The Clinical Value of the Ferning Test in Monitoring Dry Eye Syndrome in Patients with Sarcoidosis

Sarcoidosis is a systemic inflammatory disease characterized by the formation of non-caseating granulomas, predominantly affecting the lungs and lymph nodes. However, the disease can affect any organ, including the eye, where it most commonly manifests as uveitis and dry eye disease (DED). The Ferning Test (FT), a non-invasive method for tear film analysis, offers insight into tear quality. Through this study, we aimed to evaluate the ability of the FT to diagnose and differentiate DED in patients with sarcoidosis.

The study included a sample of 30 patients, divided into three groups, each consisting of 10 patients: one group of patients with sarcoidosis and dry eye disease (S-DED), one group of patients with DED without other systemic pathologies, and a control group of healthy individuals. Tear film samples were collected from the right eye of each participant, without stimulation, by microcapillarity. A drop of tear was spread on a microscope slide, allowed to dry, and then examined under a microscope to analyze the crystallization pattern.

Microscopic analysis revealed a significant difference in the structure and morphology of crystallization, as well as in the number of formed branchings, in sarcoidosis patients compared to patients in the other two groups. This finding suggests a distinct alteration in tear film composition in patients with sarcoidosis.

Based on these results, the FT represents a valuable and promising tool for the diagnosis of DED associated with sarcoidosis. Being a non-invasive, easy-to-perform, and inexpensive test, it can be widely implemented in any ophthalmology department, opening perspectives for the test to become an important component among the diagnostic elements of dry eye syndrome in patients with sarcoidosis.