In vivo laser confocal microscopy findings for Bowman's layer dystrophies (Thiel-Behnke and Reis-Bücklers corneal dystrophies).

OBJECTIVE: To investigate microstructures in patients with genetically confirmed Bowman's layer dystrophies (Thiel-Behnke or Reis-Bücklers corneal dystrophy) using an in vivo laser scanning confocal microscope.
DESIGN: Single-center, prospective, comparative small case series. PARTICIPANTS: Two patients from one pedigree (a 29-year-old woman and 58-year-old man) with Thiel-Behnke corneal dystrophy (Arg555Gln [R555Q] heterozygous missense mutation of human transforming growth factor beta-induced [TGFBI] gene) and 3 patients from one pedigree (a 70-year-old woman, 58-year-old man, and 14-year old man) with Reis-Bücklers corneal dystrophy (Arg124Leu [R124L] heterozygous missense mutation of the TGFBI gene) were examined. Two patients with Reis-Bücklers corneal dystrophy exhibited recurrence after corneal transplantation. TESTING: All patients were examined by slit-lamp biomicroscopy. The center and the peripheral cornea of both eyes also were examined by in vivo laser scanning confocal microscopey. Image analysis was used to identify the corneal epithelial and stromal deposits correlated with each disorder. MAIN OUTCOME MEASURES: Selected images of the corneal layers were evaluated qualitatively for the shape and degree of light reflection of the deposits.
RESULTS: In each dystrophy, distinct characteristic deposits were observed in the epithelium and Bowman's layer, respectively, by in vivo laser scanning confocal microscopy. In Thiel-Behnke corneal dystrophy, the deposits in the epithelial basal cell layer showed homogeneous reflectivity with round edges accompanying dark shadows. In contrast, deposits in Reis-Bücklers corneal dystrophy in the same cell layer showed extremely high reflectivity from small granular materials without any shadows in all cases. In each dystrophy, Bowman's layer was replaced totally with pathological materials; the reflectivity of those materials is much higher in Reis-Bücklers corneal dystrophy than in Thiel-Behnke corneal dystrophy.
CONCLUSIONS: In vivo laser scanning confocal microscopy is capable of identifying in vivo corneal microstructural changes related to Thiel-Behnke and Reis-Bückler corneal dystrophy with a higher resolution than is available with slit-lamp biomicroscopy or in vivo white-light confocal microscopy. As a result, this device may enable differentiation of Thiel-Behnke and Reis-Bücklers corneal dystrophy in vivo. In vivo laser scanning confocal microscopy also may be a valuable tool for further research into the corneal dystrophies, especially to follow the natural course.