OCT angiography (OCT-A) offers clinicians the ability to noninvasively assess the vasculature of the retina, choroid and optic disc region, which is key for diagnosing and managing glaucoma progression. A recent study launched by the American Academy of Ophthalmology as part of its Ophthalmic Technology Assessment evaluated the current published literature on OCT-A’s role in glaucoma. The review found that vessel density parameters measured by OCT-A complement visual field and structural OCT measurements.
Members of the Ophthalmic Technology Assessment Committee, other Academy committees, relevant subspecialty societies and legal counsel conducted searches of peer-reviewed literature. The 75 articles that met qualifying criteria were rated by a panel of methodologists for strength of evidence; three were rated level I, 57 were rated level II and 15 were rated level III. Level III articles were excluded, as they were the weakest.
The investigators found that OCT-A “can detect decreased capillary vessel density within the peripapillary nerve fiber layer (level II) and macula (levels I and II) in patients with suspected glaucoma, preperimetric glaucoma and perimetric glaucoma.”
Some studies found that peripapillary and macular vessel density on OCT-A were useful in differentiating glaucomatous from healthy eyes and that these measurements were comparable to the diagnostic ability of structural OCT retinal nerve fiber layer and ganglion cell thickness measurements. Other studies found that structural OCT measurements performed better.
Additionally, the investigators identified studies indicating that choroidal or deep-layer microvasculature dropout measured by OCT-A is associated with glaucoma damage (levels I and II). Lower peripapillary density, macular vessel density and choroidal microvasculature dropout were all associated with faster disease progression rates.
The committee members concluded, “These studies indicate that OCT-A changes in glaucomatous eyes are consistent with glaucomatous pathophysiologic features and suggest that OCT-A of the peripapillary and macular microvasculature can be useful in the diagnosis of primary open-angle glaucoma.”
WuDunn D, Takusagawa HL, Sit AJ, et al. OCT angiography for the diagnosis of glaucoma: a report by the American Academy of Ophthalmology. Ophthalmology. 2021;S0161-6420(20):31203-3.