Abstract
Purpose :
There is a lack of data regarding the effect of demographic variables and the retinal thickness on vascular density. Therefore, we observed the effects of age, gender and retinal thickness on the vascular density in the normal population.
Methods :
A total of 209 eyes of 209 healthy patients (106 males and 103 females) were scanned using the optical coherence tomography angiography (AngioVue, Optovue, Inc., Fremont, CA, USA) on an outpatient basis at the Hashmanis Hospital, Pakistan. Patients were 20 to 75 years of age. We used the software version 2016.10 to cover a 3 x 3 mm circle centered at the macula. The circle was divided into 5 sectors: a 1 mm central foveal circle, and an upper, lower, nasal and temporal circle each spanning 1 to 3 mm away from the central circle. The vascular density at the superficial capillary plexus was measured which spanned from the inner limiting membrane to the inner plexiform layer. The Pearson correlation and independent t tests were used for statistical analysis.
Results :
The fovea was the least dense area (32.5 ± 5.9%) and the temporal area was the densest (52.4 ± 4.4%). Similarly, the fovea was the thinnest part of the retina (237.8 ± 20.7 μm), however, the nasal sector was the thickest (308.5 ± 15.1 μm). We did not find any correlation of the retinal thickness with the vascular density except at the fovea (r=0.541, p<0.001). Similarly, no differences in terms of gender were found except at the foveal region (p=0.002). All regions significantly and negatively correlated with age even after adjusting for axial length. When plotting the mean whole image vessel density with each age group, we observed that the vascular density was stable until the age of 50 years, and then saw a sharp decline. Lastly, when plotting the standard deviation against the age, we saw a rise after the age of 50 years.
Conclusions :
Vascular density only correlates with the retinal thickness at the fovea and this is the only zone affected by gender. Age, however, negatively correlates with all regions of the macular map. Additionally, we see that vascular density sees a sharp decline after the fifth decade along with an increase in variability. This study helps us observe how the superficial capillary plexus at the macula is affected by demographic variables.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.