FL-41 Tint Improves Blink Frequency, Light Sensitivity, and Functional Limitations in Patients with Benign Essential Blepharospasm

Authors: Marcus K. Blackburn, MD, Randy D. Lamb, MD, Kathleen B. Digre, MD, A. Gordon Smith, MD, Judith E.A. Warner, MD, Robert W. McClane, MS, Sanjeev D. Nandedkar, PhD, Wendy J. Langeberg, MPH, Richard Holubkov, PhD, Bradley J. Katz, MD, PhD MD, PhD Bradley J. Katz
Source: Ophthalmology. 2009 May; 116(5): 997–1001.



The objective of these 2 studies was to assess the efficacy of FL-41-tinted lenses in the treatment of benign essential blepharospasm (BEB).


A randomized crossover study and a randomized crossover case-control study.


The first study included 30 subjects with BEB. The second study included 26 subjects with BEB and 26 controls.


For the first study, subjects were randomized to wear either FL-41 or gray-tinted lenses for 2 weeks. After a 2-week washout period, the other lens was worn for 2 weeks. Questionnaires were completed at baseline, after the first lens, and after the second lens. In the second study, surface electromyography (EMG) was used to measure blink frequency, duration, and force while subjects read and wore FL-41, rose, or gray-tinted lenses.

Main Outcome Measures

Questionnaires were used to assess perceptions of light sensitivity and the effect of light sensitivity on activities of daily living (ADL). EMG was used to measure blink frequency, duration, and force.


Most participants observed improvement while wearing both FL-41 and gray-tinted lenses. FL-41-tinted lenses provided superior improvement in the areas of reading, fluorescent light sensitivity, overall light sensitivity, blepharospasm frequency, and blepharospasm severity. FL-41 lenses reduced mean blink rate compared with both rose and gray-tinted lenses, and reduced eyelid contraction force compared with rose-tinted lenses.


FL-41 lenses provided both subjective and objective benefit to subjects with BEB. Physicians should consider recommending this noninvasive and inexpensive lens tint to patients with BEB.

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