Why does the dry eye cause photophobia?

[cvowr]

A question without clear answers, still... It is very important to understand this. Photophobia is a major symptom of dry eye and therefore your etiology needs to be carefully studied to obtain solutions. I think the dry eye causes photophobia by the increased sensitivity to light of the nervous ocular surface. This increased sensitivity in turn can be caused by friction of the lids on the ocular surface. Maybe the tear also functions as a bandage, regulating over-stimulation. I also still think that the decrease in tear may allow greater passage of light to the retina, sensitizing it.
Hugs

[kitty]

http://milnesjs.com/DryEyes.aspx

"Light sensitivity is caused by dry eye, because as a result of the uneven tear film, the light entering the eye, hits the retina at irregular angles. Adding to that is the complication of an irregular cornea, or distortion caused by ocular surface disease...".

[bakunin]

http://milnesjs.com/DryEyes.aspx

"Light sensitivity is caused by dry eye, because as a result of the uneven tear film, the light entering the eye, hits the retina at irregular angles. Adding to that is the complication of an irregular cornea, or distortion caused by ocular surface disease...".

I think it is hard to believe it's only about uneven tear film. I think it may have something to do with epithelial damage...

[cvowr]

Kitty, interesting! Bakunin, I agree with you! At least, the Kitty found a official explanation! Let's try to find others explanations.

[poppy]

I agree with bakunin. Severe photophobia (eg photophobia that significantly limits your ability to carry out everyday tasks like use a computer or drive even with sunglasses on) is very unlikely to be caused purely by dry eye. I know some people do experience severe photophobia with clinically mild dry eye (eg no corneal damage) but I think most cases of photophobia in dry eye are due to secondary issues particularly inflammation of cornea (keratitis), damage to surface of cornea including abrasions, ulcerations, erosions etc...