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Poonam Misra, Lama Al-Aswad, Suzanne Daly, Dana Blumberg, Ronald H Silverman; The Use of Anterior Segment OCT AOD and TISA Parameters as an Objective Way to Evaluate the Angle (Pilot Study). Invest. Ophthalmol. Vis. Sci. 2019;60(9):5567. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Anterior segment OCT (ASOCT) is a useful adjuvant for evaluating the anterior chamber angle. The relationship between ASOCT and clinical gonioscopy has not been fully elucidated. Today we are unable to predict which eyes will go into angle closure. Objective parameters provide a reproducible way of examining and monitoring angle progression.
Eyes undergoing both ASOCT and gonioscopy were identified by retrospective chart review. The gonioscopy grading by the glaucoma specialist was compared to a masked grading of the ASOCT. An observer masked to the type of glaucoma and gonioscopy findings evaluated AS-OCT parameters including the angle-opening distance (AOD), at 500 and 750 μm distant from the scleral spur (AOD500 and AOD750), trabecular-iris space area (TISA) measured at a distance of 500 and 750 μm (TISA500 and TISA750). The ASOCT findings were compared to Shaffer gonioscopy grades.
In the initial cohort, 20 eyes were reviewed by the clinician and masked anterior segment imaging expert. By gonioscopy, 14 of 20 (70%) of eyes were found to have narrow angles. Twelve of these eyes (85.7%) subsequently underwent peripheral iridotomies. The average AOD500 of the ten right eyes was 0.365 (+/-0.0576), of the left eyes 0.351 (+/-0.0374). The average AOD750 was 0.476 in right and left eyes. The average TISA500 in right and left eyes was 0.128 (+/-0.0188) and 0.119 (+/-0.0148), respectively. The average TISA750 in right and left eyes was 0.229 (+/-0.0307) and 0.219 (+/-0.0229), respectively.
Gonioscopy can be subjective based on observer and technique. The use of ASOCT can provide a more objective and reproducible way to evaluate the angle. Precise parameters such as AOD and TISA are standardized measures which can help guide the decision to perform a peripheral iridotomy in the future.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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