Uneven Pupil Dilation

Dilation means expansion or growing in size, and pupil dilation is the expansion of the hole located in the iris that allows passing of the light into the eye. Pupils dilate for various reasons, they can dilate in the dark when we have to strain our eyes to see, sexual stimulation can be one reason, and if you are paying attention to something your pupils can get dilated. The pupils dilate for everyone, however, uneven pupil dilation is seen in very few people. Uneven pupils are mostly seen in children, although it is quite common in adults also. Anisocoria is the medical term for uneven pupils. It is important that you visit an ophthalmologist or a neuro-ophthalmologist for eye care if you have uneven pupils, as they can be symptoms of some underlying problems.

Causes of Uneven Pupils

Some people have uneven pupils for no apparent reason and they are termed as people with physiological anisocoria and this is a harmless condition. The people who have dilated pupils for a sustained period of time need to be careful and get checked up immediately. In some people, this uneven dilation just stays for a short period which is also harmless, but if the condition prevails it can be dangerous. Uneven pupil dilation causes can be varied, let's take a look at some of these.

Eye Medication
Some eye drops can cause the pupil in one eye to dilate more than the other, although this effect is temporary. Allergy medications can also have similar effect on the eyes, prompting one eye to dilate more than the other. Specialized eye drops used for eye inspections by ophthalmologists can also have this effect on the eye.

Plants
The Brugmansia Plant, commonly known as Angels Trumpet, is poisonous and can cause dilated pupils. This plant is found in parts of America like Florida, Georgia, etc. Other plants like Deadly Nightshade, which are natives to Asia can also cause uneven pupils.

Holmes Aide Syndrome
This is a neurological disorder affecting the pupil and the autonomic nervous system. It is caused by a viral or bacterial infection which affects an area of the brain responsible for eye movements. Holmes Aide Syndrome (HAS) is known to cause uneven pupil dilation.

Head Trauma
Accidents which cause head trauma are one of the most common reasons behind dilated pupils. In an accident, one of the visible signs of head injury is uneven pupil dilation and eye problems. If someone has uneven pupils due to an accident it is a cause for worry, and needs to be taken to the ER immediately.

Tumors
Brain tumors are sometimes the underlying causes of uneven pupils, as the movement of the eyes is controlled by neurons in the ciliary ganglio, an area of the brain. If pupil dilation is caused by brain tumors it is generally accompanied by severe headaches.

Nerve Damage
Nerves that run from the base of the brain to other parts of the brain are susceptible to damage by injury. These cranial nerves control our movements and the cranial nerves in the oculomotor, specifically the somatic motor, control the movements of the eyes. If they are damaged they can cause dilated pupils. Visiting an neurologist is the best uneven pupil dilation treatment in such cases.

Although some reasons for uneven pupil dilation are not a cause for worry, some can be serious. The best thing to do in case of uneven pupils is to unearth the possible reason and visit a physician.