Diagnostic utility of in vivo confocal microscopy in Acanthamoeba keratitis following corneal crosslinking.

Acanthamoeba keratitis (AK) is a rare but potentially sight-threatening complication of corneal collagen crosslinking (CXL) for keratoconus. In this report, we describe an early adolescent male who underwent routine CXL for progressive keratoconus in his left eye. Preprocedural left visual acuity (VA) was 6/9. At day 5 postprocedure, multifocal corneal infiltrates were identified. Corneal scrape, bandage contact lens cultures and herpetic and Acanthamoeba PCR were negative. In vivo, confocal microscopy (IVCM) identified Acanthamoeba cysts within the corneal stroma. Intensive amoebicidal therapy was initiated, but recovery was complicated by significant inflammation, resulting in widespread aggressive corneal vascularisation necessitating topical steroids and steroid-sparing agents. At 10 months, his left VA was 6/24. This report emphasises the importance of maintaining a high index of suspicion for AK in cases of post-CXL microbial keratitis and highlights the diagnostic value of IVCM, particularly in culture-negative and PCR-negative cases.

Exome-based mutation screening in South African children with primary congenital glaucoma.

OBJECTIVES: To identify pathogenic variants in a cohort of 23 black South African children with sporadic primary congenital glaucoma (PCG) using an exome-based approach. METHODS: Children with PCG were recruited from two Paediatric Ophthalmology Clinics in Johannesburg, South Africa. Whole exome sequencing was performed on genomic DNA. Of the 23 children, 19 were male and 19 had bilateral PCG. A variant prioritization strategy was employed whereby variants in known PCG genes (CYP1B1, LTBP2 and TEK) were evaluated first, followed by the identification of putative disease-causing variants in other genes related to eye diseases and phenotypes. RESULTS: Validated pathogenic variants in the CYP1B1 gene (c.1169 G>A; p.Arg390His) and TEK gene (c.922 G>A; p.Gly308Arg) were identified in one child each. No LTBP2 mutations were identified in this cohort. In silico predictions identified potentially damaging rare variants in genes previously associated with eye development phenotypes or glaucoma in a further 12 children. CONCLUSIONS: This study demonstrates the value of whole exome sequencing in identifying disease-causing variants in African children with PCG. It is the first report of a TEK disease-causing variant in an African PCG patient. Potential causative variants detected in PCG candidate genes warrant further investigation.

A 20-Year Retrospective Review of Retinoblastoma at Two Tertiary Academic Hospitals in Johannesburg, South Africa.

AIM: This paper presents a 20-year review of retinoblastoma in Johannesburg, South Africa, aiming to better characterize the disease in this sub-Saharan setting. METHODS: The study represents a retrospective case series of retinoblastoma patients presenting to Charlotte Maxeke Johannesburg Academic Hospital and Chris Hani Baragwanath Academic Hospital between January 1, 1992, and December 31, 2011. RESULTS: The total number of cases identified was 282, with 245 meeting the study inclusion criteria. Retinoblastoma comprised 6.9% of the total pediatric oncology presentations; 65.3% were unilateral, 34.3% bilateral, and 0.4% trilateral. The overall male-to-female ratio was 1.08. The mean age at presentation overall was 32.6 months (median 28.0), in the unilateral group 39.4 months (median 33.0), and in the bilateral group 19.7 months (median 17.0). The mean delay to presentation overall was 7.0 months (median 4.0). The most frequent presenting symptoms were leukocoria (37.1%) and proptosis (34.7%). The distribution of disease stages at presentation (International Retinoblastoma Staging System) was 1.6% stage 0, 24.1% stage I, 27.8% stage II, 16.3% stage III, and 25.3% stage IV. 26.5% defaulted care. The 5-year Kaplan-Meier survival estimate was 57.7% overall. CONCLUSION: This study shows that delayed presentation and refusal of therapy remains a significant barrier to effective treatment in this African setting.