3 Tests That Help Determine Your Eyeglass Prescription

Many consumers rely on eyeglasses or contact lenses to enhance their vision. The right prescription can help you bring your vision into focus, but determining what that prescription should be is a complex task that requires the administration of several tests.

You should expect to undergo three very important tests during your next eye exam to help you determine your optimal eyeglass prescription.

1. Retinoscopy

One consideration that an optometrist must make when determining your prescription is the way light interacts with your eyes. A retinoscope is used to measure how light refracts when it hits your eyes through different lenses.

A retinoscopy is administered by having you stare at a letter on the optometrist's eye chart. A series of lenses are then flipped in front of your eyes while the doctor shines a light on them. Your optometrist can use his or her observations to make a recommendation for the correct eyeglass prescription.

2. Keratometry Test

In order to provide you with the proper prescription, your optometrist will need to know the shape of your eye. Of particular interest is the shape of the cornea, which can affect the way your eyes process light and send signals to your brain to produce images.

A keratometry is used to determine the shape of your eye. During a keratometry test, your optometrist will have you look into a special machine. This machine is designed to align with your eye and produce a series of measurements. Based on the measurements, your optometrist will be able to determine the shape of your eye and the type of lens prescription that will be best suited to enhance your vision.

3. Intraocular Pressure Test

Before your optometrist can write you a prescription for eyeglasses, he or she needs to know that your eyes are in good health. An intraocular pressure test is used to test for the warning signs of glaucoma.

During this test, the optometrist will use a special machine to blast your eye with a small puff of air. The puff of air will surprise your eye, causing it to close. The machine will then measure your eye pressure based on your eye's ability to withstand the puff of air and the force with which your eye closes.

A combination of tests is required to help you get the most accurate eyeglass prescription possible. Be sure that you are prepared for these tests when visiting your optometrist in the future.