Optic nerve evaluation among optometrists

To determine agreement among optometrists regarding assessment of optic nerve C/D ratios and perceived glaucomatous damage and to separately analyze these results on the basis of residency training, practice setting, and glaucoma patient experience.

Fifty-six optometrists from various modes of professional practice evaluated 33 stereoscopic optic nerve photographs. Observers were asked to estimate the vertical cup-to-disk (C/D) ratio and determine the glaucomatous status of the optic nerve. The mean vertical C/D ratio, percentage perceived as glaucomatous, and levels of interobserver and intraobserver agreement (kappa) are reported.

Estimated C/D ratios differ significantly on the basis of training (p = 0.02) practice setting (p = 0.001), glaucoma patient experience (p = 0.001). Glaucomatous damage interpretation was significantly different (p = 0.006) based upon an optometrist's practice setting. Interobserver agreement regarding C/D ratios is significantly higher among optometrists who have completed a residency (kappaw = 0.59) and practice in clinical settings (optometry school/medical center/hospital) (kappaw = 0.59) compared with non-residency-trained optometrists (kappaw = 0.52) and those practicing in commercial settings (kappaw = 0.54). Interobserver agreement of glaucomatous damage is significantly higher among optometrists who have completed a residency (kappa = 0.50) compared with non-residency-trained optometrists (kappa = 0.42).

Intraobserver agreement is higher than interobserver agreement among optometrists when C/D ratios are estimated and the glaucomatous status of the optic nerve is assessed. Optic nerve evaluation among optometrists is significantly influenced by residency training, practice setting, and glaucoma patient encounters.