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

OBJECTIVE: 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). DESIGN: Longitudinal fundamental research study. SUBJECTS: 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. INTERVENTION: 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]). MAIN OUTCOME MEASURES: 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. RESULTS: 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. CONCLUSIONS: 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. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.