Comprehensive Eye Exam
Diabetes can cause blood vessels in the retina to become damaged or blocked, resulting in vision loss — a condition known as diabetic retinopathy. The National Eye Institute (NEI) estimates that half of all people with diabetes will develop retinopathy at some point in their lifetime. They are also at risk for developing cataracts and glaucoma, which may impair vision.
Both the ADA and the NEI recommend an annual dilated-eye exam for people with diabetes. If you have type 1 diabetes and have no known vision problems, the first exam should be five years following initial diagnosis; for type 2 diabetes, it should be at or shortly following diagnosis. If you have diagnosed eye disease, you may require more frequent assessment to monitor treatment and disease progression.
Pregnant women with pre-existing diabetes (not gestational diabetes) should have a dilated-eye examination during the first trimester of pregnancy to screen for microvascular (blood vessel) problems, with exams through pregnancy and the postpartum period. The ADA also recommends a preconception eye examination.
In a dilated-eye exam, eyedrops are used to counteract the reflexes that normally trigger the pupil to shrink in bright light. The ophthalmologist or optometrist uses a high-intensity focused light called a slit-lamp to illuminate the eye. Dilation opens up the pupil, allowing the ophthalmologist to view the back, or fundus, of the eye and the blood vessels and optic nerve situated there.
An intraocular pressure test, also called a tonometry test, is used to screen for glaucoma. Tonometry is sometimes called a puff test because it may involve blowing a quick puff of air at your eye and measuring the resistance it meets. Another type of pressure test, applanation, uses fluorescein dye to temporarily color the cornea before a tonometer instrument is placed against the eye to measure fluid pressure. Anesthetic drops are used to prevent any discomfort.
Other parts of a comprehensive eye exam may include the following tests:
Visual acuity test: The familiar Snellen eye chart
Visual field test: A test of your peripheral (side) vision
Refraction test: Checks how light reflects, or refracts, off your retina
Binocular test: Assesses your eye teamwork — how well the muscle coordination and control of your eyes work in tandem
If you wear glasses or contact lenses, your exam should also include an evaluation of your current prescription.