In vivo Imaging of Reis–Bücklers and Thiel–Behnke Corneal Dystrophies Using Anterior Segment Optical Coherence Tomography

Tsubasa Nishino, Akira Kobayashi, Natsuko Mori, Hideaki Yokogawa, Kazuhisa Sugiyama Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, Kanazawa, JapanCorrespondence: Akira KobayashiDepartment of Ophthalmology, Kanazawa University Graduate School of Medical Science, 13-1 Takara-Machi, Kanazawa-shi, Ishikawa-ken 920-8641, JapanTel +81-76-265-2403Fax +81-76-222-9660Email eyekoba@gmail.comPurpose: To investigate in vivo corneal changes of genetically confirmed Reis–Bücklers corneal dystrophy (RBCD) and Thiel–Behnke corneal dystrophy (TBCD) using anterior segment optical coherence tomography (AS-OCT).Design: A single-center, prospective, comparative case series.Methods: Seven patients from 3 pedigrees (3 males, 4 females) with RBCD [Arg124Leu (R124L) heterozygous missense mutation of human transforming growth factor beta-induced (TGFBI) gene] and 4 patients from 3 pedigrees (3 males, 1 female) with TBCD [Arg555Gln (R555Q) heterozygous missense mutation of TGFBI gene] were examined. Six patients with RBCD and three patients with TBCD exhibited recurrence after corneal surgery including penetrating keratoplasty, phototherapeutic keratectomy, and electrolysis. All patients were examined by slit-lamp biomicroscopy followed by AS-OCT. Selected AS-OCT images of the cornea were evaluated qualitatively for changes in shape and degree of light reflection of corneal deposits.Results: Slit-lamp biomicroscopy showed characteristic irregular gray opacities in Bowman’s layer in each dystrophy: a geographic pattern in RBCD and a honeycomb pattern in TBCD. In each dystrophy, distinct characteristic deposits were observed by AS-OCT as a banding lesion in Bowman’s layer and its adjacent epithelium/stroma. In RBCD, the banding lesion was highly reflective and sharply margined at the stroma. In contrast, deposits in TBCD in the same layer showed a saw-tooth pattern toward the epithelium and poorly margined at the stroma.Conclusion: AS-OCT is able to clearly identify characteristic in vivo corneal microstructural changes associated with RBCD and TBCD. As a result, in vivo differentiation of RBCD and TBCD can be achieved.Keywords: Reis–Bücklers corneal dystrophy, Thiel–Behnke corneal dystrophy, anterior segment optical coherence tomography, genetic mutational analysis, human transforming growth factor beta-induced gene, TGFBI