Iris-fixated Intraocular Lens Research Articles

Indications for Penetrating Keratoplasty and Associated Procedures, 1989???1995

To identify changing trends in indications for penetrating keratoplasty and associated surgical procedures. Review of charts from all patients who underwent penetrating keratoplasty at Wills Eye Hospital from January 1, 1989 through December 31, 1995. A total of 2,442 corneal transplants were performed in 2,186 patients. The leading indication for penetrating keratoplasty was pseudophakic corneal edema, accounting for 634 cases (26.0%); 54.7% of them were associated with anterior chamber intraocular lenses, 36.4% with posterior chamber intraocular lenses, and 3.1% with iris-fixated intraocular lenses. Regraft (17.8%), Fuchs' dystrophy (15.7%), and keratoconus (13.2%) followed pseudophakic corneal edema in frequency. Cataract extraction, with or without intraocular lens implantation, was combined with penetrating keratoplasty in 439 cases of 1,264 phakic eyes (34.7%). Intraocular lens exchange was performed in 285 of the 634 cases of pseudophakic corneal edema (44.9%). Pseudophakic corneal edema was the leading indication for penetrating keratoplasty, with an increasing number of cases associated with posterior chamber intraocular lenses during the study period (p = 0.001). The number of regrafts steadily increased between 1989 and 1995 (p = 0.001), being the second most common indication for corneal transplantation since 1992.

Iris-fixated Worst claw versus sulcus-fixated posterior chamber lenses in the absence of capsular support

Purpose: To evaluate visual outcomes and complications of iris-fixated intraocular lenses (IOLs) (lobster-claw) and sutured sulcus-fixated posterior chamber (PC) IOLs in primary and secondary implantation.Setting: Eye Department, University Hospital “La Fe”, Valencia, Spain.Methods: This retrospective study reviewed 47 patients who had primary implantation of an iris-fixated (n = 34) or sulcus-fixated (n = 13) IOL and 54 patients who had secondary implantation of an iris-fixated (n = 41) or sulcus-fixated (n = 13) IOL.Results: Visual acuity in the primary implantation group was similar with both lens types. Overall, 54.0% had a postoperative acuity of 20/40 or better. In eyes without pre-existing pathology, 60.0% with an iris-fixated IOL and 54.6% with a sutured PC IOL had this level of postoperative acuity (P = .768). In the secondary implantation group, the percentage of patients with a postoperative visual acuity of 20/40 or better was significantly higher in iris-fixated IOL eyes (78.0%) than in sulcus-fixated PC IOL eyes (46.2%) (P < .05). In eyes without pre-existing pathology, the difference was maintained. No intraoperative complications directly associated with iris-fixated lens implantation occurred. The incidence of postoperative complications common to either IOL type in primary and secondary implantation did not differ significantly. The incidence of retinal complications was higher in eyes that had primary implantation of either lens type, although the differences between both lenses in either primary or secondary implantation were not significant.Conclusion: The good visual outcomes and low incidence of intraoperative and postoperative complications in eyes with iris-fixated IOLs indicate that these lenses should be considered an alternative to sutured PC IOLs in eyes in which capsular support is inadequate or absent.

Changing Indications for Intraocular Lens Removal

OBJECTIVE: To evaluate the effect of progress made in cataract surgery techniques on indications and results of intraocular lens (IOL) removal. PATIENTS AND METHODS: The charts of all patients who underwent IOL explantation at our institution between January 1990 and December 1992 were reviewed. Data recorded included patients' age and sex, time interval from implantation to removal, indication for IOL explantation, type of IOL removed, bestcorrected visual acuity before and after explantation, and length of follow-up after removal. Indications were divided into six groups: (a) chronic, low-grade endophthalmitis; (b) pseudophakic bullous keratopathy; (c) luxation; (d) traumatic expulsion; (e) high-degree anisometropia; (f) acute endophthalmitis. Visual acuities were grouped according to good (20/20 to 20/40), acceptable (20/50 to 20/400), or poor (less than 20/400) outcome. RESULTS: Fifty-two IOLs were removed from 52 eyes of 52 patients over the period of time considered in this study. Sixteen were anterior chamber IOLs, five were iris-fixated IOLs, and 31 were posterior chamber IOLs. Sixteen (30.8%) IOLs were removed for chronic, low-grade endophthalmitis, 15 (28.8%) for bullous keratopathy, 15 (28.8%) for luxation, three (5.8%) for traumatic expulsion, two (3.8%) for high-degree aniseikonia, and one (1.9%) for acute endophthalmitis. After explantation, vision equal to or better than 20/400 could be achieved by the vast majority of patients of all groups excepted for those with bullous keratopathy. CONCLUSION: The progress made in cataract surgery techniques over the last decade has greatly influenced the relative frequency of the different reasons for IOL removal. Continuous monitoring of explanted IOLs is mandatory to evaluate further changes in surgical techniques and lens design.

Clinicopathologic Study of Ocular Trauma in Eyes With Intraocular Lenses

Data on 41 cases (37 intraocular lenses and four globes) of intraocular lenses explanted or expulsed after ocular trauma were retrieved from over 5,000 intraocular lenses and 1,200 globes. The age of the male and female donors varied significantly (male, 64.4 +/- 13.1 years; female, 75.5 +/- 12.6 years; P = .0334). Twenty-two were posterior chamber, 11 were anterior chamber, and eight were iris-fixated lenses. The mean implant durations were 0.66 +/- 0.9 years for posterior chamber intraocular lenses, 4.0 +/- 3.4 years for anterior chamber lenses, and 9.0 +/- 4.9 years for iris-fixated lenses. Accidental falling was the most common trauma in 14 of 21 cases (67%). In the posterior chamber intraocular lens group, trauma was more severe and resulted in rupture of the globe in 19 of 22 cases (86%) and expulsion of the intraocular lens in 15 of 22 cases (68%). Rupture usually occurred at the surgical wound, even when the trauma happened five years postoperatively. In contrast, most of the eyes with anterior chamber intraocular lenses and iris-fixated intraocular lenses did not rupture, but a minor trauma often resulted in intraocular lens dislocation and secondary complications that necessitated intraocular lens explantation. The pathologic findings were nonspecific (proteinaceous deposits, blood and pigment adherent to the intraocular lens). Severity of trauma and pathologic findings were not correlated. Posterior chamber intraocular lenses are more resistant to minor ocular trauma compared to anterior chamber and iris-fixated intraocular lenses.

Retinal Detachment after Cataract Surgery: Predisposing Factors

The authors studied the characteristics of 376 eyes of 361 patients with primary retinal detachment (RD) and surgical aphakia (103 eyes) or pseudophakia (273 eyes). Of the pseudophakic eyes, 17 had an iris-fixated intraocular lens (IOL), 111 had an anterior chamber (AC) IOL, and 145 had a posterior chamber (PC) IOL. Of the PC IOL cases, 48 (33%) had undergone YAG capsulotomy, and 46% of them developed RD within 6 months after capsulotomy. The frequency of no breaks found in pseudophakic RD (15%) was significantly higher than in RD with simple aphakia (5%). The most frequent reasons were incomplete fundus view due to a small pupil in the iris-fixated (83%) and the AC (44%) groups, and cloudiness of capsular remnants in the PC group (78%). In pseudophakic RD, sizable single tears, located more posteriorly than in RD with simple aphakia, were frequent. The authors speculate that in pseudophakic RD the retinal breaks may resemble those noted in phakic RD.

Retinal Detachment after Cataract Surgery: Surgical Results

The authors studied the results obtained by the Retina Associates in 376 eyes of 361 patients operated on for retinal detachment associated with aphakia or pseudophakia with a postoperative follow-up of at least 6 months. All eyes underwent scleral buckling. The series included 103 eyes with aphakia, 17 eyes with iris-fixated intraocular lens, 111 eyes with anterior chamber (AC) IOL, and 145 eyes with posterior chamber (PC) IOL. The overall success rate for retinal detachment was 93%, without significant difference among the different groups. The aphakia and PC IOL groups had significantly higher prevalence (63% and 60%, respectively) of visual acuity equal to or better than 20/40 compared with the AC IOL group (33%). The prevalence of postoperative corneal edema in the AC IOL group was significantly higher than in the aphakia and PC IOL groups. Preoperative vitreous hemorrhage, large retinal breaks, posterior retinal breaks, total retinal detachment, proliferative vitreoretinopathy, and the need for performing a closed vitrectomy were significant factors in predicting ultimate failure.

Complications of Intraocular Lenses with Special Reference to an Analysis of 2500 Explanted Intraocular Lenses (IOLs)

The incidence and types of complications seen with the major intraocular lens (IOL) types in a series of 2500 explant cases is reported. We confirm that the rate of complications is higher with anterior chamber IOLs (AC-IOLs) and with iris-fixated IOLs (IF-IOLs) than with posterior chamber IOLs (PC-IOLs). However, the open-loop AC-IOL fared better than the closed-loop designs. Although tissue complications of PC-IOLs (inflammation, glaucoma, cystoid macular oedema and retinal detachment) have decreased markedly, this study shows that decentration/ malposition remains a significant problem. With increased use of smaller diameter or aspherical optic (5.5 mm × 5.5 mm or 5 mm × 6 mm), as well as increasing use of bifocal/multifocal IOLs, it is important that the problem of decentration be addressed.

Penetrating Keratoplasty for Exogenous Paecilomyces Keratitis Followed by Postoperative Endophthalmitis

Three patients developed Paecilomyces lilacinus keratitis while being treated with topical corticosteroids and antibiotics. The first patient, a diabetic man, suffered superficial ocular trauma while being treated for recurrent anterior uveitis related to an iris-fixated intraocular lens. The second patient developed keratitis while being treated for anterior segment inflammation associated with herpes zoster ophthalmicus. The third patient, a woman with chronic lymphoma in remission, was receiving topical antibiotics and corticosteroids for a corneal transplant performed one year previously. All three patients underwent penetrating keratoplasty after progression to perforation or failure of medical therapy. Two eyes (cases 1 and 2) eventually required enucleation. The fungal isolates demonstrated in vitro resistance to amphotericin and natamycin with greater sensitivity to imidazole derivatives. Thus, we recommend prompt and prolonged topical treatment with miconazole or other imidazole derivatives along with avoidance of penetrating keratoplasty and corticosteroids.

Pseudophakia and the pupil

Postoperative disturbances of the pupil are discussed on the basis of experience with more than 2500 intraocular lenses implanted after extracapsular cataract extraction (planned extracapsular or phacoemulsification). Apart from the changes to the pupil caused by an iris-fixed intraocular lens itself, the pupil may also be affected by blood, fibrinous inflammation, or remnants of cortex material or the anterior capsule after posterior chamber lens implantation. These conditions are frequently followed by synechiae between the pseudophakia and the iris. Mechanical damage to the iris or the sphincter muscle may also occur. Changes in the shape of the pupil often affect its function, and synechiae do so regularly. Secondary cataract necessitating treatment occurred in about 10% of our patients over a 7-year period. Today, YAG laser surgery represents the best means of restoring clarity to the pupil, though there are still a number of unresolved problems with the method. Neither primary nor secondary capsulotomy after pseudophakia implantation can be recommended. The methods of extracapsular cataract extraction with posterior chamber lens implantation are still at a stage of development which is not altogether satisfactory, since optic irregularities of the pseudophakia or the central posterior capsule may result in glare, disturbing the patient in spite of good visual acuity.