A serious adverse surgical event: Management of suspected HSV-1 keratitis in a donor cornea.

PURPOSE: To describe the management of a serious adverse event in a patient undergoing penetrating keratoplasty (PK). CASE REPORT: A 68-year-old man underwent PK for an aphakic bullous keratopathy following previous complicated cataract surgery. He had no past history of herpetic disease. Storage of the corneoscleral disc in the transport bottle precluded microscopic examination. After placement of the trephined donor cornea on the open eye of the recipient, a large dendritiform geographic ulcer was noted on the donor cornea. A replacement cornea was used after changing potentially contaminated instruments. Intravenous antiviral treatment was commenced intraoperatively to reduce the risk of infection to the central nervous system. Postoperatively, oral and topical antiviral treatment was commenced and 6 months following surgery the patient developed a geographic corneal ulcer at the graft host interface. CONCLUSION: Containers to transport corneoscleral discs should enable microscopic examination by the surgeon prior to use. High dose systemic antivirals may reduce the risk of herpetic disease involving the posterior segment of the eye and neuroretina in the aphakic eye and spread to the central nervous system.

Reliability of the Effect of Artificial Anterior Chamber Pressure and Corneal Drying on Corneal Graft Thickness.

PURPOSE: To investigate the effect of artificial anterior chamber (AAC) pressure and corneal drying on the graft thickness in preparation for Descemet stripping automated endothelial keratoplasty. METHODS: Twenty-seven corneoscleral discs were placed in an AAC. The AAC pressure (15, 45, 92, 109, and 198 mm Hg) was controlled using the height of an infusion bottle and a roller clamp. The endothelium was removed in 1 subgroup. Corneas were exposed to room air or repeatedly dried using cellulose spears. Central corneal thickness was measured every 90 seconds for the first 15 minutes and again at 20 minutes using an ultrasound pachymeter (SP-100, Tomey). RESULTS: There was a significant linear relationship between the corneal thickness and both AAC pressure and corneal drying. Very high coefficients of determination and narrow 95% confidence intervals were present, in particular for high pressures and drying. The rate of thinning increased with increasing pressure and drying to 1.6% per minute. At the maximum rate of thinning, a 10% reduction in corneal thickness occurred in 6 minutes or 100 µm in 8.8 minutes. Removal of the corneal endothelium reduced the rate of thinning to 0.3% per minute (R = 0.72). CONCLUSIONS: Increasing AAC pressure and corneal drying reduced the graft thickness at a very predictable rate. Adequate corneal thinning can be achieved by increasing the pressure in the AAC by closing the clamp followed by removal of the residual corneal epithelium and repeated drying with a cellulose spear for 5 to 10 minutes, depending on the initial corneal thickness. This method is simple and is both suitable for use in the eye bank and by the surgeon.

Novel quantitative trait loci for central corneal thickness identified by candidate gene analysis of osteogenesis imperfecta genes.

Osteogenesis imperfecta (OI) is a rare connective tissue disorder caused by mutations in the type I collagen genes, COL1A1 and COL1A2, and is characterised by low bone mass and bone fragility. In this study, we explored the relationship between type 1 collagen genes and the quantitative trait central corneal thickness (CCT). CCT was measured in a cohort of 28 Australian type I OI patients and mean CCT was found to be significantly lower compared to a normal population (P < 0.001). We then investigated CCT and corneal collagen fibril diameter and density in a mouse model of OI with a col1a2 mutation. Mean CCT was significantly lower in mutant mice (P = 0.002), as was corneal collagen fibril diameter (P = 0.034), whilst collagen fibril density was significantly greater in mutants (P = 0.034). Finally, we conducted a genetic study to determine whether common single nucleotide polymorphisms (SNPs) in COL1A1 and COL1A2 are associated with CCT variation in the normal human population. Polymorphism rs2696297 (P = 0.003) in COL1A1 and a three SNP haplotype in COL1A2 (P = 0.007) were all significantly associated with normal CCT variation. These data implicate type 1 collagen in the determination of CCT in both OI patients and normal individuals. This provides the first evidence of quantitative trait loci that influence CCT in a normal population and has potential implications for investigating genes involved in glaucoma pathogenesis, a common eye disease in which the severity and progression is influenced by CCT.

Orbital plexiform neurofibroma and high axial myopia.

PURPOSE: To report a group of children with neurofibromatosis type 1 and orbital plexiform neurofibroma who developed axial myopia in the associated eye. METHODS: The clinical records and imaging of 3 patients with neurofibromatosis type 1 and orbital plexiform neurofibromas were reviewed. RESULTS: Three patients were identified who were diagnosed with orbital plexiform neurofibromas at the ages of 10 months, 9 months, and 16 years old. In all cases the axial length of the eye associated with the neurofibroma increased with length compared with the unaffected eye over time. Accordingly, the affected eye became increasing myopic with age, while the unaffected eye remained emmetropic. CONCLUSIONS: Eyes affected with orbital plexiform neurofibroma, a hallmark of neurofibromatosis type 1, appear to be associated with increased axial length and myopia. This is of particular importance in children, to diagnose and treat unilateral high myopia early and prevent anisometropic amblyopia.