Novel grading system for pupillary ruff changes and associated features

Abstract

To evaluate the reproducibility of a new system for grading pupil ruff changes and associated findings. Observational comparative study. Forty-seven photograph sets including iris, pupil edge and ruff, and inferior anterior chamber drainage angle. A novel system for recording pupillary ruff changes was developed, along with reference iris, pupil and gonioscopy images. A prospective masked agreement study was undertaken using two observers who graded the photograph sets using this new system. Parameters included pupillary ruff absence and abnormality, pupil edge pigment, trabecular meshwork pigment, Sampaolesi line pigment, iris root pigment, and pigment 'lumps' and 'piles'. Intraobserver and interobserver agreement for the parameters of the grading system, assessed with the intraclass correlation coefficient and Bland-Altman plots. Photographs of 47 eyes of 47 glaucoma suspects and glaucoma patients were evaluated. Agreement percentages of ≥95% (average 96%) and ≥60% (average 70%) were obtained for intraobserver and interobserver agreement, respectively. The average interobserver single-measure intraclass correlation coefficient and repeat-measures intraclass correlation coefficient were 0.75 (range 0.54-0.88) and 0.85 (range 0.70-0.94), respectively. There was a non-significant trend towards interobserver systematic bias on one of the nine parameters (iris stroma pigment at the pupil edge). This grading system provides a reliable and reproducible system for encoding of clinical signs of pupil ruff atrophy for clinical research.