Eyes/pupils different size
Key points
- One pupil (of the eye) is a different size from the other one.
- Occasionally, differing pupil size is inherited and there is no underlying disorder.
- Home Care Treatment depends on the cause of the enlargement of one pupil.
- What to expect at your health care provider's office The medical history will be obtained and a physical examination performed.
Alternative names
Enlargement of one pupil; Pupils of different size; Anisocoria
Definition
One pupil (of the eye) is a different size from the other one.
Considerations
Occasionally, differing pupil size is inherited and there is no underlying disorder. If other family members also have this condition, then pupil size is probably genetic and is nothing to worry about.
Occasionally, for unknown reasons, pupils may differ in size. If there are no other symptoms and if the pupils return to normal, then the transient condition is nothing to worry about.
Head injuries that cause differing pupil sizes are usually curable with early recognition of danger signs and medical treatment. Complications, however, can be life-threatening or cause permanent disability.
Common Causes
- Bleeding inside the skull caused by head injury
- Brain tumor or abscess
- Infection of membranes around the brain caused by meningitis or encephalitis
- Expanding brain lesion such as an aneurysm
- Excess pressure in one eye caused by glaucoma
- Birth injury, tumor in the chest, or lymph-node pressure that may be accompanied by decreased sweating on the side with a dilated pupil or drooping eyelid on the affected side
- Eye-drops
Home Care
Treatment depends on the cause of the enlargement of one pupil. For example:
- For pupil size inequality caused by a head injury, get immediate medical help.
- For pupil size inequality caused by a tumor, follow prescribed therapy. Stay active as strength allows. Work and exercise moderately. Rest when tired.
- For pupil size inequality caused by meningitis or encephalitis, follow prescribed therapy and rest in bed in a darkened room.
- For pupil size inequality caused by acute glaucoma, avoid emotional upset, which raises pressure in the eye. Don't smoke. Tobacco constricts blood vessels, reducing the blood supply to the eye. Follow prescribed therapy that may include eye drops to lower pressure inside the eye, diuretics to decrease fluid pressure in the eye, or pain relievers. After treatment, resume normal activities, but avoid fatigue. A low-salt diet is recommended.
Call your health care provider if
Written and revised by
David Cohen, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
health.am provides general information, not medical advice. Always consult a qualified health professional about your own health.