Corneal Subbasal Nerve Analysis Using In Vivo Confocal Microscopy in Patients With Dry Eye: Analysis and Clinical Correlations

Purpose: This study aimed to observe corneal subbasal nerves and Langerhans cells (LCs) using in vivo confocal microscopy (IVCM) in patients with dry eye, a tool for the evaluation of disease stage and severity and for treatment monitoring at the microstructural level. Methods: A total of 107 eyes from 62 patients were included. The Ocular Surface Disease Index (OSDI) questionnaire and other examinations were used to assess dry eye symptoms and signs. IVCM was performed to observe subbasal corneal nerves and LCs. Corneal nerves were graded using both objective and subjective methods. The correlations between dry eye symptoms and corneal nerve parameters, corneal nerve grading, and LC number were analyzed. Results: Corneal nerve length was negatively correlated with sensitivity to light [correlation coefficient (CC)= -0.24, P < 0.05]; nerve width was positively correlated with the OSDI score, painful eyes, and blurred vision (CC = 0.41, 0.23, and 0.46, respectively, all P < 0.05); and nerve tortuosity was positively correlated with sensitivity to light (CC = 0.23, P < 0.05). Moreover, both total objective and subjective grading scores were positively correlated with OSDI scores (CC = 0.48 and 0.27, respectively, both P < 0.05). LC number was found not to be significantly correlated with dry eye symptoms (P > 0.05). Conclusions: IVCM is a useful tool to evaluate corneal subbasal nerve changes in patients with dry eye. Detailed nerve grading could help to understand and evaluate the pathophysiologic conditions of the disease and could be used for further treatment follow-up in the future.