You look in the mirror and notice that the dark circles in the middle of your are bigger than usual. What\’s going on? Those dark circles are your pupils, the openings that let light enter your eye so you can see. Muscles in the colored part of your, called the iris, control your pupil size. Your pupils get bigger or smaller, depending on the amount of light around you. In low light, your pupils open up, or dilate, to let in more light. When itвs bright, they get smaller, or constrict, to let in less light. Sometimes your pupils can dilate without any change in the light. The medical term for it is mydriasis. Medicines, injuries, and diseases can all cause this eye condition. A few medicines can affect the muscles that control your pupils and prevent them from getting smaller when light shines in.
These meds include:
(Atropen), which treats problems with rhythm, issues, and some types of poisoning, like diphenhydramine, like and anti- medicines such as Parkinson\’s medications such as ( ) and -levodopa ( like amitriptyline ( ) and ( (, Myobloc) Anti- drugs, such as ( ) and topiramate ( Dilated pupils are one sign that someone has used, such as: These drugs affect the muscle that widens the pupil, slowing how it reacts to light. So even in a bright room, the stay dilated. Withdrawal from these drugs can also make the pupils stay open wide. Pressure that builds inside your after a head injury, or tumor can damage the muscles in your iris that normally make your pupils open and close.
One or both of your pupils can become fixed in the dilated position and canвt react to light. If that happens, you should see a doctor right away. If you\’ve had a, your doctor or nurse might shine a light into your during the exam to see if your pupils get smaller. There isn\’t enough information to answer with any specificity as more details are required. In the case where one pupil does not respond to dilating drops there are several possibilities. The iris could be partially stuck to the lens because of prior inflammation or trauma or prior surgery. The condition of one pupil being larger than the other without having received dilating drops is called. The causes of this are too numerous to discuss in detail. Most common is simple anisocoria, which is usually a small difference between the pupil sizes and is a normal variant.
If this is a new observation then the ophthalmologist would have to determine if the abnormal pupil is the smaller one or the larger one. A unilaterally constricted pupil can be caused by local ocular factors such as inflammation or trauma but also may be related to a failure of the dilator muscle due to a neurological condition such as Horner\’s syndrome. Horner\’s syndrome can be a benign condition or be caused by a vast array of things such as a tumor in the chest, carotid artery dissection, migraines, trauma and some medications to name just a few. It can also be congenital. Some drops and some systemic medications and drugs may cause a constricted pupil.
A unilaterally dilated pupil can be a benign finding such as a tonic pupil. It can be related to local factors such as a history of eye trauma or surgery. It can also be a result of paralysis of the iris constrictor muscle which may result from many neurological conditions but especially from involvement of the third nerve. If that is the case this can be an emergency resulting from a brain aneurysm. There are also many drugs and systemic medications that can cause a dilated pupil. The main point here is that differences in pupil size, reactivity, or reaction, while often benign, may be a harbinger of a very serious condition or even an emergent life threatening condition. Examination by an ophthalmologist is required.