Leber's congenital amaurosis is an inherited eye condition that causes very low vision. Here are three things parents need to know about it.

What are the signs of Leber's congenital amaurosis?

The signs of this condition usually appear within a child's first year of life. You may notice that your child is rubbing or pressing on their eyes. Their pupils may respond slowly—or not at all—to changes in light conditions. Rapid, involuntary eye movements, known as nystagmus, can also be present.

Photophobia is another sign of Leber's congenital amaurosis. Photophobia means that the light hurts your child's eyes, and you may notice them turning their head away from light sources or crying when you turn on the lights.

Poor vision is another common sign of this condition. Affected children don't usually have vision better than 20/400, which means that they can see at 20 feet what a child with 20/20 vision could see from 400 feet away. Babies and young children with poor vision may not react to mobiles or other distractions.

What causes Leber's congenital amaurosis?

This condition is caused by mutations of the RPE65 gene. RPE65 is important for vision because it encodes a protein within the retina. It also plays an important role in the regeneration of visual pigments, the molecules that absorb light and create sight. It's autosomal recessive, so both parents need to carry a mutated copy of RPE65 for their child to get Leber's congenital amaurosis.

Can Leber's congenital amaurosis be treated?

This condition was untreatable until very recently, but gene therapy can now be used to treat affected children. Gene therapy involves introducing RPE65 to your child's body in the hopes that the normal copies of the genes will replace their mutated copies. The genes are introduced through subretinal injections.

Gene therapy hasn't been shown to significantly improve central vision, but it can lead to dramatic improvements in peripheral vision. Vision improvements can be noticed in the first month after treatment and the results last for between one and three years. Since gene therapy is a new treatment, scientists are still trying to improve it. The treatment may provide better or longer-lasting results in the future.

In addition to gene therapy, low vision aids can be used as your child gets older to help them function. Devices like stand magnifiers can be used to make tasks like reading or going to school possible. Telescopes can also be mounted to their glasses to help them do things like watch television.

If you think your child has Leber's congenital amaurosis, take them to an optometrist immediately.