Comparison of time-domain, spectral-domain and swept-source OCT in evaluating aqueous cells in vitro

Different optical coherence tomography (OCT), both time-domain OCT and spectral-domain OCT, has been used to evaluate anterior chamber cells in previous studies. Recently, commercial swept-source OCT was available. The comparison among three kinds of OCTs have not been done before. Here, we compared their feasibility in discerning aqueous cells in vitro. The peripheral blood was diluted to eight different cell concentrations and was packed into plastic-film bag. Each sample was tested using different scan modes of three OCTs. It was easy to discern aqueous cells from background noise in both Visante AS-OCT and RTVue XR Avanti OCT, but difficult in Casia SS-1000 OCT. The measured blood cell densities in high-resolution corneal cross-sectional scan of Visante AS-OCT, cornea line scan and 3D cornea scan of RTVue XR Avanti OCT were highly correlated with the actual blood cell concentration (Pearson correlation=0.991, 0.989, and 0.993 respectively). The mean adjusted cell densities of cornea line scan (10.46±2.87 spots mm^-2) and 3D cornea scan (11.01±2.47 spots mm^-2) of RTVue XR Avanti OCT were significantly larger than that of Visante AS-OCT (1.55±1.75 spots mm^-2) (P<0.01). Our study demonstrated that RTVue XR Avanti OCT, a spectral-domain OCT, is superior to other two OCTs in evaluating aqueous cells.