Receiving a comprehensive vision exam each year helps people to maintain healthy vision. An eye doctor can check a person's vision, determining whether the person is in the early stages of an eye disease. Many eye diseases do not reveal obvious symptoms or signs; therefore, visiting the eye doctor for a vision exam can prevent the deterioration of a person's eyesight. When patients visit the eye doctor, they will be subjected to a variety of vision tests.
First, the patient may fill out a questionnaire concerning his history. He will be asked if he has any medical problems or if there is a history of specific diseases in his family. The patient will need to notify the eye doctor of current medications he takes as well. Next, the eye doctor will begin to administer a series of tests that measure the health of the patient's eyes.
Initially, the eye doctor often begins with a retinoscopy. In this particular type of exam, the patient looks through lenses of a machine as he reads of series of letters. The lights in the room are dimmed and the patient is asked to read the letters on the wall before him. As he does so, the doctor shines a light into the patient's eye and changes the lenses to see which prescription lens is the best fit for the patient.
Eye doctors may also choose to administer a test called the cover test. During this type of exam, the eye doctor tells the patient to focus on a distant object while the doctor covers one of the patient's eyes. This allows the eye doctor to determine how much the eye needs to move in order to focus on the distant object. The cover exam, although a simple test, helps the doctor to see if the patient has an eye problem that can lead to difficulties with depth perception or other types of binocular vision problems.
Another type of vision test used by eye doctors is the refraction test, a test used to accurately pinpoint a patient's specific lens prescription. During this procedure, a machine called a phoropter is placed in front of the patient's eyes and periodically changes the lenses. The doctor will then ask the patient which lenses allow the patient to see the most clearly.
In order to evaluate whether a patient has an eye disease, the eye doctor will perform a slit-lamp exam. This particular test uses an instrument that magnifies the structure of the eye. The patient places his chin on a small platform, and the instrument shines a light into the patient's eye. Next, the doctor looks through an eyepiece similar to a microscope in order to conduct the examination. By using the slit-lamp, the doctor can diagnose serious eye diseases such as macular degeneration and corneal ulcers.
Glaucoma tests measure the pressure inside the patient's eyes. The non-contact tonometer and the applanation tonometer are two common ways to test for glaucoma, a serious disease where the optic nerve becomes severely damaged. Non-contact tonometer uses puffs of air to test pressure inside the eye. First, the patient puts his chin on a chin rest and focuses on a light inside the machine. The doctor will then direct a small amount of air toward the eye.
The applanation tonometer is an instrument that tests eye pressure as well. Numbing eye drops are placed inside the patient's eye. Next, the patient stares ahead as the eye doctor gently touches the eye with an instrument that emits a blue light.
Following a vision exam, the eye doctor will share the test results with the patient. He or she will discuss treatments for any diagnosed eye diseases or prescribe corrective lenses for the patient. A yearly vision exam is a necessary part of any wellness plan, as it can help to detect or prevent vision problems that can adversely affect a patient's life.