Selective cone photoreceptor injury in acute macular neuroretinopathy.

PURPOSE

To evaluate retinal structural and functional abnormalities in a patient with acute macular neuroretinopathy.

METHODS

An adaptive optics scanning light ophthalmoscope was used to image the photoreceptor mosaic and assess rod and cone structure. Spectral-domain optical coherence tomography was used to examine retinal lamination. Microperimetry was used to assess function across the macula.

RESULTS

Microperimetry showed reduced function of localized areas within retinal lesions corresponding to subjective scotomas. Spectral-domain optical coherence tomography imaging revealed attenuation of two outer retinal bands typically thought to reflect photoreceptor structure. Adaptive optics scanning light ophthalmoscope images of the photoreceptor mosaic revealed a heterogeneous presentation within these lesions. There were areas containing non-waveguiding cones and other areas of decreased cone density where the remaining rods had expanded to fill in the vacant space. Within these lesions, cone densities were shown to be significantly lower than eccentricity-matched areas of normal retina, as well as accepted histologic measurements. A 6-month follow-up revealed no change in rod or cone structure.

CONCLUSION

Imaging of acute macular neuroretinopathy using an adaptive optics scanning light ophthalmoscope shows a preferential disruption of cone photoreceptor structure within the region of decreased retinal sensitivity (as measured by microperimetry). Adaptive optics-based imaging tools provide a noninvasive way to assess photoreceptor structure at a level of detail that is not resolved by use of conventional spectral-domain optical coherence tomography or other clinical measures.