Posters - COMPARISON OF AN OBJECTIVE METHOD OF MEASURING BULBAR REDNESS TO THE USE OF TRADITIONAL GRADING SCALES

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Posters

August 2002

COMPARISON OF AN OBJECTIVE METHOD OF MEASURING BULBAR REDNESS TO THE USE OF TRADITIONAL GRADING SCALES

Luigina Sorbara, OD, MSc, Trefford Simpson, PhD, DipOptom, Desmond Fonn, MOptom, DipOptom,
University of Waterloo, School of Optometry, Waterloo, ON, Canada.

Purpose:

The primary objective was to compare measures of bulbar redness (hyperemia) objectively using a photometric method with standard methods of grading. Both measurers of redness were made on thirty study participants wearing a Silicone Hydrogel contact lens in one eye for overnight wear. This report compares hyperemia after 1 week of daily wear up to three months of extended wear.

Method:

A new method of objectively measuring the bulbar conjunctival hyperemia (redness) was done using the Spectrascan650ä Photometer by Photoresearch ä 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. Photometric measures in CIEu units of redness involve the measurement of chromaticity, a physical analogue of redness, greenness and blueness in the image. The CCLR analogue grading scales from 0 (none) to 100 (extreme) were used for the comparison.

Results:

Strong correlations were found between the CIEu units and the analogue data (R=0.82 and R=0.85 resp.), that will be demonstrated graphically at each of the one week daily wear visit and the one day, one week, one month and 3 month extended wear visits.

Conclusions:

This new standardized and 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. This method may also detect smaller changes between visits or between eyes when those changes are being sought. This work was supported by Bausch and Lomb Inc.

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COMPARISON OF AN OBJECTIVE METHOD OF MEASURING BULBAR REDNESS TO THE USE OF TRADITIONAL GRADING SCALES - 117KB

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