When acquiring glasses or contacts, one must have an eye exam. Most people do not think about whether there is a difference between the two exams. There are actual distinct differences between an eye exam for eyeglasses and an eye exam for contact lenses.
The following describes the differences with an eye exam for eyeglasses and an exam for contact lenses:
Eye Exam for Eyeglasses
The purpose of an eye exam is to diagnose problems with one’s vision and any diseases of the eye. You will be required to read an eye chart. This includes reading with both eyes than each on their own. The eye doctor will then perform a Retinoscopy. In a darkened exam room, the doctor will provide you with a point to stare at, and then the doctor will shine a light in the eye. How the light bounces off the eye is a determining factor in what the strength of your eyeglass prescription will be. The eye doctor will also perform a Refraction test. A device called a Phoropter is used to perform the test. You will look through a mask device held up to your face and the doctor will show you a series of letters and ask you to state which one is clearer. The doctor will be flipping lenses in the mask to different strengths. This test determines whether one has nearsightedness, farsightedness, astigmatism, and/or presbyopia. The eye doctor will then perform a slit-lamp exam. This device allows the doctor to assess the structures of the eye. It is used to identify eye infection and eye disease.
Eye Exam for Contact Lenses
A contact lens exam concentrates on only one feature of eye health. The eye doctor will run tests to assess the eye’s cornea surface to make sure the contact lenses will fit properly. You will be asked questions about your lifestyle so the doctor can select the best type of contact lens for your situation. A device called a keratometer measures the surface and curvature of the eye. The doctor will measure this by using an instrument called a keratometer. A keratometer is a type of digital camera that takes pictures of your eye to create mathematical depictions of the curvature of your cornea’s surface. This test determines the correct curve and size for your contact lenses. Corneal topography may also be done to give more details about the surface of the cornea. The health of your cornea may be evaluated using a biomicroscope.You may also have your pupils measured using a pupil card, ruler, or pupillometer. A card or ruler displaying different pupil sizes will be held next to your eye to find the best match. Contact lens fittings may also include a tear film evaluation. The amount of eye moisture may be assessed using a small strip of paper placed under the lower eyelid. As well, a fluorescein dye may be placed in your eye and then the doctor will assess how long it takes for the dye to be washed away by tears.
After the tests have been completed and evaluated, your eye doctor will select the best contact lenses for you. You will then have to maintain regular eye check visits to make sure you are not developing any problems.
There are differences between exams for eyeglasses and exams for contacts. The important thing to remember is that these tests are designed to ensure that you maintain good eye health.