Hereditary Optic Neuropathies

Hereditary optic neuropathies result from genetic defects that are passed down through families. They cause vision loss and sometimes cardiac or neurologic abnormalities and are usually diagnosed in childhood or adolescence.

The two most common types of hereditary optic neuropathies include:

· Dominant optic atrophy (degeneration of the optic nerve, usually beginning before age 10)

· Leber hereditary optic neuropathy (vision loss, usually beginning in the teenage or young adult years)

Symptoms of these conditions include:

· Progressive vision loss

· Cardiac conduction defect (problem with the electrical impulses in your heart)

· Other neurologic problems, such as a tremor, loss of ankle reflexes, dystonia (repetitive muscle contractions that result in abnormal bodily positions), spasticity (when certain muscles are continuously contracted), or a multiple sclerosis-like illness

Tests

Comprehensive Exam – Your doctor will conduct a thorough physical examination– as well as gather a complete health history – to help determine if you have a hereditary optic neuropathy.

Electrocardiogram (ECG) – If your doctor suspects you have Leber hereditary optic neuropathy, you may need to undergo an ECG to check for related cardiac problems.

Genetic Testing – Your doctor will likely order molecular genetic testing, which can confirm many mutations that cause these conditions.

Optical coherence tomography – The test measures the thickness of the cell layers and nerve fibres that make up the optic nerves to assess optic nerve damage.

Optic nerve photos – The test documents the amount of optic nerve swelling.

Visual field – A visual field test assesses both central and peripheral vision.

Treatments

Visual Aids – There are no cures for these conditions. However, there are a variety of low-vision aids available – such as magnifiers, large-print devices, and talking watches – that can help make your life easier.