My sister has been complaining of her eyes....?

Dry eye, astigmatism, allergic reaction to any meds, foods, allergens, ETC....

Honestly it could be anything. Have her rinse her eyes out with warm/cold running water. Also If you have city water the chlorine they put in there could help cause that so but purified water and do it. Rinse for 15 min straight to get anything in there out.

If this continues to bother her for more then 3 days then please contact your doctor and have a full check up.

~RED