Abstract
Abstract: :
Purpose: The primary objective was to compare measures of bulbar redness (hyperemia) objectively using a photometric method with standard methods of grading and analogue scales. Method: Bulbar conjunctival redness of the ninety-one participants was measured using a Spectrascan650® Photometer by Photoresearch® under fixed illumination conditions. This method has been previously described (Simpson et al. Optom and Vis Science Supple. 75:125, 279, 1998) and has been shown to provide a repeatable and reliable measure of bulbar redness. Redness was quantified using CIE u' chromaticity units. Redness of the temporal bulbar conjunctiva was graded by the investigators, using analogue grading scales from 0 (none) to 100 (extreme). Each participant subjectively graded the redness of their own bulbar conjunctiva on a 0 (none) to 50 (red) point scale. The strength of the associations between these three measures of redness was estimated using linear correlation. Results: Significant correlations were found among the all redness measures. The strongest correlation was between objective and investigator estimated redness (r=0.67). The correlation between self-reported redness and chromaticity was 036 and between investigator and self-reported redness was 0.30 (all p<0.05). Conclusion: This new objective method of measuring bulbar hyperemia has great potential to replace subjective grading scales, especially if multi-centre studies are being conducted, where variability by investigator may occur. Self-reported redness does not correlate well with either investigator estimated or objectively measured redness. This work was supported by Allergan Inc.
Keywords: 356 clinical (human) or epidemiologic studies: systems/equipment/techniques • 365 conjunctiva • 430 imaging/image analysis: clinical