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Christopher Lee, Varshini Varadaraj, Sophie LaBarre, Lucy I Mudie, David S Friedman, Michele Pascolini, Mattia Minozzi, Simone Pajaro, Cesare Tanassi; Auto-gonioscopy: a novel method for imaging the irido-corneal angle. Invest. Ophthalmol. Vis. Sci. 2016;57(12):5117.
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© ARVO (1962-2015); The Authors (2016-present)
Gonioscopy is an integral part of the comprehensive ophthalmic examination. However, it is subjective with imperfect intra- and inter-observer reproducibility, and is often not performed due to physician and patient discomfort. An automated device has been developed that obtains 360° images of the irido-corneal angle. This study aims to assess the device’s feasibility, correlation with parameters measured by traditional gonioscopy, and comparison with parameters measured by anterior segment optical coherence tomography (AS-OCT).
We enrolled 19 patients presenting to the Wilmer Eye Institute glaucoma service between July and November 2015. Subjects underwent a slit lamp examination by a glaucoma specialist including assessment of the limbal anterior chamber depth using Foster’s modified van Herrick technique, and irido-corneal angle with Goldmann gonioscopy using Schaffer’s classification. This was followed by AS-OCT and automated gonioscopy. The Nidek Technologies NGS-1 auto-gonioscope consists of a 16 mirror faceted prism that uses a clear, viscous gel interface to make contact with an anesthetized cornea. Five images at varying focal depths are obtained for each of the 16 sections over 2 seconds and a stitched 360° image of the irido-corneal angle is created.
Preliminary analyses of 23 eyes of 17 patients were performed. We were unable to procure images for two subjects due to facial anthropometry; one subject had deep-set orbit with a prominent brow, and the other had narrow inter-palpebral fissures, making prism alignment difficult. Among the 23 eyes that were evaluated, poor image quality precluded correlation analyses with traditional gonioscopy and AS-OCT. Modifications to the device are in process and additional results will be reported.
The preliminary images obtained were largely un-gradable, but this might be related to a steep learning curve for optimal use of the device and some software and hardware issues with the prototype. Software and hardware updates are in the process of being developed to improve patient fixation, device alignment and image quality. Despite issues with the initial data, these updates combined with increased training makes for a promising tool in glaucoma diagnosis as it provides objective, repeatable images that can be documented for monitoring of disease progression.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
Example of a good image
Example of a Stitched image
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