Cone Dystrophy, Peripheral

Background and History: 

Rods and cones in the retina respond to light and send their responses to the brain which is a vital link in the mechanism of seeing.  There are numerous gene mutations that impact the function of these specialized cells which may lead to loss of vision as well as symptoms such as night blindness and defects in color vision.  In this disorder, the defect seems to involve primarily the cones located in the periphery of the retina. 

Clinical Correlations: 

Some patients in the first two decades of life are aware of blurred vision whereas it may be normal in others.  Night blindness does not occur as the rods seem to function normally.  Color vision is variably impaired since the cones in the macula, the region of the retina we use for the highest resolution of vision, function relatively normally.  The cones beyond this area, called the periphery, are primarily impaired.  Vision ranges from normal to about 20/100.

No other health problems have been reported. 


The inheritance pattern in this disease is unknown.  No responsible gene mutation has been found.  The occurrence in two sibs of one family is consistent with autosomal recessive inheritance in which two copies of the mutation are required for expression of the disease.

Diagnosis and Prognosis: 

This is solely an ocular disorder and can only be diagnosed by an ophthalmologist using an electrophysiological test called an electroretinogram or ERG.  No treatment is available but low vision aids can be helpful to some patients. 

Additional Information
Autosomal recessive