Bright Sight

Oliver Backhouse, Consultant Eye Surgeon www.cataract.org.uk

Optic Atrophy

The Optic nerve is the cable that takes the message from the eye to the brain to enable one to have vision. It is only 1.5mm in diameter and has approximately 1 million nerve fibres packed into this small space. When some of these nerves are damaged it causes loss of visual signal to the brain which is experienced as loss of vision. This is called Optic Atrophy. Some of the symptoms and signs of Optic Atrophy include: Blurred vision, Reduced colour appreciation, Disturbance to the field of vision, Dimming of what one can see along with poor pupil reaction to light and optic nerve paleness (the healthy optic nerve is pink).

There are many causes of Optic Atrophy. Some of the more common causes are Glaucoma; Lack of blood supply (see separate information sheet on Anterior Ischaemic Optic Neuropathy); Inflammation conditions such as Sarcoidosis and Optic Neuritis (see separate information sheets); Inherited – eg: Lebers Optic Atrophy and Dominant Optic Atrophy being the most common 2 of a very large list; Trauma or Pressure on the nerve; Something Toxic such as alcohol and certain medications. As Optic Atrophy can be part of a more generalised problem it is important that it is correctly identified. Some Ophthalmologists have a special interest in these disorders and have a dedicated Neuro-Ophthalmology clinic. A Neurologist may also be in this clinic as well to help with the management.

Treatment very much depends on the cause. Blood tests, X-ray, Magnetic Resonance Imaging (MRI) and some other tests can help find out. If it is felt to be due to active inflammation then Steroids may help reduce the amount of damage. Once the nerve is pale it means that there has been irreversible damage to the nerve and so vision will not return to normal. If there is an inherited (genetic) part to the Optic Atrophy then a Clinical Geneticist can be involved to further explain the risk of possibly passing on the problem to the next generation. This is important as genetic conditions such as Lebers Optic Atrophy in a male can not be passed on if the genetic change lies in the mitochondria (‘power house’) of the cell. Theoretically in this condition stopping smoking and alcohol intake could help.

Getting the diagnosis correct is important and will therefore direct possible treatment. Should the damage to the nerve be permanent then looking at magnification aids in the Visual Aid Clinic and being registered as having sight difficulty can be of enormous help.