Abstract
Purpose: :
To investigate the photoreceptor cone mosaic in patients with type I diabetes mellitus (DM1).
Methods: :
An Adaptive Optics (AO) retinal camera prototype (rtx1, Imagine Eyes, France) was used to image the retinal microscopy of 12 DM1 patients (33-49 years old): 5 patients were diagnosed with no signs of diabetic retinopathy (DR) and 7 with mild DR. AO images were compared to standard imaging techniques (Scanning Laser Ophthalmoscopy/SLO and SD-OCT). Cone density was estimated at 230-, 350- and 460-µm from the foveal center along the horizontal meridian. The vascular structure was investigated at fixed superior-temporal and inferior-nasal distances from fixation.
Results: :
A high correspondence in the intra-retinal haemorrages visualization between SLO and AO was found when the lesions were wider than 20 µm. Cones were well resolved in all except 2 eyes where the presence of focal oedema at SD-OCT precluded the ability to resolve cone photoreceptors in the corresponding areas. Cone density declined from 50573 to 38664 cells/mm2 between 230- and 460-µm from the fovea. DR cone density fell within the lower end of normal limits for matched age healthy eyes found in the AO literature.
Conclusions: :
The authors present the first in vivo report on cone photoreceptor layer in DM1 patients. AO ophthalmoscopy provides the opportunity to understand the pathological variation of the retina in DM1 at microscopic scale resolution.
Keywords: diabetic retinopathy • photoreceptors • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)