Indications for and results of intraocular lens explantation

Indications for and results of intraocular lens explantation Gregory S. Doren, M.D., George A. Stern, M.D., William T. Driebe, M.D.

Cataract surgery and the use of intraocular lenses (IOLs) have undergone dramatic technical changes over the past 15 years. Ophthalmic surgeons have witnessed improvements in the prognosis for their cataract patients as they have shifted to an extracapsular approach for cataract surgery. 1,2 With the retention of the posterior capsule and use of posterior chamber IOLs, the incidence of corneal edema, retinal detachment, cystoid macular edema, and other complications seems to be decreasing. 1-4 When complications occur, one fre-

From the Department 0/ Ophthalmology, University

0/ Florida

quently suspects the IOL as the cause of the problem, and removal or exchange is often considered. Ophthalmologists have been surveyed to obtain general information about explanted IOLs. These surveys have indicated that closed-loop, semi flexible anterior chamber and iris-fixated lenses are the ones most often removed. 5 We looked at the results and complications of lens explantation surgery, with or without IOL exchange, and tried to determine whether the shift to extracapsular cataract surgery and the use of posterior chamber implants

College

0/ Medicine,

Gainesville.

Supported in part by an unrestricted departmental grant from Research to Prevent Blindness, Inc. Reprint requests to George A. Stem, M.D., Department o/Ophthalmology, University o/Florida College o/Medicine, Box J-284 JHMHC, Gainesville, Florida 32610-0284. J CATARACf REFRACf SURG-VOL 18, JANUARY 1992

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has altered the relative proportions of lens styles being explanted. MATERIALS AND METHODS We retrospectively reviewed the records of all patients who had IOL removal, with or without exchange, at the University of Florida Medical Center from January 1, 1983, to December 31, 1987. Data analyzed included patient age and sex, method of original cataract surgery, style of IOL implanted, time from original surgery to the onset of symptoms, nature of complication requiring IOL explantation, corrective surgical procedures performed, preoperative and best postoperative Snellen visual acuities, complications of explantation surgery, preoperative and post -explantation intraocular pressures, and other ocular conditions that resulted from the original surgery or the IOL explantation/ exchange. Snellen visual acuities were divided into three groups: good acuity of 20/20-40, moderate acuity of20/50-100, and poor acuity of20/200 or worse. Cystoid macular edema (CME) was usually diagnosed on clinical examination, with fluorescein angiography used to confirm the diagnosis in questionable cases. Glaucoma was defined as persistently increased intraocular pressure, greater than 21 mm Hg, which required treatment. The indications for lens removal were (1) pseudophakic bullous keratopathy (PBK) , (2) uveitis-glaucoma-hyphema (UGH) syndrome, (3) IOL instability/malposition, (4) endophthalmitis, (5) retinal detachment (recurrent with IOL inhibiting visualization), and (6) intractable glaucoma. Data for each diagnostic category were statistically evaluated. When evaluating the treatment outcome, only patients who had at least six months of follow-up or who were felt to have attained a stable final vision (e.g., a patient with a macular scar and 20/200 acuity) were included in the analysis. Statistical evaluation was done using chi-square tests and Fisher's exact test with a Yates correction when appropriate. Closed-loop anterior chamber IOLs were removed by cutting the loops where necessary and removing the optic through a limbal or keratoplasty incision. The remaining loops were atraumatically slid through their fibrous tunnels and removed; in some cases it was necessary to dissect the loops from surrounding uveal tissue. In all cases, all IOL material was removed from the eye. When surgery was performed through a limbal incision, a viscoelastic agent was used; when combined with keratoplasty, this part of the procedure was performed in an open-sky fashion. 80

Iris-fixated IOLs were removed by cutting any fixation sutures, dislocating the lens into the anterior chamber, and removing the lens through the limbal or keratoplasty incision. Posterior chamber IOLs were removed through a limbal incision, often dialing out the lens. A mechanical vitrectomy was performed in all cases in which vitreous prolapsed into the incision or when necessary to facilitate the implantation of another IOL. Another IOL was inserted if there was adequate anterior chamber depth and iris support and if there were no contraindications to IOL reinsertion, such as chronic uveitis, peripheral anterior synechias, or uncontrolled glaucoma. In most cases, an open-loop, one-piece poly(methyl methacrylate) (PMMA) anterior chamber IOL with three or fourpoint fixation was used. In a few cases, posterior chamber IOLs were inserted using two 10-0 polypropylene (Prolene R ) iris-fixation sutures to secure the IOL in the absence of capsular support. Penetrating keratoplasty was performed in patients with corneal edema. A scleral fixation ring was sutured to the eye with 6-0 silk sutures. A partial thickness trephination, usually 7.5 mm or 8.0 mm in diameter, was performed using a vacuum or hand-held trephine, the anterior chamber was entered, and the incision was completed using corneal scissors. Following the completion of IOL removal/exchange and anterior vitrectomy, a 0.5 mm oversized donor button, punched from the endothelial side, was sutured in place using interrupted 10-0 nylon sutures or a combination of interrupted 10-0 nylon sutures and a continuous, either 10-0 or 11-0, nylon suture. A viscoelastic agent was used to prevent contact of the donor button with the IOL. All patients with a diagnosis of endophthalmitis had a vitrectomy in addition to IOL removal, and all received intravitreal antibiotics. All patients with retinal detachments had pars plana vitrectomy with air/fluid exchange and new or revised scleral buckling procedures. In patients with endophthalmitis or retinal detachment, IOLs were not reimplanted. Patients with neovascular glaucoma had a filtering procedure. RESULTS One hundred one IOLs were explanted from 101 eyes of 97 patients. Fifty-eight patients were female and 39 were male; the average age of all patients was 72.9 ± 10 years. Indications for IOL explantation are shown in Table 1. Pseudophakic bullous keratopathy was the most common indication, followed by the UGH syndrome and problems relating to IOL malposition or instability. Types of

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Table 1. Indications for IOL explanation. Number of IOLs Explanted (%)

Indication for Explantation

69 9 7 7

Pseudophakic bullous keratopathy Uveitis-glaucoma-hyphema syndrome IOL instability/malposition Retinal detachment

(68.4) (8.9) (6.9) (6.9)

6 (5.9)

Endophthalmitis Neovascular glaucoma

(2.9) 101 (100)

~

Total

IOLs that were explanted are described in Table 2, and the categories of IOLs explanted for each diagnostic group are described in Table 3. Anterior chamber lenses accounted for 54 (53.9%) of the explanted IOLs; 33 (32.7% of the total and 61.1 % of the anterior chamber lenses) were the closedloop, semiflexible varieties. Iris-fixated lenses accounted for 39 (38.9%) of the explanted IOLs.

Table 2. Types of IOLs explanted. Style of IOL Explanted

Number

Anterior chamber, closed-loop Azar (IOLAB 91Z)

33 13

ORC Stableflex Leiske Hessburg

10 6 3

McGhan, closed polypropylene loop, 4-point Anterior chamber, rigid or open-loop

1 21

Choyce/Tennant Mark VIII or IX Kelman Omnifit Open loop, one-piece PMMA (e.g., Multiflex)

8 5 4

Tennant anchor

1

~mmll

1 1 1

Rigid Azar Dubroff Iris-fixated Copeland Binkhorst Worst medallion Platina Fyodorov sputnik Posterior chamber

39 17 12 8 1 1 8

Pseudophakic Bullous Keratopathy Sixty-nine eyes of 65 patients had IOL explantation because of a diagnosis of PBK. Sixty one of these eyes had at least six months follow-up and comprise the database for statistical evaluation in this category. All patients had penetrating keratoplasty as the primary surgical procedure; in 59 patients (85.6 %) the IOL was exchanged, and in 10 (14.4%) the IOL was explanted without exchange. In the latter 10 patients, anterior segment abnormalities precluded the reimplantation of anterior chamber lenses, and we had not begun implanting posterior chamber lenses in the absence of capsular support. Anterior vitrectomy was performed in 86.9% of these patients. Ninety-one percent of grafts were clear at the six-month follow-up visit, 89.7% at 12 months, and 85.7% at 18 months (there were no graft failures after the six-month interval; the decreasing success rate represents a loss of successful patients to follow-up). Of the six grafts that failed, three were due to primary donor failure and were all successfully regrafted; one failed from immunologic rejection, one from intractable glaucoma, and one from multiple vitreoretinal procedures, including silicone oil injection, to repair a recurrent retinal detachment. There was no correlation between graft failure and the style of IOL explanted or the style of lens reimplanted. The visual results for all patients are shown in Table 4. For patients with PBK, 41.0% achieved good visual acuity in the 20/20-20/40 range, 23.0% achieved moderate visual acuities in the 20/50-20/100 range, and 36.0% had poor acuity of 20/200 or worse. There was no correlation between final vision and the type of IOL explanted, or patient age, sex, or race. Most of the primary surgeries were intracapsular extractions (ICCE) with implantation of an anterior chamber or irisfixated IOL (77.0%); 23.0% of patients had extracapsular extraction (ECCE) with implantation of an anterior chamber IOL in most cases because of the surgical complications of vitreous loss and/or posterior capsular rupture. There was a significant association (P < .05) between the type of original surgery and the final visual result; patients who had ICCE were more likely to see 20/40 or better than those who had ECCE. The presence of CME was more common in the group receiving vitrectomies, but this was not found to be a statistically significant association. In addition, there was no difference in the visual results in patients who had vitrectomies as part of their surgical procedures and those who did not.

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Table 3. Styles of IOLs explanted in diagnostic categories. Anterior Chamber Diagnosis Pseudophakic bullous keratopathy

Closed Loop

Other

Iris Fixated

Posterior Chamber

32 2 2

0 0

28

7

UGH syndrome Instability (dislocated malpositioned or unstable IOL) Recurrent retinal detachment

3 1

4 4

1

1

Endophthalmitis Neovascular glaucoma Total

0 0

2 3 21

33

2

3 0 0 39

Total 69 9 7

2

7

4 0

6

8

3 101

Table 4. Visual results before and after IOL explantation. Preoperative Visual Acuity (%) Diagnosis (n)

Postoperative Visual Acuity (%)

20/20-40 0

20/50-100 12 (19.7)

>20/200 49 (80.3)

20/20-40 25 (41.0)

20/50-100 14 (23.0)

>20/200 22 (36.0)

0 2 (33 .3)

1 (16.7) I (16.7)

5 (83 .3) 3 (50.0)

0 3 (50.0)

I (16.7) 2 (33.3)

5 (83.3)

Recurrent retinal detachment (7)

0

2 (28 .6)

5 (71.4)

0

I (14.3)

6 (85.7)

Endophthalmitis (6) Glaucoma (3)

0 0

0

6 (100) 3 (100)

0

0 0

6 (100) 3 (100)

Pseudophakic bullous keratopathy (61) UGH syndrome (6) Instability (IOL instability or malposition) (6)

0

Uveitis-Glaucoma-Hyphema Syndrome Nine eyes of nine patients had IOL explantation because of the UGH syndrome. Six of the primary surgeries were ICCE and three were ECCE in which the surgery was complicated. Three of the patients had closed-loop anterior chamber lenses, four had rigid anterior chamber lenses, and two had iris-fixated lenses. Three of the nine patients had IOL exchange and the remaining six had IOL explantation only. Five of the nine patients presented within three months of the time of their primary surgery; three of these patients had had complicated ECCEs and two had had ICCEs. The remaining four patients presented late, at least four years, after their primary surgery. Visual results in this group were poor; five of six patients, in whom there was six months or greater follow-up, had 20/200 or worse visual acuity postoperatively as well as preoperatively. This level of postoperative vision was significantly worse than that found in either the PBK or IOL instability patients (P < .05) . Cystoid macular edema was present in five of the six patients and glaucoma was present postoperatively in two of the six. Although 82

0

I (16.7)

visual results in this group were poor, all patients achieved resolution of their intraocular inflammation and improved control of their glaucoma.

Intraocular Lens Instability/Malposition Seven patients had a diagnosis ofIOL instability. Two had chronically or recurrently dislocated irisfixated lenses and four had mobile, nonfixated anterior chamber lenses. The seventh patient had erosion of an anterior chamber IOL footplate into the ciliary body with resultant superior displacement of the IOL and intermittent corneal touch. Five of the seven patients had IOL exchange and two had IOL explantation only. Six of the seven patients had six months followup and were evaluated for the visual results of the surgery. Three of the six achieved good visual acuity of20/40 or better, two achieved moderate acuity between 20/50 and 20/100, and one had a poor visual result . These visual results were superior to those found in the UGH syndrome group (P < .05) and equivalent to the results in the PBK group. Postoperatively, only one of these patients had

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CME and glaucoma.

two

had

medically

controllable

Retinal Detachment, Endophthalmitis, Glaucoma The visual results in the three groups were uniformly poor, as would be expected from the nature of the diagnoses. These were the only groups in which a substantial proportion of posterior chamber IOLs were explanted (six of 16 patients in the combined three groups). However, IOL explantation was performed in these cases to facilitate visualization during difficult vitreoretinal surgery and not because of a lens-related complication. In the retinal detachment group, three of seven patients had retinas successfully reattached and one of these patients achieved moderate acuity between 20/50 and 20/100. In the endophthalmitis group, microbiological cure was achieved in two of five patients, but visual results were poor, even in those patients who were "cured." In the intractable glaucoma group, combined IOL explantation and filtering surgery was successful in achieving good control of intraocular pressure after six months, but all patients had poor acuity. DISCUSSION Pseudophakic bullous keratopathy was the most common indication for IOL explantation or exchange in our series. While this may reflect the fact that our institution has a very active corneal service, other studies, performed by investigators who were not primarily corneal surgeons, have also found that PBK is a common indication for IOL explantation. 5,6 We wish to emphasize that IOL explantation, by itself, is not a treatment for pseudophakic corneal edema. The permanent structural damage of the corneal endothelium which PBK represents is treatable only by corneal transplantation; IOL explantation or exchange is performed to protect the new transplant from the deleterious effects of an implant that may cause progressive endothelial cell loss. The majority of IOLs that were removed because ofPBK were the iris-fixated or closed-loop, semiflexible anterior chamber styles, which are known to cause an accelerated loss of endothelial cells. In our series, these IOL styles were almost always removed at the time of penetrating keratoplasty. Posterior chamber IOLs or well-positioned one-piece, rigid or open-loop anterior chamber lenses may have been retained if the PBK was believed to be due to preexisting corneal disease (e.g., Fuchs' dystrophy) or corneal injury that occurred at the time of the original cataract surgery. The combination of penetrating keratoplasty and

IOL explantation or exchange proved to be highly effective treatment for PBK. Clear corneal transplants were achieved in greater than 90% of patients. Since virtually all these patients had preoperative visual acuities of 20/400 or worse, nearly all patients achieved some visual improvement as a result of surgery. Forty-one percent of our patients achieved excellent acuity of 20/40 or better, and an additional 23% recovered moderate visual acuity between 20/50 and 20/100. This level of visual improvement is comparable to other published reports of the results of penetrating keratoplasty for PBK.7-13 While several investigators have reported using posterior chamber IOLs sutured either to the iris or ciliary sulcus for IOL exchange,14,15 almost all our patients received a one-piece, open-loop anterior chamber IOL as the exchange lens with comparable results in graft success and postoperative visual acuity. Therefore, the use of a semi-flexible open-loop anterior chamber lens style as the exchange lens at the time of keratoplasty appears to offer comparable results to more difficult surgical techniques. The duration of corneal edema did not affect the ultimate graft success or visual outcome. Keratoplasty for PBK is an elective procedure that should be performed when the patient desires visual improvement. The most significant factor affecting the ultimate visual outcome for patients having surgery for PBK was the patient's original cataract surgery. Patients who originally had ECCE complicated by posterior capsular rupture and vitreous loss had a significantly poorer visual outcome than patients whose original cataract surgery was uncomplicated, whether intracapsular or extracapsular. The inflammation associated with capsular rupture, vitreous loss, and retained lens cortex, in combination with a closed-loop anterior chamber lens, evidently causes more severe macular edema with a poorer visual outcome. Patients who developed PBK as part of an inflammatory syndrome related to the presence of a closed-loop, semiflexible, anterior chamber IOL achieved visual results that were comparable to patients with other IOL styles. Nine patients in our series had IOL explantation or exchange because of UGH syndromes. Seven of these patients had anterior chamber lenses (this syndrome was not observed with posterior chamber lenses). The indication for surgery in these patients was glaucoma and/or chronic inflammation that could not be controlled medically. Therefore our series does not include all patients seen with this diagnosis since some were controlled with medical treatment consisting of topical corticosteroids and beta-adrenergic blocking agents. Intra-

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ocular lens explantation/exchange did not lead to visual improvement in patients with UGH syndromes, since 83.3% of patients with six months or longer follow-up had visual acuities of 20/200 or worse before and after surgery. Other investigators 6 have noted similarly poor results in this group of patients. However, all patients having IOL explantation/exchange achieved better control of their glaucoma and resolution of their pain and chronic inflammation. Seven patients had IOL instability or malposition. These were usually rigid anterior chamber lenses that were undersized and mobile within the anterior chamber. In some cases, an IOL footplate had rotated through an iridectomy, leading to actual IOL dislocation. Two patients had chronically or recurrently dislocated iris-fixated lenses. While dislocation has been reported to be a common problem with iris-fixated lenses,16 the low frequency seen in our series indicates that these lenses were not being used by physicians in our area during the study. In addition, some patients with unstable iris-fixated lenses were managed with chronic pupillary constriction or placement of additional iris-fixation sutures. Instability was a rare problem in patients with closed-loop anterior chamber IOLs because of their tendency to become firmly enmeshed in uveal tissue. Visually significant malposition of posterior chamber IOLs is a relatively common problem in our practice. However, none of these patients are included in the series because we manage these patients by repositioning and refixating the existing lens rather than exchanging the IOL. Our best visual results were in this group; 50% of patients achieved 20/40 or better acuity and 50% improved to a better visual acuity category. In two cases, chronic CME, which had persisted for 12 to 15 months after surgery, resolved following exchange of a loose anterior chamber IOL, a finding also observed by Smith. 17 Based on these results, we believe that surgeons can explant or exchange unstable or malpositioned IOLs with a reasonable expectation that vision will be improved or unchanged. Our visual results were predictably poor in our final three groups of endophthalmitis, recurrent retinal detachment, and neovascular glaucoma. We emphasize that these were particularly difficult cases, since most of our patients with these diagnoses were managed without manipulating their IOL. The endophthalmitis and retinal detachment groups were the only ones that contained a significant number of patients with posterior chamber IOLs. In these patients, IOL explantation was performed not because of a problem with the IOL, but 84

rather to facilitate difficult vitreoretinal or filtration procedures. This study represents the experience of a major university referral institution with patients who required IOL explantation for the treatment of postcataract surgical complications. The results are biased in several ways. First, many of the patients were believed to have complex problems that required management at a tertiary care institution. More "routine" cases requiring IOL explantation may have been treated in the patients' local communities. Second, referrals were often directed to subspecialists because of their expertise in managing problems other than the implant itself (e.g., corneal specialists for treatment of PBK or retinal specialists for the treatment of recurrent retinal detachment). For example, in our series, no patients had IOL explantation for complications such as incorrect IOL power; the cataract surgeon may have managed this problem himself or herself. Third, this study does not represent the entire spectrum ofIOL surgery complications, only those that required IOL explantation or exchange. Complications that could be managed medically (e.g., low-grade chronic uveitis), were not believed to be reversible by surgical intervention (e.g., longstanding CME), or were managed by a surgical procedure other than IOL explantation (e.g., refixation of a dislocated IOL) were not included. Intraocular lens explantation is sometimes necessary to manage IOL-related complications. Our findings confirm that the most commonly explanted lenses are the iris-fixated and closed-loop, semiflexible anterior chamber styles, neither of which are commonly used today. Currently used posterior chamber and one-piece, open-loop anterior chamber lenses rarely require explantation and then only for acute complications that are usually unrelated to the IOL itself. The visual prognosis following IOL explantation or exchange varies from excellent to poor depending on the pre-explantation diagnosis. REFERENCES 1. Tasman W, Jaeger EA, eds. Duane's Clinical Ophthalmology. Philadelphia, JB Lippincott Co, 1988; vol 5, chap 7:32 2. Pearce JL. Modern simple extracapsular surgery. Trans Ophthalmol Soc UK 1979; 99:176-182 3. Wetzig PC, Thatcher DB, Christiansen JM. The intracapsular versus the extracapsular cataract technique in relationship to retinal problems. Trans Am Ophthalmol Soc 1979; 77: 339-347 4. Jaffe NS, Clayman HM, Jaffe MS. Cystoid macular edema after intracapsular and extracapsular cataract extraction with and without an intraocular lens. Ophthalmology 1982; 89:25-29 5. Kraff MC, Sanders DR, Raanan MG. A survey of intraocular lens explantations. J Cataract Refract Surg 1986; 12:644-650

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6. Brown DC, Snead JW. Intraocular lens implant exchanges. Am Intraocular Implant Soc J 1985; 11:376-379 7. Polack FM. Keratoplasty and intraocular lenses. Cornea 1985/ 1986; 4:137-147 8. Polack FM. Management of anterior segment complications of intraocular lenses. Ophthalmology 1980; 87:881-886 9. Schanzlin DJ, Robin JB, Gomez DS, et al. Results of penetrating keratoplasty for aphakic and pseudophakic bullous keratopathy. Am J Ophthalmol1984; 98:302-312 10. Waring GO III, Welch SN, Cavanagh HD, Wilson LA. Results of penetrating keratoplasty in 123 eyes with pseudophakic or aphakic corneal edema. Ophthalmology 1983; 90:25-33 11. Waring GO III, Stulting RD, Street D. Penetrating keratoplasty for pseudophakic corneal edema with exchange of intraocular lenses. Arch Ophthalmol1987; 105:58-62 12. Speaker MG, Lugo M, Laibson PR, et al. Penetrating keratoplasty for pseudophakic bullous keratopathy; management

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of the intraocular lens. Ophthalmology 1988; 95:12601268 Busin M, Arffa RC, McDonald MB, Kaufman HE. Intraocular lens removal during penetrating keratoplasty for pseudophakic bullous keratopathy. Ophthalmology 1987; 94:505509 Wong SK, Stark WJ, Gottsch JD, et al. Use of posterior chamber lenses in pseudophakic bullous keratopathy. Arch Ophthalmol1987; 105:856-858 Price FW Jr, Whitson WE. Visual results of suture-fixated posterior chamber lenses during penetrating keratoplasty. Ophthalmology 1989; 96:1234-1240 Apple DJ, Mamalis N, Loftfield K, et al. Complications of intraocular lenses. A historical and histopathological review. Surv Ophthalmol1984; 29:1-54 Smith SG. Intraocular lens removal for chronic cystoid macular edema. J Cataract Refract Surg 1989; 15:442-444

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