Abstract
Purpose :
To determine the reliability and agreement of a new comprehensive pterygium grading scale for use in clinical research and clinical trials.
Methods :
Thirty eyes of twenty four patients with pterygia were enrolled in this study. Primary gaze position and lateral gaze position images were taken of each eye with a Canfield Camera system (Canfield Scientific Inc, Fairfield, NJ, USA). The grading scale includes five parameters: two hyperemia parameters of pterygia on two different gaze position images and three size parameters, length, width, and area of the cornea encroachment of pterygium, quantified with Image J software (National Institutes of Health, Bethesda, Maryland, USA). All images were graded on the five parameters by two masked, certified graders at the Doheny Imaging Reading Center. Two graders independently graded all 60 images to determine intergrader reliability. One grader regraded the images after 3 days to determine intragrader reliability. Intraclass correlation coefficient (ICC) and inter-grater agreement statistic (kappa) calculationswere performed.
Results :
The intragrader reliability for hyperemia grading was high on both primary and lateral gazing positions (kappa value is 0.83 and 0.92). The intragrader reliability for hyperemia grading was also good (kappa value is 0.68 and 0.81). The mean value of width, length, and area of the cornea encroachment of pterygium was 4.31±2.04 mm, 2.08±1.43 mm, 7.84±7.62 mm2 respectively. The intragrader agreement on width, length, and area were excellent, with ICCs of 0.98 (95%CI: 0.96-0.99), 0.99(95%CI: 0.98-1.0), and 0.97 (95%CI: 0.94-0.99), respectively. The intergrader agreement on width, length, and area were also excellent, with ICCs of 0.96 (95%CI: 0.90-0.98), 0.99(95%CI: 0.98-0.99), and 0.99 (95%CI: 0.97-0.99), respectively.
Conclusions :
There was excellent intra- and inter- observer reproducibility with the new comprehensive grading scale. This scale could lead to the development of standardized grading assessments and quantification of pterygia that would be valid in clinical research and clinical trials.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.