Circumpapillary Vessel Density May Foretell Glaucomatous Visual Field Loss

Lower baseline inferior temporal circumpapillary vessel density (cpVD) in eyes with preperimetric glaucoma (PPG) appears to be associated with glaucomatous visual field (VF) defect development and a faster rate of global VF loss, according to research published in the British Journal of Ophthalmology.

Investigators evaluated whether baseline VD parameters derived from optical coherence tomography angiography (OCT-A) images are associated with the development of glaucomatous VF defects in patients with PPG. They retrospectively analyzed baseline data from normal standard automated perimetry (SAP) and OCT-A of a single eye from each of 200 consecutive patients with PPG.

The cpVD and parafoveal and perifoveal VD were measured using OCT-A, with the retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer thicknesses as reference standards. 

The researchers stratified the patients into 2 groups based on the development of repeatable glaucomatous VF loss. They used Cox proportional hazards modeling to determine the predictive ability of OCT-A parameters for VF defects and linear regression analysis to evaluate the correlation between these baseline OCT-A parameters and the rate of global VF sensitivity loss (decibels/year).

With an average follow-up of 3.1 years, the researchers observed that 9.0% of eyes developed glaucomatous VF defects. The study shows lower inferior temporal cpVD (hazard ratio [HR], 0.934; 95% CI, 0.883-0.988; P =.017) and thinner inferior RNFL (HR, 0.895; 95% CI, 0.839-0.956; P =.001) are predictive of glaucomatous VF loss. The researchers also report that a lower inferior temporal cpVD and thinner RNFL at baseline were associated with a faster rate of global VF sensitivity loss (β=0.015; P =.001).

“Differentiating PPG eyes with subsequent VF loss from stable cases can assist clinicians with timely treatment approaches to minimize the risk of irreversible VF loss, and to avoid unnecessary interventions in low-risk cases,” according to the investigators. “A low baseline inferior temporal cpVD is predictive of the development of repeatable VF damage and of a faster rate of global VF sensitivity loss. Moreover, we found that the presence of [choroidal microvasculature dropout] at baseline is significantly associated with a greater rate of RNFL thinning in our present study series.”

Limitations of the study include the potential for ocular hypotensive drops to affect ocular blood flow, manual interpretation of en-face OCT-A images, and the use of an all-Koren patient base recruited from a single university hospital.