Examinations
Retinoscopy
In this exam, the room lights will be dimmed and you will be given a large target (usually the big "E" on the chart) to fixate on. As you stare at the "E," the eye doctor will move a line of light across your eye and turn lenses in a instrument (called a phoropter) in front of your eyes. The doctor will often perform this test early in the eye exam in order to obtain an approximation of your prescription from which to start. This test is especially useful for children and non-verbal patients.
Refraction
During a refraction, the doctor puts the phoropter in front of your eyes and shows you a series of lens choices. He will then ask you which of the two lenses in each choice looks clearer. Based on your answers, the doctor will continue to fine-tune your power until reaching a final prescription for clarity and comfort which is then used for your eyeglasses and contacts. Refraction determines your level of farsightedness, nearsightedness, astigmatism and presbyopia.
Slit-Lamp Examination
The slit lamp, also called a biomicroscope, allows the doctor to get a highly magnified image of the structures of the front of the eye in order to thoroughly evaluate them for signs of infection or disease. During this test the doctor will have you place your chin on the chin rest of the slit lamp and will then shine the lamp's light at your eye. The doctor looks through a set of oculars (much like a microscope in a science lab) and examines each part of the eye in turn. A whole range of eye conditions and diseases can be detected with slit-lamp examination, such as corneal scars, conjunctivitis (pink eye) and signs related to diabetes and glaucoma.
Dilation
Requires drops that the eye doctor puts in your eyes to make the pupils bigger in order to get a better view of the internal structures of the eye. Dilating drops usually take about 15 to 20 minutes to start working. While the dilating drops are working, you will be sensitive to light (because more light is getting into your eye) and may notice difficulty focusing on near objects. These effects can last for up to several hours depending on the strength of the drop used. Once the drops have taken effect, the doctor will use a variety of instruments and light sources to look inside of your eyes. You should bring sunglasses with you, to minimize glare and light sensitivity on the way home.