LCA Diagnosis

LCA Diagnosis

LCA may be suspected on the basis of a child’s symptoms and the findings of a simple eye examination. The diagnosis of LCA can be confirmed with the following tests:

 

ERG (electroretinography): This is a test that measures the electrical responses of the retina to light, evaluating responses of both rod and cone photoreceptors. The ERG test involves staying in a darkened room for 30 minutes, with drops put into the eye or eyes being tested. A special contact lens or gold-foil electrode is then placed on the eye or lower eyelid, and the eye is exposed to flashes of light.

OCT (optical coherence tomography): This is an imaging technique that involves taking digital images of the various layers of the retina. The process is uses light rather than sound or radio waves, which is why the images are in high resolution.

Genetic counselling: While not a test in the traditional diagnostic sense, genetic counselling is an important part of the diagnostic process. It can help determine the gene or genes that have been mutated, as well as the hereditary factors that are involved. See our section on genetic testing for more information: Know Your Code – Genetic Testing

Some forms of LCA do not show a change in vision over time, while others progress. The type of LCA determines the amount of visual loss. LCA can be caused by mutations in different genes. While it can be sometimes inherited in an autosomal dominant pattern, it is usually inherited in an autosomal recessive pattern.