Are there acceptable anterior chamber intraocular lenses for clinical use in the 1990s? An analysis of 4104 explanted anterior chamber intraocular lenses

Long term clinical outcome of a randomised controlled trial of anterior chamber lenses after high volume intracapsular cataract surgery

BACKGROUND

Age related cataract remains the major cause of blindness throughout the world. In many countries, the majority of cataract surgery continues to be done by the intracapsular cataract extraction (ICCE) method. The results of a large randomised controlled trial of multiflex open loop anterior chamber intraocular lenses (ACIOL) were reported from a busy eye hospital in Nepal.

METHODS

There was a randomised controlled trial of 2000 people with bilateral cataract reducing vision to less than 6/36. Interventions were ICCE with an ACIOL compared with ICCE with aphakic spectacles (+11 dioptres). Participants were followed at discharge, 6 weeks, 1 year, and 1 1/2-5 years after surgery. Visual acuity and clinical outcome were measured. A poor outcome was defined as vision <6/60.

RESULTS

Visual outcome was comparable in the two groups. More of the control group experienced functional blindness due to loss of aphakic spectacles at 1 year. The majority of cases of poor outcome occurred in the first year after surgery. There was no indication of any lens related problems after 1 year.

CONCLUSION

Multiflex open loop anterior chamber lenses are safe for up to 1 year of follow up when used by experienced surgeons, and the available evidence of 2-5 years of follow up suggests that the complication rate is reasonably low. An ACIOL at the time of cataract surgery offers benefits over routine ICCE surgery with aphakic spectacle correction as it avoids the problem of replacing lost and broken spectacles.

The South Asian cataract management study: complications, vision outcomes, and corneal endothelial cell loss in a randomized multicenter clinical trial comparing intracapsular cataract extraction with and without anterior chamber intraocular lens implantation

OBJECTIVE

To determine clinical outcomes of primary intracapsular cataract surgery with and without implantation of anterior chamber lenses.

DESIGN

A multicenter randomized clinical trial.

PARTICIPANTS

One thousand two hundred twenty-nine male and female patients 40-75 years of age with senile cataract.

METHODS

Study patients were recruited from screening eye camps and outpatient clinics. Randomization to the two treatment groups was performed after screening for predetermined inclusion and exclusion criteria. Demographics, visual acuity, intraocular pressures, and corneal endothelial cell data were recorded before surgery and at 6 weeks, 12 months, and 24 months after surgery. Monitoring of the study was secured by a standardized image documentation procedure on all patients using the IMAGEnet digital imaging system. Analysis of corneal endothelial cell images was performed with the Cell Soft software (Topcon Corporation, Japan).

MAIN OUTCOME MEASURES

Visual acuity and central corneal endothelial cell loss.

RESULTS

The patients were randomized to intraocular lens (IOL; n = 616) and no IOL (n = 613) implantation. Surgical complications were reported in 177 (14.4%) patients (IOL = 14.8%; no IOL = 14.0%). The most frequent complication observed was vitreous loss which occurred in 10.3% of eyes (IOL = 11.2%; no IOL = 9.5%). At the final examination (2 years after surgery), 88% of the operated eyes had a best corrected vision of 6/18 or better (IOL = 88.8%; no IOL = 86.6%). Analysis of corneal endothelial cell data showed a small but significantly greater cell loss 6 weeks after surgery in eyes with IOL compared with those without IOL, but no overall difference was found between the treatment groups in the long term follow-up.

CONCLUSIONS

The findings indicate that there is a rationale for the use of anterior chamber intraocular lenses in primary intracapsular cataract surgery.

Intraocular lens tilt and decentration, anterior chamber depth, and refractive error after trans-scleral suture fixation surgery

OBJECTIVES

To compare the extent of intraocular lens (IOL) tilt and decentration, as well as the anterior chamber depth after trans-scleral suture IOL fixation after either secondary out-of-the-bag or primary in-the-bag IOL implantation.

DESIGN

Retrospective, comparative, nonrandomized, interventional study.

PARTICIPANTS

Fifty-two eyes that underwent scleral suture fixation were compared with 51 eyes that underwent secondary out-of-the-bag implantation and 50 eyes that underwent in-the-bag implantation.

INTERVENTION

One-piece polymethyl methacrylate IOL implantation by three different techniques.

MAIN OUTCOME MEASURES

The tilt angle and decentration length of the IOL, as well as the anterior chamber depth, were measured by the Scheimpflug videophotography system. The spherical equivalent error from the predicted value was also examined.

RESULTS

The mean tilt angle in the scleral suture fixation group was significantly greater than that in either the out-of-the-bag or the in-the-bag implantation group (P<0.0001). The mean decentration length was also largest in the suture group, followed by the out-of-the-bag group and the in-the-bag group (P<0.0001). The anterior chamber depth in the suture group and the out-of-the-bag group was significantly smaller than that in the in-the-bag group (P<0.0001). The spherical equivalent error in the suture group and the out-of-the-bag group was also greater than that in the in-the-bag group (P<0.0001).

CONCLUSIONS

The extent of both tilt and decentration after scleral suture fixation was greater than that observed after either out-of-the-bag or in-the-bag implantation. The anterior chamber depth with the sutured or out-of-the-bag fixated IOL was shallower than that with the in-the-bag fixated IOL, which resulted in a significant myopic shift.

Is anterior chamber lens implantation after intracapsular cataract extraction safe in rural black patients in Africa? A pilot study in KwaZulu-Natal, South Africa

PURPOSE

There are an estimated 16 million people blind from cataract world-wide. In many areas the routine operation is intracapsular cataract extraction (ICCE). The role of modern anterior chamber (AC) intraocular lenses (IOLs) is being explored, and they have been shown to be safe and successful in Asia. Are they equally safe in rural black African populations?

METHODS

One hundred black patients aged 50 years and over who attended Edendale Hospital were enrolled in a pilot study of insertion of AC IOLs after ICCE. They were followed up for 6 months.

RESULTS

With financial remuneration, the follow-up rate at 8 weeks increased from the usual 30% to 72%. At 6 months, 67% of eyes achieved a correlated visual acuity of 6/18 or better. Thirty per cent had persistent uveitis, 16% had peripheral anterior synechiae beyond the points of haptic contact, and 5% had an intraocular pressure greater than 21 mmHg.

CONCLUSIONS

A randomised trial comparing ICCE with AC IOL and extracapsular cataract extraction with posterior chamber IOL is probably not justified at this time in this population. However, there may be wide variations in the reaction of the eyes of different African ethnic groups to IOLs. In view of the successful use of AC IOLs in Asian eyes, further pilot studies of AC IOLs may be warranted in other parts of Africa where ICCE is the routine procedure.

Comparison of the results of primary and secondary implantation of flexible open-loop anterior chamber intraocular lens

PURPOSE

To assess and compare the results of primary and secondary implantation of flexible open-loop anterior chamber intraocular lenses (AC-IOLs).

METHODS

A series of 57 eyes of 56 patients with flexible AC-IOLs were reviewed in two groups. In group I (n = 35) an AC-IOL was implanted primarily, because of posterior capsule problems during extracapsular cataract extraction (ECCE), and in group II (n = 22) secondarily after intracapsular cataract extraction (ICCE). Follow-up was from 12 to 38 months.

RESULTS

Mean post-operative best-corrected visual acuity in group I was significantly lower (20/37.38) than that of group II (20/29.20) (p = 0.044). Best corrected visual acuity of 20/40 or better was achieved in 19 of 29 eyes (65%) in group I, and in 16 of 21 eyes (76%) in group II. The difference was not statistically significant (p > 0.05). In group II 18 eyes (86%) maintained or improved visual acuity. In group I, 17 eyes (49%) had a total of 22 complications, while 7 eyes (32%) had 9 complications in group II (p > 0.05).

CONCLUSIONS

Flexible open-loop AC-IOLs are suitable for both primary and secondary implantation to correct aphakia. Secondary implantation of flexible open-loop AC-IOLs after ICCE seems to have a more favourable visual outcome and a lower complication rate than primary implantation in complicated ECCE cases.

Long-term follow-up of primary anterior chamber intraocular lens implantation

PURPOSE

To evaluate the long-term outcome in eyes having primary anterior chamber intraocular lens (AC IOL) implantation.

SETTING

Kimura Eye and Internal Medicine Hospital, Hiroshima, Japan.

METHODS

Primary AC IOL implantation was performed in 171 eyes from 1983 to 1988. Two lenses were implanted: the open C-loop Simcoe lens and the 4-point fixation Kelman lens. In 86 eyes that had a mean follow-up of 9 years 7 months, visual acuity, corneal endothelial cell density, pupil shape, and the presence of associated complications were examined.

RESULTS

Although the final visual acuity was 0.5 or better in 60 eyes (69%), corneal endothelial cell density was less than 2000 cells/mm2 in 46 eyes (57%). Postoperative complications included a deformed pupil in 48 eyes (56%) and bullous keratopathy in 12 eyes (14%). In 14 eyes the AC IOL was explanted; 11 of these were the open C-loop Simcoe lens.

CONCLUSION

Although our findings show that the open C-loop AC IOL (Simcoe) is contraindicated, implantation of the 4-point fixation AC IOL may be acceptable in selected cases.

Ten-year postoperative results of penetrating keratoplasty

OBJECTIVE

To investigate the changes in central corneal endothelial cells and corneal thickness in transplanted corneas from 5 to 10 years after grafting. This study also aimed to investigate the development of glaucoma, graft rejection, and graft failure during the first 10 postoperative years.

DESIGN/PARTICIPANTS

Longitudinal cohort study of 500 consecutive penetrating keratoplasties by 1 surgeon. Patients were asked to return for follow-up examinations at 2 months and at 1, 3, 5, and 10 years after grafting. The authors excluded eyes regrafted during the study and the fellow eyes of bilateral cases, leaving 394 grafts in 394 patients for analysis.

INTERVENTION

Penetrating keratoplasty was performed.

MAIN OUTCOME MEASURES

Using specular microscopy, the authors measured endothelial cell density, coefficient of variation of cell area, percentage of hexagonal cells, and corneal thickness. The authors performed clinical examinations to determine graft rejection or failure and the development of glaucoma.

RESULTS

By 10 years postkeratoplasty, 80 of the 394 patients had died and 68 grafts had failed. Of the remaining 246 patients, 119 (48%) returned for their 10-year examinations. For the 72 patients who returned for all of the scheduled postoperative visits and had no rejection episodes, reoperations, or failure, endothelial cell loss from preoperative donor levels at 10 years was 67 +/- 18% (mean +/- standard deviation), endothelial cell density was 958 +/- 471 cells/mm2, coefficient of variation was 0.32 +/- 0.11, hexagonal cells were 56 +/- 12%, and corneal thickness was 0.58 +/- 0.05 mm. The 5- to 10-year changes for all these values were significant (P < or = 0.004). The mean rate of late endothelial cell loss from 5 to 10 years postkeratoplasty was 4.2% per year. Eyes that were aphakic after grafting had the lowest endothelial cell loss (57 +/- 24%) and the lowest interval cell loss from 5 to 10 years postkeratoplasty (4 +/- 19%). Eyes that were phakic had the highest endothelial cell loss (73 +/- 8%) and 5- to 10-year-interval cell loss (17 +/- 31%). Eyes with posterior chamber lenses had a greater endothelial cell loss (71 +/- 9%) than did eyes with anterior chamber lenses (51 +/- 25%, P = 0.03). The 10-year cumulative risk of glaucoma, rejection, or failure was 21%, 21%, and 22%, respectively. Late endothelial failure became the major cause for graft failure, accounting for 9 of the 11 failures after 5 postoperative years.

CONCLUSIONS

From 5 to 10 years after penetrating keratoplasty, the annual rate of endothelial cell loss was seven times the normal rate. The endothelial cell loss, pleomorphism, polymegethism, and corneal thickness increased significantly during this time, indicating continued endothelial instability and dysfunction, resulting in an increasing rate of late endothelial failure.

Intraocular lens complications requiring removal or exchange

Intraocular lens (IOL)-related complications are caused primarily by mechanical trauma, inflammatory or infectious complications, or optical problems. Complications may occur at the time of surgery or be the result of an ongoing postoperative process. Mechanical and inflammatory injury may produce corneal decompensation, cystoid macular edema, hyphema, uveitis, and glaucoma, causing reduced vision and in some cases chronic pain. Optical problems may be due to a wrong power of the IOL or to postoperative decentration or dislocation of the lens. Ophthalmologists should be aware of the indications for IOL removal or exchange in those patients who have ongoing IOL-induced injury or impairment. Removal or exchange of an IOL frequently involves a complex decision-making process and is often associated with immense technical challenge. Various medical and surgical treatments may be tried to correct IOL problems before the decision is made to remove or exchange the lens.

Pediatric intraocular lens implantation. Surgical results and complications in more than 300 patients

OBJECTIVE

The study aimed to review pediatric intraocular lens (IOL) implantations performed in the authors' institution for the past 7 years.

STUDY DESIGN

The study design was a retrospective chart review.

PARTICIPANTS

All children who underwent IOL placement between January 1, 1989, and January 31, 1996, at ages 2 to 16 years were studied. Follow-up was a minimum of 6 months up to 4 years with an average of 13 months.

INTERVENTION

Placement of a primary or secondary posterior chamber IOL was performed.

MAIN OUTCOME MEASURES

Visual acuity and possible complications were tabulated.

RESULTS

Fifty-seven percent of the cataracts were caused by trauma, and 37% were infantile cataracts. Visual acuities of 20/40 or better were attained in 44% of eyes and visual acuities of 20/50 to 20/80 were attained in 27% of eyes. Visual acuities were better in children older than 4 years of age (P = 0.001). Compliance with amblyopia therapy improved vision (P = 0.004). Fibrinous membranes occurred in 41 eyes (13%), and posterior capsule opacification occurred in 120 eyes (39%). There were no significant differences in visual outcome and complications between primary and secondary implants (17%) or between capsular bag and sulcus fixation (27%). The first stable postoperative refraction was predicted accurately in most patients, based on the Sanders-Retzlaff-Kraff II (SRK II) formula and intraoperative corneal curvature and axial length determinations. The mean refraction differed from the goal by only +0.28 diopter and 84% were within +/- 2 diopters. A few patients showed large overcorrections or undercorrections. On average, no myopic shift occurred.

CONCLUSIONS

Short-term results of IOLs implanted in children older than 2 years of age were favorable. Visual acuities obtained were better than 20/80 in 71% despite a high prevalence (28%) of penetrating trauma. Major complications were rare.

Sutureless scleral fixation of intraocular lenses

A technique is presented in which pars plana fixation of a posterior chamber intraocular lens (IOL) is achieved by the transscleral passage of the haptics. The IOL used has three equidistant supple loops, each attached to an armed suture, which serve as haptics. A specially designed needle driver is used to pass the sutures into and out of the eye through the pars plana and along the surface of the sclera, where they are severed by cautery. Stable fixation is achieved without contact with the inner tissues of the eye, and no additional sutures are necessary. Lens stability is maintained even in the presence of asymmetrical fibrosis of the capsular remnants.

Uveitis-glaucoma-hyphema syndrome after handmade, anterior chamber lens implantation

Two patients developed uveitis-glaucoma-hyphema syndrome secondary to implantation of handmade anterior chamber intraocular lenses (IOLs). The IOLs were designed and made by the patients' ophthalmologists in their native Ukraine. The cases illustrate innovative and unusual solutions to the shortage of quality IOLs in the developing world and the challenging management of patients who present with complications arising from these IOLs.

Randomised controlled trial of anterior-chamber intraocular lenses

BACKGROUND

There are an estimated 16 million people blind in both eyes with cataracts. Most live in rural areas of developing countries where surgical resources are scarce. There is no consensus on the most appropriate type of intraocular lens in situations where high-volume low-cost surgery is required. This study was undertaken to evaluate the safety of multiflex open-loop anterior-chamber lenses (ACIOLs).

METHODS

2000 people attending Lahan Eye Hospital, southern Nepal, with bilateral cataracts reducing vision to 6/36 or less were randomly allocated to receive standard surgery--intracapsular extraction (ICCE) with aphakic correction--or ICCE with an ACIOL in their first operated eye. The primary outcome was a visual acuity of less than 6/60 in the operated eye at 1 year follow-up. Visual acuity was measured for 91% of the cohort at 1 year. The sample size was estimated to detect a doubling in poor visual outcome from an estimated rate of 4% in the standard surgery (control) group.

FINDINGS

The median (range) time taken to do the surgery was 6.0 (3.0-17.2) min for the ACIOL group and 4.1 (2.4-10.3) min for the control group. 1 year after surgery, 5.0% of the ACIOL group and 5.4% of controls had functional vision less than 6/60 (OR 0.93 [0.60-1.43], p = 0.71). The causes of poor vision in the ACIOL and control groups were: correctable refractive error (22 and 29), uveitis/secondary glaucoma (13 and two), endophthalmitis (four and seven), pre-existing eye disease (four and five), retinal detachment (none and four), cystoid macular oedema (two and none), corneal ulcer (one and one), and corneal decompensation (none and one).

INTERPRETATION

This study provides evidence that, in rural areas of developing countries, multiflex open-loop ACIOLs can be implanted safely by experienced ophthalmologists after routine ICCE, avoiding the disadvantages of aphakic spectacle correction. Further follow-up is planned.

Ultrasound Biomicroscopy of Baikoff Anterior Chamber Phakic Intraocular Lenses

BACKGROUND

The purpose of the study was to analyze qualitatively and quantitatively anatomic relationships of anterior chamber Baikoff phakic intraocular lenses (IOL) to the cornea, angle, iris, and lens in myopic eyes.

METHODS

Thirteen phakic myopic eyes (-9.00 to -15.00 diopters) corrected by minus power, angle-supported, anterior chamber intraocular lenses of the ZB5M style (Chiron-Domilens), with a mean follow-up of 25 months (range 18 to 36 months), were examined clinically and by ultrasound biomicroscopy.

RESULTS

The mean distance (+/- SD) between the central cornea and the IOL was 2.05 +/- 0.18 mm (range 1.8 to 2.47 mm); mean distance between the corneal periphery and the IOL was 1.56 +/- 0.17 mm (range 1.33 to 1.95 mm); and the mean distance between the IOL and the lens was 0.58 +/- 0.12 mm (range 0.48 to 0.81 mm). IOL footplates seemed to be correctly positioned in the angle in all eyes. We observed no goniosynechiae. In six eyes, we found localized posterior indentation of the iris caused by the haptics. Four of these six eyes exhibited oval pupils associated with an oversized IOL.

CONCLUSIONS

High frequency ultrasound biomicroscopy can define anatomic relationships of anterior chamber phakic IOLs, and help analyze the mechanisms of corneal and iris complications.

Age-related changes of the ciliary sulcus: implications for implanting sulcus-fixated lenses

PURPOSE

To examine age-related anatomical changes of the ciliary sulcus and the implication of these changes for placement of posterior chamber intraocular lenses (IOLs).

SETTING

Department of Ophthalmology, University of Heidelberg, Germany.

METHODS

In this study, 64 human autopsy eyes from 38 donors were divided by age into six groups from younger than 40 years (Group 1) to 80 years and older (Group 6) in 10 year increments. External diameter, capsular bag size, and lens thickness were determined for each eye. The horizontal and vertical diameters of the ciliary sulcus were measured and histological sectioning, staining, and light microscopy performed.

RESULTS

The external diameters of the eyes showed no age correlation; the lenses exhibited the expected increase in thickness with age. The mean vertical diameter of the ciliary sulcus decreased in all age groups from 12.02 mm +/- 0.12 (SD) to 10.71 +/- 0.91 mm and the mean horizontal diameter, from 11.36 +/- 0.24 mm to 10.33 +/- 0.76 mm. Statistical analysis confirmed the overall significance (P < .05) of the differences among age groups.

CONCLUSION

The ciliary sulcus became smaller with age. This might affect the size of sulcus-implanted IOLs and should be noted for transsclerally sutured IOLs.

Intraocular lens implants: a biocompatibility review

The natural aging process of the eye inevitably leads to the formation of a cataract, resulting in an increasing loss of vision. A cataract is the clouding of the natural lens in the eye and represents a major physical impairment. Modern surgical techniques allow for removal of the clouded lens and replacement with a prosthetic intraocular lens. This article reviews the intraocular tissue response to the implant, which frequently leads to postoperative complications for the patient.

Infantile cataracts

Cataracts are one of the most treatable causes of visual impairment during infancy. Recent epidemiological studies have shown that they have a prevalence of 1.2 to 6.0 cases per 10,000 infants. The morphology of infantile cataracts can be helpful in establishing their etiology and prognosis. Early surgery and optical correction have resulted in an improved outcome for infants with either unilateral or bilateral cataracts. While contact lenses continue to be the standard means of optically correcting an infant's eyes after cataract surgery, intraocular lenses are gaining in popularity as an alternative means of optically correcting these eyes. Post-operative complications occur more commonly after infantile than adult cataract surgery and many of these complications do not develop until years later. As a result, it is critical that children be followed closely on a long term basis after infantile cataract surgery.

The South Asian Cataract Management Study. I. The first 662 cataract surgeries: a preliminary report

AIMS

The first 662 cases of a multicentre randomised clinical trial of intracapsular cataract extraction (ICCE) with and without implantation of a four point multiflex (Cilco Kelman Choyce Modification) anterior chamber intraocular lens (AC IOL) were studied after 6 weeks to compare frequency of surgical complications, short term clinical outcomes, and corneal endothelial cell loss between groups.

METHODS

Randomisation was performed after screening for predetermined inclusion and exclusion criteria. Demographics, visual acuities, intraocular pressures, and corneal endothelium cell data were recorded preoperatively and at 6 weeks. Details of surgical procedure, complications, and postoperative adverse reactions were recorded. Monitoring of the study was secured by a standardised image documentation procedure on all patients using the IMAGEnet digital imaging system. Analysis of corneal endothelial cell images was done using the CELL SOFT software analysis program.

RESULTS

343 patients were randomised to IOL and 319 to no IOL. Twelve IOL implantations (3.5%) were aborted because of complications. A complication was reported in 103 (15.6%) of the surgical procedures (IOL = 16.9%, no IOL = 14.1%, p = 0.37). The most frequent complication observed was vitreous loss followed by plain capsular rupture, unplanned ECCE, and iris dialysis. Mean corneal endothelial cell loss 6 weeks after surgery was 17.2% (SD 13.1%) in the total study population (IOL = 18.5% no IOL = 16.1%, p = 0.05). The postoperative complications registered until 6 week follow up were significantly higher in the IOL group (IOL = 6.9%, no IOL = 2.6%, p = 0.02), mainly due to mild to moderate iritis needing prolonged use of steroids. Eighty nine per cent of the patients had a best corrected visual acuity of 6/18 or better. There was no significant difference in visual outcome between study groups.

CONCLUSIONS

The implantation of a multiflex AC IOL in primary ICCE surgery in the centres of this study did not increase the risk of surgical complications or short term sight threatening adverse clinical outcomes compared with ICCE without lens. Comparisons of corneal endothelial cell loss after 6 weeks between study groups showed no clinically significant difference. The difference in mean cell loss between groups was statistically significant.