Purpose
This study was designed to test the sensitivity and specificity of SD-OCT (Heidelberg Spectralis) disorganisation of the retinal inner layers (DRIL) in detecting angiographic evidence of macular capillary nonperfusion in diabetic retinopathy.
Methods
SD-OCT images from 45 separate areas of macular capillary nonperfusion excluding the foveal avascular zone were obtained from 37 eyes and compared with similar images from areas of macular perfusion in the same eye. Each SD-OCT line scan was marked, anonymised, coded and graded by two masked investigators for presence of DRIL with arbitration by a senior clinician.
Results
The intergrader agreement was high (Cohen’s Kappa = 0.909). Of the 45 SD-OCT lines scans, DRIL was present in 84.4% (38/45) of nonperfused retina and 0% (0/45) of perfused retina. The sensitivity and specificity of DRIL in detecting angiographic evidence of capillary nonperfusion was 84.4% and 100% respectively. Positive Predictive Value was 100% and the Negative Predictive Value, 86.5%.
Conclusions
The presence of DRIL is highly correlated to areas of nonperfusion but is not a universal finding. The absence of DRIL is very highly correlated with perfused retina. DRIL may be a useful marker for retinal capillary nonperfusion.