Adaptive optics scanning laser ophthalmoscopy allows for noninvasive, in vivo visualization of retinal abnormalities at a cellular level. We herein describe for the first time, to our knowledge, the utility of high-resolution retinal imaging in studying the photoreceptor mosaic in an otherwise unexplained visual disturbance. Imaging of the cone mosaic was performed in a 64-year-old man with a unilateral ringlike paracentral distortion that could not be explained using common clinical imaging instruments. Adaptive optics scanning laser ophthalmoscopy findings revealed a parafoveal circular abnormality of the cone mosaic approximately 3 degrees in diameter that corresponded to the ring of visual disturbance. Visualization of the cone mosaic with adaptive optics scanning laser ophthalmoscopy can reveal photoreceptor damage that may not be detectable with standard imaging devices. Optical axial sectioning of the retina may help in identifying and localizing abnormalities within the retinal layers.