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

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.

Resonance Raman measurement of macular carotenoids in normal subjects and in age-related macular degeneration patients.

PURPOSE: Dietary carotenoids lutein and zeaxanthin may play a protective role against visual loss from age-related macular degeneration (AMD) through antioxidant and light screening mechanisms. We used a novel noninvasive objective method to quantify lutein and zeaxanthin in the human macula using resonance Raman spectroscopy and compared macular pigment levels in AMD and normal subjects. DESIGN: Observational study of an ophthalmology clinic-based population. PARTICIPANTS AND CONTROLS: Ninety-three AMD eyes from 63 patients and 220 normal eyes from 138 subjects. METHODS: Macular carotenoid levels were quantified by illuminating the macula with a low-power argon laser spot and measuring Raman backscattered light using a spectrograph. This technique is sensitive, specific, and repeatable even in subjects with significant macular pathologic features. MAIN OUTCOME MEASURE: Raman signal intensity at 1525 cm(-1) generated by the carbon-carbon double-bond vibrations of lutein and zeaxanthin. RESULTS: Carotenoid Raman signal intensity declined with age in normal eyes (P < 0.001). Average levels of lutein and zeaxanthin were 32% lower in AMD eyes versus normal elderly control eyes as long as the subjects were not consuming high-dose lutein supplements (P = 0.001). Patients who had begun to consume supplements containing high doses of lutein (> or =4 mg/day) regularly after their initial diagnosis of AMD had average macular pigment levels that were in the normal range (P = 0.829) and that were significantly higher than in AMD patients not consuming these supplements (P = 0.038). CONCLUSIONS: These findings are consistent with the hypothesis that low levels of lutein and zeaxanthin in the human macula may represent a pathogenic risk factor for the development of AMD. Resonance Raman measurement of macular carotenoid pigments could play an important role in facilitating large-scale prospective clinical studies of lutein and zeaxanthin protection against AMD, and this technology may someday prove useful in the early detection of individuals at risk for visual loss from AMD.

In vivo resonant Raman measurement of macular carotenoid pigments in the young and the aging human retina.

We have used resonant Raman scattering spectroscopy as a novel, noninvasive, in vivo optical technique to measure the concentration of the macular carotenoid pigments lutein and zeaxanthin in the living human retina of young and elderly adults. Using a backscattering geometry and resonant molecular excitation in the visible wavelength range, we measure the Raman signals originating from the single- and double-bond stretch vibrations of the pi-conjugated molecule's carbon backbone. The Raman signals scale linearly with carotenoid content, and the required laser excitation is well below safety limits for macular exposure. Furthermore, the signals decline significantly with increasing age in normal eyes. The Raman technique is objective and quantitative and may lead to a new method for rapid screening of carotenoid pigment levels in large populations at risk for vision loss from age-related macular degeneration, the leading cause of blindness in the elderly in the United States.

Raman imaging of human macular pigments.

We have imaged the spatial distribution of macular carotenoid pigments (MPs) in the human retina, employing Raman spectroscopy. Using excised human eyecups as initial test samples and resonant excitation of the pigment molecules with narrow-bandwidth blue light from a mercury arc lamp, we record Raman images originating from the carbon-carbon double-bond stretch vibrations of the molecules. Preliminary Raman images reveal significant differences in the MPs of different samples in regard to absolute levels as well as spatial variation. This technique holds promise as a method of rapid screening of MPs in large populations at risk for vision loss from age-related macular degeneration, a leading cause of blindness.