OCT angiography (OCT-A) could be a useful tool in detecting changes that help diagnose primary open-angle glaucoma, including vessel density loss, according to a report by the American Academy of Ophthalmology (AAO), published in Ophthalmology.

“Peripapillary, macular, and choroidal vessel density parameters may complement visual field and structural OCT measurements in the diagnosis of glaucoma,” according to investigators.

The study, a review of peer-reviewed literature conducted in March 2018, June 2018, April 2019, December 2019, and June 2020 in the PubMed and Cochrane Library databases, examined abstracts of 459 articles, with 75 selected and rated for strength of evidence. Three articles were rated level I; 57 were rated level II, and 15 level III articles were excluded.


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Investigators found that in these studies, OCT-A detected decreased capillary vessel density within the peripapillary nerve fiber layer (level II) and macula (level I and II) in patients with suspected glaucoma, preperimetric glaucoma, and perimetric glaucoma. Vessel density loss correlated significantly with glaucoma severity overall and topographically (level II) and longitudinally (level I). 

“For differentiating glaucomatous from healthy eyes, some studies found that peripapillary and macular vessel density measurements by OCTA show a diagnostic ability (area under the receiver operating characteristic curve) that is comparable with structural OCT retinal nerve fiber and ganglion cell thickness measurements, whereas other studies found that structural OCT measurements perform better,” the report shows.

Other parameters associated with glaucoma damage at levels I and II on OCTA were choroidal or deep-layer microvasculature dropout, while lower peripapillary, macular vessel density, and choroidal microvasculature dropout were associated with faster disease progression (level I and II).

Additional study is needed to learn more about the technology and its usefulness in predicting glaucoma onset and progression, investigators report. 

“As hardware and software technology advances, improvements can be expected in overcoming current limitations, such as projection artifacts, motion blur, difficulty in imaging deep optic nerve vasculature, and limited ability to quantitate blood flow through individual vessels. OCT angiography may improve our understanding of the mechanisms of glaucoma and thus lead to improved care for patients with glaucoma,” the research says.

Disclosure: Several study authors declared affiliations with the biotech or pharmaceutical industries. Please see the original reference for a full list of authors’ disclosures.

Reference

WuDunn D, Takusagawa HL, Sit AJ, et al. OCT angiography for the diagnosis of glaucoma: a report by the American Academy of Ophthalmology. Ophthalmol. Published online February 22, 2021. doi:10.1016/j.ophtha.2020.12.027