Question
Greetings,
In a recent human biology class numerous questions regarding eye function were asked and I was hoping you could provide some insight. I haven?t been able to find any answers from trustworthy, reputable sites. First, why are you more sensitive to light when you have a migraine? Mayo clinic has a great video on aura associated with migraine but nothing on sensitivity. Second, why does it seem to help you focus when you squint? Third, do adults normally experience changes in eye color? Numerous students claim that their eyes change color back-and-forth.
Thank you very much for providing your expertise.
Answer
Dear Elaine,
1. The nerves supplying the eyes and eye muscles are the same which supply other parts of the head, face and neck. When there is a bright light, the natural reaction is to reduce the size of the pupil or squint to let in less light inside the eye.
Even a normal perosn with no migraine will feel a little discomfort in bright light, which is exacerbated in migraine and the nerve supply being common, this comes as an uncomfortable reaction.
2. The central rays of light passing through the pupil or the central hole in the coloured part of the eye, pass without bending and fall on the retina. the rays of light on the periphery need to bend.
hence a pin hole or seeing by squinting tends to allow only the central rays to apss through without being bent and hence the vision is clear since it blocks the peripheral rays which bend light and cause the uncler part of vision.
3. Yes, eye colour can change as you age in some who have light pigmented eyes, which gain more pigment as they grow older as this is to do with changes (natural) in the melanin cells of the iris. Also, some medications can cause a change in colour.
Hope this helps,
Best,
Dr Shroff
