In vivo laser confocal microscopic findings in patients with epithelial basement membrane dystrophy

To evaluate the corneal characteristics of patients with epithelial basement membrane dystrophy (EBMD) using an in vivo laser confocal microscope, Heidelberg Retina Tomograph II, Rostock Cornea Module (HRT II RCM).

Sixteen women and 13 men who were diagnosed with or suspected to have EBMD were included in the study. The mean age of the patients was 56.4+/-17.2 years within a range of 25 to 81 years. Nine patients (31%) had a history of recurrent corneal erosions and 3 patients had been misdiagnosed with herpetic epithelial keratitis. The remaining 17 patients were asymptomatic and EBMD was diagnosed incidentally during routine eye examinations.

Confocal microscopy revealed highly reflective tissue in various configurations within the intermediate and basal epithelial cell layers corresponding to the abnormal basement membrane extending into the epithelium. There were thin, parallel hyperreflective lines and high contrast round lesions in sizes ranging between 10 and 250 microm within the epithelium. Basal epithelial cells around the abnormal basement membrane and cysts seemed to be highly distorted. In two subjects with bleb-like disorder, the authors observed circular or oval hyporeflective areas with a diameter ranging between 40 and 100 microm at the level of basal epithelium and the Bowman layer, accompanied by hyperreflective, linear structures extending into the epithelium.

EBMD is most commonly asymptomatic and undiagnosed; however, it might be associated with recurrent corneal erosions and lead to severe complications after LASIK surgery. The confocal images are highly characteristic for EBMD; therefore, confocal microscopy seems to be a valuable tool in the diagnosis of EBMD.