Hi,
How old is your daughter?
Headaches, blurry vision and cold sweats may be due to an underlying hormonal disorder.Are there other associated symptoms like tremors, weight loss, loss of appetite, thinning of hair, rash, flulike symptoms ?
Other differentials will be an underlying anemic state, a cardiac disorder, a peripheral vascular disease, a viral infection. Your daughter's symptoms are actually nonspecific and may actually be a manifestation of several factors such as those I have mentioned above.
I suggest that she be fully evaluated. A complete blood count may be taken to rule out anemia and an underlying infection .Also, her cardiac function (EKG and 2DECHO) as well evaluation of her neck vessels may be done to rule out a cardiovascular cause. Thyroids and parathyroids may need to be assessed.
A localized cause such as eye problems may also need to be excluded. Only when all these organic causes have been ruled out that psychological factors may need to be focused on. Are there any current changes in your daughter's life that could be contributing to a high level of stress lately?
It may be that she is getting migraines as i have all of the above symptoms and thats what i've been told i have. It may also be low blood pressure mixed with this, have you asked her gp about this? She may need to go to a neurologist who can help more with a diagnosis. There are medications and other ways of sorting this. You'd have to ask her doctor about the low bp. but for the migraines she needs a good sleeping pattern, a balanced diet with plenty of iron, and exercise. I've been told walking doesn't count as it doesn't get the heart rate going fast enough, but swimming, jogging or joining a sports club may help :)
Low bp
Thats one of my issues and I have a lot of the same symptoms that you have mentioned except for the cold sweats, It happend in the morning and late night because thouse are the times when your bp is really low. Sorry I cant help much more, Good Luck