Histomorphological study of corneal dystrophies

Introduction: The term Corneal Dystrophy refers to a rare heterogeneous group of genetically determined, bilateral, symmetric, primary diseases, restricted to cornea and not associated with previous ocular inflammation. The dystrophies are classified based on the layer of cornea involved, into superficial, stromal and posterior dystrophies, each of which is genetically determined. Though the clinical features are often characteristic, definitive diagnosis is possible only after histological examination. The management protocols and visual prognosis vary with the underlying conditions. The incidence of the subtypes varies with the geographic locations. Objective: To study the prevalence of various subtypes of Corneal Dystrophies in corneal button specimens obtained after penetrating keratoplasty in a referral ophthalmic institute and to correlate with the patient's age and sex. Materials and Methods: Corneal button specimens received in the ocular pathology laboratory over a period of five years were reviewed. Histopathological features of Corneal Dystrophies were studied and subcategorised. Cliniopathological analysis was made. Results: Out of 660 corneal biopsies reviewed, 42 cases were of corneal dystrophy. The patients were between 2 and 71 years of age, with 14 males and 28 females. Macular dystrophy was the most common with 20 cases, followed by Congenital Hereditary Endothelial Dystrophy (CHED) and Fuch's endothelial dystrophy (FECD), with 7 cases each. Epithelial basement membrane dystrophy, Reis Buckler Dystrophy (RBCD), Granular dystrophy were the other types. Conclusion: Histopathological sub categorisation of various types of Corneal Dystrophies not only helps in understanding the prevalence, but also in predicting the genetic link and prognosis of the disease category.