Khairidzan Mohd. Kamal

Epithelial debridement and Bowman's layer polishing for visually significant epithelial irregularity and recurrent corneal erosions

Purpose: To report the utility of epithelial debridement and diamond burr polishing of Bowmans layer (ED + DBP) in the management of recurrent corneal erosions and visually significant epithelial irregularity associated with epithelial basement membrane dystrophy (EBMD). Design: Retrospective interventional consecutive case series. Participants: All patients who underwent ED + DBP by a single surgeon between November 1, 2002 and November 1, 2008. Methods: Data were collected regarding the frequency and severity of symptoms associated with EBMD as well as previous treatments. Details regarding the procedure and the postoperative course were recorded as well. The significance of the improvement in visual acuity after treatment was determined using Wilcoxon signed rank test. Main Outcome Measures: Change in visual acuity and recurrent corneal erosions after treatment. Results: ED + DBP was performed on 56 eyes (42 patients) during the 72-month period under review. Of the 56 eyes, 37 (66%) were treated for recurrent corneal erosions and 22 (39%) were treated for visually significant epithelial irregularity (3 eyes were treated for both conditions). EBMD was diagnosed in 46 eyes (82%), and a history of corneal trauma was elicited in 9 eyes (16%). Visual acuity improved significantly (P = 0.016), and recurrent corneal erosions resolved after treatment in 24 (96%) of the 25 eyes with a history of corneal erosions before treatment with more than 3 months of follow-up (average, 18.9 months; range, 3.5-66.5 months). Visual acuity improved significantly (P = 0.004), and visual aberrations related to epithelial irregularity resolved in all 14 eyes treated for visually significant EBMD with more than 3 months of follow-up (average, 14.2 months; range, 3.4-50.8 months). Mild, central subepithelial corneal haze developed in 12 (26%) of the 47 eyes that did not demonstrate subepithelial haze before ED + DBP, although it was not associated with decreased vision at the last follow-up visit in any patient. Conclusions: ED + DBP is a safe and effective technique in the management of recurrent corneal erosions and visually significant epithelial irregularity associated with EBMD.

Exclusion of positional candidate gene coding region mutations in the common posterior polymorphous corneal dystrophy 1 candidate gene interval.

Purpose: Posterior polymorphous corneal dystrophy (PPCD) is an autosomal-dominant disorder of the corneal endothelium associated with visually significant corneal edema and glaucoma. Statistical genetic analysis of 4 families with PPCD has demonstrated linkage to a 2.4 cM common support interval on chromosome 20 bordered by the markers D20S182 and D20S139. We sought to identify the genetic basis of PPCD linked to chromosome 20 (PPCD1) by screening the 26 positional candidate genes between these markers in a family previously mapped to the PPCD1 region. Methods: The coding regions of the 26 positional candidate genes mapped to the common PPCD1 support interval were amplified and sequenced in affected and unaffected individuals from a family previously linked to the PPCD1 locus. Nine other genes positioned just outside of the common PPCD1 support interval but within the autosomal-dominant congenital hereditary endothelial dystrophy interval were also screened. Results: Four DNA sequence variants in 3 of the positional candidate genes demonstrated complete segregation with the affected phenotype: p.Thr109Thr (rs6111803) in OVOL2, p.Arg56Gln (novel variant-RPSnovel) in RPS19P1, and p.Thr85Thr (rs1053834) and p.Pro99Ser (rs1053839) in C20orf79. Each of these 4 sequence variants demonstrated significant linkage with the affected phenotype in this family (P = 2.5 × 10-7 for RPSnovel, rs1053834 and rs1053839; P = 8.6 × 10-7 for rs6111803). However, we also identified each of these 4 sequence variants in ≥9% unaffected control individuals. The haplotype on which the disease-causing mutation is segregating was found to have a population frequency of 4.2% in the CEPH HapMap trios. Although a number of other previously described and novel single nucleotide polymorphisms were identified in the 35 positional candidate genes located within the PPCD1 and congenital hereditary endothelial dystrophy intervals, none segregated with the affected phenotype. Conclusions: We report the absence of a presumed pathogenic coding region mutation in the common PPCD1 support interval. Although minor alleles of 4 single nucleotide polymorphisms were identified that segregated with the affected phenotype, the relatively high frequency of each minor allele in the general population indicates that none is a candidate for the causal variant for PPCD. Instead, the causal variant is most likely a coding region deletion or a variant in a noncoding region of the PPCD1 common support interval.

Classic Lattice Corneal Dystrophy Associated With Monoclonal Gammopathy Following Exclusion of a TGFBI Mutation

Purpose: The purpose of this study was to report the association of phenotypic features characteristic of lattice corneal dystrophy (LCD) with a monoclonal gammopathy of undetermined significance (MGUS) after exclusion of a coding region mutation in transforming growth factor beta-induced (TGFBI) gene. Design: Case report. Methods: Slit-lamp examination and collection of DNA for TGFBI screening were performed. A systemic evaluation was also performed to evaluate for conditions associated with systemic amyloidosis. Results: A 65-year-old man demonstrated bilateral linear branching corneal stromal opacities characteristic of classic LCD. No mutations were found in any of the 17 exons of TGFBI or in the intron-exon boundary regions. Four previously described single nucleotide polymorphisms were identified: c.698C>G (p.Leu217Leu; rs1442), c.1028A>G (p.Val327Val; rs1054124), c.1416C>T (p.Leu472Leu; rs1133170), and c.1667T>C (p.Phe540Phe; rs4669). Serum protein electrophoresis revealed the presence of a monoclonal spike, and based on the results of additional investigations, the patient was diagnosed with MGUS. Conclusions: Although the presence of bilateral thin branching lattice lines in the corneal stroma is characteristic of classic LCD, this distinctive phenotype may not be associated with a TGFBI coding region mutation but instead with a myeloproliferative disorder such as MGUS. Therefore, appropriate genetic and serologic testing should be performed in patients with a late-onset LCD phenotype in the absence of a positive family history.

Prediction of Changes in Visual Acuity and Contrast Sensitivity Function by Tissue Redness after Pterygium Surgery

ABSTRACT Purpose: The goal of this study was to predict visual acuity (VA) and contrast sensitivity function (CSF) with tissue redness grading after pterygium surgery. Materials and methods: A total of 67 primary pterygium participants were selected from patients who visited an ophthalmology clinic. We developed a semi-automated computer program to measure the pterygium fibrovascular redness from digital pterygium images. The final outcome of this software is a continuous scale grading of 1 (minimum redness) to 3 (maximum redness). The region of interest (ROI) was selected manually using the software. Reliability was determined by repeat grading of all 67 images, and its association with CSF and VA was examined. Results: The mean and standard deviation of redness of the pterygium fibrovascular images was 1.88 ± 0.55. Intra-grader and inter-grader reliability estimates were high with intraclass correlation ranging from 0.97 to 0.98. The new grading was positively associated with CSF (p < 0.01) and VA (p < 0.01). The redness grading was able to predict 25% and 23% of the variance in the CSF and the VA, respectively. Conclusions: The new grading of pterygium fibrovascular redness can be reliably measured from digital images and showed a good correlation with CSF and VA. The redness grading can be used in addition to the existing pterygium grading.

Fibrovascular redness grading using Gaussian process regression with radial basis function kernel

Information obtained from redness grading can assist clinician for diagnosis and in making clinical decision. This research work aims to mimic human perception of fibrovascular redness using features extracted from color entropy. Gaussian process regression with the radial basis function kernel has been employed to fuse relevant features and established the model of redness perception. In this paper, we present the results of the radial basis function kernel incorporated as the covariance function in the GPR as the scale, sigma is varied.

Automated inferior tear meniscus height measurement in a sequence of video

Video analysis of the dynamics of the tear meniscus height (TMH) have been used in the diagnosis of dry eye. However, the existing techniques require substantial manual intervention. This research work aims to automate the process of estimating the change in the inferior TMH without manual intervention.