Abstract
Purpose:
To evaluate structural differences in the patient recovered from diabetic macular edema by using multimodal non-invasive imaging methods, including adaptive optics scanning laser ophthalmoscopy (AO-SLO).
Methods:
An eighty-one year old Indian male suffered from diabetic retinopathy with macular edema. Following resolution of the macular edema in one eye, the visual acuity did not recover fully. The patient underwent a complete ophthalmic examination that included fundus color photography, IR imaging, OCT. High-resolution image of cone structure and measurement of the number and shape of cones was investigated by AO-SLO. After 14 months, the patient received the same examination. For the accurate analysis of condition of cone cells, we focused on the same portions of macula by manual estimation.
Results:
OCT revealed no macular edema with a central thickness of 231um in his right eye and central thickness of 289 um with inferior 0.5mm local edema of 352um in his left eye. 14 months later, OCT showed no specific difference on the right eye with central thickness of 229 um, but the central and inferior 0.5mm thickness had declined to 275 um and 339 um. Central vision metamorphopsia had almost subsided and the visual acuity had improved. At the 14-month follow up visit, the density of cone photoreceptors, as measured by AO-SLO examination, had only decreased slightly, but the cellular hexagon rate declined remarkably in both eyes on average. Compared to the initial inferior local edema of 0.5 mm in the left eye, the cellular hexagon rate decreased from 36.4% to 22.8% at the 14-month follow-up exam.
Conclusions:
The analyses by AO-SLO imaging revealed only a slightly lower density of cone cells, but the cellular hexagon rate decreased in both eyes as compared to the examination 14 months prior. The cellular hexagon rate of previous edema area of left eye showed marked decline. The macular edema from long-term diabetic macular edema had subsided, based on the OCT image which showed flatter retina. The visual acuity had also improved, but the detail density and morphology still remained and even worsened. Long-term edema, diabetic retinopathy, or aging might be the risk factors. However, AO-SLO is more sensitive to the level of a single cone cell, and the ability to visualize the cone cells in vivo should be used in a larger diabetic retinopathy survey and may also be useful for studying other retinal diseases as well.
Keywords: 689 retina: distal (photoreceptors, horizontal cells, bipolar cells) •
499 diabetic retinopathy