Retrospektive Studie zur Validierung & Entwicklung einer objektiven Beurteilung des konjunktivalen Rötungsgrades mittels Videotopographen

Purpose. The purpose of this exploratory study was to evaluate and validate the objective determination of bulbar, limbal and total conjunctival redness with the K5M video topographer (Oculus, Germany), the measurement software (R-Scan) and the JENVIS grading scale in comparison to subjectively recorded redness levels. Material and Methods. The conjunctival redness level was documented three consecutive times in a total of 75 subjects (150 eyes). The average age was 33.9 ± 15.7 years. The survey took place at the Centre for Contact Lens Research Waterloo, Canada and at the Helios hospital Erfurt, Germany. From the survey, 25 images were selected and entered into a website for subjective grading. On the website, the images were presented in a randomized order six times (3× limbal & 3× bulbar redness), so that each of the 20 investigators graded a total of 150 images. The reference images of the redness grades were based on the JENVIS grading scale. The subjective results were compared using the five analyzed grades with the objective findings by the R-Scan of the K5M. The results were analyzed using descriptive statistics. Results. With regard to the images obtained using the software, the mean grade of findings was 1.3 ± 0.3, with 24 % of the results being assessed as grade 0, 48 % as grade 1, 14 % as grade 2 and grade 3. The subjective findings resulted in a mean grade of 1.5 ± 0.3. 17 % were assessed as grade 0, 45 % as grade 1, 19 % as grade 2 and 5 % as grade 3. The results of the subjective and objective classification of temporal and nasal bulbar redness are not statistically different. In contrast, the results of temporal and nasal limbal redness are statistically different, with the subjective findings within grade 1 being statistically significantly higher than those of the objective findings. The mean dispersion of the objective classifications is 11 %, that of the subjective 31 %. Conclusion. The software (R-Scan, K5M) primarily evaluates the number and redness of the conjunctival vessels, whereas the subjective evaluation is based on the overall redness of the eye as perceived by the examiner. As the degree of severity increases, the spread of the results increases with objective classification, but decreases with subjective classification, with the latter showing an almost 3-times greater spread on average. This means that automated conjunctival classifications are more accurate than subjective classifications for lower degrees of severity and comparable for higher degrees of severity.