No Pathogenic Mutations Identified in the COL8A2 Gene or Four Positional Candidate Genes in Patients with Posterior Polymorphous Corneal Dystrophy

PURPOSE. To identify the genetic basis of posterior polymorphous corneal dystrophy (PPCD) through screening of four positional candidate genes and the COL8A2 gene, in which a presumed pathogenic mutation has previously been identified in affected patients. METHODS. DNA extraction, PCR amplification, and direct sequencing of the COL8A2, BFSP1, CST3, MMP9, and SLPI genes were performed in 14 unrelated, affected patients and in unaffected family members. RESULTS. In the COL8A2 gene, the previously identified, presumed pathogenic mutation (Gln455Lys) was not discovered in any of the affected patients. A missense mutation, Thr502Met, was identified in 2 of the 14 affected probands, although it was not considered to be pathogenic, as it has been identified in unaffected individuals. Although several novel and previously identified single nucleotide polymorphisms producing synonymous and missense amino acid substitutions were identified in the COL8A2, BFSP1, CST3, MMP9, and SLPI genes, no presumed pathogenic sequence variants were found. CONCLUSIONS. No pathogenic mutations were identified in the COL8A2 gene or in several positional candidate genes in a series of patients with PPCD, indicating that other genetic factors are involved in the development of this autosomal dominant corneal dystrophy. (Invest Ophthalmol Vis Sci

Visual Acuity Outcomes of the Boston Keratoprosthesis Type 1: Multicenter Study Results

PurposeTo report logarithm of the minimal angle of resolution (logMAR) visual outcomes of the Boston keratoprosthesis type 1.DesignProspective cohort study.MethodsPreoperative, intraoperative, and postoperative parameters of 300 eyes of 300 patients who underwent implantation of a Boston keratoprosthesis type 1 device between January 2003 and July 2008 by 1 of 19 surgeons at 18 medical centers were collected.ResultsAfter an average of 17.1 ± 14.8 months, visual acuity improved significantly (P < .0001) to a mean final value of 0.89 ± 0.64 (20/150). There were also significantly fewer eyes with light perception (6.7%; n = 19; P < .0001), although 3.1% (n = 9) progressed to no light perception. There was no association between age (P = .08), sex (P = .959), operative side (P = .167), or failure (P = .494) and final visual acuity. The median time to achieve 20/200 visual acuity was 1 month (95% confidence interval 1.0-6.0) and it was retained for an average of 47.8 months. Multivariate analysis, controlling for preoperative visual acuity, demonstrated 2 factors associated with final visual outcome: chemical injury was associated with better final vision (P = .007), whereas age-related macular degeneration was associated with poorer vision (P < .0001).ConclusionsThe Boston keratoprosthesis type 1 is an effective device for rehabilitation in advanced ocular surface disease, resulting in a significant improvement in visual acuity. Eyes achieved a mean value of 20/150 (0.89 ± 0.64 logMAR units) after 6 months and this was relatively stable thereafter. The best visual prognosis is observed in chemical injury eyes, whereas the worst prognosis is in aniridia, although the latter has limited visual potential