Peripheral Hypertrophic Subepithelial Corneal Degeneration

<b>Objectives</b>: To characterize the clinical features, corneal topography, and imaging findings of peripheral hypertrophic subepithelial corneal degeneration (PHSCD) in a single-center study and to evaluate potential associations with systemic conditions. <b>Methods</b>: All patients underwent comprehensive ophthalmic examination, anterior segment photography, high-resolution spectral-domain optical coherence tomography (OCT), and corneal topography/tomography. Patient demographics, ocular history, systemic conditions, and corneal parameters were analyzed. <b>Results</b>: Fourteen patients were included in the study (11 females and 3 males). The mean age was 52.6 ± 12.4 years, and the mean best-corrected visual acuity was 0.56 ± 0.23. Five females had Hashimoto's disease and two had hyperthyroidism. The mean central corneal thickness was 549.4 μm (SD = 71.0 μm), with significant sectoral thickness variations, particularly in the superior-nasal quadrants (SN-IT sector mean difference: 56.4 μm). High-resolution OCT revealed sharply demarcated, hyperreflective fibrosis within the anterior stroma, predominantly in the superior-nasal quadrants, causing corneal flattening with compensatory steepening and astigmatism. Three patients underwent in vivo confocal microscopy, which showed fibrotic acellular tissue adjacent to normal corneal epithelium. <b>Conclusions</b>: PHSCD predominantly affects middle-aged females and presents with characteristic peripheral, subepithelial fibrosis, causing significant corneal thickness variations and astigmatism. The observed association with thyroid disorders, particularly Hashimoto's disease, suggests a potential immunological component in PHSCD pathogenesis that warrants further investigation. Advanced imaging with OCT and confocal microscopy provides valuable diagnostic information to accurately characterize this rare corneal condition.