What Is Miosis

What Is Mydriasis?

Mydriasis is a condition where the eyelids do not close completely. When I say closed, it means that they are slightly raised from their normal position. The eyes are usually very red when affected with mydriasis. A person may have one or both eyes affected with mydriasis. The most common cause of mydriasis is cataracts which often leads to partial blindness due to reduced vision in one or both eyes (myopia). Other causes include diabetes mellitus, glaucoma, and other diseases affecting the lens of the eye.

Miosis Causes:

The exact causes of mydriasis are unknown but there are several theories that could explain it. One theory suggests that mydriasis occurs because the eyeballs cannot accommodate to the pressure of the fluid inside them. Another theory says that it is caused by inflammation in the eye’s tissue and/or blood vessels causing increased pressure within the eyeball. Still another theory states that mydriasis is caused by a lack of oxygen to the eye cells. There are many different theories about what causes mydriasis but none of them are proven yet.

Diagnosing Mydriasis:

There are two ways to diagnose mydriasis; by physical examination and ophthalmological examination. Physical exam includes looking at the eyeballs, examining the cornea, and checking for any abnormalities in the retina. Ophthalmological examination is done in a dark room, the doctor uses an ophthalmoscope to examine the back of the eye and look for signs of cataracts.

Treating Mydriasis:

In most cases mydriasis clears up on its own. In some cases, mydriasis are caused by an underlying medical condition that must be treated first. For example, mydriasis caused by glaucoma must be treated with medicine and/or surgery. It is important to treat the underlying condition because if the condition is left untreated, it can lead to blindness. In some cases, mydriasis caused by certain drugs must be treated with topical decongestants to relieve the pressure inside the eye and help the lids close.


Miosis is the medical term for a condition in which the pupils of the eye are constricted. Miosis is the opposite of mydriasis and it is also referred to as pin point pupils. The cause of this condition can be several things including certain drugs, alcohol, abdominal tumors, liver disease, kidney failure, diabetes, glaucoma, and brain damage.

Miosis Symptoms:

Pin point pupils, blurred vision, sensitivity to light, headache, dry eyes, and/or blurred vision.

Miosis Diagnosis:

Your doctor will ask about your medical history and do a physical examination of your eyes. In some cases your doctor may refer you to an opthalmologist.

Miosis Treatment:

Treatment for miosis depends on the underlying cause. For example, a common cause for miosis is opiates (drugs such as morphine, codeine, Vicodin, etc.) which will be treated by weaning the patient off the drug. Miosis caused by brain damage may be irreversible.