Ophthalmologists could have a new tool to assess progression in glaucoma by measuring vascular damage in the retina and optical nerve head. Optical coherence tomography angiography (OCTA) can directly measure retinal vessel densities in a non-invasive, reliable, and reproducible manner, and provide indirect measurements of ocular perfusion and blood flow.
“We know that retinal blood flow is reduced with increasing glaucoma severity,” said Vikas Chopra, MD.
“We have not had an easily performed, reliable, noninvasive method to assess retinal blood flow or changes in retinal blood flow before OCTA,” said Dr. Chopra, associate professor of clinical ophthalmology, David Geffen School of Medicine, University of California Los Angeles, associate medical director, Doheny Image Reading Center, and medical director, UCLA Doheny Eye Centers.
“Retinal specialists already use OCTA to assess retinal vascular in various diseases, and glaucoma specialists should soon be able do the same after some software tweaking to eliminate measurement artifacts and derive quantitative measures of blood flow,” he added.
Dr. Chopra was senior author on a proof-of-concept study that used swept-source OCTA (DRI OCT Triton, Topcon) to distinguish between normal eyes versus eyes with pre-perimetric glaucoma versus eyes with early primary open-angle glaucoma (POAG).
Ophthalmologists recognize that ischemia plays a role in apoptotic ganglion cell death and that glaucoma patients typically suffer from impaired ocular blood flow. Current diagnostic and management methods for glaucoma depend exclusively on the measurement and control of intraocular pressure (IOP).
While epidemiologic and clinical evidence have long indicated risk factors other than IOP in glaucoma, IOP has long been the only risk factor which clinicians could both measure routinely and modify.