Performance comparison of macular thickness generated from a low-cost OCT with a commercial OCT system

Abstract

Purpose : Macular Thickness Analysis (MTA) is commonly used for diagnosing and monitoring patients. Technology constraints of low-cost OCT can result in limited image quality and can affect the MTA when compared to commercial OCT systems. The purpose of this study is to compare the performance of MTA generated using an automated scan selection method from a low-cost OCT with MTA generated from a commercial OCT system.

Methods : In this prospective study a low-cost OCT prototype system (ZEISS, Dublin, CA) and a commercial CIRRUS^TM HD-OCT 5000 (ZEISS, Dublin, CA) were used to image 55 eyes with age-related macular degeneration. For each eye, operator acquired one 6 x 6 mm OCT volume with 512 x 128 A-scans from the commercial OCT system and subjects were asked to self-acquire three 5.78 x 7 mm OCT volumes with 512 x 128 A-scans from the low-cost OCT. For both commercial and low-cost OCT volumes, MTA was calculated over 5.78 x 5.78 mm area. The thickness maps from both systems were registered and the ETDRS grids were centered on the scans. An automated scan selection method [Fard et al., IOVS 2022;63(7):3312] was used to select the number of scans to generate thickness maps for low-cost OCT. Bland-Altman analysis was used to compare the MTA from low-cost OCT with the commercial OCT.

Results : The summary of results from automated scan selection method in the 55 eyes are as follows: in 1, 12 and 42 volumes, MTA was calculated using 3 of 3, 2 of 3 and 1 of 3 acquisitions respectively. Figure 1 shows examples of both low-cost OCT and commercial OCT thickness maps. Bland-Altman analyses from various ETDRS sectors are shown in Table 1. The mean difference between low-cost and commercial OCT ranges from -5.5 to 4.6 µm. The coefficient of determination (R²) ranges from 0.83 to 0.97 in the ETDRS sectors showing good correlation.

Conclusions : The results from this study suggest that the MTA results from various ETDRS sectors of low-cost OCT show good correlation with MTA results from commercial OCT. This suggests that the automated scan selection method may be effective in generating MTA in low-cost OCT system.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

Figure 1 Macular thickness (MT) map from low-cost and commercial OCT for two subjects

 

Table 1 Bland-Altman analyses between low-cost and commercial OCT