Software-assisted optic nerve assessment for glaucoma tele-screening.

Increased optic nerve head (ONH) cup-to-disc ratio (CDR) may indicate glaucoma but evaluation needs to be performed by a trained examiner. This research assessed new software to calculate CDR from ONH images. Digital stereoscopic ONH images from 28 subjects acquired during screening using a nonmydriatic 45-degree camera with 8.2-Megapixel resolution (Canon, Tokyo, Japan) were analyzed by 3 individuals with different levels of ophthalmic training: glaucoma specialist (GS), an optometrist (OD), and trainees. Images were logged and accessed by raters masked to each other's evaluations. Images from two groups were included: normal-appearing ONH (Group 1) and confirmed glaucoma (Group 2). All images were captured in DICOM format. Images were evaluated on a 32-bit, 1,600 x 1,200-pixel resolution monitor. EyeScape software (v. 7.4, Synemed, Inc., Benicia, CA) was used for CDR analysis. Software CDR determination requires an operator to place ONH disc and cup contour lines. Once lines were placed, the software provided CDR calculations (range 0.00-1.00). A total of 84 ONH evaluations were analyzed. Overall CDR mean, standard deviation, standard error of the mean, and mean difference from GS CDR evaluations were determined. Reproducibility was similar for all operators. The trainee had a small, statistically significant greater CDR in group 1 and 2 evaluations. Evaluation of ONH images for CDR can be performed using EyeScape software, by individuals with different levels of ophthalmic training. Accurate determination of CDR is important in tele-screening for vision-threatening diseases, and can aid in identifying subjects with suspicious ONH in need of specialty eye care.