Identifying epithelial basement membrane disorder (EBMD) by slit lamp may be difficult for an untrained eye, and many patients who suffer from the condition are often misdiagnosed with dry eye disease (DED) instead. In pursuit of a noninvasive, objective, repeatable and quantitative clinical test that can detect EBMD as a differential diagnosis of DED, researchers recently proposed corneal epithelial thickness mapping and epithelial thickness irregularity assessment as possible tools in EBMD detection.
The study included 45 eyes of EBMD patients, 26 eyes of DED patients and 22 eyes of control subjects. The team used 9mm corneal epithelial mapping with OCT and assessed vision quality with the optical quality analysis system using the objective scatter index (OSI).
The investigators observed thicker mean central, inferior and maximum epithelial thicknesses (56.4μm, 58.9μm and 67.1μm, respectively) in the EBMD patients than the DED patients and control subjects. EBMD patients also had more epithelial thickness irregularity (5.1μm) than their DED (2.6μm) and healthy counterparts (2.1μm). The mean OSI was worse in EBMD patients and correlated with epithelial thickness irregularity.
The study authors noted that their OCT characterization of EMBD provides a better understanding of the dystrophy’s epithelial behavior and its role in vision quality. “The established characterization of this epithelial accumulation in the lower part of the cornea suggests an explanation of the behavior of the epithelium in this dystrophy and provides a simple and noninvasive tool to monitor patients with EBMD, capable of supporting future research and treatment strategies,” they concluded in their paper.
Buffault J, Zéboulion P, Liang H, et al. Assessment of corneal epithelial thickness mapping in epithelial basement membrane dystrophy. PLOS One. 2020;15(11):e0239124.