Deborah L Lam1, Jim Axtelle2, Susan Rath1, Andrew Dyer2, Benjamin Harrison2, Claude Rogers2, Naresh Menon2, Russell N Van Gelder3. 1. Department of Ophthalmology, University of Washington Medical School, Seattle, WA, USA. 2. Chromologic, Inc., Monrovia, CA, USA. 3. Department of Ophthalmology, University of Washington Medical School, Seattle, WA, USA ; Department of Biological Structure, University of Washington Medical School, Seattle, WA, USA ; Department of Pathology, University of Washington Medical School, Seattle, WA, USA.
Abstract
PURPOSE: Existing flare photometers are based on the Tyndall effect, which requires sophisticated laser photometry. The ocular flare analysis meter (OFAM) is a nonlaser photometer that uses quantitative Rayleigh scatter and absorption from visible light to compute a flare value. This study is designed to correlate OFAM measurements with qualitative measurements of flare in vitro and in vivo. METHODS: Following validation of the device on artificial anterior chambers containing known protein concentrations, flare readings were obtained from 90 subjects (46 with and 44 without uveitis) in one eye. Subjects were graded by the Standardization of Uveitis Nomenclature (SUN) working group flare scoring system and received the OFAM flare measurements. RESULTS: The OFAM showed linear response in vitro to protein concentrations ranging from 0 to 0.5 mg/ml. In clinical use in subjects ranging from SUN flare scores of 0+ to 2+, OFAM showed statistically significant measurement accuracy (P = 0.0008 of flare 0 versus flare 2; P = 0.031 of flare 0 versus flare 1). Distinction of SUN scores 1 and 2 was borderline significant (P = 0.057). CONCLUSION: The OFAM photometry correlates with the standard SUN scoring system. This method may provide an objective method to diagnosis and monitor uveitis. Further longitudinal studies are warranted. TRANSLATIONAL RELEVANCE: Currently, ocular flare is assessed qualitatively in most clinical settings. The existing methodology uses only Tyndall effect to measure flare. The OFAM uses an alternate, nonlaser means for measurement of anterior chamber flare by measure of Raleigh scatter. This pilot clinical study suggests that the OFAM device may be useful in measurement of uveitis activity.
PURPOSE: Existing flare photometers are based on the Tyndall effect, which requires sophisticated laser photometry. The ocular flare analysis meter (OFAM) is a nonlaser photometer that uses quantitative Rayleigh scatter and absorption from visible light to compute a flare value. This study is designed to correlate OFAM measurements with qualitative measurements of flare in vitro and in vivo. METHODS: Following validation of the device on artificial anterior chambers containing known protein concentrations, flare readings were obtained from 90 subjects (46 with and 44 without uveitis) in one eye. Subjects were graded by the Standardization of Uveitis Nomenclature (SUN) working group flare scoring system and received the OFAM flare measurements. RESULTS: The OFAM showed linear response in vitro to protein concentrations ranging from 0 to 0.5 mg/ml. In clinical use in subjects ranging from SUN flare scores of 0+ to 2+, OFAM showed statistically significant measurement accuracy (P = 0.0008 of flare 0 versus flare 2; P = 0.031 of flare 0 versus flare 1). Distinction of SUN scores 1 and 2 was borderline significant (P = 0.057). CONCLUSION: The OFAM photometry correlates with the standard SUN scoring system. This method may provide an objective method to diagnosis and monitor uveitis. Further longitudinal studies are warranted. TRANSLATIONAL RELEVANCE: Currently, ocular flare is assessed qualitatively in most clinical settings. The existing methodology uses only Tyndall effect to measure flare. The OFAM uses an alternate, nonlaser means for measurement of anterior chamber flare by measure of Raleigh scatter. This pilot clinical study suggests that the OFAM device may be useful in measurement of uveitis activity.
Authors: John G Ladas; Noel C Wheeler; Patrick J Morhun; Steven O Rimmer; Gary N Holland Journal: Surv Ophthalmol Date: 2005 Jan-Feb Impact factor: 6.048
Authors: Viera Kalinina Ayuso; Joke H de Boer; Helen L Byers; Gary R Coulton; Jojanneke Dekkers; Lenneke de Visser; Anton M van Loon; Peter A W J F Schellekens; Aniki Rothova; Jolanda D F de Groot-Mijnes Journal: Invest Ophthalmol Vis Sci Date: 2013-05-01 Impact factor: 4.799