**5. Retinal imaging**

AO retinal imaging reveals information about retinal structures and pathology currently not available in a clinical setting. The resolution of retinal features on a cellular level offers the possibility to reveal microscopic changes during the earliest stages of a retinal disease. One of the most important future applications of this technique is consequently in clinical prac‐ tice where it will facilitate early diagnosis of retinal disease, follow-up of treatment effects, and follow-up of disease progression.

Both the DCAO demonstrator and the PoC prototype feature a narrow depth of focus, ap‐ proximately 25 µm and 9 µm in the retina, respectively. This allows for imaging of different retinal layers, from the deeper photoreceptor layer to the superficial blood vessel and nerve fiber layers. Images are flat-fielded using a low-pass filtered image to reduce uneven illumi‐ nation [39]. A Gaussian kernel with σ = 8 - 25 pixels is chosen depending on the imaged reti‐ nal layer. A smaller kernel is used for images of the photoreceptor layer and a larger kernel is consequently used for images of superficial layers. Final post-processing is performed by convolving an image with a σ = 0.75 pixel Gaussian kernel to reduce shot and readout noise. As the PoC prototype is still under construction all retinal images shown below have been acquired with the DCAO demonstrator.
