Strabismus. Strabismus is defined as crossed or turned eyes. The examiner will check your eyes' alignment to be sure that they are working together. Strabismus causes problems with depth perception and can lead to amblyopia.
Eye teaming problems. Even if you eyes appear to be properly aligned, it's possible they do not work together efficiently as a team. Such binocular vision problems can cause headaches, eye strain and other problems that can affect reading and other near vision tasks.
Focusing problems. These problems can range from incompletely developed focusing skills in children to normal age-related declines in focusing ability (presbyopia) among older adults.
Eye diseases. Many eye diseases, such as glaucoma and diabetic retinopathy, have no symptoms in their early stages. Your eye doctor will check the health of your eyes inside and out for signs of early problems. In most cases, early detection and treatment of eye diseases can help reduce your risk for permanent vision loss.
Other diseases. Eye doctors can detect early signs of some conditions and diseases by looking at your eye's blood vessels, retina and so forth. Your eye doctor may be able to tell you if you are developing high blood pressure, high cholesterol or other problems.
For example, diabetes can cause small blood vessel leaks or bleeding in the eye, as well as swelling of the macula, which can lead to vision loss. Your eye doctor will likely detect this during a complete eye exam. It is estimated that one-third of Americans who have diabetes don't know it; your eye doctor may detect the disease before your primary care physician does, especially if you're overdue for a physical.
Why Vision Screenings Are No Substitute for a Complete Eye Exam
Vision screenings are limited eye tests that help identify people who are at risk for vision problems. These are the brief vision tests performed by the school nurse, a pediatrician, other health care providers or volunteers.
The eye test that you take when you get your driver's license renewed is an example of a vision screening.
Depending on who is performing the test and where the test is given, vision screenings may include tests for blur, muscle coordination and/or common eye diseases.
Keep in mind that a vision screening can indicate that you need to get your eyes checked, but it does not serve as a substitute for a comprehensive eye exam.
A comprehensive eye examination is performed by an eye doctor and includes careful testing of all aspects of your vision. Based on the results of your exam, your eye doctor will then recommend a treatment plan for your individual needs.
Remember, only an optometrist or ophthalmologist can provide a comprehensive eye exam — family physicians and pediatricians are not fully trained to do this, and studies have shown that they can miss important vision problems that require treatment.