Typically, the pupils dilate, or widen, in response to low light so they can collect more light. (healthline.com)
Sometimes pupils will dilate for a reason unrelated to the levels of light in the environment. (healthline.com)
A doctor or optometrist will sometimes apply a substance called a mydriatic to your eye to dilate the pupils. (healthline.com)
Often, you'll be given eye drops to open up (dilate) your pupils. (medlineplus.gov)
You may need someone to drive you home if the doctor uses eye drops to dilate your pupils. (medlineplus.gov)
When you're in low or no light, your pupils (that black circle in the center of your eyes) will get bigger (dilate) so that more light will enter your eye. (clevelandclinic.org)
An earlier version of this story incorrectly said doctors who shine a light into a patient's eyes check to see if the pupils dilate. (wamc.org)
Horner Syndrome Horner syndrome affects one side of the face, causing the eyelid to droop, the pupil to become small (constricted), and sweating to decrease. (merckmanuals.com)
These pathways carry nerve impulses to the pupil and to the muscles that control the eye and eyelid. (merckmanuals.com)
Thus, people with nervous system disorders that affect the pupil often also have a drooping eyelid, double vision, and/or visibly misaligned eyes. (merckmanuals.com)
Horner syndrome refers to the combination of a constricted pupil, drooping eyelid, and loss of sweating around the affected eye. (merckmanuals.com)
If pupil sizes are very unequal, a person may notice the discrepancy. (merckmanuals.com)
More often, unequal pupils are noticed only during a doctor's examination. (merckmanuals.com)
Unequal pupils themselves usually cause no symptoms, but occasionally a person may have trouble focusing on near objects. (merckmanuals.com)
These more noticeable symptoms are often the reason people seek medical care rather than the unequal pupils. (merckmanuals.com)
Eye disorders that cause unequal pupils include birth defects and eye injury. (merckmanuals.com)
Inflammation of the iris (iritis) and certain types of glaucoma cause unequal pupils, but this finding is usually overshadowed by severe eye pain. (merckmanuals.com)
Miosis1
When this occurs, the pupil constricts (miosis), and the iris becomes swollen and the conjunctiva reddened (bloodshot). (petplace.com)
Injury to the eye, such as blunt force trauma, may damage the nerves controlling the pupils or the iris, the pigmented part of your eye. (healthline.com)
If optical aberrations in the eye could be eliminated, the theoretical limit of foveal acuity would be 20/12 for a small pupil and up to 20/5 for a dilated pupil. (medscape.com)
Light7
This can disrupt the normal response pupils have to levels of light in the environment. (healthline.com)
Examine the pupils with a penlight to see if they respond (constrict) properly to light. (medlineplus.gov)
EMS providers noted that Officer 1's pupils were 4 mm (normal range is 2-4mm in diameter depending on ambient light) and reactive. (cdc.gov)
Finally, doctors may check to see if a person's pupils are dilated and whether they constrict in response to light. (wamc.org)
Usually both pupils are about the same size and respond to light equally. (merckmanuals.com)
In such people, both pupils react normally to light and darkness and there are no symptoms. (merckmanuals.com)
Either the larger or the smaller pupil may be the abnormal one depending on the cause. (merckmanuals.com)
If the smaller pupil is abnormal, the difference is greater in the dark. (merckmanuals.com)
Lens1
The pupil was round and reactive, the lens was clear, and a slight iridodonesis was observed. (cdc.gov)
Symptoms1
Activation of the sympathetic nerve system-such as in a dangerous situation that mobilizes the flight response-can result in dilated pupils, dry mouth, restlessness, higher risk readiness, and other observable symptoms. (aacc.org)