Abstract:
To validate a new digital simultaneous stereo–photographysystem against film in the assessment of optic nerve head featuresin glaucoma patients. Fifteen digital and 15 correspondingfilm simultaneous stereo–photographs (SSP) of the opticnerve from glaucoma patients were graded by two glaucoma specialists.Cup–to–Disc (C/D) ratio vertically (V) and horizontally(H), and image quality score (1=worse, 5=best) were evaluatedfor each image. Digital and film SSP were presented in randomorder, two times to each grader. A total of 60 evaluations (30digital and 30 film) per grader were collected. The Nidek 3–DXstereo disc camera was used with standard 35 mm film, and thenwith a new 6.1 mega pixel camera system for capture of digitalimages. Digital SSP were evaluated directly from a computermonitor with compatible resolution to the digital camera andcomparable magnification with the film, using the Screen–Vustereo viewer held at a fixed angle to the monitor. Film SSPwere evaluated using a Pentax stereo slide viewer from a lightbox over a neutral density filter to match luminance betweenthe computer screen and the light box. The mean differencebetween digital and film was near zero for all three evaluatedoutcomes (C/D V, C/D H, quality score), and there was no significantrater effect for any of the outcomes (Tables 1, 2).Digitalphotography has several advantages including instant feedbackon quality, electronic storage, and use in telemedicine. Digitalimages correlated well with film for SSP of the optic nervein glaucoma.
Keywords: imaging/image analysis: clinical • optic disc