Abstract
Purpose::
To investigate microstructures in patients with genetically confirmed Bowman’s layer dystrophies (Thiel-Behnke or Reis-Bucklers corneal dystrophy) using an in vivo laser scanning confocal microscope (Heidelberg Retina Tomograph 2 Rostock Cornea Module, HRT 2-RCM).
Methods::
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 three patients from one pedigree (a 70-year-old woman, 58-year-old man and 14-year old man) with Reis-Bucklers corneal dystrophy (Arg124Leu (R124L) heterozygous missense mutation of TGFBI gene) were examined. All patients were examined by slit-lamp biomicroscopy. The center and the peripheral cornea of both eyes were also examined by HRT 2-RCM. Image analysis was used to identify the corneal epithelial and stromal deposits correlated with each disorder.
Results::
In each dystrophy, distinct characteristic deposits were observed in the epithelium and Bowman’s layer, respectively, by HRT2-RCM. In Thiel-Behnke corneal dystrophy, the deposits in the epithelial basal cell layer showed homogeneous reflectivity with round-shaped edges accompanying dark shadows. In contrast, deposits in Reis-Bucklers 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 totally replaced with pathological materials; the reflectivity of those materials is much higher in Reis-Bucklers corneal dystrophy compared to those in Thiel-Behnke corneal dystrophy.
Conclusions::
HRT 2-RCM is capable of identifying in vivo corneal microstructural changes related to Thiel-Behnke and Reis-Buckler 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-Bucklers corneal dystrophy in vivo. HRT 2-RCM may also be a valuable tool for further research into the corneal dystrophies especially to follow the natural course.
Keywords: cornea: stroma and keratocytes • microscopy: confocal/tunneling • degenerations/dystrophies