Congenital aniridia: long-term clinical course, visual outcome, and prognostic factors

New horizons in aniridia management: Clinical insights and therapeutic advances

Congenital aniridia is a rare genetic eye disorder characterized by the complete or partial absence of the iris from birth. Various theories and animal models have been proposed to understand and explain the pathogenesis of aniridia. In the majority of cases, aniridia is caused by a mutation in the PAX6 gene, which affects multiple structures within the eye. Treating these ocular complications is challenging and carries a high risk of side effects. However, emerging approaches for the treatment of aniridia-associated keratopathy, iris abnormalities, cataract abnormalities, and foveal hypoplasia show promise for improved outcomes. Genetic counseling plays a very important role to make informed choices. We also provide an overview of the newer diagnostic and therapeutic approaches such as next generation sequencing, gene therapy, in vivo silencing, and miRNA modulation.

Challenges in Surgical Intervention for a Rare Case of Anterior Segment Dysgenesis: A Case Report

Anterior Segment Dysgenesis (ASD) represents a spectrum of rare, congenital disorders that pose significant challenges to ophthalmological management due to their complex and heterogeneous nature. The management of ASD becomes particularly complex when associated with other serious ocular conditions. This report discusses the case of a 4-year-old girl diagnosed with ASD exhibiting a combination of sclerocornea, aphakia, aniridia, and secondary glaucoma. Owing to the complexity of such condition, a multi-disciplinary approach is required. Despite successful initial surgical interventions on the left eye, eye was lost due to subsequent endophthalmitis and retinal detachment, resulting in a decision to adopt a conservative, non-surgical approach for the right eye. Although a series of therapeutic interventions have been performed, the final visual outcome was poor, demonstrating the complexity and seriousness of such cases. This case serves as a reminder of the need for regular follow-up, prompt recognition, and management of potential complications. Further research is necessary to optimize the outcomes in patients with similar presentations.

Surgical correction of corneal opacity and aniridia with penetrating keratoplasty and a new iris prosthesis implant

PURPOSE

This study is to describe the clinical outcome of penetrating keratoplasty combined with implantation of a novel intraocular lens with an artificial iris, aided by continuous vitreous chamber infusion, in patients with severe aniridia and corneal alterations.

METHODS

This was a prospective single-center case series study involving five patients with corneal alterations and aniridia. All subjects underwent simultaneous penetrating keratoplasty and implantation of a new intraocular lens with an artificial iris with the assistance of infusion into the vitreous chamber to regulate intraocular pressure during the surgical procedure. Visual acuity, corneal endothelial cell density, and intraocular pressure assessments were performed in the postoperative period. The final cosmetic outcome of the iris prosthesis placement was also evaluated.

RESULTS

In all cases, increased visual acuity and a good aesthetic result were observed in all affected eyes except one in which, despite the excellent aesthetic outcome, the eye was very hypotonic as it had high myopia and had undergone several previous surgeries.

CONCLUSION

The single surgical procedure combining implantation of an intraocular lens-iris prosthesis with penetrating keratoplasty is an effective technique for the simultaneous treatment of aphakia and aniridia. However, larger series with longer-term follow-up are needed to definitively establish the benefits of this technique.

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.

Clinical outcomes and visual prognostic factors in congenital aniridia

Background

Evaluate outcomes and identify prognostic factors in congenital aniridia.

Methods

Retrospective interventional case series of patients with congenital aniridia treated between 2012–2020. Ocular examination and surgical details were collected. Surgical failure was defined as disease progression or need for additional surgery for same/related indication. Kaplan–Meier survival curves, Wilcoxon test, and univariate and multivariate linear regression analyses were performed.

Results

Ninety-four patients with congenital aniridia presented at median 19.0 years. Two-thirds of patients underwent ≥ 1intraocular surgery, with average of 1.7 ± 2.3 surgeries/eye. At final follow-up (median 4.0 years), 45% of eyes had undergone lensectomy. Aphakic eyes showed worse visual acuity (VA) than phakic or pseudophakic eyes. Glaucoma affected 52% of eyes, of which half required IOP-lowering surgery. Glaucoma drainage devices showed the highest success rate (71%) at 14.2 ± 15.4 years of follow-up. Keratopathy affected 65% of eyes and one-third underwent corneal surgery. Keratoprosthesis had the longest survival rates at 10-years (64% with 95% CI [32,84]). LogMAR VA at presentation and final follow-up were not statistically different. Half of patients were legally blind at final follow-up. Final VA was associated with presenting VA, glaucoma diagnosis, and cataract or keratopathy at presentation. Penetrating keratoplasty and keratoprosthesis implantation correlated with worse BCVA.

Conclusions

Most aniridic patients in this large US-based cohort underwent at least 1 intraocular surgery. Cataract, glaucoma, and keratopathy were associated with worse VA and are important prognostic factors to consider when managing congenital aniridia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02460-5.

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.

Improving long-term intraocular pressure and visual outcomes in eyes with aniridic glaucoma

PURPOSE

To study the long-term intraocular pressure (IOP) and visual outcomes in treated aniridic glaucoma.

METHODS

A retrospective chart review of patients with aniridia and glaucoma, with ≥ 2-year follow-up, was performed. Eyes in early glaucomatous stages were medically managed, while moderate-severe stage eyes underwent a trabeculectomy with mitomycin-c (MMC). Success was termed 'complete' when average final IOP was ≤ 18 mmHg without usage of glaucoma medications, and 'qualified' when with/without topical glaucoma therapy. A significant change in vision was defined as > 2-line change on Snellen vision chart or > 0.2 change in logMAR units in in either direction (better or worse).

RESULTS

Thirty-five eyes of 20 patients were included. The mean duration of follow-up was 7.29 ± 5.75 years. Associated ocular anomalies were present in 19 eyes (54.29%). Twelve eyes (34.28%) were maintained on medical management, while 23 eyes (65.71%) had undergone a trabeculectomy with MMC. The mean baseline IOP was 31.46 ± 6.34 mmHg, and mean IOP on last follow-up was 13.25 ± 5.82 mmHg, p < 0.001. Seventy-five percent of the medically managed eyes achieved an IOP ≤ 18 mmHg. 52.17% and 95.65% of the surgically treated eyes achieved 'complete' and 'qualified' success respectively. The median best corrected visual acuity (BCVA) at baseline was 1.48(0.6-2) logMAR units and on final follow-up was 1.3 (0.48-5) logMAR units, p = 0.21. Fifty percent of the eyes remained stable, 35.71% showed an improvement and 14.29% a deterioration of > 0.2 logMAR units. Patients with a longer follow-up (> 10 years) and those who had undergone a trabeculectomy with MMC were more likely to show good IOP control (p = 0.003; p = 0.004 respectively).

CONCLUSION

Aniridic glaucoma can be managed efficiently by medications in early glaucomatous neuropathy, and with trabeculectomy augmented with mitomycin-C and releasable sutures for more advanced glaucomas, offering favourable long-term IOP control, visual stability and safety.

Congenital aniridia: clinical profile of children seen at the University College Hospital, Ibadan, South-West Nigeria

Purpose:

To describe the clinical features of patients younger than 16 years with aniridia presenting to the Paediatric Ophthalmology unit of the Eye Clinic, University College Hospital, Ibadan, Nigeria.

Methods:

The is a retrospective review of children with aniridia seen between May 2015 and April 2019 at the Paediatric Ophthalmology unit of the Eye Clinic, University College Hospital in Ibadan. Data on demographic characteristics, presenting complaints, ocular and systemic examination findings, and interventions were collected and descriptively summarised.

Results:

A total of 28 eyes of 14 patients were studied. The mean age was 6.37 ± 4.98 years. Seven (50%) patients were male. Aniridia was diagnosed in first-degree relatives of nine patients. The most common complaint at presentation was poor vision in 11 (78.6%) patients. Objective visual acuity assessment was obtained in 22 (78.6%) eyes. Presenting visual acuity was worse than 20/60 in all 22 eyes and worse than 20/400 in 8 (36.4%) eyes. Refraction was performed in 17 (60.7%) eyes and revealed a mean spherical equivalent of −3.93 ± 5.99 diopters. Twenty (71.4%) eyes had corneal opacities, and lenticular opacities were seen in 15 (62.5%) of 24 eyes. Mean intraocular pressure (IOP) at presentation was 21.62 ± 10.4 mmHg; 12 (41.4%) eyes had elevated IOP at presentation. Ten (35.7%) eyes had cataract surgery and six (21.4%) eyes had glaucoma surgery.

Conclusion:

Familial aniridia was common in this study, and most of the patients presented with moderate to severe visual impairment. The common ocular associations were refractive error, cataract, corneal opacity and glaucoma.

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.

Outcomes and complications of Boston keratoprosthesis type I implantation in unilateral versus bilateral corneal blindness

OBJECTIVE

To compare the outcomes of Boston keratoprosthesis (KPro) type I implantation between patients who are legally blind versus sighted in the contralateral eye.

DESIGN

Single centre retrospective comparative case series.

PARTICIPANTS

Patients who underwent Boston KPro type I implantation between 2008 and 2017.

METHODS

Single-center retrospective comparative case series. Patients were divided into 2 groups based on the preoperative best-corrected visual acuity (BCVA) in the contralateral eye: group I (>20/200) and group II (20/200).

MAIN OUTCOME MEASURES

Postoperative BCVA, device retention, and complications.

RESULTS

Group I (56 eyes) and group II (53 eyes) had similar demographics, median preoperative BCVA (hand movements) in the operated eye, and median duration of postoperative follow-up (76.92 vs 85.6 months, respectively). Final postoperative BCVA of the operated eye was statistically better in group I compared with group II (20/400 and hand movements, respectively, p = 0.03). There was no statistical significance in device retention mean survival time. The most common complication in both groups was retroprosthetic membrane. Cystoid macular edema occurred more frequently in group I (p = 0.004), whereas retinal detachment was more common in group II (p = 0.052).

CONCLUSIONS

Most patients who underwent Boston KPro type I implantation experienced an improvement in their vision, with final BCVA being superior in the unilateral blind group. Despite similar complication rates and device retention, there are additional socioeconomic factors that need to be considered in sighted individuals. Because the prognosis is tied to the underlying etiology, it is important to recognize that some diagnoses may influence a better outcome.

Functional outcomes after combined iris and intraocular lens implantation in various iris and lens defects

BACKGROUND

To assess the functional outcomes after combined iris and intraocular lens (IOL) repair in aniridia patients.

METHODS

Retrospective observational study in 59 aniridic and aphakic eyes for ArtificialIris (AI) and IOL reconstruction. The iris prostheses were placed together with the IOL in the capsular bag using an injection system or were fixed by transscleral suturing of the IOL and AI. The primary outcomes measured were visual acuity, contrast and glare sensitivity (Pelli-Robson chart for photopic and dark adaptometer for mesopic conditions), intraocular pressure, endothelial cell density (ECD) and patient impairment.

RESULTS

Blunt trauma (37 eyes) and penetrating injuries (16 eyes) were observed more frequently than congenital aniridia (1 eye), iatrogenic causes (1 eye), aniridic state after severe iritis (2 eyes) or iris tumor (2 eyes). Monocular CDVA improved significantly (p < 0.0001) from median 0.7 logMAR (0.0-1.98) to 0.3 logMAR (- 0.08-2.0). Median pupillary area could significantly (p < 0.0001) be reduced by 79.3% from 51.27 mm² (17.91 to 98.23) to 8.81 mm² (4.16 to 8.84). Median ECD decreased from 2646.0 mm² to 2497.5 mm² (p = 0.007). Contrast and glare sensitivity improved significantly (p = 0.008) in photopic light conditions from 0.9 (0.0-1.95) to 1.35 (0.0-1.8). Patients reported to be highly satisfied with the functional improvement.

CONCLUSION

The flexible ArtificialIris seems to be a safe and effective iris prosthesis in combination with an IOL having functionally and cosmetically exceptional reconstruction options.

Anatomical and functional results of ILM peeling vs. non-peeling in macula-off rhegmatogenous retinal detachment

PURPOSE

To compare anatomical and functional results between internal limiting membrane (ILM) peeling and non-ILM peeling in macula-off rhegmatogenous retinal detachment (RRD).

METHODS

We completed a retrospective cohort study of patients who underwent pars plana vitrectomy (PPV) due to macula-off RRD. ILM peeling (P) versus non-ILM peeling (NP) groups were compared regarding best-corrected visual acuity (BCVA), anatomical success, endotamponade, concomitant scleral band placement and BCVA gain for epiretinal membranes (ERM) resubjected to PPV. Statistical significance was considered when p < 0.05.

RESULTS

PPV was conducted in 352 patients, among which 43.5% (n = 153) were in the P group and 55.6% (n = 196) were in the NP group. Both groups had significant BCVA improvement during the study period (p < 0.001), but with no significant difference between them. Anatomical success was similar between P (84.2%) and NP (87.2%) groups. No difference was found with regard to endotamponade (p = 0.07) or concomitant scleral band placement (p = 0.43). The NP group developed subsequent ERM more frequently (p = 0.004), but BCVA gains for eyes requiring repeat PPV for ERM were not found (p = 0.14).

CONCLUSIONS

Although ERM formation and greater anatomical success are reasons to support the use of ILM peeling in RRD, we did not observe any anatomical or functional difference regarding ILM peeling or functional gain with secondary ERM peeling.

Valproic acid's effects on visual acuity in retinitis pigmentosa: a systemic review and Meta-analysis

AIM

To gain a better understanding of the overall efficacy of valproic acid (VPA) treatment for retinitis pigmentosa (RP).

METHODS

Publications in PubMed, EMBASE, Cochrane Library, Web of Science and Clinicaltrials.gov were searched for clinical trials of patients with RP assigned to treatment with VPA. Patients' pre- and post-treatment visual field (VF) and best-corrected visual acuity (BCVA) scores were extracted and compared to assess changes.

RESULTS

A total of 78 reports were retrieved and 6 studies involving 116 patients were included in the Meta-analysis. The combined results showed a significant decrease in logarithm of minimal angle of resolution (logMAR) scores, calculated using baseline and post-treatment BCVA (P<0.00001, mean difference=-0.05, 95%CI: -0.05, -0.04, I ²=36%) scores, which means there was considerable improvement in visual acuity. Meanwhile, more BCVA changes were observed in short-term (≤6mo) treatment studies (P<0.00001, mean difference=-0.05, 95%CI: -0.05, -0.04, I ²=38%), studies conducted in Asia (P<0.00001, mean difference=-0.05, 95%CI: -0.05, -0.04, I ²=4%), studies with a sample size of 30 or fewer patients (P<0.00001, mean difference=-0.05, 95%CI: -0.05, -0.04, I ²=38%) and prospective studies (P<0.00001, mean difference=-0.05, 95%CI: -0.05, -0.04, I ²=0%). However, VPA's effect on VF was inconsistent across studies (P=0.75, mean difference=-22.76, 95%CI: -160.56, 115.05, I ²=68%).

CONCLUSION

This Meta-analysis reveals that most RP patients who were treated with VPA showed improvement in BCVA. However, its effect on VF remains inconsistent. VPA may be a promising treatment for RP.

Outer retinal layers as predictors of visual acuity in retinitis pigmentosa: a cross-sectional study

PURPOSE

To evaluate the integrity of the outer retinal layers-outer nuclear layer (ONL), external limiting membrane (ELM), ellipsoid (EZ), and interdigitation band (IZ)-using spectral-domain optical coherence tomography and estimate their effect on visual acuity in retinitis pigmentosa (RP).

METHODS

A cross-sectional study was performed in the Ophthalmology Department of Hospital de Braga, Portugal. Patients with RP followed in the Hospital de Braga during January to August 2017 were included. Exclusion criteria were lack of data, macular edema due to RP, and concomitant retinal, optic nerve, or corneal disease that could interfere with visual acuity. Age, sex, time from diagnosis, phakic status, ONL thickness, and presence or absence of foveal ELM, EZ, and IZ were correlated to the best-corrected visual acuity (BCVA).

RESULTS

Forty-eight eyes were analyzed. There was a strong and positive correlation in BCVA between both eyes (p < .001*). ONL thickness was decreased in 95.8%. The EZ was the most absent layer (79.2%), followed by IZ (70.8%) and ELM (45.8%). A positive family history (p = .04*) and increased time from diagnosis (p = .037*) correlated with worse BCVA. A thicker ONL (p = .001*) and the presence of subfoveal ELM (p < .001*), EZ (p < .001*), and IZ (p = .02*) are correlated with better BCVA. There was a strong and positive correlation between the number of layers affected and a lower BCVA (p < .001). The presence of EZ was a significant predictor of BCVA (p = .02*).

CONCLUSIONS

The status of the outer retinal layers seems to influence BCVA. The status of the EZ was the most important predictor of BCVA but the ONL, ELM, and IZ may have a cumulative effect in the progression of visual loss.

Corneal Abnormalities in Congenital Aniridia: Congenital Central Corneal Opacity Versus Aniridia-associated Keratopathy

PURPOSE

To clinically characterize and compare 2 types of corneal abnormalities in patients with congenital aniridia: (1) congenital central corneal opacity from birth (CCO) and (2) aniridia-associated keratopathy (AAK) that develops progressively with age.

DESIGN

Retrospective cohort study.

METHODS

Medical records of Korean patients who were diagnosed with congenital aniridia at Seoul National University Hospital between 1991 and 2016 were reviewed. Prevalence of corneal abnormalities (CCO and AAK), other ocular and systemic comorbidities, severity of AAK depending on the age, logarithm of the minimum angle of resolution (logMAR) visual acuities, and types and results of surgical intervention were collected.

RESULTS

Among a total of 275 eyes (138 patients), 13% (35 eyes, 20 patients) had CCO and 25% (68 eyes, 35 patients) developed AAK. The AAK became prominent at a mean of 21.6 years of age, and the severity progressed with age. Glaucoma was more prevalent in aniridia patients with CCO (74%), compared to those with AAK (37%) (P = .0003). Cataract frequently occurred in patients with AAK (78%), who required cataract surgeries at mean 26.6 years. The logMAR visual acuity was worse in patients with CCO (2.04 ± 0.71) than in those with AAK (1.29 ± 0.62) (P < .0001). Penetrating keratoplasty was performed in 6 eyes with CCO, and the graft survival was 33.3% during mean 45 months of follow-up (range 14-79 months).

CONCLUSIONS

In total, 13% of aniridia patients had CCO at birth, while 25% progressively developed clinically significant AAK with age. The visual outcome was worse in patients with CCO than in those with AAK.

Efficacy of carbonic anhydrase inhibitors in management of cystoid macular edema in retinitis pigmentosa: A meta-analysis

Background

Carbonic anhydrase inhibitors (CAI) are often used in the treatment of cystoid macular edema (CME) in retinitis pigmentosa (RP) patients. The aim of this meta-analysis is to gain a better understanding of the overall efficacy of CAI treatment.

Methods

Databases including PubMed, EMBASE, and Cochrane Library were searched to identify relevant studies. Eligible studies were clinical trials of patients with RP assigned topical or oral CAIs such as dorzolamide and acetazolamide. Changes in central macular thickness (CMT) by OCT in μm and best-corrected visual acuity (BCVA) in log MAR equivalents were extracted and results compared between baseline and after treatment.

Results

11 clinical reports were identified which included a total of 194 patients (358 eyes) available for analysis, with 59 patients (115 eyes) assigned oral CAI treatment and 135 patients (243 eyes) assigned topical CAI treatment. The combined results showed a significant reduction of macular edema, as calculated by baseline and final central macular thickness (CMT) based on OCT examination (46.02μm, 95%CI: -60.96, -31.08, I² = 65%). However, the effect on visual acuity was inconsistent across studies.

Conclusion

Based on non randomized controlled clinical studies, RP patients with CME who were treated with CAIs had better anatomical outcomes, but the effect on visual acuity was contradictory across studies. Multicenter prospective randomized controlled trials would be ideal to definitively test its clinical efficacy in RP patients.

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)

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 and the Ocular Surface

Aniridia is a congenital pan-ocular disorder caused by haplo-insufficiency of Pax6, a crucial gene for proper development of the eye. Aniridia affects a range of eye structures, including the cornea, iris, anterior chamber angle, lens, and fovea. The ocular surface, in particular, can be severely affected by a progressive pathology termed aniridia-associated keratopathy (AAK), markedly contributing to impaired vision. The purpose of this review is to provide an update of the current knowledge of the genetic, clinical, micro-morphological, and molecular aspects of AAK. We draw upon material presented in the literature and from our own observations in large aniridia cohorts. We summarize signs and symptoms of AAK, describe current options for management, and discuss the latest research findings that may lead to better diagnosis and new treatment or prevention strategies for this debilitating ocular surface condition.