Here’s a brief guide to the special tests your eye doctor may perform during an eye exam.
Applanation Tonometry
This test measures the amount of pressure it takes to flatten a portion of your cornea. Pressure readings help your doctor diagnose and keep track of glaucoma. They’ll give you drops to numb your eye, then press lightly on it with a tool called a tonometer.
Corneal Topography
This computerized test maps the curve of your cornea. It can show problems with your eye’s surface, like swelling or scarring, or conditions such as astigmatism or diseases like keratoconus. You might have it before you have surgery, a cornea transplant, or a contact lens fitting.
Fluorescein Angiogram
This lets the doctor see how well blood moves in your retina. It helps diagnose diabetic retinopathy, retina detachment, and macular degeneration. The doctor will inject a special dye, called fluorescein, into a vein in your arm. It travels quickly to blood vessels inside your eye. Once it gets there, the doctor uses a camera with special filters to highlight the dye. They takes pictures of the dye as it goes through the blood vessels in the back of your eye. This helps them spot circulation problems, swelling, leaking, or abnormal blood vessels.