Background Spectral domain optical coherence tomography (SDOCT) allows for higher resolution scans and higher scanning speeds compared to time domain OCT (TDOCT). The purpose of this study is to compare the pathology detection rates of various SDOCT devices to the Stratus TDOCT.
Methods Patients with neovascular age-related macular degeneration were imaged on the Stratus and one of four SDOCT devices. The images were then analysed in a masked manner evaluating for the presence of epiretinal membrane (ERM), pigment epithelial detachment (PED) and subretinal fluid (SRF). After determining that low scan density with one of the devices was likely the cause of missed PED and SRF compared to the other SDOCT devices the study was repeated with a higher scan density.
Results 60 eyes from 60 patients with neovascular macular degeneration were imaged on each SDOCT device, for a total of 240 eyes from 240 patients imaged on Stratus. There were no instances where pathology was visible on Stratus but was missed on SDOCT. The highest incidence of missed pathology was with SRF, followed by ERM and PED.
Conclusions The increased resolution and image quality of SDOCT devices over TDOCT allows for finer discrimination of retinal structures. The increased speed of SDOCT allows for dense coverage of the macula resulting in the ability to see smaller areas of PED and SRF. There was a critical threshold for the distance between B-scans in the three-dimensional cube scan for detection of pathology.