Age-matched Database of a Novel OCT Angiography (OCTA) Parafoveal Capillary Density Deviation Mapping Technique and its Clinical Application on Retinal Vasculopathy

Abstract

Purpose : To evaluate the effect of age on parafoveal capillary density (PCD) and develop an age-matched database for a novel deviation mapping approach.

Methods : 117 healthy subjects classified in 6 groups (≤19, 20-29, 30-39, 40-49, 50-59, and ≥ 60 years) and 3 patients with distinct retinal vasculopathies were imaged using a commercial SDOCT system (Avanti RTVue-XR; Optovue). A 3x3 mm macular OCTA scan was obtained for each subject. Axial length was obtained for the correction of retinal magnification. Full vascular layer OCTA (large vessels and capillaries located between the ILM and 70-µm below the posterior boundary of the IPL) was used for image processing and analysis. After the removal of large vessels, 8 consecutive distance annuli were created from the border of the FAZ (200-µm in width for each annulus). Mean±SD of PCD was calculated in each annulus for all groups. One-way ANOVA and post-hoc Tukey-Kramer test were used to assess PCD differences. PCD deviation maps highlighting regions with density below the age-matched database were generated for patients with sickle cell retinopathy, retinal vein occlusion, and diabetic retinopathy.

Results : Mean±SD of PCD was 41.38±5.03% for all healthy subjects. The highest (43.74±3.99%) and lowest (38.09±5.48%) PCD were found in the youngest and oldest group, respectively. For the innermost annulus, PCD decreased by 5.07% from the youngest to the oldest group. One-way ANOVA indicated statistical significant difference between groups (p=0.001). Post-hoc test showed statistical significance between various age groups at different annuli. Our deviation mapping approach was able to identify areas with subnormal PCD in patients with retinal vasculopathies (Fig 1).

Conclusions : Our findings demonstrate that PCD normally decreases with increasing age. Use of an age-matched OCTA database should be considered for more accurate evaluation of disease severity and therapeutic response. Our novel deviation mapping allows for a quick and efficient way to identify regional abnormality in PCD.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

Figure 1. A) Full layer OCTA image of a patient with sickle cell retinopathy. B) Corresponding deviation map highlighting regions with capillary density below 5% (in yellow) and 1% (in red) of the age-matched database.