synechiae are usually not formed with the modern AC lenses. Synechiae are commonly seen in the meridian of the haptics with older, rigid AC lens types.

If one accepts the premise that the behavior of an IOL that is retained at penetrating keratoplasty is an indication of the stability of the lens in the eye in general, then the study by Sugar^[29] is illuminating. In a study of 469 patients over a 10-year period, he found that vision was best if the older lens was exchanged for a flexible open-loop AC IOL. The results were even better than if iris-sutured PC IOLs were used. Also, corneal transplant failure rates were lowest if flexible open-loop AC lenses were used at the time of penetrating keratoplasty. He found that the corneal transplant failure rate (as opposed to corneal rejection) was highest if closed-loop rigid AC lenses were left in the eye at the time of corneal transplantation and lowest for retained in-the-bag PC IOLs. Retained rigid closed-loop AC lenses were associated with a 33.6% rate of transplant failure. Iris pupillary-supported (not sutured) IOLs were associated with a 28.9% corneal transplant failure rate, and retained primary implanted PC IOLs (standard, unsutured) were associated with only a 6.4% rate of transplant failure. Endothelial cell counts confirmed this data for penetrating keratoplasty and retained IOLs. The rigid closed-loop AC lenses were associated with a 34% drop in endothelial cell counts. Iris pupillary-supported IOLs were associated with a 31% drop in endothelial cell count. However, retained PC IOLs (unsutured) were associated with only a 17% drop in endothelial cell count.

Conclusions

Little debate exists that the placement of a standard PC IOL is the method of choice for a secondary IOL in the presence of sufficient capsular support. In the cases without capsular support, the decision is more difficult. It is impossible to reach firm conclusions regarding sutured PC lenses with present information. It seems clear that modern AC lenses have been disregarded prematurely by some surgeons and that they provide a valuable alternative to sutured PC lenses for many patients. The visual results for most patients with scleral-sutured lenses are comparable to those with other lens types. However, there is some reason to be concerned about the higher risk of some serious complications with scleral-sutured PC IOLs. These complications include a higher risk of retinal detachment, choroidal hemorrhage, lens dislocation, suture exposure and endophthalmitis, glaucoma, and persistent CME. On the other hand, scleral-sutured PC IOLs are an attractive alternative for patients with complications attributable to an AC IOL, such as chronic iritis and CME, and for patients where relative contraindications to an AC IOL are present, such as iris or angle abnormalities.

No large study has yet addressed long-term outcomes in patients randomized between modern, flexible open-loop AC IOLs and scleral-sutured PC IOLs, especially regarding endothelial cell loss.

References

[1]. Apple D.J., Price F.W., Gwin T., et al: Sutured retropupillary posterior chamber intraocular lenses for exchange or secondary implantation. Ophthalmology 1989; 96:1241-1247.

[2]. Soong H.K., Meyer R.F., Sugar A.: Techniques of posterior chamber lens implantation without capsular support during penetrating keratoplasty: a review. J Refract Corneal Surg 1989; 5:249-255.

[3]. Gaster R.N., Ong H.V.: Results of penetrating keratoplasty with posterior chamber intraocular lens implantation in the absence of a lens capsule. Cornea 1991; 10:498-506.

[4]. Duffey R.J., Holland E.J., Agapitos P.J., et al: Anatomic study of transsclerally sutured intraocular lens implantation. Am J Ophthalmol 1989; 108:300-309.

[5]. Spigelman A.V., Lindstrom R.L., Nichols B.D., et al: Implantation of a posterior chamber intraocular lens without capsular support during penetrating keratoplasty or as a secondary lens implant. Ophthalmic Surg 1988; 19:396-398.

[6]. Panton R.W., Sulewski M.E., Parker J.S., et al: Surgical management of subluxed posterior-chamber intraocular lenses. Arch Ophthalmol 1983; 111:919-926.

[7]. Price F.W., Whitson W.E., Collins K., et al: Explantation of posterior chamber intraocular lenses. J Cataract Refract Surg 1992; 18:475-479.

[8]. Doren G., Stern G., Driebe W.T.: Indications for and results of intraocular lens explantation. J Cataract Refract Surg 1992; 18:79-85.

[9]. Soong H.K., Musch D.C., Kowal V., et al: Implantation of posterior chamber intraocular lenses in the absence of lens capsule during penetrating keratoplasty. Arch Ophthalmol 1989; 107:660-665.

[10]. Stark W.J., Gottsch J.D., Goodman D.F., et al: Posterior chamber intraocular lens implantation in the absence of capsular support. Arch Ophthalmol 1989; 107:1078-1083.

[11]. Smiddy W.E., Sawusch M.R., O'Brien T.P., et al: Implantation of scleral-fixated posterior chamber intraocular lenses. J Cataract Refract Surg 1990; 16:691-696.

[12]. Lindquist T.D., Agapitos P.J., Lindstrom R.L., et al: Transscleral fixation of posterior chamber intraocular lenses in the absence of capsular support. Ophthalmic Surg 1989; 20:769-775.

[13]. Yasukawa T., Suga K., Akita J., et al: Comparison of ciliary sulcus fixation techniques for posterior chamber intraocular lenses. J Cataract Refract Surg 1998; 24:840-845.

[14]. Heidemann D.G., Dunn S.P.: Transsclerally sutured intraocular lenses in penetrating keratoplasty. Am J Ophthalmol 1992; 113:619-625.

[15]. Hu B.V., Shin D.H., Gibbs K.A., et al: Implantation of posterior chamber intraocular lens in the absence of capsular and zonular support. Arch Ophthalmol 1988; 106:416-420.

[16]. Oshima Y., Oida H., Emi K.: Transscleral fixation of acrylic intraocular lenses in the absence of capsular support through 3.5mm self-sealing incisions. J Cataract Refract Surg 1998; 24:1223-1229.

[17]. Lewis J.S.: Ab externo sulcus fixation. Ophthalmic Surg 1991; 22:692-695.

[18]. Lewis J.S.: Sulcus fixation without flaps. Ophthalmology 1993; 100:1346-1350.

[19]. Kornmehl E.W., Steinert R.F., Odrich M.G., et al: Penetrating keratoplasty for pseudophakic bullous keratopathy associated with closed-loop anterior chamber intraocular lenses. Ophthalmology 1990; 97:407-414.

[20]. Schein O.D., Kenyon K.R., Steinert R.F., et al: A randomized trial of intraocular lens fixation techniques with penetrating keratoplasty. Invest Ophthalmology 1993; 100:1437-1443.

[21]. Van Der Schaft T.L., Van Riij G., Renardel De Lavalette J.G.C., et al: Results of penetrating keratoplasty for pseudophakic bullous keratopathy with the exchange of an intraocular lens. Br J Ophthalmol 1989; 73:704-708.

[22]. Hayward J.M., Noble B.A., George N.: Secondary intraocular lens implantation: eight year experience. Eye 1990; 4:548-556.

[23]. Wong S.K., Koch D.D., Emery J.M.: Secondary intraocular lens implantation. J Cataract Refract Surg 1987; 13:17-20.

[24]. Heidemann D.G., Dunn S.P.: Visual results and complications of transsclerally-sutured intraocular lenses in penetrating keratoplasty. Ophthalmic Surg 1990; 21:609-614.

[25]. Sundmacher R., Althaus C., Webster R., et al: Two years experience with transscleral fixation of posterior chamber lenses. Dev Ophthalmol 1991; 22:89-93.

[26]. Lass J.H., DeSantis D.M., Reinhart W.J., et al: Clinical and morphometric results of penetrating keratoplasty with one-piece anterior-chamber or suture-fixated posterior-chamber lenses in the absence of lens capsule. Arch Ophthalmol 1990; 108:1427-1431.

[27]. Wagoner M.D., Cox T.A., Ariyasu R.G., Jacobs D.S., Karp C.L.: Intraocular lens implantation in the absence of capsular support: a report by the American Academy of Ophthalmology. Ophthalmology 2003; 110:840-859.

[28]. Hennig A., Evans J.R., Pradhan D., et al: Randomised controlled trial of anterior-chamber intraocular lenses. Lancet 1997; 349:1129-1133.

[29]. Sugar A.: An analysis of corneal endothelial and graft survival in pseudophakic bullous keratopathy. Trans Am Ophthalmol Soc 1990; 87:762-801.

[30]. Davis R.M., Best D., Gilbert G.E.: Comparison of intraocular lens fixation techniques performed during penetrating keratoplasty. Am J Ophthalmol 1991; 111:743-749.

[31]. Lyle W.A., Jin J.C.: Secondary intraocular lens implantation: anterior chamber vs posterior chamber lenses. Ophthalmic Surg 1993; 24:375-381.

[32]. Bellucci R., Pucci V., Morselli S., Bonomi L.: Secondary implantation of angle-supported anterior chamber and scleral-fixated posterior chamber intraocular lenses. J Cataract Refract Surg 1996; 22:247-252.

[33]. Collins J.F., Gaster R.N., Krol W.F., Colling C.L., Kirk G.F., Smith T.J.: Department of Veterans Affairs Cooperative Cataract Study. A comparison of anterior chamber and posterior chamber intraocular lenses after vitreous presentation during cataract surgery: the Department of Veterans Affairs Cooperative Cataract Study. Am J Ophthalmol 2003; 136:1-9.

[34]. Collins J.F., Gaster R.N., Krol W.F.: Outcomes in patients having vitreous presentation during cataract surgery who lack capsular support for a nonsutured PC IOL. Am J Ophthalmol 2006; 141:71-78.

[35]. Holland E.J., Daya S.M., Evangelista A., et al: Penetrating keratoplasty and transscleral fixation of posterior chamber lens. Am J Ophthalmol 1992; 114:182-187.

[36]. Hayashi K., Hayashi H., Nakao F., et al: Intraocular lens tilt and decentration, anterior chamber depth, and refractive error after trans-scleral suture fixation surgery. Ophthalmology 1999; 106:878-882.

[37]. Solomon K., Gussler J.R., Gussler C., et al: Incidence and management of complications of transsclerally sutured posterior chamber intraocular lenses. J Cataract Refract Surg 1993; 19:488-493.

[38]. Schechter R.J.: Suture-wick endophthalmitis with sutured posterior chamber intraocular lenses. J Cataract Refract Surg 1990; 16:755-756.

[39]. Kora Y., Fukado Y., Yaguchi S.: Sulcus fixations of posterior chamber intraocular lenses by transscleral sutures. J Cataract Refract Surg 1991; 17:636-639.

[40]. Rajpal R.K., Carney M.D., Weinberg R.S., et al: Complications of transscleral sutured posterior chamber lenses. Ophthalmology 1991; 98:98.

[41]. Lee J., Lee J., Chung H.: Factors contributing to retinal detachment after transscleral fixation of posterior chamber intraocular lenses. J Cataract Refract Surg 1998; 24:697-702.

[42]. Lubniewski A.J., Holland E.J., Van Meter W.S., et al: Histologic study of eyes with transsclerally sutured posterior chamber intraocular lenses. Am J Ophthalmol 1990; 110:237-243.

[43]. Price F.W., Whitson W.E., Collins K., et al: Changing trends in explanting intraocular lenses: a single center study. J Cataract Refract Surg 1992; 18:470-474.

[44]. Hahn T.W., Kim M.S., Kim J.H.: Secondary intraocular lens implantation in aphakia. J Cataract Refract Surg 1992; 18:174-179.

[45]. Mamalis N., Crandall A.S., Pulsipher M.V., et al: Intraocular lens explantation and exchange: a review of lens styles, clinical indications, clinical results, and visual outcome. J Cataract Refract Surg 1991; 17:811-818.

[46]. Hassan T.S., Soong H.K., Sugar A., et al: Implantation of Kelman-style, open-loop anterior chamber lenses during keratoplasty for aphakic and pseudophakic bullous keratopathy: a comparison with iris-sutured posterior chamber lenses. Ophthalmology 1991; 98:875-880.

Page

Contents

If you find an error or have any questions, please email us at admin@doctorlib.org. Thank you!