A number of muscle conditions affect the the eyes. The two most common are:

  • oculopharyngeal muscular dystrophy (OPMD)
  • mitochondrial chronic progressive external opthalmoplegia (CPEO)


OPMD is a condition caused by a faulty gene. Although the abnormal gene is present from birth, the individual won’t usually develop symptoms until they are in their 50s or 60s. As OPMD causes weakness in the eye (ocular) and throat (pharyngeal) muscles, the first signs are droopy eyelids and a difficulty swallowing. After many years the person may develop mild limb weakness around the shoulders and hips. Life expectancy is rarely affected.
OPMD is mainly inherited as an autosomal dominant disorder.

CPEO causes similar symptoms to OPMD and in older patients it’s not always easy to distinguish between the two conditions. The first symptom is droopy eyelids followed by a progressive limitation of the range of eye movements. This is more severe than in OPMD and sometimes all eye movements are lost.

A faulty structure or function of certain mitochondria causes CPEO. Mitochondria are tiny structures present in every cell of the body. They are vitally important in the chemical processes that generate energy needed to keep the cell alive and working normally.

Mitochondrial DNA is passed from mother to child therefore a child can only inherit the conditions from an affected mother. An affected father cannot pass on the condition.

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