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Masanori Hangai, Takuhei Shoji, Yoko Shindo, Cesare Tanassi, Michele Pascolini; Automated 360-Degree Gonioscopic Color Photography and its Current Problems to be Solved for Clinical Use. Invest. Ophthalmol. Vis. Sci. 2016;57(12):5115. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To determine how successfully 360-degree iridocorneal angle images were captured by using our prototype digital gonioscope camera, and to determine the problems to be solved for routine clinical use.
Whole circumference iridocorneal angle images were captured in healthy eyes by using a prototype automated gonioscope camera (GONIOSCOPE NGS-1), which was developed by NIDEK Technologies Srl. (Padova, Italy), to test the focusing and image brightness in the 360-degree. This system circumferentially captures 16 single gonioscopic images of 16 portions illuminated by a white LED using an automatically-rotating optical gonioprism. The 16 iridocorneal angle images are overlapping and consecutive. Iridocorneal angle images on the 4 screens in the superior, nasal, inferior and temporal portions of the 16 portions were used for the alignment of capturing position and focusing. Twenty four eyes of 12 Japanese (all Asian) subjects (23-62 years old, mean 37.5) were examined twice by this protocol. Two Italians (all Caucasian) were examined as a reference. The frequency of good focus and brightness on the trabecular meshwork area was evaluated.
Cornea thickness, corneal diameter, and axial length of the Japanese eyes ranged from 482 to 562 μm (mean ± standard deviation [SD], 529.1±22.6 μm), from 5.4 to 12.8 mm (11.4±1.9 mm) and from 22.7 to 27.66 mm (24.6±1.4 mm), respectively. The pupil diameter as measured immediately before examination ranged from 3.5 to 11.9 mm (5.2±2.2 mm). The number of single gonioscopic images with poor focus per 360-degree imaging ranged from 0 to 8 (44.4%) (mean±SD, 3.96 [22.0%]±2.5). The number of single gonioscopic images with dark trabecular meshwork images per 360-degree imaging ranged from 0 to 6.0 (33.3%) (mean±SD, 0.7 [7.7%]±1.4). Both the number of single gonioscopic images with poor focus and with dark trabecular meshwork images were significantly correlated only with the greater corneal diameter (P=0.025 and 0.020, rho=-0.446 and -0.461, respectively, in Spearman's rank correlation coefficients).
These results suggest that focusing is more difficult than lightening in the automated 360-degree gonioscopic photography based on automatically-rotating optical gonioprism system. Greater corneal diameter appeared to cause poor focusing and dark trabecular meshwork images.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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