The parts of a comprehensive eye examination vary according to the patient's age and date of last exam, as well as some other factors. Not all parts of the eye exam may be needed or performed, but the first part of the eye exam will always include documenting medical history. Here are some eye and vision tests that are likely to be encountered during a comprehensive eye exam:
Visual acuity tests measure the sharpness of vision. They are usually performed using a projected eye chart to measure visual acuity at a distance and a hand-held small acuity chart to measure the near vision (for reading).
This screening test checks color vision and is often performed early in a comprehensive eye exam to rule out color blindness.
This test checks for misalignment of the eyes, or strabismus, as well as more subtle binocular vision problems that could cause eye strain or amblyopia (lazy eye).
Ocular motility testing determines how well eyes can follow a moving object and how quickly they can move between and accurately fixate on two separate targets.
This test assesses the perception of depth and 3-dimensional structure obtained from visual information deriving from two eyes in individuals with normally-developed binocular vision.
This test estimates which lens powers will best correct distance vision. Based on the way the light reflects from the eye, the doctor is able to obtain an approximation of the eyeglass prescription. This test is helpful in treating children and patients who are unable to accurately answer the doctor's questions.
This is the test the doctor will use to determine the patient's exact eyeglass prescription.
Autorefractor or aberrometer may be used to estimate the eyeglass prescription automatically. This is helpful for determining an eyeglass prescription for young children and other patients who may have trouble sitting still, paying attention, and providing the feedback that the doctor needs to perform accurate manual refraction. They can also save time as they take only a few seconds.
A slit lamp is a binocular microscope (or biomicroscope) used to examine the structures of the eye, including the eyelids, cornea, conjunctiva, iris, and lens, under high magnification. With the help of a hand-held lens, the doctor may also use a slit lamp to examine structures located farther back in the eye, such as the retina and optic nerve.
The slit lamp exam can be used to detect a wide range of eye conditions and diseases, including cataracts, macular degeneration, corneal ulcers, and diabetic retinopathy.
Testing for glaucoma typically begins with measuring the pressure inside the eyes. This can be done by the "puff-of-air" test. Based on the eye's resistance to the puff of air, the machine calculates intraocular pressure (IOP).
High eye pressure patients may be at risk for or have glaucoma. The test is completely painless, and the tonometer does not touch the eye.
To obtain a better view of the eye's internal structures, the eye doctor instills dilating eye drops to enlarge the pupils, which usually takes about 20-30 minutes to start working. When the pupils are dilated, the eyes will be sensitive to light (because more light is getting into the eyes), and patients may notice difficulty focusing on objects up close. These effects can last for several hours, depending on the strength of the drops used.
This test checks for the possible presence of blind spots (scotomas) in the peripheral (side) vision by performing a visual field test. These blind spots can originate from eye diseases like glaucoma or may help identify specific areas of brain damage caused by a stroke or tumor.
A comprehensive eye exam can take 1 hour or longer, depending on the number and complexity of tests required to fully evaluate vision and eye health. If the eyes are dilated, at least a 90-minute appointment should be planned.
Many patients can drive themselves after having their eyes dilated. Still, it is important to remember that the eyes will be sensitive to light, vision may be blurry, and patients should wear sunglasses after their exam.
For your safety, if you do not feel comfortable driving, arrange for someone to drive you home.