Comparison of upper eyelid pressure and ocular surface parameters in dry eye disease and benign essential Blepharospasm: A cross-sectional study

Purpose: To compare the upper eyelid pressure (UEP) and ocular surface parameters between dry eye disease (DED) and DED coexisting with benign essential blepharospasm (BEB), exploring which parameters could assist in distinguishing between DED and BEB, as potential risk factors for DED with BEB. Methods: All enrolled participants diagnosed with DED or DED coexisting with BEB were initially subjected to ocular surface disease index (OSDI) determination. Subsequently, the upper eyelid pressure was recorded using an innovative eyelid pressure measurement device, followed by a series of ocular surface examinations. The two groups were compared using the independent t-test and Mann-Whitney U test. A logistic regression analysis was performed to identify which parameters can predict the onset of blepharospasm. Results: The BEB group achieved a higher upper eyelid pressure (101.9 f 23.5mN vs 88.4 f 18.1mN, P = 0.009), lower number of total blink (6.2 f 4.2 vs 7.1 f 4.1, P = 0.016), higher corneal fluorescein staining score (4.0 f 1.9 vs 3.0 f 1.7, P = 0.046), higher partial blink rate (0.9 f 0.2 vs 0.5 f 0.4, P = 0.000) and the lower grade of meibum expressibility (1 (1, 2) vs 2 (1, 3), P = 0.000) and meibum quality (1 (1, 1) vs 1 (1, 1), P = 0.033) compared with the DED group. The upper eyelid pressure (OR = 1.123), partial blink rate (OR = 0.014) and the grade of meibum expressibility (OR = 10.804) showed significant associations with BEB (P < 0.05). Conclusion: Despite similar OSDI scores, DED coexisting with BEB exhibited higher upper eyelid pressure, lower corneal fluorescein staining score, lower partial blink rate, more total blinks, lower grades of meibum expressibility, and lower meibum quality compared to DED alone. Among these, higher upper eyelid pressure, lower partial blink rate, and worse grade of meibum expressibility were identified as risk factors for BEB in DED.