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TL Simpson, T Sin; The Effect of Topical Vasoconstriction on Bulbar Redness Measured Objectively . Invest. Ophthalmol. Vis. Sci. 2002;43(13):3108.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To objectively determine the effects of an OTC vasoconstrictor on the bulbar conjunctival redness. Methods: Ten normal subjects used one drop of an OTC vasoconstrictor containing Phenylephrine HCl 0.12% in one (experimental) eye and normal saline in the other (control) eye (selected randomly). Temporal bulbar conjunctival redness (expressed as CIE u') was measured objectively using a Photo Research PR650 spectroradiometer. Measurements were made before and 1, 2, 3, 4, 5, 25, 45 and 60 minutes after drop instillation. Results: Repeated measures ANOVA of redness for the control and experimental eyes at each time point showed significant effects of time, eyes and most importantly an interaction between eyes and time (all p's<0.02). Using nonlinear curve fitting, a 2 compartment model with exponential components for the reduction and recovery of redness was fit to the experimental eye data (r=0.92) but could not be used for control data (r approx.=0.1). In the experimental eyes, the mean time constant for the decrease in redness was 2.6 minutes and the recovery to baseline was 19.8 minutes. Conclusion: There were statistical differences between mean redness in experimental and control eyes, redness at different times and a difference over time that depended on which eye received the vasoconstrictor, with redness decreasing in the experimental eye and staying approximately constant in the control eye. These measurements of the decline in redness and return to baseline demonstrate the utility of real time objective photometric measures of bulbar redness.
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