Quantification of Ocular Biomechanics In Ocular Manifestations of Systemic Autoimmune Diseases

Purpose: To quantify biomechanical change associated with autoimmune diseases using Corvis ST deformation data. Methods: Cross-sectional, observational, case control study of 76 patients with systemic autoimmune disease and 21 control subjects. All patients underwent detailed ophthalmic examination with Corvis-ST (Oculus Optikgerate Gmbh, Germany) measurements for biomechanical properties of the eye. Corneal deformation and also deformation caused by the extracorneal tissue were recorded. Using a mathematical formula, the three parameters, namely, corneal stiffness (kc), extracorneal tissue stiffness (kg), and extracorneal tissue viscosity (?g), were defined. Results: The biomechanical analysis showed that kc and ?g were significantly lower in patients with systemic autoimmune disease with eye manifestations than control group. However statistically, it was significant in rheumatoid arthritis (RA) patients only. Conclusion: The new parameters, namely, kc, kg, and ?g, can provide a sensitive marker of the ocular activity of the collagen vascular diseases.