Optical coherence tomography angiography (OCT-A) may help monitor microvascular changes in glaucoma related to glaucoma progression or surgical intraocular pressure (IOP) lowering, a systematic review of 10 studies published in Br J Ophthalmol indicated. However, its validity for glaucoma follow-up in routine clinical practice are yet to be determined due to the heterogeneity of studies completed so far in this subject area, the researchers noted.
The researchers sought to perform the first systematic review of the ability of OCT-A to detect and measure glaucoma progression and identify heterogeneity moderators. They searched MEDLINE, Scopus, ISI Web of Science, and Google Scholar from inception to September 20, 2019, to find prospective, longitudinal studies with at least 3 months of follow-up that evaluated prospective glaucomatous changes using OCTA either with primary open-angle glaucoma (POAG) or comparing healthy control subjects to POAG. POAG was studied with OCT or visual field (VF) or both.
The review included 10 studies. A Kappa agreement of .81 was obtained for the eligibility of the full texts (good agreement).
They found that vessel density (VD) change in glaucoma varied from 0.036/year to 1.08/year and 1.3% to 3.2% per year, with significantly different rates between glaucoma and healthy controls.
Prior studies have employed OCT-A to show that VD continues to decrease in advanced glaucoma, detecting progression even in the absence of measurable RNFL change. The researchers add that OCT-A imaging is less patient-dependent than a VF exam, making it more reproducible.
The differences in study designs, methodologies, parameters, and reporting present among the 10 studies limited the researchers’ ability to form additional, firm conclusions, and they were therefore unable to perform a meta-analysis.
The investigators speculate that OCT-A may provide information on the vascular pathophysiology of glaucoma.
Miguel A, Silva A, Barbosa-Breda J, et al. OCT-angiography detects longitudinal microvascular changes in glaucoma: a systematic review. Br J Ophthalmol. Published online January 15, 2021. doi: 10.1136/bjophthalmol-2020-318166