LHON Symptoms

What are the symptoms of LHON?

The major symptom of LHON is sudden, painless loss of central vision.

Doctors have not found any symptoms which can warn someone they are likely to lose eyesight.

LHON can affect someone at any age.  There are people affected by LHON under the age of five and over seventy.

Rough graph showing that people can be affected from childhood to over 70 years, but most are affected as early adults.

The commonest age for some to be affected by LHON is in their late teens or twenties.


Generally, doctors call the time when eyesight is rapidly getting worse the ACUTE PHASE.

Doctors call the time after the Acute Phase the CHRONIC PHASE or the ATROPHIC PHASE.


Central Loss of Vision

In most cases LHON affects eyesight in one eye first, and the second eye is affected two or three months later.

Some people say that their eyesight was affected in both eyes at the same time, but doctors think that this is because the vision system compensates for loss of sight in one eye. the patient does not notice the problem until the second eye starts being affected.

There are some cases where LHON only affects one eye, or the gap between eyes being affected is very long.

Vision is blurred or obscured in the very center of the field of vision. The patient might see small spots of bright colour or greyness.

The central loss of vision grows over a period of a few weeks then the growth slows.

This loss of central vision is called a CENTRAL SCOTOMA.

If both eyes are affected this is called a BILATERAL CENTRAL SCOTOMA.

The central field of vision might be “grayed” or blacked out.

Many people affected by LHON are left with enough peripheral vision to walk around without a white cane.

Most people will not have enough vision left to read print, recognise faces or drive a car.

Visual acuity is severely reduced, often to the point where the patient cannot see an eye chart and is assessed at “Counting Fingers”. Most people will have acuity low enough to be  legally blind.

Painless loss of vision

The optic nerve damage usually happens without severe inflammation or pain.

People affected by LHON might experience some pain or headaches due to the strain of learning to use their remaining visioni.

Retinal Symptoms

During the Acute phase there may be disc swelling and edema of the peripapillary nerve fiber layers. (swelling and fluid build up in the retinal nerve fiber layer)

Retinal telangiectasia – small blood vessels dilating and appearing as spidery red or purple clusters.

Increased vascular tortuosity – Twisting of the blood vessels.

There is a distinctive change in the Visually Evoked Response seen in PERG testing.

At the end of the Acute Phase the Optic Disc is pale due to atrophy.

An OCT test will show changes in the thickness of the Retinal Nerve Fiber Layer. (22562299)


Vision is usually relatively stable after the Acute Phase, but some people experience changes in usable vision in the next 12 to 24 months.

Rarely, vision can continue to deteriorate very slowly, or can show some recovery in the next 12 to 24 months.

Most patients do not see any significant changes in eyesight in this phase.

The LHON Recovery page has information on research documenting patients who have shown some recovery.

Care of the patient is rehabilitation, orientation and emotioinal support.  Refer to the Living with LHON pages such as  Emotional Support and Useful Aids.


Other Symptoms

Some people have experienced tremors and muscle weakness.

Some people develop symptoms similar to Multiple Sclerosis.  There are several studies documenting this in women carrying a LHON muation. (15002319)(24198293)(14593764)(24610697)(18344382)(25677293)(18061280)(11589893)(25677293)(21685233)(25053773)(19800080)(19009343)(15002319)(12510724)(12225323)(11741103)(11589893)(9300066)

Researchers have found som eevidence of hearing impairment due to Auditory Neuropathy  in people with a LHON mutation. (21887510)(12820379)(15026512)

Some people affected by LHON, particularly women, might also develop some Multiple Sclerosis like symptoms.    See the page on LHON and Multiple Sclerosis.

One research study has found an increased chance of Aortic stiffness in people with LHON. (18320530)


This page was last updated September 14 2015


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