These are a lot like the drops your eye doctor uses to dilate your eyes during an exam, but they can last up to 2 weeks. If your pupils are small because of inflammation in your eye, they can give you long-lasting dilating drops ( atropine or homatropine) that make your pupils wider. If a medication is to blame, they may be able to find a different option that solves the issue. Your doctor's recommendations will depend on what's causing your abnormal miosis. Or they may order images of your chest, brain, or neck to rule out signs of Horner's syndrome. Sometimes, your doctor may use drops that are supposed to make your pupils big to see how yours react. Your doctor can measure your pupils in both eyes to see how well they shrink and grow.

Normal pupils are 2 to 4 millimeters in bright light and 4 to 8 millimeters in the dark. They'll ask you to look at a faraway object.

To find out if you have abnormal miosis, your doctor will take a close look at your eyes in a dark room. Neurosyphilis (a bacterial infection in your brain that comes from untreated syphilis, a sexually transmitted disease).Less sweat on the side of your face with the miotic eye.Lighter eye color in the eye with miosis ( heterochromia).Horner's syndrome may cause no other symptoms, or you could have issues like: Sometimes kids get it if they have a rare type of cancer called neuroblastoma or a tumor in another part of their body. You can also get it if your chest, neck, or brain doesn't form correctly. You can inherit it from your parents, or it can happen after a neck injury or neck surgery. It can make one of your pupils smaller than the other. Horner's syndrome: This rare condition affects the way your brain 'talks' to one side of your face, including one of your eyes. Or you may have glaucoma, which means there's too much pressure inside your eyeball. If you have it, you may also be nearsighted and have trouble seeing things far away. You get it when one or both of your parents pass down a problem gene to you. Genes: Being born without the muscle that controls your pupils or with pupil muscles that aren't formed correctly is called congenital miosis or microcoria. So can narcotics, either prescribed or illicit. Side effect of a medication: Certain anxiety, muscle spasm, and seizure medications like diazepam ( Valium) or antihistamines like diphenhydramine ( Benadryl) can make your pupils shrink. It may also be because of a condition called uveitis, which is swelling in your iris - the part that gives your eye its color - and the tissues around it. Sometimes this happens if you've injured your eye. Inflammation: Swelling inside your eye can make it hard for your pupils to get bigger. This can make it harder for you to see at night.

The muscles that work your pupils can get weak and have a tough time opening them. Your pupils tend to get smaller as you get older, too. CausesĪge: It's normal for a newborn's pupils to stay small for about 2 weeks so their eyes have extra protection from bright light. This is called abnormal miosis, and it can happen in one or both of your eyes. If your pupils stay small even in dim light, it can be a sign that things in your eye aren't working the way they should. When your pupil shrinks (constricts), it's called miosis. When you're in bright light, it shrinks to protect your eye and keep light out. When you're in dim light, it gets bigger to let more light in. It changes size thousands of times a day. The black circle in the center of your eye is your pupil.

Constricted pupil size