When compared to a normative database, assessing central retina vessel density on OCT-A can offer insight to diseases such as glaucoma, diabetes, Alzheimer’s and retinal disorders. Photo: Vercellin AV, et al. J Clin Med. July 18, 2024. Click image to enlarge.

OCT angiography is being used by a growing number of clinicians to monitor and diagnose various pathologies through noninvasive evaluation of the retinal microvasculature and foveal avascular zone (FAZ). In the central retina, for example, vascular changes can be indicative of numerous diseases, such as glaucoma, diabetes, retinal disease and Alzheimer’s; however, limited studies have obtained reliable normative values of the FAZ and macular vessel density required to properly interpret these measurements and their clinical implications.

To close this knowledge gap, researchers recently conducted a cross-sectional study to assess these parameters in 792 healthy adults (56% female; mean age: 40 years). They used 3x3mm and 6x6mm OCT-A scans to evaluate the vessel density of the macular superficial capillary plexus (SCP), deep capillary plexus (DCP) and the FAZ area of all participants.

The data revealed the following mean values for each ocular parameter:

• SCP vessel density: 45.9%
• DCP vessel density: 50.2 ±3%
• FAZ area: 0.3mm²
• FAZ perimeter: 2.1mm
• Foveal vessel density: 50.4%

The researchers observed that women and younger participants generally had higher vessel density values. All FAZ parameters were significantly higher in females, and younger participants exhibited significantly increased foveal vessel density values.

There was a significant linear negative correlation between age and SCP and DCP vessel density values in the right eyes; in other words, as age increased, vessel density in both the SCP and DCP decreased. Additional correlations include a negative association between DCP vessel density and both height and weight, while SCP vessel density was positively correlated with diastolic blood pressure.

The researchers note in their paper for the journal Eye that while their study was limited by enrolling subjects under 20 and over 60 years of age, “the large sample size allowed us to establish average values for macula vessel density and FAZ in otherwise healthy adults between the third and sixth decades of life.”