RETINAL DYSTROPHIES AND SYNDROMES
Cone-Rod Dystrophies (CRD) are inherited progressive diseases that cause deterioration of the cone and rod photoreceptor cells and frequently lead to blindness.
The symptoms of CRD include an initial loss of color vision and visual acuity followed by nyctalopia and peripheral visual loss.
There is a wide variety of phenotypical expression of this group of disorders. Fundus findings at an early stage include a normal macula or macular RPE granularity. At later stages, the fundus picture discloses a pale optic disc, peripheral bone spicule-like hyperpigmentation and generalized atrophic changes of the peripheral retina. Attenuation of the retinal vessels evolves with disease progression.
Electroretinography shows the cone-isolated ERG waveform proportionally worse than the rod-isolated signal, and both...