Abstract
Purpose :
Panretinal photocoagulation (PRP) remains the mainstay of treatment for proliferative diabetic retinopathy (PDR). However, tailoring adequate PRP is important as excessive laser increases risks of visual field loss and night blindness. Hence, prognostic biomarkers are needed for individualized approach for PRP insufficient or excessive treatment. The retinal vascular structure is altered in PDR and may serve as a noninvasive marker of treatment outcome.
We aimed to investigate if retinal vascular structure (caliber, tortuosity, and fractal dimension) could be used as prognostic biomarkers for disease activity six months after PRP in patients with treatment-naïve PDR.
Methods :
We conducted a prospective clinical study with 42 eyes from 42 patients with PDR. We used wide-field fluorescein angiography (Optomap, Optos PLC., Dunfermline, Scotland, UK) to diagnose PDR at baseline and to assess disease activity at month six. At baseline, a trained grader measured retinal vessel geometry between 0.5–2.0 disc diameters from the disc marginby a semi-automated software (VAMPIRE, Vessel Assessment and Measurement Platform for Images of the Retina, Dundee, Scotland) following a standardized protocol. All patients received full standard PRP and additional treatment was given at month three in cases of early progression.
Results :
At baseline, mean age and duration of diabetes was 51.3 and 18.5 years, and 66.7% were male. Mean HbA1c and blood pressure were 64.5 mmol/mol and 153/84 mmHg. Prior to PRP, mean retinal arteriolar and venular parameters were: 29.37 and 45.45 pixels (caliber), -8.355 and -8.378 (tortuosity) and 1.210 and 1.237 (fractal dimension). At month six, seven eyes had progression of PDR (16.7%). Retinal vessel geometry did not differ between the groups at baseline, but patients with progression of PDR had a trend towards a higher median venular fractal dimension as compared to patients without progression (1.269 ±0.090 vs. 1.231 ±0.079, p=0.07).
Conclusions :
Retinal vascular structure at baseline was not a predictor of disease activity after PRP. However, there was a trend towards a more branched venular vascular tree in patients with progression of PDR after PRP. Studying changing patterns of retinal vascular geometry may provide further insights into role of these measures as a marker of PDR activity and adequacy of PRP treatment.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.