RESUMEN
PURPOSE: We aimed to analyze the tears of patients with Benin Essential Blepharospasm (BEB) to explore possible corneo-conjunctival mechanisms for photophobia, tear deficiency and ocular pain. METHODS: Using an observational cohort of 42 patients diagnosed with BEB, we performed Schirmer's testing, measurement of tear film pH, tear film protein electrophoresis and conjunctival impression cytology. RESULTS: Schirmer's testing showed dry eye (8.4±9.7mm) with 71.3% eyes having a Schirmer's score<10mm. Surprisingly, the pH was basic (8.4±0.4) and was improved in patients receiving the standard treatment of quarterly botulinum toxin injections (8.32±0.36 for treated patients vs. 8.74±0.53 for untreated patients; P=0.045). Together, tear protein electrophoresis and conjunctival impression cytology showed conjunctival inflammation associated with BEB. CONCLUSION: For the first time, this study emphasizes corneo-conjunctival mechanisms to explain the photophobia, dry eye and pain in Benign Essential Blepharospasm. While encouraging, complementary studies remain necessary to evaluate the effect of correcting tear film pH and inflammation on the quality of life of blepharospasm patients.