Adaptive Optics Flood Illumination Ophthalmoscopy in Nonhuman Primates: Findings in Normal and Short-term Induced Detached Retinae

To describe adaptive optics flood illumination ophthalmoscopy (AO-FIO) of the photoreceptor layer in normal nonhuman primates (NHPs) and in the case of a short-term induced retinal detachment (RD).

Longitudinal fundamental research study.

Four NHPs were used to image normal retinae with AO-FIO (in comparison with 4 healthy humans); 2 NHPs were used to assess the effects of RD.

The photoreceptor layer (cone mosaic metrics, including cone density, cone spacing, and cone regularity) was followed with AO-FIO imaging (rtx1, Imagine Eyes) during a surgically induced RD in 2 NHPs using a vehicle solution containing dimethyl sulfoxide, classically used as a chemical solvent. We also performed functional testing of the retina (full-field and multifocal electroretinogram [ERG]).

Correlation of cone mosaic metrics (cone density, spacing, and regularity) between normal retinae of NHPs and humans, and cone metrics, power spectrum, and ERG wave amplitudes after RD.

Imaging features were very similar in terms of cone reflectivity, cell density, regularity, and spacing values, showing strong positive correlations between NHPs and humans. After RD, AO-FIO revealed several alterations of the cone mosaic slowly recovering during the 3 months after the reattachment, which were not detected functionally by ERG.

These results demonstrate by in vivo AO-FIO imaging the transient structural changes of photoreceptors after an RD in the primate retina. They also provide an interesting illustration of the AO-FIO potential for investigating photoreceptor toxicity during preclinical studies in NHPs with a high translatability to human studies.

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