Though it may be impractical for routine clinical use, confocal microscopy can document corneal nerve changes at the cellular level in patients with dry eye, a study in Cornea suggests.

The investigation examined both Langerhans cells and corneal subbasal nerves in 107 eyes of 62 patients using in vivo confocal microscopy.

Researchers found corneal nerve length was negatively associated with sensitivity to light, and nerve width was positively correlated with Ocular Surface

Disease Index (OSDI) scores, painful eyes and blurred vision. Additionally, the researchers reported nerve tortuosity was positively correlated with sensitivity to light, and both total objective and subjective grading scores were linked to OSDI scores.

The study also found dry eye symptoms were not significantly tied to Langerhans cell numbers.

“With the development of microstructural examination methods, our understanding of ocular surface disease has progressed to the cellular level. Confocal microscopy is a new, emerging, noninvasive technology that can aid in the in vivo assessment of structural changes in several ocular surface diseases,” the researchers wrote in their paper.

They added that detailed nerve grading could help clinicians understand and evaluate the pathophysiologic conditions of the disease and could one day be used for further treatment follow-up. 

Liu Y, Chou Y, Dong X, et al. Corneal subbasal nerve analysis using in vivo confocal microscopy in patients with dry eye: analysis and clinical correlations. Cornea. July 10, 2019. [Epub ahead of print].