OCT-A Metrics Improve Predictive Discrimination in Normal Tension Glaucoma

Lower superotemporal circumpapillary vessel density (cpVD) at the peripapillary region measured by optical coherence tomography angiography (OCT-A) improves the prediction of visual field (VF) progression in normal tension glaucoma (NTG). 

Between January 2017 and October 2021, researchers assessed OCT-A metrics of NTG patients including the peripapillary region — cpVD, vessel diameter index, and fractal dimension (FD) in the radial superficial capillary network — and at the macular region — macular vessel density, foveal avascular zone (FAZ) area, FAZ circularity and macular FD in superficial capillary plexus and deep capillary plexus. They evaluated patients’ VF at baseline and every 6 months using standard automated perimetry (SAP) and relied on a Cox proportional hazards model to evaluate the relationship of OCT-A metrics at baseline and the risk of NTG progression.

A total of 270 eyes of 164 patients with NTG were included in the study. At a mean follow-up duration of 48.58±7.98 months, 15.56% of eyes experienced VF progression (patient mean age, 59.73±11.15 years), while 84.44% of eyes did not experience VF progression (patient mean age, 60.54±11.72). 

In the multivariable Cox regression analysis adjusted for reported risk factors (axial length, intraocular pressure, VF mean deviation, and retinal nerve fiber layer thickness), the researchers found that lower baseline superotemporal cpVD at the peripapillary region was associated with VF deterioration (hazard ratio per standard deviation decrease, 1.401; 95% confidence interval, 1.017-1.929; P =.039). No other metrics were associated with VF deterioration after adjusting for reported risk factors.

“Baseline attenuation of superotemporal cpVD conferred an increased risk of NTG progression, and these OCT-A metrics improved predictive discrimination of NTG progression,” researchers report.

Limitations of the study included evaluation of the peripapillary and macular OCT-A metrics with a 3×3 mm field of view only, lack of evaluation of the peripheral retina, mild-to-moderate glaucoma at baseline in a majority of the eyes, and a relatively short follow-up period.

Reference

Wang YM, Shen R, Lin TPH, et al. Optical coherence tomography angiography metrics predict normal tension glaucoma progression. Acta Ophthalmol. Published online March 8, 2022. doi:10.1111/aos.15117