Pharmacologic anisocoria can develop as a side effect from certain medications.

Pupil displacement and lens dislocation (ectopic pupil).

Total or partial absence of the iris (aniridia).

Mechanical anisocoria may also develop from an ocular tumor or congenital condition that affects the structure of the iris, such as: Mechanical anisocoria can occur following a trauma to the eye that has caused damage to the iris or the structures around it.Įye trauma can be caused by an eye injury, eye surgery complications, angle-closure glaucoma, iritis, or uveitis. If these symptoms come on suddenly, seek immediate medical attention. Third nerve palsy is considered a medical emergency.

Poor accommodation, or ability to shift focus.

If this nerve becomes paralyzed from an aneurysm, brain hemorrhage, or tumor, the pupil will appear dilated at all times.Ĭhildren with third nerve palsy can develop this condition from a migraine, meningitis, or other severe infection. Third nerve palsy: The third cranial nerve (oculomotor nerve) innervates some of the muscles that control eyelid and eye movement, as well as pupil size. In most cases, the cause of Adie’s tonic pupil is not understood, though it primarily affects women ages 20 to 40 years. When this occurs, the affected pupil usually does not respond to light normally. Horner’s syndrome affects the pupils’ ability to dilate normally in low light (within five seconds) and instead generally leads to a delayed pupil response of around 10 to 20 seconds.Īdie’s tonic pupil: generally affects only one pupil, and can develop when the nerves that innervate the muscles responsible for pupil constriction, become damaged.

Facial anhidrosis- inability to sweat around the eye.

Horner’s syndrome: is usually caused by an underlying medical condition, such as a tumor, spinal cord injury, or stroke- though sometimes, the cause is unknown. Though sometimes, the pupils may remain unequal even after the iritis has been treated. The anisocoria is generally treated with the treatment of the iritis.

Presence of inflammatory cells in the eye’s anterior chamber.

Iritis: is a type of uveitis, or inflammatory eye disease, caused by an eye infection, another inflammatory eye disease, or eye trauma. Pathologic anisocoria develops from an underlying disease or condition, often iritis. If you have different size pupils, contact an eye doctor near you, who can diagnose and treat the condition. The precise cause of this type of anisocoria has yet to be discovered. This condition can be intermittent or constant, and may even go away on its own without medical intervention. This is a benign condition that causes the pupils to differ in size, usually by up to one millimeter in diameter, without affecting the pupils’ response to light. Simple anisocoriaĪlso called essential anisocoria and physiologic anisocoria, this is the most common type of anisocoria, that has been shown to affect 20 percent of people. There are four main types and causes of anisocoria: 1. In some cases, the pupils may continue to respond normally to light, while in other cases, their responses may differ from one another.Ĭaution: If you notice that your pupils suddenly become unequal in size, seek immediate medical attention as this can be a symptom of a medical condition that requires prompt treatment. What causes unequal pupils?Īnisocoria may be diagnosed if one pupil is bigger or smaller than the other.

In most cases, having two different pupil sizes is not a cause for concern - but in some cases, it can indicate a serious problem, requiring emergency medical attention. Occasionally, the two pupils can appear unequal in size. The pupil controls the amount of light that enters the eye by widening and constricting in response to light intensity.

The pupil is the black hole in the center of the iris, the part that gives your eye its unique color. Different sized pupils could indicate a serious health issue requiring urgent medical care.

Unequal pupil size means