Aim To investigate by electron microscopy the plane of separation of the epithelial sheet from its substratum in the procedure of alcohol delamination (ALD) in patients with recurrent corneal erosion syndrome.

Methods Ten cases of recurrent corneal erosions (RCE) secondary to trauma and seven cases related to map–dot–fingerprint dystrophy (MDFP) were treated with ALD. The epithelial sheets obtained from these patients were examined by transmission electron microscopy. Similarly sheets obtained from 20 patients undergoing photorefractive keratectomy (10 by mechanical removal and 10 by ALD) were also examined as control group. Five further corneal buttons obtained at keratoplasty were treated with ALD and the epithelial sheet and corresponding stroma were both examined.

Results In all specimens, whether removed mechanically or by ALD, the intercellular surfaces did not show any disruption and desmosomes were preserved. In patients with traumatic RCE and in corneal buttons obtained at keratoplasty, tissue separation occurred along the lamina lucida, whereas in patients with MDFP the whole basal lamina was removed along with the epithelium. Focal areas of basal cell degeneration and epithelial detachment from the basal lamina were also noted.

Conclusions ALD enables efficient removal of the epithelium with an almost complete preservation of the lamina densa in traumatic RCE. In RCE due to MDFP the epithelium separates from the stroma below the basal lamina and may reflect the pathology of the condition.