Approach to primary congenital glaucoma: A perspective.

Primary congenital glaucoma (PCG) occurs worldwide and has a broad range of ocular manifestations. It poses a therapeutic challenge to the ophthalmologist. A proper diagnostic evaluation under anesthesia is advisable for all children who do not cooperate for an office examination. Medical therapy only serves as a supportive role, and surgical intervention remains the principal therapeutic modality. Angle incision surgery such as goniotomy or trabeculotomy ab externo is the preferred choice of surgery in the Caucasian population. Primary combined trabeculotomy-trabeculectomy with or without antifibrotic therapy is the preferred choice in certain regions such as India and the Middle East where the disease usually presents with severe forms of corneal edema along with megalocornea. In refractory cases, trabeculectomy with antifibrotic therapy or glaucoma drainage devices are available options in the armamentarium. Cycloablative procedures should be reserved for eyes with poor visual potential. Myopia is common among children with PCG, and appropriate optical refractive correction in the form of glasses or contact lenses should be provided. Amblyopia therapy should be instituted to ensure overall visual development in the early developmental years. Low-vision rehabilitation services should be provided to children with vision impairment. Long-term follow-up is mandatory and carers of children with PCG should be counseled and educated about this need. Regardless of the visual outcomes, clinicians should emphasize the need for education of these children during the clinic visit. The overall goal of the management should be to improve the overall quality of life of the children with PCG and their carers.

Objectively measuring anterior segment alterations in the eyes of mucopolysaccharidoses: Its utility in early diagnosis of glaucoma.

Purpose: Our study aimed to evaluate the utility of the anterior segment morphometry for objectively assessing anterior segment architectural changes of corneal clouding in the mucopolysaccharidoses (MPS) cohort and to investigate whether these measurements correlate with the slit-lamp findings on the cornea and early diagnosis of glaucoma. Methods: This retrospective study involved 70 eyes of 35 children with cloudy cornea due to MPS variants. Anterior segment architectural alterations were measured using anterior segment imaging and biometry in MPS children and compared with controls. Results: Mean age of the cohort at the time of assessment was 7.9 ± 4.5 years. Males constituted two-thirds of the cohort. Variants of MPS with cloudy cornea were as follows: Type I (62%), Type IV (11%), and Type VI (22%). Morphometric measurements were available in 22 eyes of 11 MPS children and an age-matched healthy control group. There were significant differences between MPS cohort and controls in refraction in Diopters (5.03 ± 0.39 and 0.01 ± 0.04; P < 0.0001), axial length (AXL) in mm (21.39 ± 0.28 and 23.04 ± 0.28; P = 0.0002), average keratometry in Diopters (40.67 ± 0.44 and 42.83 ± 0.44; P < 0.0001), anterior chamber depth (ACD) in mm (2.92 ± 0.07 and 3.65 ± 0.07; P < 0.0001), and intraocular pressure (IOP) in mmHg (25.2 ± 2.0 and 14.1 ± 2.3; P = 0.0003). Secondary glaucoma was observed in 28% of the MPS cohort. Conclusion: The anterior segment morphometry in the cloudy cornea due to MPS provides an objective measurement of anterior segment architectural changes, thus diagnosing early-onset secondary glaucoma. These findings highlight that cloudy cornea due to MPS variants merits close monitoring throughout life.

Selective Endothelialectomy in Peters Anomaly: A Novel Surgical Technique and Its Clinical Outcomes in Children.

PURPOSE: This study describes the surgical outcomes of selective endothelialectomy in Peters anomaly (SEPA), a relatively new technique to manage Peters anomaly (PA). METHODS: This study included 34 eyes of 28 children who had a visually significant posterior corneal defect due to PA and underwent SEPA between 2012 and 2019. A selective endothelialectomy from the posterior corneal defect was performed while preserving Descemet membrane. The primary outcome measure was the resolution of corneal opacification. The secondary outcome measures were functional vision, complications, and risk factors for failure. RESULTS: At a mean postoperative follow-up of 0.96 ± 0.20 years, 29 eyes (85.3%) maintained a successful outcome. Mean preoperative and postoperative best-corrected visual acuities were 2.55 ± 0.13 and 1.78 ± 0.13 ( P < 0.0001), respectively. Ambulatory functional visual improvement was seen in 97%, and 23% attained vision ranging between 20/190 and 20/50. Corneal opacification failed to clear in 5 eyes (15%). Risk factors associated with surgical failure were female sex ( P = 0.006), disease severity ( P < 0.0001), glaucoma ( P = 0.001), and additional interventions after SEPA ( P = 0.002). In multivariate analysis, only disease severity (ie, a type 2 PA) was a significant risk factor for the failure of SEPA. There were no sight-threatening complications. CONCLUSIONS: SEPA is a safe and effective technique in select cases of posterior corneal defect due to PA. SEPA could be a potential surgical alternative to pediatric keratoplasty or optical iridectomy in children with central corneal opacification smaller than 7 mm due to PA.

Glycosaminoglycans, hyperglycemia, and disease.

SIGNIFICANCE: Diabetes is a widespread disease with many clinical pathologies. Despite numerous pharmaceutical strategies for treatment, the incidence of diabetes continues to increase. Hyperglycemia, observed in diabetes, causes endothelial injury resulting in microvascular and macrovascular complications such as nephropathy, retinopathy, neuropathy, and increased atherosclerosis. RECENT ADVANCES: Proteoglycans are chemically diverse macromolecules consisting of a protein core with glycosaminoglycans (GAGs) attached. Heparan sulfate proteoglycans are important compounds found on the endothelial cell membrane and in the extracellular matrix, which play an important role in growth regulation and serve as a reservoir for cytokines and other bioactive molecules. Endothelial cells are altered in hyperglycemia by a reduction in heparan sulfate and upregulation and secretion of heparanase, an enzyme that degrades heparan sulfate GAGs on proteoglycans. Reactive oxygen species, increased in diabetes, also destroy GAGs. CRITICAL ISSUES: Preservation of heparan sulfate proteoglycans on endothelial cells may be a strategy to prevent angiopathy associated with diabetes. The use of GAGs and GAG-like compounds may increase endothelial heparan sulfate and prevent an increase in the heparanase enzyme. FUTURE DIRECTIONS: Elucidating the mechanisms of GAG depletion and its significance in endothelial health may help to further understand, prevent, and treat cardiovascular complications associated with diabetes. Further studies examining the role of GAGs and GAG-like compounds in maintaining endothelial health, including their effect on heparanase, will determine the feasibility of these compounds in diabetes treatment. Preservation of heparan sulfate by decreasing heparanase may have important implications not only in diabetes, but also in cardiovascular disease and tumor biology.

Clinical manifestations of congenital aniridia.

PURPOSE: To study the various clinical manifestations associated with congenital aniridia in an Indian population. METHODS: In this retrospective, consecutive, observational case series, all patients with the diagnosis of congenital aniridia seen at the institute from January 2005 to December 2010 were reviewed. In all patients, the demographic profile, visual acuity, and associated systemic and ocular manifestations were studied. RESULTS: The study included 262 eyes of 131 patients with congenital aniridia. Median patient age at the time of initial visit was 8 years (range: 1 day to 73 years). Most cases were sporadic and none of the patients had parents afflicted with aniridia. The most common anterior segment abnormality identified was lenticular changes. Cataract was the predominant lens finding, observed in 93 of 231 (40.3%) phakic eyes. Other lens abnormalities were subluxation, coloboma, posterior lenticonus, and microspherophakia. Corneal involvement of varying degrees was seen in 157 of 262 (59.9%) eyes, glaucoma was identified in 95 of 262 (36.3%) eyes, and foveal hypoplasia could be assessed in 230 of 262 (87.7%) eyes. Median age when glaucoma and cataract were noted was 7 and 14 years, respectively. None of the patients had Wilm's tumor. CONCLUSIONS: Congenital aniridia was commonly associated with classically described ocular features. However, systemic associations were characteristically absent in this population. Notably, cataract and glaucoma were seen at an early age. This warrants a careful evaluation and periodic follow-up in these patients for timely identification and appropriate management.

Edema: a systematic approach to diagnosis and management.

Edema is defined by fluid accumulation in the tissues and its onset frequently first noticed by the patients. Mild edema is common and reversible. Generalized edema requires intensive therapy. Causes of edema are numerous. Investigation of the causes is essential for appropriate therapy.

Evaluation of Optineurin as a candidate gene in Indian patients with primary open angle glaucoma.

PURPOSE: To evaluate the role of the optineurin gene (OPTN) in Indian primary open angle glaucoma (POAG) patients from different parts of the country. METHODS: Two hundred patients with POAG and 200 ethnically matched normal controls were recruited from various parts of India for the study. The entire coding region of OPTN along with the intron-exon boundaries were screened by PCR and single strand conformation polymorphism (SSCP) followed by direct sequencing. A rapid screening method was developed for some of the observed variants by denaturing high performance liquid chromatography (dHPLC). Four variants were also confirmed by digesting the amplicon with appropriate restriction enzymes. RESULTS: Seven nucleotide changes were observed in OPTN of which one was a putative mutation in exon 16 (Arg545Gln) that was observed in six POAG patients and not in the controls (p<0.05). The remaining variants comprised four single nucleotide polymorphisms (SNPs) in the coding region (Thr34Thr, Met98Lys, Arg149Arg, and Asn303Lys) and two in intron 6 (879-10G>A and 879-5C>T). But frequencies of the minor allele were not significantly different among the patients and controls. The Met98Lys variant that was identified to be a potential risk factor for NTG and POAG in some Asian populations and also for modulating IOP in Caucasian populations, did not exhibit any significant association to the disease phenotype. CONCLUSIONS: Despite a putative mutation (Arg545Gln) in some patients, the present study does not suggest a significant involvement of OPTN in POAG patients of Indian origin.

Mutation spectrum of the CYP1B1 gene in Indian primary congenital glaucoma patients.

PURPOSE: The human Cytochrome P450 gene CYP1B1 has been implicated in primary congenital glaucoma worldwide. The aim of this study was to understand the role of CYP1B1 mutations in causing primary congenital glaucoma in Indian populations. METHODS: The study included 64 new and unrelated cases of primary congenital glaucoma from different ethnic groups of India. Direct sequencing screened the coding and the promoter regions of CYP1B1. RESULTS: Sixteen pathogenic mutations were observed in 24 cases, of which 7 were novel. These included two frameshift mutations leading to deletions of 23 bp (g.3905del23bp) and 2 bp (g.7900-7901delCG) in exons II and III, respectively. Four novel missense mutations viz. A115P, M132R, Q144P, S239R were noted in exon II, and one in exon III (G466D), whose residue is a part of the "signature sequence" (NH2-FXXGXXXCXG-COOH) and is present in all heme binding cytochromes. Overall, CYP1B1 was involved in 37.50% (24/64) cases and homozygosity of the mutant allele was seen in 29.68% (19/64) and compound heterozygosity in 3.12% (2/64) of the cases, respectively. The frequency of CYP1B1 mutations was comparatively lower than Saudi Arabian, Slovakian Gypsys, and Turkish populations, largely due to genetic heterogeneity and ethnic diversities in Indian populations. Genotype-phenotype correlation indicated variable prognosis that could be due to the type of mutation, leading to alteration of CYP1B1 protein. CONCLUSIONS: This study provides a mutation spectrum of CYP1B1 causing primary congenital glaucoma in Indian populations that has implications in devising molecular diagnostics for rapid screening.

Energy transfer--a tool for probing micellar media.

The non-ionic polyoxyethylene chain-containing surfactant Triton X-100 (TX-100) forms well-defined micelles and reverse micelles in aqueous and hydrocarbon media, respectively. Nonradiative energy transfer between two charged fluorescent dyes, fluorescein (FL) and acridine orange (AO) has been used to probe the micelles and reverse micelles of TX-100. In the energy transfer system employed, FL acts as the donor and AO as the acceptor. This is borne out by the fluorescence spectral data. Time-resolved studies further corroborate the steady-state results. As the fluorescence emission spectra of the two dyes show a considerable amount of overlap, they are resolved into individual donor and acceptor components using the principal component analysis (PCA) method. This study also focuses on the more important role played by hydrophobic forces (compared with electrostatic interactions) in promoting energy transfer between charged species in micellar media.

Mutation spectrum of FOXC1 and clinical genetic heterogeneity of Axenfeld-Rieger anomaly in India.

PURPOSE: Axenfeld-Rieger anomaly (ARA) is a form of anterior segment dysgenesis of the eye, mainly caused by mutations in the FOXC1 gene. We had earlier reported a novel mutation in the wing region of FOXC1 in an autosomal dominant family. The present study was aimed to identify the spectrum of mutations in the FOXC1 gene in a cohort of Indian ARA patients from different ethnic backgrounds, and to understand its role in the disease pathogenesis. METHODS: Two new autosomal dominant families and seven sporadic cases of ARA from different ethnic backgrounds were screened for mutations by direct sequencing of the coding region of the FOXC1 gene. Another autosomal dominant ARA family that was previously reported by us was also included for comparative analysis of clinical genetic parameters. The segregation of the mutations in the autosomal dominant families was analyzed by haplotype and restriction analysis. Genotype-phenotype correlation were also undertaken to study the role of FOXC1 in phenotypic manifestation in the patient cohort. RESULTS: Three of the nine ARA cases harbored mutations in FOXC1, of which two novel nonsense mutations Q2X and Q123X, resulted in haploinsufficiency of the gene product. The missense mutation (M161K) that we previously reported in an autosomal dominant family was also found in another family. Haplotype analysis of these two families suggested multiple founders in the same ethnic group. The mutations resulted in variable expressions of phenotype among the patients as assessed from their prognosis based on visual outcomes. CONCLUSIONS: Significant genetic heterogeneity of FOXC1 was observed in a multi-ethnic population studied in this region of India resulting in variable ARA phenotypes. The different visual outcome seen in the patients suggest a variable expression of FOXC1 and also provide some insight for understanding the gene functions in this population.