Thinning of the anterior capsule associated with congenital aniridia

Preventing the Argentinian flag sign and managing anterior capsular tears: A review

The Argentinian flag sign (AFS) is a feared complication during cataract extraction. Intralenticular pressures, especially excessive posterior pressure, have been identified as potential mechanisms for capsular stress and tearing associated with AFS. Capsular tension is created by positive intralenticular pressures, which cause the irido-lens diaphragm to move anteriorly once the manual capsulorhexis has been initiated. This tension can cause inadvertent tears that self-propagate to the lens equator, causing an AFS, among other intraoperative complications. Thus, this review highlights the importance of identifying intumescent cataracts as well as a combination of techniques to relieve intracapsular pressures needed to prevent AFS. However, some instances of anterior capsular tears are unavoidable. Therefore, focus will also be placed on techniques during cataract extraction used to manage anterior capsular tears, mitigating extension to the posterior capsule.

Congenital aniridia beyond black eyes: From phenotype and novel genetic mechanisms to innovative therapeutic approaches

Congenital PAX6-aniridia, initially characterized by the absence of the iris, has progressively been shown to be associated with other developmental ocular abnormalities and systemic features making congenital aniridia a complex syndromic disorder rather than a simple isolated disease of the iris. Moreover, foveal hypoplasia is now recognized as a more frequent feature than complete iris hypoplasia and a major visual prognosis determinant, reversing the classical clinical picture of this disease. Conversely, iris malformation is also a feature of various anterior segment dysgenesis disorders caused by PAX6-related developmental genes, adding a level of genetic complexity for accurate molecular diagnosis of aniridia. Therefore, the clinical recognition and differential genetic diagnosis of PAX6-related aniridia has been revealed to be much more challenging than initially thought, and still remains under-investigated. Here, we update specific clinical features of aniridia, with emphasis on their genotype correlations, as well as provide new knowledge regarding the PAX6 gene and its mutational spectrum, and highlight the beneficial utility of clinically implementing targeted Next-Generation Sequencing combined with Whole-Genome Sequencing to increase the genetic diagnostic yield of aniridia. We also present new molecular mechanisms underlying aniridia and aniridia-like phenotypes. Finally, we discuss the appropriate medical and surgical management of aniridic eyes, as well as innovative therapeutic options. Altogether, these combined clinical-genetic approaches will help to accelerate time to diagnosis, provide better determination of the disease prognosis and management, and confirm eligibility for future clinical trials or genetic-specific therapies.

Novel clinical presentation and PAX6 mutation in families with congenital aniridia

Purpose

To explore the clinical phenotype and genetic defects of families with congenital aniridia.

Methods

Four Chinese families with aniridia were enrolled in this study. The detailed ocular presentations of the patients were recorded. Whole exome sequencing (BGI MGIEasy V4 chip) was used to detect the gene mutation. Sanger sequencing was performed to validate the potential pathogenic variants, and segregation analysis was performed on all available family members.

Results

By whole exome sequencing and Sanger sequencing, three recurrent mutations (c.112del, p.Arg38Glyfs*16; c.299G > A, p.Trp100* and c.718C > T, p.Arg240*) and one novel mutation (c.278_281del, p.Glu93Alafs*30) of PAX6 were identified. All the mutations were co-segregated with the phenotype in the families. We also observed spontaneous anterior lens capsule rupture in aniridia for the first time.

Conclusion

We report spontaneous anterior lens capsule rupture as a novel phenotype of aniridia and three recurrent mutations and one novel mutation of PAX6 in families with aniridia. Our results expanded the phenotype and genotype spectra of aniridia and can help us better understand the disease.

Clinical and molecular aspects of congenital aniridia - A review of current concepts

Congenital aniridia is a pan ocular disorder characterized by partial or total loss of iris tissue as the defining feature. Classic aniridia, however, has a spectrum of ocular findings, including foveal hypoplasia, optic nerve hypoplasia, nystagmus, late-onset cataract, glaucoma, and keratopathy. The latter three are reasons for further visual compromise in such patients. This entity is often due to mutations in the PAX6 (Paired box protein Pax-6) gene. Recently, aniridia-like phenotypes have been reported due to non-PAX6 mutations as in PITX2, FOXC1, FOXD3, TRIM44, and CYP1B1 as well wherein there is an overlap of aniridia, such as iris defects with congenital glaucoma or anterior segment dysgenesis. In this review, we describe the various clinical features of classic aniridia, the comorbidities and their management, the mutation spectrum of the genes involved, genotype-phenotype correlation of PAX6 and non-PAX6 mutations, and the genetic testing plan. The various systemic associations and their implications in screening and genetic testing have been discussed. Finally, the future course of aniridia treatment in the form of drugs (such as ataluren) and targeted gene therapy has been discussed.

Crystalline lens alterations in congenital aniridia

Congenital aniridia is a rare genetic disease associated with mutations in the PAX6 gene. Changes in the lens in aniridia can be alterations of size and shape, of position - which generally reveal zonular weakness and determines subluxation of the lens - and mainly changes in transparency, cataracts, with variable morphology of polar, cortical, subcapsular, lamellar, and more rarely, nuclear cataract. Visual acuity and quality of vision in patients with congenital aniridia complicated by cataracts can be improved by carefully planned surgery, when lack of media transparency justifies surgical indication. Most patients have some improvement in visual acuity and quality of retinal image. Cataract surgery with aniridia is complicated by pathological changes due to the underlying cause of the aniridia. Challenges include corneal opacification, friable capsule and, above all, iris and pupil reconstruction. It can also determine late complications, such as secondary glaucoma or deterioration of pre-existent glaucoma, and corneal endothelial decompensation. After crystalline lens surgery in these patients, either by cataract or dislocation, for visual rehabilitation there are various techniques such as keratopigmentation, prosthetic iris devices or Morcher intraocular lenses with a black diaphragm. An appropriate individualised surgical plan should be selected depending on patient and surgical experience, in order to minimise complications and give the best chance of postoperative success.

Pathophysiology of aniridia-associated keratopathy: Developmental aspects and unanswered questions

Aniridia, a rare congenital disease, is often characterized by a progressive, pronounced limbal insufficiency and ocular surface pathology termed aniridia-associated keratopathy (AAK). Due to the characteristics of AAK and its bilateral nature, clinical management is challenging and complicated by the multiple coexisting ocular and systemic morbidities in aniridia. Although it is primarily assumed that AAK originates from a congenital limbal stem cell deficiency, in recent years AAK and its pathogenesis has been questioned in the light of new evidence and a refined understanding of ocular development and the biology of limbal stem cells (LSCs) and their niche. Here, by consolidating and comparing the latest clinical and preclinical evidence, we discuss key unanswered questions regarding ocular developmental aspects crucial to AAK. We also highlight hypotheses on the potential role of LSCs and the ocular surface microenvironment in AAK. The insights thus gained lead to a greater appreciation for the role of developmental and cellular processes in the emergence of AAK. They also highlight areas for future research to enable a deeper understanding of aniridia, and thereby the potential to develop new treatments for this rare but blinding ocular surface disease.

Pathological Changes of the Anterior Lens Capsule

The anterior lens capsule (ALC), as the thickest basement membrane in the body, is an acellular, soft, smooth, transparent membrane secreted by lens epithelial cells. The ALC has its unique biomechanical properties to serve as a barrier and separate the lens from infectious viruses and bacteria together with the posterior capsule and pericapsular membrane. However, the biomechanical and ultrastructural properties of the ALC can be changed under certain conditions. Here, we provide a brief review of the pathological changes of the ALC in several eye disorders, including cataract, aniridia, climatic droplet keratopathy, exfoliation syndrome, true exfoliation syndrome, Alport syndrome, and silicone oil tamponade.

Congenital aniridia - A comprehensive review of clinical features and therapeutic approaches

Congenital aniridia is a rare genetic eye disorder with total or partial absence of the iris from birth. In most cases the genetic origin of aniridia is a mutation in the PAX6 gene, leading to involvement of most eye structures. Hypoplasia of the fovea is usually present and is associated with reduced visual acuity and nystagmus. Aniridia-associated keratopathy, glaucoma, and cataract are serious and progressive complications that can further reduce visual function. Treatment of the ocular complications of aniridia is challenging and has a high risk of side effects. New approaches such as stem cell therapy may, however, offer better prognoses. We describe the various ocular manifestations of aniridia, with a special focus on conditions that commonly require treatment. We also review the growing literature reporting systemic manifestations of the disease.

Crystalline lens alterations in congenital aniridia

Congenital aniridia is a rare genetic disease associated with mutations in the PAX6 gene. Changes in the lens in aniridia can be alterations of size and shape, of position - which generally reveal zonular weakness and determines subluxation of the lens - and mainly changes in transparency, cataracts, with variable morphology of polar, cortical, subcapsular, lamellar, and more rarely, nuclear cataract. Visual acuity and quality of vision in patients with congenital aniridia complicated by cataracts can be improved by carefully planned surgery, when lack of media transparency justifies surgical indication. Most patients have some improvement in visual acuity and quality of retinal image. Cataract surgery with aniridia is complicated by pathological changes due to the underlying cause of the aniridia. Challenges include corneal opacification, friable capsule and, above all, iris and pupil reconstruction. It can also determine late complications, such as secondary glaucoma or deterioration of pre-existent glaucoma, and corneal endothelial decompensation. After crystalline lens surgery in these patients, either by cataract or dislocation, for visual rehabilitation there are various techniques such as keratopigmentation, prosthetic iris devices or Morcher intraocular lenses with a black diaphragm. An appropriate individualised surgical plan should be selected depending on patient and surgical experience, in order to minimise complications and give the best chance of postoperative success.

Long-term follow-up of a custom-made prosthetic iris device in patients with congenital aniridia

PURPOSE

To investigate the effectiveness and safety of a custom-made iris prosthetic device used to reduce photic symptoms in patients with congenital aniridia.

SETTING

Cincinnati Eye Institute, Cincinnati, Ohio, USA.

DESIGN

Retrospective single-surgeon case series.

METHODS

The charts of all eyes of patients diagnosed with congenital aniridia syndrome who underwent implantation of the custom-made iris prosthesis at the setting institution between 2008 and 2018 were reviewed. Eyes with more than 6 months of follow-up were included in evaluation. Charts were carefully reviewed for comorbid conditions, interventions, and outcomes.

RESULTS

Ninety-six eyes of 50 patients were included in the study. Subjective reduction in photophobia and glare was reported in 95.7% and 95.2% of cases, respectively. The incidence of aniridia fibrosis syndrome (AFS) in this study (3.1%; 95% confidence interval, 0.6%-8.9%) was similar to previous studies in the literature.

CONCLUSIONS

The custom-made iris prosthesis was an effective and safe option to reduce photic symptoms in patients with congenital aniridia. The custom, flexible iris implant does not appear to alter the risk for AFS. These highly complex eyes with significant comorbid pathologies demand an individualized approach and careful long-term follow-up.

The genetic architecture of aniridia and Gillespie syndrome

Absence of part or all of the iris, aniridia, is a feature of several genetically distinct conditions. This review focuses on iris development and then the clinical features and molecular genetics of these iris malformations. Classical aniridia, a panocular eye malformation including foveal hypoplasia, is the archetypal phenotype associated with heterozygous PAX6 loss-of-function mutations. Since this was identified in 1991, many genetic mechanisms of PAX6 inactivation have been elucidated, the commonest alleles being intragenic mutations causing premature stop codons, followed by those causing C-terminal extensions. Rarely, aniridia cases are associated with FOXC1, PITX2 and/or their regulatory regions. Aniridia can also occur as a component of many severe global eye malformations. Gillespie syndrome—a triad of partial aniridia, non-progressive cerebellar ataxia and intellectual disability—is phenotypically and genotypically distinct from classical aniridia. The causative gene has recently been identified as ITPR1. The same characteristic Gillespie syndrome-like iris, with aplasia of the pupillary sphincter and a scalloped margin, is seen in ACTA2-related multisystemic smooth muscle dysfunction syndrome. WAGR syndrome (Wilms tumour, aniridia, genitourinary anomalies and mental retardation/intellectual disability), is caused by contiguous deletion of PAX6 and WT1 on chromosome 11p. Deletions encompassing BDNF have been causally implicated in the obesity and intellectual disability associated with the condition. Lastly, we outline a genetic investigation strategy for aniridia in light of recent developments, suggesting an approach based principally on chromosomal array and gene panel testing. This strategy aims to test all known aniridia loci—including the rarer, life-limiting causes—whilst remaining simple and practical.

PAX6 aniridia syndrome: clinics, genetics, and therapeutics

PURPOSE OF REVIEW

Aniridia is a rare and panocular disorder affecting most of the ocular structures which may have significant impact on vision. The purpose of this review is to describe the clinical features, genetics, and therapeutic options for this disease and to provide an update of current knowledge and latest research findings.

RECENT FINDINGS

Aside from the ocular features, a variety of associated systemic abnormalities, including hormonal, metabolic, gastrointestinal, genitourinary, and neurologic pathologies have been reported in children with aniridia. Although mutations in PAX6 are a major cause of aniridia, genetic defects in nearby genes, such as TRIM44 or ELP4, have also been reported to cause aniridia. Recent improvement in genetic testing technique will help more rapid and precise diagnosis for aniridia. A promising therapeutic approach called nonsense suppression therapy has been introduced and successfully used in an animal model.

SUMMARY

Aniridia is a challenging disease. The progressive nature of this condition and its potential complications require continuous and life-long ophthalmologic care. Genetic diagnosis for aniridia is important for establishing definitive molecular characterization as well as identifying individuals at high risk for Wilms tumor. Recent advancement in understanding the genetic pathogenesis of this disease offers promise for the approaches to treatment.

Congenital aniridia with cataract: case series

Background

This study evaluates patients with congenital aniridia and cataract who underwent phacoemulsification, capsular tension ring placement, and foldable intraocular lens implantation.

Methods

In this prospective case series, 10 patients (17 eyes) underwent cataract surgery via a 3.2 mm clear corneal incision. A continuous circular capsulorhexis with <6 mm diameter was employed. A capsular tension ring and HOYA yellow foldable posterior chamber intraocular lens was implanted. All patients wore color contact lenses postoperatively. Paired t test was used to compare visual acuity, intraocular pressure, and corneal endothelial changes before and after surgery.

Results

A single surgeon performed all surgeries. The best-corrected visual acuity improved from value 1.03 ± 0.27LogMAR preoperatively to value 0.78 ± 0.26LogMAR postoperatively (p = 0.000). The photophobic symptoms improved significantly after surgery. The mean corneal endothelial cell density before and after surgery was 3280 ± 473 cells/mm2 and 2669 ± 850 cells/mm2, respectively (p = 0.006). None of the patients developed corneal endothelial decompensation or secondary glaucoma after surgery.

Conclusions

Treatment of congenital aniridia and coexistent cataract by phacoemulsification, posterior chamber foldable lens implantation, capsular tension ring placement was safe and effective. Use of colored contact lenses in the postoperative period can reduce photophobic symptoms in this group of patients.

Trial registration

ChiCTR-OOC-17011638 (retrospectively registered at 12,June,2017)

Analysis of corneal morphologic and pathologic changes in early-stage congenital aniridic keratopathy

AIM

To determine typical corneal changes of congenital aniridic keratopathy (CAK) using corneal topography and confocal systems, and to identify characteristics that might assist in early diagnosis.

METHODS

Patients with CAK and healthy control subjects underwent detailed ophthalmic examinations including axial length, corneal thickness, tear film condition, corneal topography, and laser-scanning in vivo confocal microscopy (IVCM).

RESULTS

In early stage aniridic keratopathy, Schirmer I test (SIT), break-up time (BUT), mean keratometry (mean K) and simulated keratometry (sim K) were reduced relative to controls (P<0.05), while simulation of corneal astigmatism (sim A) and corneal thickness were increased (P<0.05). In addition, significantly more eyes exhibited flat cornea compared with the control group. Inflammatory dendritic cells were present in the aniridic epithelium, with significantly increased density relative to controls (P<0.05). Palisade ridge-like features and abnormal cell morphology were observed in six out of sixteen CAK cases. In central cornea area, the aniridic corneas had the increased subbasal nerve density.

CONCLUSION

These changes in corneal morphology in borderline situations can be useful to confirm the diagnosis of CAK.

Intraoperative management of anterior capsular tear

PURPOSE OF REVIEW

The article reviews the current literature on intraoperative techniques to properly manage anterior capsular tears during cataract surgery.

RECENT FINDINGS

Femtosecond laser-assisted cataract surgery creates a more consistent capsulorhexis than traditional capsulotomies, but can also present with new challenges. Irregularities, like microadhesions and tags, can lead to anterior tears if not properly treated. New technology, like the Zepto (Mynosys, Fremont, CA, USA) pulse precision capsulotomy, may produce a smoother edge and reduce the incidence of capsular tears. However, there are novel rescue techniques in the case that a tear-out does occur.

SUMMARY

Anterior capsular tears can occur at any stage of cataract surgery. The proper management of these tears will prevent them from extending into the posterior capsule and compromising the structural integrity of the capsular bag. This is essential for endocapsular placement of artificial lenses and for optimal visual outcomes for the patient.

Congenital aniridia: etiology, manifestations and management

Congenital aniridia manifests as total or partial absence of the iris caused most commonly by mutations in PAX6, FOXC1, PITX2, and CYP1B1. Recently two new genes, FOXD3 and TRIM44, have also been implicated in isolated studies. We discuss the genotype-phenotype correlations for the main implicated genes. Classic aniridia is a panocular condition, which includes aniridia, cataract, corneal pannus, foveal, and optic nerve hypoplasia associated with mutations in the PAX6 gene. Classical aniridia is due to PAX6 mutations, while other genes contribute to aniridia-like phenotypes. We review the challenges involved in the management of aniridia, and discuss various surgical interventions. The clinical importance of defining the genotype in cases of congenital aniridia has become acutely apparent with the advent of possible therapies for classical aniridia, which are discussed.

Congenital Aniridia: Clinic, Genetics, Therapeutics, and Prognosis

Congenital aniridia is a rare condition related to a deficiency in the PAX6 gene expression, which may occur as a result of a family inheritance or a sporadic occurrence. Additionally, this condition may occur as an isolated ocular phenotype or in association with a systemic syndrome. The most common abnormality is iris hypoplasia; however, a panocular disease which also affects the cornea, anterior chamber of the eye, lens, and the posterior segment with presence of optic nerve and foveal hypoplasia is also evident. The development of keratopathy, glaucoma, and cataract is frequent and its presence has implications in the patient's visual acuity. Managing aniridia is challenging since the focus is on treating the previously mentioned disorders, and the outcomes are often disappointing. In this paper, we shall review the epidemiology, pathophysiology, and clinical characteristics of patients with aniridia. We shall also make a review of the therapeutic options for the several conditions affecting this syndrome and consider the genetics and prognostic factors.

Treatment of congenital aniridia associated with subluxated infantile cataract

A 5 year old boy was presented at Eye clinic University clinical center Tuzla with congenital aniridia in both eyes. Clinical examination revealed visual acuity of 0,08 without correction in right and 0.7 with -5.0 Dsph and -1.0 Dcyl Axx 109° in left eye. Opthalmologic examination showed bilateral aniridia associated with moderate cataract in the right and incipient cataract in the left eye. In the right eye, zonular weakness with incipient capsular displacement and esotropia of Δ6º, were noted. The patient underwent phacoemulsification, implantation of capsular tension ring and Artificial Iris implant in the capsular bag. Phacoemulsification went uneventful and early postoperative recovery was successful with no signs of aniridia-associated keratopathy development and normal values of intra ocular pressure. Patient was not motivated for operation of the left eye and it was corrected with soft contact lens. Six month after the operation visual acuity in the right eye improved to 0.9 with +1.25Dsph and maintained stable in left eye, with complete elimination of esotropia and signs of binocular vision restoration. Small incision cataract extraction with IOL and Artificial Iris implantation in one procedure can be used to correct congenital aniridia and cataract with significant visual function improvement.

Aniridia associated with ptosis in three generations of the same family

Aniridia is a spectrum of abnormalities of the iris anatomy, which range from a total absence of the iris to a mild stromal hypoplasia with normal pupil. Aniridia associated with ptosis in three generations of the same family is described. The cases fit the autosomal dominant familial aniridia (AN1) type, a genetic form of congenital aniridia characterised by isolated ocular defects.

Evaluation of pediatric cataracts and systemic disorders

PURPOSE OF REVIEW

The purpose of this review is to outline those systemic disorders with associated cataracts to help in the evaluation and diagnosis of the patient with pediatric cataract who has systemic abnormalities.

RECENT FINDINGS

With the profound advancement in genetics, both making and confirming a diagnosis in rare syndromic disorders have become even more possible. By diagnosing a syndromic cataract, the patient and family members are afforded the opportunity to obtain a better understanding of their disorder as well as develop expectations as to the course of their child's disorder.

SUMMARY

The intent of this article is to act as a resource for helping to determine the cause of cataracts based on the lens appearance, age of onset and systemic findings. Children with cataracts, especially when bilateral, require a comprehensive history and ophthalmic examination with physician awareness toward other organ system involvement. A basic assessment of facial, skeletal, genitourinary, gastrointestinal and integumentary abnormalities is beneficial. In this review, there are numerous tables that are to act as a resource in developing a differential diagnosis and guide further systemic and genetic evaluation.

Complications and visual prognosis in children with aniridia

PURPOSE

To characterize the ophthalmological findings, assess surgical outcomes, and review visual outcomes in aniridia.

METHODS

A retrospective case review was performed and data were collected, including patient demographics, incidence of aniridia-associated keratopathy, glaucoma, cataract, retinal breaks or detachments, optic nerve hypoplasia, macular hypoplasia, poor vision, and nystagmus. All outcomes from surgery, including penetrating keratoplasty, trabeculectomy, Ahmed valve insertion, and cataract extraction, were recorded.

RESULTS

Six children (12 eyes) had corneal abnormalities, 4 had optic nerve hypoplasia, 9 had nystagmus, and 2 had retinal detachments. Four patients (7 eyes) required penetrating keratoplasty. Five patients (9 eyes) developed glaucoma and only 1 of the 4 trabeculectomies performed succeeded. Of the 6 Ahmed valve procedures performed, all succeeded in maintaining a satisfactory intraocular pressure but some required needling and 5-fluorouracil. Eight patients developed cataract and 7 required surgery. Visual outcomes were poor despite treatment. Nine patients had Snellen acuity of 6/60 or less and required low visual aids to function.

CONCLUSION

Aniridia is a disorder that requires multiple surgeries. It has a poor visual prognosis despite early diagnosis and aggressive management. Newer techniques such as Ahmed valves and Boston keratoprostheses offer hope, but its proliferative nature makes treatment difficult.

Crossed-swords, capsule-pinch technique for capsulotomy in pediatric and/or loose lens cataract extraction

Puncturing the anterior capsule in a patient with a very soft lens, an elastic capsule, and/or deficient zonular countertraction can be challenging even with a sharp needle or blade. The crossed-swords, capsule-pinch technique capitalizes on opposing forces from 2 needles directed toward each other with a "pinch" of the capsule between their tips. This affords a controlled and facile puncture of the capsule without creating stress on the zonules or anteroposterior displacement of the lens.

Contributions of mouse genetic background and age on anterior lens capsule thickness

Accurate lens capsule thickness measurements are necessary for studies investigating mechanical characteristics of the capsule. Confocal Z-axis imaging was used to measure the anterior lens capsule thickness of living intact lenses with minimal tissue manipulation. Measurements of the anterior capsule thickness is reported for the first time in young and old mice from four inbred strains, BALB/c, FVB/N, C57BL/6, and 129X1, and the outbred strain ICR. Our data demonstrates that the mouse anterior lens capsule continues to grow postnatally similar to that described in other mammals. It is also shown there is a significant difference in anterior lens capsule thickness between unrelated mouse strains, suggesting that capsule thickness is a quantitative trait shared by strains with common ancestry. Measurements, taken from other regions of FVB/N capsules revealed the anterior pole to be the thickest, followed by the equatorial region and posterior pole. In addition to mouse, anterior capsule measurements taken from intact cattle, rabbit, rat lenses, and human capsulotomy specimens correlated with the overall size of the animal.

Aniridia: current pathology and management

Aniridia is a rare panocular disorder affecting the cornea, anterior chamber, iris, lens, retina, macula and optic nerve. It occurs because of mutations in PAX6 on band p13 of chromosome 11. It is associated with a number of syndromes, including Wilm's tumour, bilateral sporadic aniridia, genitourinary abnormalities and mental retardation (WAGR) syndrome. PAX6 mutations result in alterations in corneal cytokeratin expression, cell adhesion and glycoconjugate expression. This, in addition to stem-cell deficiency, results in a fragile cornea and aniridia-associated keratopathy (AAK). It also results in abnormalities in the differentiation of the angle, resulting in glaucoma. Glaucoma may also develop as a result of progressive angle closure from synechiae. There is cataract development, and this is associated with a fragile lens capsule. The iris is deficient. The optic nerve and fovea are hypoplastic, and the retina may be prone to detachment. Aniridia is a profibrotic disorder, and as a result many interventions--including penetrating keratoplasty and filtration surgery--fail. The Boston keratoprosthesis may provide a more effective approach in the management of AAK. Guarded filtration surgery appears to be effective in glaucoma. Despite our increasing understanding of the genetics and pathology of this condition, effective treatment remains elusive.

Keratopathy in congenital aniridia

Although the most apparent clinical finding in aniridia is the absence of iris tissue, additional ocular structures are often affected. Mutations of the Pax 6 gene, which is important for eye development, have been identified in families with members affected by aniridia. Poor vision in aniridic eyes may be the result of macular hypoplasia, nystagmus, amblyopia, cataracts, glaucoma, and corneal disease, termed aniridic keratopathy. Advances in surgical techniques have improved management of some of the visually disabling manifestations of aniridia, but aniridic keratopathy remains a significant source of visual loss. We have conducted a large, retrospective study of patients with aniridia to gain information about the natural course of aniridic keratopathy. In this paper, we report the results of our study, as well as findings reported in the literature. Penetrating keratoplasty alone has not been a successful treatment for severe stromal scarring, as it does not treat the underlying epithelial causes of corneal disease. However, it has been successful in corneas that have achieved stable epithelium following limbal stem cell transplantation.

Fate of anterior capsule tears during cataract surgery

PURPOSE

To determine the incidence of anterior capsule tears, at what stage of surgery they occurred, and their intraoperative behavior.

SETTING

Ambulatory surgery center, Cincinnati Eye Institute, Cincinnati, Ohio, USA.

METHODS

This 5-year retrospective study was of patients having phacoemulsification with posterior chamber intraocular lens (IOL) implantation complicated by unplanned peripheral extension of the capsulorhexis tear or a radial anterior capsule tear. The operative notes and a videotape of the surgery were reviewed. The stage at which the tear was initially observed and when it extended were identified, as was whether the tear extended to the posterior capsule. Anterior vitrectomy and the design and location of the IOL implanted were also analyzed.

RESULTS

A discontinuous anterior capsulorhexis or a break in the anterior capsule rim was observed in 21 eyes of 2646 cases, for an overall incidence of 0.79%. Anterior capsule tears were identified during ophthalmic viscosurgical device injection in 1 eye, capsulorhexis in 13 eyes, hydrodissection in 2 eyes, phacoemulsification in 3 eyes, irrigation/aspiration (I/A) in 1 eye, and implantation of a prosthetic iris device in 1 eye. Seven of the 13 tears identified during the capsulorhexis were managed by redirecting the second edge of the "safety" capsulorhexis to incorporate the tear. In 14 eyes, the tear in the anterior capsule extended into the zonules; 4 of these tears were limited. Ten tears extended around the equator and through the posterior capsule, occurring during the hydrodissection in 1 eye, phacoemulsification in 2 eyes, I/A in 1 eye, and IOL implantation in 6 eyes. An anterior vitrectomy was required in 4 eyes that had posterior capsule involvement. Endocapsular fixation of a 1-piece acrylic IOL was achieved in 18 eyes. Three eyes required implantation of a 3-piece acrylic IOL in the ciliary sulcus.

CONCLUSIONS

Extension of an anterior capsule tear can complicate cataract surgery at any stage. Extension of the tear through the posterior capsule occurred in almost half the eyes with an anterior capsule tear, often requiring an anterior vitrectomy. Managing an anterior capsule tear can be challenging yet compatible with implantation of a posterior chamber IOL.

Managing intraoperative complications in cataract surgery

PURPOSE OF REVIEW

This article surveys the literature from 2002 and 2003 and addresses a variety of complications that may arise during cataract surgery. Modern surgical techniques and technology contribute to the decreased incidence of complications. Surgeon experience, early recognition of potential complications, and optimal handling of events lead to better outcomes.

RECENT FINDINGS

Recognizing eyes preoperatively that are particularly at risk for having dysgenesis of the capsular bag, cortical-capsular adhesions, low endothelial cell reserve, dropped nucleus, and bag-lens dislocation will allow for contingency planning and appropriate tailoring of techniques. Capsular tension rings are indispensable for achieving in-the-bag implantation in the presence of weak zonules and zonulolysis. Viscolevitation to rescue sinking implants, avoidance of foldable lens complications, and proper lens placement with an open capsule are discussed. High-frequency ultrasound biomicroscopy is a useful diagnostic tool. Noninjection sub-Tenon anesthesia is not benign. Complications have been documented that include traumatic optic neuropathy. Immediate diagnosis and a trial of corticosteroids could be vision saving. Mastering topical anesthesia is a worthy goal. In some cases, faulty instruments result in complications. Routine inspection of reusable instruments, or the use of disposable instruments is warranted. Though there is no FDA-recognized use, at the time of this writing, for trypan blue dye, it has become the world standard for intraocular staining because of its safety and efficacy. Clear corneal self-sealing incisions are increasingly mainstream and, when properly constructed, are extremely secure. The most significant trend for successful management of intraoperative complications this year is the increasing use of pars plana anterior vitrectomy. The ability to identify prolapsed vitreous by intracameral Kenalog staining is an invaluable tool. Surgeons depend on a team of nurses and technicians for optimal outcomes.

SUMMARY

With new technology and techniques highlighted by capsular tension rings, Kenalog vitreous identification, and fourth-generation fluoroquinolones, even complicated cataract surgery can result in optimal outcomes.