Fig. 18.

Spatiotemporal characterization of functional OCT-IOS imaging. A 10-ms flash stimulus was used for retinal stimulation of the frog eye. Raw OCT images were collected with a frame rate of 100 Hz. Stimulus onset is indicated by time “0.” OCT B-scan images are presented with a linear scale. (a1–a3) OCT B-scan images and spatial IOS image sequences of one control and two experimental groups. All the images were averaged over 10 frames (100 ms interval). Images consisted of $140\text{\hspace{0.17em}\hspace{0.17em}pixels\hspace{0.17em}}(\text{lateral})\times 200\text{\hspace{0.17em}\hspace{0.17em}pixels\hspace{0.17em}}(\text{axial})$, corresponding to $200\mathrm{mm}(\text{lateral})\times 360\mathrm{mm}(\text{axial})$. (b) Temporal curves of the number of activated (positive and negative) pixels corresponding to (a1–a3). (c) Temporal curves of positive and negative IOSs averaged from six recording trials. (d) To better visualize the signal onset time, an enlarged profile of the early 80 ms period from (c) is illustrated. (e) IOS distribution map superimposed on the OCT B-scan image. Positive signals (increasing reflectance) and negative signals (decreasing reflectance) are presented in red and green, respectively. Signal magnitude is not indicated in the image. (f) Comparative OCT-IOS and histological images of the outer retina. In the histological image, cone photoreceptors are highlighted in green or red to show cell sizes and locations. Cone photoreceptor OSs highlighted with red circles are located at the level of the rod ISe. Scale bars indicate $50\mu \mathrm{m}$. Reprinted with permission from Ref. 130.