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A.S. Khouri, B. Szirth, F. Gilliberti, P.J. Lama, R.D. Fechtner; Non–Mydriatic Simultaneous Stereo Imaging of the Optic Nerve in Glaucoma Patients . Invest. Ophthalmol. Vis. Sci. 2006;47(13):3355.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the ability of a novel digital non–mydriatic (NM) camera to obtain simultaneous stereo images of the optic nerve in patients with glaucoma.
A Nidek 3–DxNM (Gamagori, Japan) simultaneous stereo–photography camera, equipped with a Nikon D1x (Tokyo, Japan) 6.1 megapixel charged couple device was used to capture stereo pair images of the optic nerve in glaucoma patients. Subjects were allowed to dark adapt prior to imaging to achieve pupillary dilation. No dilating drops were used. Age, race, iris color, and duration of dark adaptation for sufficient pupillary dilation were recorded. Images were reviewed by a fellowship–trained glaucoma specialist directly from a computer monitor (32 bytes, resolution 1024 x 768 pixels) using a Berezin stereo viewer in a dark room, held at a fixed angle to the monitor. Images were classified as evaluable if at least 3 of 4 pre–defined parameters could be assessed. The 4 parameters were: cup–to–disc ratio (CDR), neuro–retinal thinning/notching (NRTN), peri–papillary atrophy (PPA), and nerve fiber layer (NFL) defects. The study was approved by the institutional review board, and informed consent was obtained.
Thirty six optic nerve images from 18 subjects were evaluated (mean age 64 y, 7 male, 11 female, 11 Caucasian, 6 African American, 1 Hispanic). Iris color was brown in 12, blue–green in 2, blue in 4 subjects. Thirty three images (33/36, 92%) were classified as evaluable. By parameter: CDR, NRTN, PPA, and NFL were evaluable in 33/33, 27/33, 26/33 and 7/33 respectively. Three images were non–evaluable. These eyes all had pupil diameter <4mm and brown iris. In contrast, all images from eyes with pupil >4mm were evaluable, and 4 images with pupil <4mm were evaluable. Time to dark adapt was <1min in 12/18 (67%), and <5min in 14/18 (78%) subjects. Time for the second eye to dilate after flash photography of the first eye was <1min in 6/18 (33%), and <5min in 13/18 (72%) subjects.
Assessment of glaucomatous optic nerves using this digital NM simultaneous stereo imaging system was possible in 92% of eyes. Pupil diameter <4mm may be the limit precluding evaluable imaging. Time to achieve sufficient pupillary size by dark adaptation without dilating drops was <5min for most patients. Digital NM simultaneous stereo photography of the optic nerve may be practical for screening or for telemedicine.
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