Abstract
Purpose :
To evaluate the usefulness of optical coherence tomography angiography (OCTA) for assessing differences in perfused perifoveal retinal capillaries in patients with proliferative diabetic retinopathy (PDR) after treatment with panretinal photocoagulation (PRP).
Methods :
This prospective study included patients with PDR. Patients with other systemic ocular conditions, except mild cataract and controlled hypertension, were excluded. All patients were imaged at baseline, 2 weeks, and 1, 2 and 3 months after PRP. A 70-kHz, 840nm wavelength spectral OCT system (Optovue, Fremont, CA) was used to obtain 3x3mm and 6x6mm perifoveal scans. A split-spectrum amplitude-decorrelation angiography (SSADA) algorithm generated en face OCT angiograms identifying perfused perifoveal capillaries. Capillary perfusion density (CPD) value was calculated and color-coded CPD maps were generated for each scan. Changes in OCTA color maps and CPD values were compared pre- and post- PRP using paired t-tests.
Results :
Preliminary results of 17 patients who completed 2 and 4 week post-PRP visits were included. Mean CPD values in 3x3mm superficial retinal capillary scans showed a small decrease after PRP. Mean CPD values were 40.46 ± 3.94% pre-PRP, 39.26 ± 3.86% 2 weeks post-PRP, and 38.08 ± 4.15% 4 weeks post-PRP (p= 0.173 and 0.45, respectively). Similar trends were seen in superficial and deep retinal capillary layers in both 3mm and 6mm scans. OCTA color-coded CPD maps also showed decreased CPD after PRP (Figure 1).
Conclusions :
OCTA is uniquely capable of imaging the perifoveal retinal capillaries allowing in a rapid, non-invasive qualitative mapping and quantitative analysis of CPD. This novel technique can identify subtle changes in response to interventions such as PRP, and may prove beneficial in monitoring response to treatment in patients with PDR. Further data is necessary to understand the relationship between perifoveal CPD and PRP treatment.
Reference: 1. Agemy S, Scripsema N, Shah C, et al. Retinal vascular perfusion density mapping using optical coherence tomography angiography in normals and diabetic retinopathy patients. Retina 2015;35(11):2353-63.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.