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Randomized Controlled Trial
. 2009 May;116(5):997-1001.
doi: 10.1016/j.ophtha.2008.12.031.

FL-41 tint improves blink frequency, light sensitivity, and functional limitations in patients with benign essential blepharospasm

Marcus K Blackburn  1 , Randy D Lamb, Kathleen B Digre, A Gordon Smith, Judith E A Warner, Robert W McClane, Sanjeev D Nandedkar, Wendy J Langeberg, Richard Holubkov, Bradley J Katz
Affiliations
Randomized Controlled Trial

FL-41 tint improves blink frequency, light sensitivity, and functional limitations in patients with benign essential blepharospasm

Marcus K Blackburn et al. Ophthalmology. 2009 May.

Abstract

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

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

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

Methods: 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.

Results: 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.

Conclusions: 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.

Financial disclosure(s): Proprietary or commercial disclosure may be found after the references.

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Conflict of interest statement

Conflicts of interest: SD Nandedkar has a proprietary interest in the use of the electromyographic amplifier and customized, Windows-based software program used to analyze blink parameters. The other authors have reported no actual or potential conflicts of interest.

Figures

Figure 1
Figure 1
Lens transmission spectra for lenses used in the study. Average percent visible transmission from 400-700 nm: FL-41=63.8%, rose=58.8%; gray=51.2%. Visible light transmission (mean of the visible transmission curve weighted by the photopic response function): FL-41=22.3%, rose=20.4%. gray=18.9%.
See this image and copyright information in PMC

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