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Dr. Dan B.
Dr. Dan B., Board Certified Ophthalmologist
Category: Eye
Satisfied Customers: 3343
Experience:  and eye surgeon experienced in cataracts, glaucoma, retina & neuro-ophthalmology
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one pupil slightly bigger than the other?

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Is it normal to have one pupil slightly bigger than the other?Sometime my right pupil appears slightly larger, the difference is marginal and they both react to light at the same rate. I'm worried because I've been having headaches recently, although this is now improving. I've seen my GP and he said that my headaches were likely due to sinus infection and the when he looked in my eyes there was no swelling behind them

Dr. Dan B. : Hello and thanks for your question. This is actually very common, especially when the difference is only slight. Let me elaborate...
Dr. Dan B. : Depending on whether there is any problems with the movements of the eyes, drooping of the eyelids or other symptoms, a mild difference in the size of the pupils is usually a benign (harmless) finding. The cause of the difference in dilation can be a normal variant but it can also be a damaged nerve that is responsible for pupil function as well as moving the eye in certain directions or it could be a malfunctioning sympathetic nervous system nerve either in the head, neck or chest. Unfortunately because the signs of these are subtle only an ophthalmologist or neurologist can can say with any degree of certainty whether this is a normal variant (called physiologic anisocoria) or one of these uncommon problems I've just mentioned. If the size difference is no more than 2mm at any one time and is not accompanied by headache or eye pain, a droopy eyelid, changes in vision, double vision or other neurological symptoms then it is likely benign. If this is not the case then I would recommend seeing your eye doctor.
Dr. Dan B. : Does this make sense?
Dr. Dan B. : Does this information help address your concerns? Do you have any other questions about this? It appears as though you are not in the chat room currently. I am happy to be able to help you today. If you need any clarification regarding anything I've said, please let me know and I will be happy to address your concerns as you voice them. If your concerns have been resolved...Your feedback is important to me and will help me improve my encounter with future customers. Please rate your encounter with me by providing positive feedback (by pressing the smiley face); any bonus you may feel prompted to provide would be welcomed and is appreciated. If you feel like your concerns are not resolved or you have a problem or issue with anything I have said or haven’t said, please don’t issue a negative feedback rating—My goal is your satisfaction and I would rather work together to solve your concerns, until you are satisfied, than have you leave our encounter unhappy and unsatisfied. My opinion is solely informative and does not constitute a formal medical opinion or recommendation. For a formal medical opinion and/or recommendation you must see an eye doctor. Thanks for your inquiry!

Thank you for your reply. I'd say the variant is never more tham 1mm and I only ever notice the difference in dimmer light.


I have been experiencing more headaches over the past few weeks but this does seem to be improving now. My GP checked for papilloedema and he said my eyes looked normal, could he have seen nerve damage with an opthalmascope alone? No drooping of the eyelid or double vision although i could probably benefit from getting my eyes tested as its been a while. When say benign do mean as opposed to disease or something else? I have quite bad health anxiety and worried this is a brain tumour?


Which eye would be of more concern, the larger or smaller pupil? They react to light at the she


*the same rate

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