Glaucoma can be diagnosed with a series of tests given by an eye care specialist. These tests are given during an eye exam that is conducted in the eye care professional's office. The exam will begin with the eye care professional or staff person asking you questions about your personal and medical history and your family’s medical history.
To detect glaucoma, your eye care professional will do the following:
Visual acuity —This test measures how well you see at various distances. You will be asked to look at a chart of letters or numbers and identify what you see.
Tonometry —This test measures the pressure inside the eye. There are several types of tonometry; in air tonometry, a puff of air is blown onto the cornea to take the measurement. Another type uses a small plastic device (Goldman tonometer) that lightly pushes against your eye in order to measure your intraocular pressure. For this test, the eye is first numbed with an eye drop, so you do not feel anything.
Gonioscopy —The eye care professional can see the drainage angle of your eye using a special lens. This can help determine if you are at risk for closed-angle glaucoma.
Pupil dilation —Drops are put in your eyes that enlarge/dilate your pupils. This allows the eye care professional to see more of the inside of your eye. Your close-up (near) vision may remain blurred for several hours afterwards and you may be sensitive to bright light. Ask your doctor for a pair of sunglasses after the dilation .
Ophthalmoscopy —Once your pupils are dilated, the eye care professional will examine your optic nerve and the rest of your retina with an instrument called an ophthalmoscope. The color and appearance of the optic nerve may indicate if damage from glaucoma is present and how extensive it is.Your doctor will probably take pictures of your optic nerve for future comparison.
Perimetry (visual field test) —This test produces a map of your field of vision. It is used to check whether there is damage to any area of vision. Since glaucoma slowly affects your peripheral, or side vision, you may not know you have any problems until detected on this test.
Pachymetry —Your physician may measure the thickness of your cornea using a special machine called a corneal pachymeter. Your eye is numbed with a drop first and it does not hurt.
Nerve Fiber Layer Analysis —Your doctor may use a special machine, such as an OCT, GDx, or HRT, to measure the thickness of the nerve fiber around your optic nerve. This can often be compared to normative data from other people without glaucoma of your age, sex, and race. It also can be rechecked in the future to see if there is any loss of nerve fiber thickness with time.
If the eye care professional finds evidence that you have glaucoma, you might begin a treatment program. Glaucoma cannot be cured, but treatment can help control the disease.