OCT angiography effective in detecting microvascular changes in glaucoma;BMJ

According to the recent findings from a systematic review, Optical coherence tomography angiography (OCTA) has shown promise in observing the microvascular changes in glaucoma related to glaucoma progression or surgical intraocular pressure (IOP) lowering .The interesting reports have been put forth in the British Journal of Opthalmology, a BMJ publication.

Optical coherence tomography (OCT) is a non-invasive, light-based imaging technique which enables in vivo, cross-sectional imaging of structures, including human tissues, at high resolution.¹ Its medical application is primarily in retinal imaging where current OCT devices can now accurately resolve the individual retinal layers and provide automated measures of retinal thickness estimated to the nearest micron.

A major advance of the last couple of years has been OCT angiography (OCTA), in which the detection of the phase shift of erythrocytes travelling through the retinal capillaries enables a detailed map of the retinal capillaries, and for the first time a real-time non-invasive map of retinal ischaemia.

Takinga cue from this, researchers intended to perform a systematic review of studies focusing on longitudinal changes in peripapillary and macular VD measurements in glaucoma.

As for the study design,a search was performed across MEDLINE, Scopus, ISI Web of Science and Google Scholar, using the following query from inception until 20 September 2019: (("optical coherence tomography angiography"[tiab]) OR (optical coherence tomography angiography[MeSH]) OR ("OCTA"[tiab]) OR ("OCT-A"[tiab]) OR ("angio-OCT"[tiab]) OR ("OCT- angiography"[tiab]) OR ("OCT-angio"[tiab]) OR ("OCT-angiographie"[tiab])) AND (glaucom*[tiab] OR glaucoma[MeSH]). Prospective studies that quantitatively assessed the longitudinal changes in VD in glaucoma with at least 3 months of follow-up were included.

Data analysis revealed the following facts.

• Ten out of 4516 studies were included. The rate of 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.
• Five studies assessed VD change after glaucoma surgery, obtaining variable results, ranging from a temporary VD decrease to increase after 3 months.
• Meta-analysis was not possible due to a wide variation in methods, measurements and region of VD.

Observing the results, the team concluded that "Measures should be taken to increase the quality and standardise the methodology of VD measures in OCTA longitudinal studies, for future meta-analyses."

For the full article follow the link: http://dx.doi.org/10.1136/bjophthalmol-2020-318166

Primary source: British Journal of Opthalmology