While there are a few online eye test tools and handheld devices that can generate a prescription for glasses or contacts, they typically don't provide all the benefits of an in-person comprehensive eye exam.
In a comprehensive exam, your eye doctor checks your overall health as well your visual acuity and any refractive error.
How do I get a prescription for glasses?
Many people who buy glasses or contact lenses today get their prescription after an eye exam during which an eye doctor (optometrist or ophthalmologist) checks their vision, eye health and so much more.
If you have vision insurance through work or an individual policy, the cost of your eye exam may be covered. If you are older or on a fixed income, there are places where you can get a low-cost eye exam.
How is my vision prescription calculated?
A vision test — whether administered by your eye doctor or via an online tool — checks the refraction of your eyes, which is the part of an eye examination in which you look at charts of letters or shapes of different sizes.
The eye chart helps determine how well you see at different distances, a measurement expressed in two numbers: 20/20 means you see at 20 feet what someone with normal vision should see at 20 feet.
If any objects on the chart are blurry or hard to read, you could have a refractive error, such as nearsightedness (myopia), farsightedness (hyperopia) or astigmatism. The "error" you keep hearing about refers to the shape of your eye — certain eye shapes don't allow light to be focused onto the back of your eye (your retina) properly, which gives you blurry vision.
But a refractive error isn't the only problem you might have with your eyes. An eye doctor also checks the health of your eyes, looking for early signs of macular degeneration, glaucoma and other eye conditions. They may also be able to spot early signs of diseases like diabetes and cancer.
Why should I get an eye exam to get glasses?
It is recommended to have an eye exam, not just a test for refractive error.
At a comprehensive eye examination, your eye doctor checks the pressure inside your eye, looks at your pupils to see if they react to light properly, inspects your corneas and peers into the back of your eye to evaluate the retina.
Each part of the exam checks a different part of your eye.
Your doctor will check how well your eyes move and if they are aligned correctly. He or she will also check your side (peripheral) vision, the loss of which could be a symptom of several eye conditions, including glaucoma.
Why is my eye doctor asking about my family history?
Before your eye exam, your eye doctor will ask you about your overall health and what medications you take. You will also be asked about any vision problems in family members.
Some eye conditions, like glaucoma, cataracts and age-related macular degeneration can run in families, she adds, which means a regular eye exam can catch them early.
It’s just as important for your eye doctor to know what drugs and vitamins you're taking.
SEE RELATED: Vision problems? Your medication side effects may be the culprit.
Do I need an eye exam if I have good vision?
If you have been blessed with good eyesight all your life, you should still have an eye exam done by the time you reach age 40. This is because the risk of developing eye disease typically goes up as you get older.
After age 40, if your eyes are in good shape, schedule an eye exam with an ophthalmologist or optometrist every two or so years.
If you have diabetes or high blood pressure, don't wait until you turn 40. These two conditions can damage your eyes if they are not well controlled. You should have your eyes checked regularly to catch any problems early.
Sudden vision problems? Book an eye exam
If you think you are having a problem with your eyes or with your vision, don’t wait for your next scheduled appointment.
If you are having any eye discomfort, irritation or pain, see your optometrist or ophthalmologist as soon as possible. This is true also if you have scratched your eye or if your eye or eyelids are swollen. Many conditions can harm vision permanently.
Is a prescription necessary to get eyeglasses or contact lenses?
Yes. In the United States, eyeglasses and contact lenses are regulated as medical devices, and, as such, you need a prescription to purchase them.
Prescriptions can be attained through your eye doctor or an FDA-approved online vision test.
Online vision test or eye exam?
Sure, you could seek out an online vision test to get a prescription for glasses, but a comprehensive eye exam checks so much more than your eyes.
Going the online route may seem like a good opportunity for savings but many insurance carriers do not cover online vision tests. And, in the long run, remember that an online test only checks your refraction and visual acuity; it typically doesn’t check for or tell you anything else about your overall health or vision.
