Massive proliferation of lens epithelial remnants after Nd-YAG laser capsulotomy

Recurrent Posterior Capsular Opacification in Adults: A Case Report and an Overview of Literature

Posterior capsular opacification (PCO), also known as "secondary cataract", is a common complication following cataract surgery that can significantly impair visual acuity. The incidence of PCO varies widely in the literature, influenced by intraocular lens (IOL) type and patient risk factors. Neodymium-doped yttrium-aluminum-garnet (YAG) laser posterior capsulotomy is the standard treatment for PCO-related visual impairment. Recurrence of PCO after initial treatment with YAG capsulotomy, though more common in children, is rare in adults. Its underlying pathophysiological mechanisms are similar to that of primary PCO, which includes proliferation, migration, and/or clustering of lens epithelial cells (LECs), with subsequent reclosure of the posterior aperture. Potential risk factors for PCO recurrence that have been speculated through a comprehensive search of the current literature include younger age, female sex, high myopia, diabetes, vitrectomized status, uveitis, low-diopter IOLs, and certain IOL types with higher water content. We present a case of recurrent PCO in a highly myopic 48-year-old male following cataract surgery and implantable collamer lens (ICL) explantation who received a hydrophobic acrylic lens with 4% water content. Surgical techniques that may reduce recurrent PCO occurrence and appropriate postoperative care are emphasized to assist surgeons in their approach to patients at high-risk for this complication.

Factors Associated with Reclosure of Posterior Capsule Aperture by Flat Opacifications with Pearls after Nd:YAG Laser Posterior Capsulotomy

In this retrospective case series, we investigated factors associated with posterior capsule aperture (PCA) reclosure following neodymium-yttrium aluminum garnet (Nd:YAG) laser posterior capsulotomy. The study encompassed patients who underwent cataract surgery with intraocular lens (IOL) implantation or a combined vitrectomy, cataract surgery, and IOL implantation between 2009 and 2022. PCA reclosure was observed in 22 eyes of 17 patients: 45% (10 eyes) underwent the triple procedure, and 55% (12 eyes) received cataract surgery with IOL implantation. In our clinic, 14% of patients were given IOLs with a 4% water content, while 73% (13 eyes) of those experiencing PCA reclosure had IOLs with a 4% water content. The mean interval between Nd:YAG capsulotomies was notably shorter than that between the initial cataract surgery and the first Nd:YAG laser capsulotomy. We also identified five stages of PCA reclosure progression. In conclusion, IOL water content may be linked to PCA reclosure, and the time to recurrence is shorter with each successive reclosure. Further research is needed to verify these findings and uncover additional contributing factors.

Long-term myofibroblast persistence in the capsular bag contributes to the late spontaneous in-the-bag intraocular lens dislocation

Late spontaneous in-the-bag intraocular lens (IOL) dislocation is a complication presenting 6 months or later after cataract surgery. We aimed to characterize the cells in the lens capsules (LCs) of 18 patients with spontaneous late in-the-bag IOL dislocation. Patients' average age was 82.6 ± 1.5 years (range 72-98), and most of them had pseudoexfoliation syndrome (PEX). Cells from the LCs were positive for myofibroblast (αSMA), proliferation (Ki-67, PCNA), early lens development/lens progenitor (SOX2, PAX6), chemokine receptor (CXCR4), and transmembrane (N-cadherin) markers, while negative for epithelial (E-cadherin) marker. Moreover, the cells produced abundant fibronectin, type I and type V collagen in the nearby extracellular matrix (ECM). During ex vivo cultivation of dislocated IOL-LCs in toto, the cells proliferated and likely migrated onto the IOL's anterior side. EdU proliferation assay confirmed the proliferation potential of the myofibroblasts (MFBs) in dislocated IOL-LCs. Primary cultured lens epithelial cells/MFBs isolated from the LC of dislocated IOLs could induce collagen matrix contraction and continuously proliferated, migrated, and induced ECM remodeling. Taken together, this indicates that long-lived MFBs of dislocated IOLs might contribute to the pathogenic mechanisms in late in-the-bag IOL dislocation.

Reopacification of posterior capsular opening after ND: YAG capsulotomy: 2 cases with the different presentation

Purpose: To report the complete opacification of posterior capsulotomy opening after neodymium: yttrium-aluminium-garnet (ND: YAG) posterior capsulotomy for posterior capsular opacification. Methods: A 70-year-old female had uneventful cataract surgery by phacoemulsification technique with implantation of in the bag hydrophilic intraocular lens (IOL) in her left eye. Eight months after surgery, the patient developed posterior capsular opacification (PCO) for which ND: YAG capsulotomy was performed. However, she returned after 7 months first post ND: YAG capsulotomy with the blurring of vision and glare at night. Slit lamp examination revealed pearl like opacification of posterior capsule occupying the YAG capsulotomy opening. A repeated ND: YAG capsulotomy restored her vision to 20/ 20. Another patient operated for posterior polar cataract had dehiscence in the posterior capsule during cataract surgery. The patient was implanted with hydrophobic IOL in the capsular bag without performing an optic capture. The patient presented 3 years later with occlusion of the posterior capsular opening with mixed pearl-like and fibrotic PCO. Conclusion: Occlusion of the posterior capsular opening may occur after ND: YAG capsulotomy and may cause a reduction in visual acuity. Pearl-like opacification is common to occur in reopacification of posterior capsular opening.

Posterior Capsular Opacification in Preschool- and School-Age Patients after Pediatric Cataract Surgery without Posterior Capsulotomy

Objectives:

We aimed to evaluate the development of posterior capsular opacification (PCO) in preschool- and school-age children with cataract who underwent cataract surgery without posterior capsulotomy and anterior vitrectomy.

Materials and Methods:

The records of 30 eyes of 21 patients who underwent pediatric cataract surgery and intraocular lens (IOL) implantation were retrospectively reviewed. Patients’ age, PCO status and duration, need for neodymium-doped yttrium aluminium garnet (Nd:YAG) laser treatment based on coverage of visual axis, and follow-up period were recorded.

Results:

The mean age of the patients was 7.6±2.83 (4-12) years. Unilateral cataract surgery and IOL implantation were performed in 12 patients (57.14%) and bilateral cataract surgery and IOL implantation were performed in nine patients (42.86%). Average follow-up time was 17.7±22.67 (3-83) months. PCO developed in 21 eyes (70%) and covered the visual axis in 15 eyes (50%), which therefore required Nd:YAG laser posterior capsulotomy. The mean duration of postoperative PCO development was 8.91±18.7 months (1 week-71 months).

Conclusion:

We believe that with adequately experienced surgeons, performing both cataract surgery and posterior capsulotomy with anterior vitrectomy in the same session is appropriate for selected preschool- and school-age children with cataract.

An Overview of Nd:YAG Laser Capsulotomy

It has been revealed that posterior capsule opacification (PCO) is the most common delayed complication of cataract surgery. On the other hand, Nd:YAG laser capsulotomy is accepted as standard treatment for PCO. Although, Nd:YAG laser capsulotomy is a noninvasive and safe treatment it carries risk of some complications. Using less total energy and performing smaller capsulotomies are effective choices to decrease complications after Nd:YAG capsulotomy. The purpose of this review is to look through the complications associated with Nd:YAG laser capsulotomy, and the effect of capsulotomy size and used total energy on such complications.

Correlation between eye aperture diameter and complications in the posterior eye segment after Nd-YAG capsulotomy

The aim of our research was to explore possible correlation between eye aperture diameter and occurrence of complications in the posterior eye segment after Nd-YAG capsulotomy. In the study, we analyzed 120 eyes of the patients who experienced opacities in the posterior capsule or developed secondary cataract after the surgery. All patients underwent Nd-YAG laser posterior capsulotomy. Thereafter, we monitored complications occurrence in the posterior eye segment in intervals of one hour, seven days, one month and six months following the surgery. The frequency of complications increased with time. Six months after Nd-YAG laser posterior capsulotomy we found changes in the posterior eye segment: hole in the anterior hyaloid membrane in case of 9 (7,50%) eyes, prolapse of the corpus vitrei in 2 (1,66%) cases, retinal hole in case of 5 (4,16%) eyes, macular hole in 3 (2,50%) eyes, retinal detachment in 3 (2,50%) eyes, cystoid macular edema in 2 (1,66%) eyes, (1,66%), and macular pack in case of 11 (9,16%) eyes. Aperture size in the posterior capsule directly correlates with the number of complications. We suggest that the aperture diameter should not exceed 4,0 mm.

Incidence and risk factors of Nd:YAG capsulotomy after phacoemulsification in non-diabetic and diabetic patients

PURPOSE

To estimate the cumulative incidence and identify the risk factors of posterior capsule opacification (PCO) that required Nd:YAG capsulotomy in non-diabetic and diabetic patients.

METHODS

Retrospective case-note review of 806 consecutive patients that underwent phacoemulsification and intraocular lens (IOL) implantation, 327 (40.6%) of whom were diabetic.

RESULTS

The cumulative incidence of Nd:YAG capsulotomy were 10.6%, 14.8%, 21.2% and 28.6% in non-diabetic patients; and 9%, 9.4%, 15.3% and 5.3% in diabetic patients after 1, 2, 3 and 4 years, respectively. A multivariate Cox regression analysis showed that, over the follow-up period, diabetes mellitus was associated with a decreased risk of Nd:YAG capsulotomy (hazard ratio [HR]=0.69; 95% confidence interval [CI] 0.47-0.99; P=0.047), whereas age of 65 years or younger (HR=1.58; 95% CI 1.09-2.27; P=0.02), polymethylmethacrylate (PMMA) (HR=3.98; 95% CI 1.60-9.95; P=0.003) or plate-haptic silicone IOLs (HR=3.75; 95% CI 1.60-8.80; P=0.002) in comparison with three-piece silicone IOLs, postoperative inflammation (HR=2.62; 95% CI 1.56-4.42; P<0.001) and pars plana vitrectomy (HR=1.85; 95% CI 1.20-2.83; P=0.005) were associated with an increased risk. Subgroup analysis showed that in non-diabetic patients, male gender (HR=1.63; 95% CI 1.04-2.57; P=0.03) was an additional risk factor and in diabetic patients there was no significant association between diabetes type, duration or retinopathy grade and the risk of Nd:YAG capsulotomy.

CONCLUSION

Although diabetes mellitus appears to be associated with a lower long-term incidence and a decreased risk of Nd:YAG capsulotomy, younger age, pars plana vitrectomy, postoperative inflammation, plate-haptic silicone and PMMA IOLs in addition to male gender in non-diabetic patients appear to be associated with a greater risk. Estimation of the incidence and risk factors of PCO should help in patient counselling and to design methods to reduce or prevent its development.

Octreotide inhibits growth factor-induced and basal proliferation of lens epithelial cells in vitro

PURPOSE

To evaluate whether a synthetic analog of somatostatin, octreotide, has an inhibitory effect on lens epithelial cell (LEC) proliferation induced by basal and basic fibroblast growth factor as well as insulin-like growth factor 1.

METHODS

Confluent LEC cultures were kept in serum-free defined medium containing [(3)H]-thymidine in the presence of octreotide alone at the concentration range of 10(-7) M to 10(-10) M or in combination with either basic fibroblast growth factor or insulin-like growth factor 1. Additionally, the expression of somatostatin receptors (1-5) in LECs were analyzed by reverse transcription-polymerase chain reaction.

RESULTS

Octreotide decreased the proliferation of human LECs in a dose-dependent manner, exhibiting a maximal inhibitory concentration at 10(-9) M (P<.03). Moreover, octreotide (10(-9) M) potently inhibited basic fibroblast growth factor- and insulin-like growth factor 1-induced bovine lens epithelial cell proliferation (P<.0001). The respective products of all 5 subtypes of somatostatin receptors were found in human LECs and somatostatin receptor type 2 in bovine LECs.

CONCLUSION

The data show that, depending on the concentration, octreotide is able to decrease proliferative responses of LECs. Moreover, the cell proliferation induced by growth factors was potently inhibited by octreotide. Therefore, octreotide could be a potential drug after cataract surgery in prevention of growth factor-dependent proliferative disorders such as posterior capsule opacification and anterior capsule contraction in diabetic patients.

YAG curios #1: repeat Nd:YAG laser posterior capsulotomy

A descriptive case series of five patients identified either opportunistically or from a retrospective review of the laser register is presented. All underwent cataract surgery between 1995 and 1999 and required initial Nd:YAG laser posterior capsulotomy 15-30 months after surgery. They subsequently developed reclosure of the capsulotomy, necessitating repeat laser capsulotomy 11-82 months later. One patient, who received a hydrogel intraocular lens, required a third capsulotomy after a further 12 months. The rate of repeat Nd:YAG laser capsulotomy in our unit was 0.31%.

YAG curios #2: Nd:YAG laser treatment following suction posterior capsulorhexis

Suction posterior capsulorhexis (SPC) is a relatively new technique for creating a posterior capsulorhexis. We present a case series of seven patients who required Nd:YAG laser treatment 27 months after SPC. No patient had pre-existing risk factors for increased postoperative inflammation and all received a one-piece polymethylmethacrylate intraocular lens placed in-the-bag. Although it reduces the need for Nd:YAG laser treatment, SPC, like the more usual forceps posterior capsulorhexis, does not completely eliminate it.

Visual axis opacification after AcrySof intraocular lens implantation in children

PURPOSE

To evaluate visual axis opacification after AcrySof intraocular lens (IOL) (Alcon) implantation in pediatric eyes.

SETTING

Iladevi Cataract and IOL Research Centre, Ahmedabad, India.

METHODS

This prospective study evaluated 103 consecutive eyes of 72 children with congenital cataract. Two groups were formed based on age at surgery: Group 1, younger than 2 years, and Group 2, older than 2 years. All eyes in Group 1 (n = 37) had primary posterior continuous curvilinear capsulorhexis (PCCC) with anterior vitrectomy. In Group 2 (n = 66), management of the posterior capsule was assigned randomly to no PCCC (Group 2A, n = 37) or PCCC (Group 2B, n = 29). The PCCC group was further randomized into 2 subgroups: no vitrectomy (Group 2BN, n = 14) or vitrectomy (Group 2BV, n = 15). The primary outcome measures were visual axis opacification and the resulting need for a secondary procedure. Statistical analysis was performed using SPSS for Windows (version 11.0.1).

RESULTS

The mean age of the patients was 5.2 years +/- 5.0 (SD) (range 0.2 to 16.0 years) and the mean follow-up, 2.3 +/- 0.9 years (range 1.0 to 4.0 years). Overall, 41 eyes (39.8%) developed visual axis opacification and 14 (13.6%) required secondary intervention. In Group 1, 4 eyes (10.8%) developed visual axis opacification and 3 (8.1%) had a secondary pars plana vitrectomy. In Group 2A, 31 eyes (83.8%) developed posterior capsule opacification (PCO) and 10 eyes (27.7%) had secondary intervention. Children 8 years or younger at the time of surgery developed significantly greater PCO than older children (P =.01). Five eyes (37.5%) in Group 2BN had opacification of the anterior vitreous face, 1 of which required a secondary procedure. One eye (6.7%) in Group 2BV had visual axis opacification that did not require a secondary procedure.

CONCLUSIONS

AcrySof IOL implantation with appropriate management of the posterior capsule maintained a clear visual axis in 60.2% of eyes. Of the 39.8% of eyes with visual axis opacification, 13.6% had visually significant opacification and required a secondary procedure.

Neodymium:YAG laser capsulotomy in vitrectomized pseudophakic eyes with persistent endotamponade

PURPOSE

To evaluate the feasibility and limits of neodymium:YAG (Nd:YAG) laser capsulotomy in eyes with persistent endotamponade.

SETTING

Department of Ophthalmology, University Cologne, Cologne, Germany.

METHODS

In this consecutive series, an Nd:YAG laser capsulotomy was performed by 1 surgeon in 6 eyes with posterior capsule opacification (PCO) and persistent endotamponade caused by proliferative vitreoretinopathy. The endotamponade was with silicone oil (5000 centistokes) in 5 eyes and with perfluorohexyloctane (F(6)H(8)) in 1 eye. Also evaluated were 6 vitrectomized eyes without endotamponade that had an Nd:YAG laser capsulotomy for PCO by the same surgeon. All 12 eyes were pseudophakic. The mean follow-up after capsulotomy was approximately 6 months (range 2 to 12 months). Follow-up examinations included visual acuity, intraocular pressure measurement, and IOL centration and capsule reopacification evaluation.

RESULTS

The total energy required was higher in eyes with persistent endotamponade. In 3 of these eyes, the laser capsulotomy could not be successfully completed and was surgically enhanced. The laser capsulotomy in eyes without endotamponade was successful in all cases. Complete reopacification occurred in 2 eyes with persistent endotamponade within 2 months and in no eye without endotamponade. Improvement in visual acuity was limited in all eyes because of retinal pathology.

CONCLUSIONS

Neodymium:YAG laser capsulotomy in pseudophakic eyes with persistent endotamponade was successful but had a relatively high reintervention rate. The visual prognosis was limited in all cases because of retinal pathology.

Anterior vitreous face behavior with AcrySof in pediatric cataract surgery

PURPOSE

To describe anterior vitreous face behavior when AcrySof (Alcon, Fort Worth, TX) intraocular lenses come in contact with the anterior vitreous face after posterior continuous curvilinear capsulorhexis without anterior vitrectomy in pediatric patients undergoing cataract surgery.

METHODS

This study comprised 14 eyes of 12 children whose mean age was 9.6 years (range, 2.3 to 16.0). All eyes underwent primary posterior continuous curvilinear capsulorhexis without anterior vitrectomy and had AcrySof IOLs implanted in the bag. Changes on the anterior vitreous face were documented, and visual acuity was recorded. Statistical analysis was performed using Student group t and Mann Whitney tests.

RESULTS

Mean length of follow-up was 21.1 +/- 7.4 months (range, 15.0 to 36 months). Nine eyes (64.3%) had a clear visual axis, whereas 5 eyes (35.7%) developed anterior vitreous face changes. Of those with anterior vitreous face changes, 60% (3 of 5) eyes showed a fine meshwork-like reticular response termed "anterior vitreous reticular response" (AVR); 20% (1 of 5) eyes showed a scaffold response; and 20% (1 of 5) eyes showed a mixed response at the last follow-up examination. The difference in visual acuity before and after the development of the AVR response was not significant (P =.712). The mean age of patients with eyes having a clear visual axis was 12.1 +/- 2.3 years (median = 11.0; range, 9.1 to 16.0), and the mean age of patients with eyes having anterior vitreous face changes was 5.1 +/- 3.4 years (median = 3.6; range, 2.3 to 11.6) (P =.0098).

CONCLUSION

The results suggest that when the AcrySof intraocular lenses come in contact with the anterior vitreous face, they produce the AVR response during the early postoperative period in younger eyes. This does not seem to have any significant impact on visual acuity.

Use of Nd:YAG laser capsulotomy

Surgery for cataract removal has become successively refined such that posterior capsular opacification is the most common problem presenting after modern cataract extraction. Various techniques and treatments exist to manage patients with posterior capsular opacification using Nd:YAG capsulotomy. There are many possible variations in initial assessment, pre-laser treatments, laser techniques, and follow-up routines. The literature on the use of Nd:YAG laser for capsulotomy was reviewed and interpreted. This article presents the currently available knowledge in a format that allows the practitioner to tailor an evidence-based protocol for treating patients with symptomatic posterior capsule opacification.

Influence of intraocular lens material on regeneratory posterior capsule opacification after neodymium:YAG laser capsulotomy

PURPOSE

To evaluate the influence of a neodymium:YAG (Nd:YAG) laser capsulotomy on the morphology and development of regeneratory opacification of the remaining surrounding posterior capsule.

SETTING

Department of Ophthalmology, Medical School, University of Vienna, Vienna, Austria.

METHODS

Standardized digital retroillumination photographs were taken immediately before and after Nd:YAG laser capsulotomy and at 1 week, 6 months, and 1 to 3 years in 38 eyes of consecutive patients. Changes in regeneratory posterior capsule opacification (PCO) and opacification around the capsulotomy opening were evaluated. The influence of the type of intraocular lens (IOL) material and design (acrylic, n = 8; hydrogel, n = 8; silicone open loop, n = 11; silicone plate haptic, n = 6; poly(methyl methacrylate) [PMMA], n = 5) was assessed. The state of the anterior vitreous surface was examined at the slitlamp in all eyes.

RESULTS

In 8 of 17 eyes with a silicone IOL, reduced regeneratory PCO was observed. Massive pearl formation on the margin of the Nd:YAG capsulotomy was typical with silicone IOLs (8 eyes) but also occurred with PMMA IOLs. Eyes with acrylic IOLs had no change in regeneratory PCO after the capsulotomy. Three of 8 eyes with hydrogel IOLs had complete closure of the posterior capsulotomy opening.

CONCLUSIONS

Neodymium:YAG laser capsulotomy induced changes in the development and morphology of regeneratory PCO. Silicone and PMMA IOLs led to significant pearl formation on the capsulotomy margin, often combined with a reduction of peripheral regeneratory PCO (silicone). Hydrogel IOLs led to a higher incidence of reclosure of the Nd:YAG capsulotomy opening.

Posterior capsule opacification after cataract surgery in patients with diabetes mellitus

PURPOSE

To examine the degree of posterior capsule opacification (PCO) after cataract surgery in patients with diabetes and in nondiabetic age-matched control patients.

DESIGN

Case-control study.

METHODS

The PCO density value in 100 consecutive diabetic patients and in 100 nondiabetic age-matched control patients who underwent cataract surgery was measured using a Scheimpflug videophotography system at 1 week and at 3, 6, 12, 18, 24, 30, and 36 months after surgery. The incidence of neodymium:yttrium-aluminum-garnet (Nd:YAG) laser posterior capsulotomy was also evaluated. Furthermore, the stage of diabetic retinopathy and systemic condition of the diabetes were correlated with the degree of PCO.

RESULTS

No significant difference between the two groups was observed in the mean value of the PCO for up to 12 months after cataract surgery. However, at 18 months and later, the PCO value in the diabetic group increased significantly and was significantly greater than in the control group. Kaplan-Meier survival curves showed that diabetic patients were significantly more likely to require Nd:YAG capsulotomy than control patients (P =.0139, Mantel-Cox log rank test). Among the diabetic patients, there was no significant correlation of PCO value with the stage of retinopathy. Furthermore, type of treatment, duration of diabetes, and hemoglobin A(1C) did not correlate with the PCO value.

CONCLUSIONS

Diabetic patients developed significantly greater PCO after cataract surgery than did nondiabetic patients, but among the diabetics, the stage of diabetic retinopathy and systemic status of the diabetes did not correlate with the degree of PCO.

Secondary closure of neodymium:YAG laser posterior capsulotomy

A 67-year-old man reported reduced vision after cataract surgery and neodymium:YAG (Nd:YAG) laser posterior capsulotomy. The diagnosis was complicated due to severe glistenings within the optic of an acrylic foldable intraocular lens (IOL), proliferation of lens epithelial remnants over the capsulotomy opening, and presumed vitreous opacity. Although IOL exchange surgery was considered, a second Nd:YAG laser intervention successfully removed the proliferated lens materials and restored the visual acuity. The glistenings were not the cause of the reduced vision.

Lens epithelial cell proliferation in human posterior capsule opacification specimens

In previous in vitro studies on capsular bags it was shown that, after a sham extracapsular cataract extraction (ECCE) on human donor eyes, lens epithelial cells (LECs) show, in the short term, a dramatically elevated mitotic activity as compared to that in the intact lens. The long term in vivo proliferation of LECs in human lenses after ECCE and intraocular lens (IOL) implantation has not been studied until now. In the present study, the mitotic activity of LECs in human post-mortem eyes with posterior capsule opacification (PCO) was investigated. Human lenses with signs of PCO were dissected from donor eyes and incubated in MEM, supplemented with fetal calf serum, for 1 day (n = 10) or 7 days (n = 9). Six additional specimens were cultured for 7 days after removal of the IOL and lens fibres. After the incubation period, mitotic activity was estimated using the BrdU procedure and the Ki67 proliferating cell marker. The mean number of BrdU-positive nuclei in the intact PCO specimens was at a level of 7.5 (day 1) and 6.5 (day 7). Removal of the IOL and the lens fibres leads to a ten-fold increase in BrdU positive cells (mean = 84.5). No correlation with donor age was found. The Ki67 observations corroborate the BrdU results. The results demonstrate that after an initial rise in proliferative activity, as shown in the capsular bag model, the mitotic activity of LECs returns to a rate comparable to that in intact cultured non-cataractous lenses. As in control lenses, removal of lens fibres significantly elevated the proliferative activity of the remaining LECs. Suppression by newly formed differentiated lens fibres in the in vivo capsular bag may be responsible for this return to control levels of mitotic activity of LECs in the PCO specimens.

Anterior hyaloid face opacification after pediatric Nd:YAG laser capsulotomy

PURPOSE

The purpose of this study was to examine the clarity of the visual axis after Nd:YAG laser capsulotomy following cataract extraction and primary intraocular lens implantation in a pediatric population.

METHODS

A retrospective review was performed of all cases of cataract extraction and primary intraocular lens implantation over a period of 5 years. A group of children who had been treated by primary surgical posterior capsulotomy and anterior vitrectomy (Group 1) was used as the "gold standard," with whom the children treated with Nd:YAG laser capsulotomy (Group 2) were compared. The groups were studied for the incidence of opacification of the visual axis after the primary procedure.

RESULTS

Data on 78 eyes were reviewed, and 56 eyes met inclusion criteria. Of these, 33 eyes were treated with primary posterior capsulotomy and anterior vitrectomy (Group 1) and 23 eyes were treated with Nd:YAG laser capsulotomy (Group 2). One eye (3%) of Group 1 experienced postoperative visual axis reopacification. Thirteen (57%) of 23 eyes in Group 2 experienced reopacification, requiring retreatment. Four eyes (17%) treated with Nd:YAG laser required a third treatment.

CONCLUSIONS

In our series, 57% of patients treated with Nd:YAG laser capsulotomy experienced reopacification across the anterior hyaloid face. With the removal of the anterior vitreous at the time of cataract extraction, the scaffolding for cell migration is removed and reopacification of the visual axis is rarely seen. For patients in whom slit-lamp capsulotomy is not possible, especially if there is no Nd:YAG laser available for use in the operating room or when loss to follow-up may be an issue, primary posterior capsulotomy and anterior vitrectomy should be strongly considered.

The development of in vitro biocompatibility tests for the evaluation of intraocular biomaterials

Recent developments in ocular implant technology require the in vitro evaluation of ocular compatibility in early stage development programs. This requires an understanding and appreciation of the biological interactions which occur in the ocular environment and their relevance with respect to the clinical complications associated with surgical implantation of devices. This paper describes the development of a series of clinically reflective in vitro assays for assessing the potential ocular compatibility of novel intraocular lens materials. Staphylococcus epidermidis attachment, fibrinogen adsorption, mouse embryo fibroblast 3T3 adhesion and proliferation, primary rabbit lens cell adhesion, human peripheral blood macrophage adhesion and granulocyte activation tests were employed to evaluate two widely used intraocular biomaterials poly(methyl methacrylate) (PMMA) and silicone, and a novel biomimetic phosphorylcholine-based coating (PC). The performance of these materials in the in vitro assays was compared to their ability to reduce postoperative inflammation in vivo in a rabbit model. The results demonstrated that the in vitro assays described here are predictive of in vivo ocular compatibility. These assays offer a more relevant means of assessing the ocular compatibility of biomaterials than those presently required by the authorities for regulatory approval of medical devices and implants.

Cell biology of posterior capsular opacification

Posterior capsular opacification (PCO), a major complication of modern cataract surgery, necessitates further surgical intervention in 10-50% of patients. PCO results from the growth and transdifferentiation of lens epithelial cells left on the anterior capsule at the time of cataract surgery. These cells proliferate to form monolayers on the capsular surfaces, and such monolayers continue to line the anterior capsule leaflet many years after surgery. Some cells, however, differentiate or undergo a transition to another cell type, and these processes greatly contribute to PCO. Equatorial differentiation of cells to fibre-like structures leads to Soemmerring's ring formation and peripheral thickening of the capsular bag. Closer to the rhexis, cell swelling can result in globular Elschnig's pearls, which may occlude the visual axis. Cells at the rhexis edge and those in the space around the optic appear to undergo epithelial-mesenchymal transition. The resulting cells are fibroblastic in morphology, express the smooth muscle isoform of actin and secrete extracellular matrix containing proteins not normally present in the lens.

Elschnig pearl formation along the posterior capsulotomy margin after neodymium:YAG capsulotomy

PURPOSE

To determine the incidence of Elschnig pearl formation along the capsulotomy margin (string of pearls) after neodymium:YAG (Nd:YAG) laser posterior capsulotomy and to elucidate its clinical features, predisposing factors, effect on visual function, and association with additional capsulotomy.

SETTING

Keio University Hospital, Tokyo, Japan.

METHODS

The records of 418 eyes that had had Nd:YAG posterior capsulotomy after cataract surgery were retrospectively reviewed. Of those, 315 were excluded for short follow-up (fewer than 12 months) or insufficient clinical examination data. In the remaining 103 eyes, the incidence of string of pearls was calculated, and its clinical features, predisposing factors, effect on visual function, and correlation with additional capsulotomy were evaluated.

RESULTS

String of pearls was identified in 49 eyes (47.6%); 37 (75.5%) developed pearls within 1 year after Nd:YAG capsulotomy. The incidence was significantly higher in patients having intraocular lens implantation and continuous curvilinear capsulorhexis (CCC) than in those without (95.9 versus 61.1% and 97.9 versus 55.6%, respectively). No significant differences were found in patient age and sex, total Nd:YAG energy, and the presence of diabetes mellitus or high myopia. String of pearls caused visual disturbances in 17 eyes (34.7%). The rate of repeat capsulotomy was higher in patients with string of pearls than in those without (36.7 and 9.3%, respectively).

CONCLUSIONS

String of pearls formation was a common and significant complication after Nd:YAG posterior capsulotomy. Intraocular lens implantation and CCC may promote its formation.