Abstract
Purpose :
Macular thickness analysis (MTA) is a widely used tool for diagnosing and monitoring patients with ocular pathologies. Here, we compare the performance of MTA of a commercial optical coherence tomography (OCT) device and a low-cost self-administered OCT prototype through a subjective quality assessment of macular thickness maps (MTM) and statistical comparison of macular thickness values.
Methods :
18 subjects with wet age-related macular degeneration (wAMD) were recruited under IRB-approved clinical study protocol. 31 eyes were imaged with a CIRRUSTM HD-OCT 5000 (ZEISS, Dublin, CA) and a low-cost OCT prototype system with self-triggered scan acquisition (ZEISS, Dublin, CA). For each eye on each scanning visit, an operator acquired one CIRRUS scan, and subjects were asked to self-acquire OCT scans with the prototype system. The system captured 5.78 x 5.78 mm OCT volumes with 512 A-scans/B-scan, 128 B-scans and 2.77 mm of depth. For each case, the resulting OCT volumes were segmented to delineate inner limiting membrane (ILM) and retinal pigment epithelium (RPE). The segmentation was used to generate macular thickness maps. The low-cost thickness map was registered to the CIRRUS map and the ETDRS grid was centered on the CIRRUS scan (Figure 1). A correlation study and Bland-Altman analysis were used to compare the two groups. Three independent expert graders (optometrists) were asked for a subjective quality assessment of MTMs generated by CIRRUS scan and low-cost OCT prototype system and their efficacy for remote monitoring of wAMD.
Results :
40 pairs of CIRRUS HD-OCT and low-cost OCT prototype scans acquired over a year were used here. Table 1 shows quantitative and qualitative comparison between MTMs of both systems. The mean differences in macular thickness measured range between -5.8 and 7.8 μm depending on the retinal sector. R2 values vary between 0.91 and 0.98. The majority agreement (2 out of 3 graders) along with the survey questions are also shown in Table 1. In 87.5% of cases, the graders agreed that the MTM quality of low-cost prototype is similar to CIRRUS HD-OCT system. In 85% of cases, they agreed that they reach the same conclusion on fluid leakage of wAMD patient using MTM of both systems.
Conclusions :
This study demonstrates the ability of our low-cost OCT prototype to measure macular thickness with similar performance to that of a commercial OCT system for wAMD monitoring.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.