How to make a “beautiful” 24mm length OCT B-scan?
A. It has to be fast. There are more A-scans than ordinary length. This 24mm scan consists of >1500 A-scans, 2560 samples along each A-scan, repeat up to 256 times for SNR improvement. That’s why TowardPi choose 400KHz speed OCT. The capture is completed in a wink.
B. It has to be sharp. Longer line makes the image look flatter. Higher resolution allows us to stretch the image axially so the structural layers can be differentiated with ease. That’s why TowardPi sets the resolution at 3.8um.
C. It has to be deep. Given the natural curvature of eyeball. Even 3mm is not deep enough to cover both sides of the retina. That’s why Toward Pi utilizes 6mm depth.
D. The signal has to be strong. Attenuation within 6mm depth is not acceptable. As you can find from the image, Vitreous, Choroid, Sclera, Lamina Cribrosa… signal strengths are identical. That’s because we use a specially designed Swept Source laser unit.
E. Last but not least. Wide field lens is needed to cover a large optical field. A special 80° lens is designed for TowardPi OCT.
Combining all the features together, we present this delectable 24mm length OCT B-scan. And that is just the entry-level preparation of our 24mm OCT Angiography (please refer to our previous post)