Glaucoma Specialist Optic Disc Margin, Rim Margin, and Rim Width Discordance in Glaucoma and Glaucoma Suspect Eyes

• Published in: American journal of ophthalmology Vol. 192; pp. 65 - 76
• Main Authors: Hong, Seung Woo, Koenigsman, Helen, Ren, Ruojin, Yang, Hongli, Gardiner, Stuart K., Reynaud, Juan, Kinast, Robert M., Mansberger, Steven L., Fortune, Brad, Demirel, Shaban, Burgoyne, Claude F.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.08.2018; Elsevier Limited
• Subjects: Accuracy; Estimates; Glaucoma; Medical imaging; Ophthalmology
• ISSN: 0002-9394; 1879-1891; 1879-1891
• DOI: 10.1016/j.ajo.2018.04.022

To quantify the variability of 5 glaucoma specialists' optic disc margin (DM), rim margin (RM), and rim width (RW) estimates. Inter-observer reliability analysis. Clinicians viewed stereo-photographs from 214 subjects with glaucoma or ocular hypertension and digitally marked the DM and RM. For each photograph, the centroid of each clinician's DM was calculated, and an averaged DMcentroid was determined. The axis between the DMcentroid and the fovea was used to establish 12 30-degree sectors. Measurements from the DMcentroid to each clinician's DM (DMradius) and RM (RMradius) were used to generate a RW (DMradius–RMradius) and cup-to-disc ratio (CDR) (RMradius/DMradius) by sector. Parameter means, standard deviations, and coefficient of variations (COVs) were calculated across all clinicians for each eye. Parameter means for each clinician, and intraclass correlation coefficients (ICC), were calculated across all eyes by sector. Among all eyes, the median COV by sector ranged from 3% to 5% for DMradius, 20% to 25% for RMradius, and 26% to 30% for RW. Sectoral ICCs for CDR ranged from 0.566 to 0.668. Sectors suspicious for rim thinning by 1 clinician were frequently overlooked by others. Among 1724 sectors in which at least 1 clinician was suspicious for rim thinning (CDR ≥ 0.7), all 5 clinicians' CDRs were ≥ 0.7 in only 499 (29%), and 2 of the 5 clinicians failed to detect rim thinning (CDR < 0.7) in 442 (26%). In this study, glaucoma specialist RM, DM, and RW discordance was frequent and substantial, even in sectors that were suspicious for rim thinning.