I am a 37 year old female. I recently priced that one pupil is slightly larger than the other in low light situations. In full light they both constrict the same and the one that does not dilate as large still dilates, just not quite as large as the other. I've always noticed that at times the same pupil larger than the other, but lately it just seemed to catch my attention I the mirror more than it would have. I recently started prozac and am building up to a higher dose. I've noticed that my eyes in general seem to act like when they're dilated, bright is brighter and sometimes things are blurrier. My psychiatrist thinks that the vision symptoms are aide effects to starting the prozac and I'm wondering if it can cause one pupil to dilate larger as well. I have had an eye exam in the past month with pressure checks and a retinal scan of both eyes although he didn't dilate my eyes. I have also had a cat scan of the brain in the past six months due to my gp checking on my migraines and it was normal. I have an Arnold chiari malformation that I had decompression surgery on ten years ago. Is this something I should return to the doctor for or would either the optometrist or gp have seen what they needed to see already? I have no other symptoms.
Most individuals have unequal pupils (with one appearing more dilated than other), but the difference between the two pupils is less than 2mm. This is known as physiological variation. If the difference between the two pupils is more than 2 mm then it could be due to a pathological cause.
The cause could be due to an abnormality in the musculature of the iris or in the parasympathetic or sympathetic innervations to the pupil. The parasympathetic system constricts the iris, while sympathetic channels dilate the iris. These parasympathetic innervations occur through a synapse at C8-T1 level of the cervical cord. So, if you have neck and upper back ache too, then this cause should be further investigated.
Well, Horner syndrome may be a possibility but it is usually associated with decreased sweating too apart from constricted pupil and drooping eyelid. The cause is usually a mass or lymph node in the chest pressing on the nerve.
Unequal pupil could also be a sign of serious brain injury. Even the Chiari malformation could be the cause, and this need to be re-checked whether you have more pressure on one side. Aneurysms, bleed in the brain, glaucoma, meningitis and tumors also cause unequal pupil size.
Please consult your doctor regarding this. Good Luck and take care!
Also I did some internet searching (which I know I shouldn't do) and read about something called Horner's Syndrome. The eye that doesn't dilate as wide does have a slightly lower eyelid, although it has been like that for sometime and I always contributed it to aging. However reading about that did make me wonder as well as made me nervous.
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