Mechanism of photophobia

Hi,
I was wondering if anyone would be able to give me a good explanation on how photophobia occurs. Particularly in meningitis or migraines.
Thanks

Hello Jessica,

Photophobia is a term used to describe light sensitivity or abnormal intolerance to light. Patients with photophobia avoid light because of pain or discomfort. It is generally seen in diseases affecting the iris and anterior segment of the eye. However, photophobia may also be seen in patients with completely normal appearing anterior segments (including blepharospasm, sub-arachnoid hemorrhage and head injury apart from migraine and meningitis that you have mentioned).

The mechanism of photophobia is not very well understood, but is thought to involve the trigeminal pathway with possible input from the occipital lobe and thalamus. Irritation to any region supplied by the trigeminal nerve can result in photophobia. This is all that is currently know about the mechanism of photophobia.

Hope this helps...
Sorry for the delay in replying,
shashikiran

thankyou for the help. its clearer to me now.
Jess