Dyslexia really has nothing to do with vision. It is a language-based learning disability that needs to be evaluated by a specialist in this area. You have a legal right to request an evaluation at your daughter's school or your school district. The evaluation is usually done by a team of professionals. A social worker or other member of the team will interview you and ask you about your daughter's developmental history (when she started walking, talking, etc.) plus information about your view of the problems she is having in school. A psychologist will administer an I.Q. test to determine your child's potential to learn. She may also give other tests to see if there are any other reasons for her difficulties. An educational evaluator will give a battery of academic tests to determine how your daughter's performance compares to others in her age/grade. After the evaluation is complete, the members of the evaluation team will share their results with you and make recommendations for any support services that may be necessary in school.
You can get more information about both the evaluation and treatment for dyslexia by calling the toll-free number of the International Dyslexia Association (IDA) at 1-800-ABCD123. The Coordinated Campaign for Learning Disabilities has an excellent, easy-to-understand booklet about learning disabilities that is free for the asking. You can request the booklet by calling 1-888-GR8-MIND. You can also get referrals for private evaluations and specially trained tutors with experience working with children with learning disabilities through these two groups. Good luck!