Peripheral hypertrophic subepithelial corneal degeneration: characterization, treatment and association with human leucocyte antigen genes

Abstract

. Purpose: To evaluate the efficacy of keratectomy in treating irregular astigmatism caused by peripheral hypertrophic subepithelial corneal degeneration (PHSD) and to study the possible underlying immunological risk factors. Materials and methods: Patients (14 eyes) with diagnosed PHSD were treated with superficial keratectomy with or without the assistance of phototherapeutic keratectomy (VisX S4; VisX Inc., Santa Ana, CA, USA). Thirteen patients were subjected to analysis of human leucocyte antigen (HLA) genes, complement C4 gene numbers and total plasma immunoglobulin levels. Immunological risk factors between patients and a control group comprising 150 individuals were compared. Results: The mean preoperative best spectacle corrected visual acuity (BCVA) improved from 0.16 ± 0.22 (LogMAR scale range 0–0.7) to 0.06 ± 0.13 (−0.1–0.4) (p < 0.01). The mean preoperative astigmatism decreased significantly from 3.8 ± 2.1 D (range 1.2–8.2) to 2.1 ± 1.4 (range 0.6–5.0, p = 0.02) based on corneal topography. The HLA‐B*44 allele and the ancestral haplotype (AH) 8.1 were found significantly more often in PHSD patients than in controls (both p = 0.03). No differences in the C4 genes were found. Conclusions: Astigmatism secondary to PHSD can be effectively treated with keratectomy. Peeling of the fibrotic tissue reduced astigmatism and improved visual performance. We suggest that HLA‐B*44 allele and AH 8.1 haplotype are immunological factors predisposing to the development of PHSD. The consequent disruption/alteration of the limbal barrier may lead to corneal peripheral fibrous formation inducing astigmatism.

Peripheral hypertrophic subepithelial corneal degeneration – clinical and histopathological features

“…Five patients in this series also appeared in our recent report on another 14 patients who were retrospectively diagnosed with PHSD (Järventausta et al. ). They were also enrolled in the present study because they fulfilled the criteria for typical PHSD and provided sufficient material for the immunohistochemical studies available (#2, 3, 4, 5 and 11 in Table ).…”

“…; Järventausta et al. ), we refined the diagnostic criteria for typical PHSD (Table ) based on clinical symptoms and signs (irregular and regular astigmatism, symptoms of ocular surface disease, peripheral subepithelial fibrosis, focal superficial neovascularization and a predilection toward superonasal location, females and bilateral disease) and the absence of evidence of any simulating lesions (corneal intraepithelial neoplasia, SND, climatic droplet keratopathy, corneal amyloidosis or keloid and hereditary hypertrophic scarring). Patients who met these criteria were included in the study.…”

“…; Järventausta et al. ). It presents with superficial fibrosis between the epithelium and Bowman's layer, with focal, mostly inconspicuous superficial neovascularization reaching the limbal margin of the fibrous tissue (Maust & Raber ; Jeng & Millstein ; Gore et al.…”

“…; Järventausta et al. ). The fibrosis causes the flattening of the central cornea and induces regular and irregular astigmatism that can be more or less efficiently treated with keratectomy (Gore et al.…”

Climatic droplet keratopathy: an old disease in new clothes

“…Differential diagnosis needs to be made with secondary spheroidal degeneration, gelatinous drop‐like dystrophy, corneal oedema, band‐shaped corneal degeneration, Salzmann′s nodular degeneration, climatic stromal proteoglycan keratopathy, Vogt limbal degeneration, super‐ficial corneal dystrophies, such as Reis‐Buckler and granular dystrophy, and peripheral hypertrophic corneal degeneration (Järventausta et al. ).…”