Optometrists as well as ophthalmologists conduct a series of tests to inspect your eyes. These tests combine a simple test like reading an eye chart to more difficult tests to check the minute structure of the interior of your eye.
A comprehensive check up of eyes may take about one hour, although it depends on the competency of the doctor and intricacies of tests performed to have an accurate assessment of your vision plus health of eyes.
A regular, all-inclusive eye exam would generally consist of the following tests:
Visual Acuity Test
This is among the simplest tests conducted to assess how sharp your vision is. Normally, an eye chart is used to evaluate your ability to read from a distance (visual acuity) followed by holding in hand and reading a small acuity chart for assessing near vision.
Color Blindness Test
This also a simple test that goes to ensure your eyes is not affected by color blindness. Other than identifying inherited lack of colored vision, this test also helps the doctor to know of likely health issues affecting your vision.
Although the doctor has many ways of checking if your eyes are working in unison, this is the most usual test for that purpose. For conducting this test, you are asked to focus on any small object at some distance away, while the doctor covers each eye one after the other as you continue staring at the defined object.
During the said process, the doctor judges if the unclarified eye necessarily moves to locate the targeted object. It could have been a sign of strabismus or slight binocular vision problem, which may cause eye strain or “lazy eye.”
This test is also performed during the early stage of eye exam to estimate prescription of eyeglasses for you. For conducting this test, lights in the room are dimmed. Then, you are generally asked to keep your eye focused on the large “E” of the chart. As you keep staring at that “E”, the doctor would throw a beam of light on your eyes while flipping lenses in a mechanism facing your eyes. Depending on how your eye reflect back that beam of light, the doctor can approximate prescription of glasses for you.
The doctor uses this test to refine prescription of eyeglasses. A phoropter is positioned before your eyes and the doctor allows you to see lenses in sequence. He will question you which two lenses give a clear picture. He keeps fine tuning the lenses to fill an accurate prescription of eyeglasses is realized.
The doctor can also assess your prescription using automatic machines like an aberrometer or autorefractor.
A slit lamp, also known as biomicroroscope, is an instrument that enables the doctor to see an extremely enlarged view of an eye to assess its health and check if it is infected. The instrument is used for examining the structure on the face of the eye, like conjunctiva, iris and cornea as also of its interiors, like macula, optic nerve and retina.
There are many variations of this test, employed for measuring pressure inside the eyes. Glaucoma, caused by high pressure on eyes, can result in loss of eyesight. Since the disease generally does not offer any symptoms, it is vital to have this test done. Early diagnosis of glaucoma can prevent loss of vision.
For getting a better view of the internal structure of your eyes, the doctor dilates your pupils, using a solution. It takes twenty to thirty minutes for eyes to get diluted when the doctor examines the eyes through different instruments. Since the pupils are enlarged as a result of this test, you may find it difficult to focus on closer objects. The effect is temporary and use of sunglasses is recommended after having undergone this test.