Inability to see well at night or in poor light.

A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule.

An absolute or relative decrease in retinal sensitivity extending from edge (periphery) of the visual field in a concentric pattern. The visual field is the area that is perceived simultaneously by a fixating eye.

Thickening of the retina that takes place due to accumulation of fluid in the macula as a nonspecific response to blood-retinal barrier breakdown. Macular edema is a common pathological response to a wide variety of ocular insults, most commonly after intraocular (e.g. cataract) surgery or in association with retinal vascular (e.g. diabetic eye disease, retinal vein occlusion) or inflammatory (e.g. uveitis) disease.

Well-demarcated area(s) of partial or complete depigmentation in the macula, reflecting atrophy of the retinal pigment epithelium with associated retinal photoreceptor loss.

Pigment migration into the retina in a bone-spicule configuration (resembling the nucleated cells within the lacuna of bone).

Absence of the combined rod-and-cone response on electroretinogram.

An inherited retinal disease subtype in which the rod photoreceptors appear to be more severely affected than the cone photoreceptors. Typical presentation is with nyctalopia (due to rod dysfunction) followed by loss of mid-peripheral field of vision, which gradually extends and leaves many patients with a small central island of vision due to the preservation of macular cones.