When you go for a routine eye exam, your eye doctor will use a variety of tests to examine your eyes and evaluate their overall health. Eye exams should be done as often as your eye care professional recommends.
Here’s what to expect during a routine eye exam.
Slit Lamp Exam
To examine the structures of your eyes, your eye doctor will use a slit lamp; a binocular microscope or bio-microscope that allows your doctor to see inside your eyes under high magnification.
You will be asked to rest your forehead and chin against the rests on the front of the instrument so your doctor can examine your eyelids, cornea, conjunctiva, iris and lens. The slit lamp may also be used, with the help of a hand-held lens, to examine the retina and optic nerve. Many eye conditions and diseases can be detected using a slit lamp.
The Glaucoma Test
A common test for glaucoma is the “puff-of-air” test. With your chin on the machine’s chin rest, you look at a light inside the machine. A small burst of air at your open eye calculates your intraocular pressure based on your eye’s resistance to the puff of air. It’s completely painless and the machine never touches your eye. You may be at risk for glaucoma if you have high eye pressure.
Typically, there are no warning signs of glaucoma until there is already significant vision loss. Routine eye exams that include a glaucoma test are essential to protect your eyesight.
In order to get a better view of the inside of your eye, your eye doctor will put dilating drops into them to enlarge the pupils. These drops usually take 20 to 30 minutes to start working. You may notice a difficulty focusing on close up objects and be sensitive to light. The effects of dilating drops can last for hours depending on the strength of the drop used. Bring sunglasses to minimize glare and light sensitivity on the way home.
After the drops have taken effect, your eye doctor will use different instruments to look inside your eyes. These tests are extremely important for people with risk factors for eye disease.
A refraction test is used to determine your level of farsightedness, nearsightedness, astigmatism and presbyopia and will give the eye doctor your exact eyeglass prescription.
Your eye doctor will put an instrument called a phoropter in front of your eyes and give you a series of lens choices. You will then be asked which of the two lenses in each choice give you clearer vision. The eye doctor will continue to adjust the lens power to reach a final eyeglass prescription.
Autorefractors and Aberrometers
An autorefractor or aberrometer may be used to automatically estimate a patient’s prescription. Both devices use a chin rest to stabilize the head while the patient looks into an instrument at a pinpoint of light or detailed image.
Autorefractors are very helpful in determining eyeglass prescriptions for young children or other patients who may have difficulty sitting still, paying attention or providing answers to questions that the doctor needs to get an accurate reading. Modern autorefractors are very accurate and save time because it only takes a few seconds.
An aberrometer uses advance wavefront technology to find even faint vision errors. It is based on the way light travels through your eye and is mainly used for vision correction procedures, such as Lasik. However, many eye doctors now incorporate this technology into routine eye exams, as well.