Complete Eye Exam – A complete eye exam involves a series of tests designed to evaluate your vision and check for eye diseases. Please allow at least 2 hours for an adult complete eye exam and 2.5 hours for a child complete eye exam. If you are prone to blurred vision after pupil dilation, you may want to bring someone to drive you home. This exam may include:
Visual Acuity Tests – measures the sharpness of your vision
Ocular Motility – the patient will be asked to focus on a small object across the room and then cover each eye alternately with an occluder while staring at a target to assess whether the uncovered eye must move to pick up the fixation target, which could indicate strabismus or a more subtle binocular vision problem that could cause eye strain or amblyopia (lazy eye).
Refraction – determines your exact eyeglass prescription. An instrument called a phoropter is placed in front of your eyes and shows you a series of lens choices. You will be asked which of the two lenses in each choice looks clearer. Your answers will be used to fine-tune the lens power until reaching a final eyeglass prescription. The refraction determines your level of hyperopia (farsightedness), myopia (nearsightedness), astigmatism and presbyopia.
Slit-Lamp Examination – examines the health of your eyes. Slit lamp examines the front of the eye, allowing a highly magnified view of the structures of your eye to thoroughly evaluate your eye health and detect any signs of infection or disease. During this test you will place your chin on the chin rest of the slit lamp; it will then shine the lamp’s light at your eye. The doctor will look through a set of oculars (much like a microscope in a science lab) and examine each part of your eye in turn. A wide range of eye conditions and diseases can be detected with a slit-lamp examination, including cataracts, macular degeneration, corneal ulcers, diabetic retinopathy, etc.
Tonometry – measures the pressure inside your eyes. The range for normal pressure is 12-21 mm Hg (“mm Hg” refers to millimeters of mercury, a scale used to record eye pressure).
For this test, eye drops will be placed in your eye to numb it. Your eyes will feel slightly heavy when the drops start working. This is not a dilating drop — it is a numbing agent combined with a yellow dye that glows under a blue light. You will be asked to stare straight ahead into the slit lamp while the surface of your eye is gently touched with a tonometer to measure your IOP. Tonometry is painless. At most, you may feel the tonometer probe tickle your eyelashes. The whole test takes just a few seconds. You typically have no warning signs of glaucoma until you already have significant vision loss. For this reason, routine eye exams that include tonometry are essential to rule out early signs of glaucoma and protect your eyesight.
Dilated Fundus Exam – obtains a better view of the eye’s internal structures. Dilating drops will be instilled in the eye to enlarge the pupils. Dilating drops usually take about 20 to 30 minutes to start working. When your pupils are dilated, you will be sensitive to light (because more light is getting into your eye) and you may notice difficulty focusing on objects up close. These effects can last for up to several hours, depending on the strength of the drop used. Once the drops have taken effect, various instruments will be used to look inside your eyes. You should bring sunglasses with you to your eye exam, to minimize glare and light sensitivity on the way home. If you forget to bring sunglasses, our staff will give you a disposable pair. Pupil dilation allows for the most thorough evaluation of the health of the inside of your eyes.
Visual Field by Confrontation Test – checks for the possible presence of blind spots (scotomas) in your peripheral or “side” vision. You will cover one eye, and stare straight ahead with the other. You will be asked to stare at a central object and let the examiner know when you can see an object that moves into your side vision.
External Eye Exam – visual inspection of brows, lashes, eye lids, and conjunctiva of both eyes.
Additional testing for children in a complete eye exam may include:
Color Blindness Test – screening test that checks your color vision
Retinoscopy – used to gain an approximation of your eyeglass prescription. 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,” your eye doctor will shine a light at your eye and flip lenses in a machine in front of your eyes. Based on the way the light reflects from your eye, your doctor is able to objectively determine the prescription with no input from the child (or non-verbal adult).
Additional Ocular Testing Preformed at Michigan Vision Institute
A-scan – measures the eye to determine the right power of a lens implant before cataract surgery. The eye is numbed with anesthetic drops, so you shouldn’t have any discomfort. An ultrasound wand (transducer) is placed against the front surface of the eye. You may be asked to look in different directions to improve the ultrasound image or so it can view different areas of your eye. The ultrasound uses high-frequency sound waves that travel through the eye. Reflections (echoes) of the sound waves form a picture of the structure of the eye. The test takes about 15 minutes.
Electroretinography (ERG) – ERG measures the function of your retina- the light-sensitive layer at the back of your eye. When light from an image enters the eye, it is converted into electrical energy by specialized cells in the retina. The ERG test records how well the cells of the retina are conveying electrical impulses within the eye. ERG results have been demonstrated to aid in the diagnosis and treatment planning of many vision disorders.
To perform this test the technician makes sure your skin is clean, dry, and free of any lotions or oils so the sensory pads can be placed on your head and on your lower eyelids. He or she may ask that you cover one eye at a time to record each eye’s response independently. Once the test begins, you will see a series of black and white patterns that appear to “flip” quickly over and over again on a computer screen. It is simply a matter of looking at the pattern for the duration of the test. The computer will capture the information and produce a report for the doctor’s interpretation of the results. These results will be used to assist your doctor in better planning your treatment (if needed) and monitoring the effects.
Fluorescein Angiogram – special dye and camera are used to look at blood flow in the retina and choroid, the two layers in the back of the eye. It can also be used to diagnose problems in the eye or to determine how well certain eye treatments are working. To obtain a better view of the eye’s internal structures, dilating drops will be instilled in the eye to enlarge the pupils. Dilating drops usually take about 20 to 30 minutes to start working. When your pupils are dilated, you will be asked to place your chin on the camera’s chin rest and your forehead against a support bar to keep your head still during the test. The health care provider will take pictures of the inside of your eye. After the first group of pictures is taken, a dye called fluorescein is injected into a vein, usually at the bend of your elbow. Then, a special camera takes pictures as the dye moves through the blood vessels in the back of your eye. A normal result means the vessels appear a normal size, there are no new abnormal vessels, and there are no blockages or leakages. If blockage or leakage is present, the pictures will map the location for possible treatment. The dye will cause your urine to be darker, and possibly orange in color, for a day or two after the test.
Fundus Photos – pictures of the retina in color or black and white. These pictures are necessary to document the health of the optic nerve, vitreous, macula, retina and its blood vessels. A customized camera is mounted to a microscope with intricate lenses and mirrors used to visualize the back of the eye by focusing light through the cornea, pupil and lens. The patient is asked to stare at a fixation device so the eyes are still. While the photographer is taking the pictures, the patient will see a series of bright flashes. After dilation, the photo process usually takes approximately five to ten minutes.
Gonioscopy – helps determine whether the angle where the iris meets the cornea is open and wide or narrow and closed. During the exam, eye drops are used to numb the eye. A hand-held contact lens is gently placed on the eye. This contact lens has a mirror that shows the doctor if the angle between the iris and cornea is closed and blocked (a possible sign of angle-closure or acute glaucoma) or wide and open (a possible sign of open-angle, chronic glaucoma).
Humphrey Visual Field (HVF) – This test helps your doctor detect and monitor glaucoma. Usually, the visual field test is taken once a year but depending on the severity of your glaucoma, your doctor may decide to check your visual field more frequently.
A visual field test measures the area of vision, or how wide of an area your eye can see. Glaucoma is often called “The Sneak Thief of Sight” because it usually is a painless process that mostly affects the peripheral, or side vision, first. The visual field shows changes that are not noticed by the patient until the damage is severe. Other diseases, such as cataract, stroke, macular degeneration and diabetes, can also influence the visual field.
During Humphrey Visual Field (HVF) testing, the patient places his head in the chinrest and fixes his gaze toward a central fixed point in a large, white bowl. When the patient sees a blinking light in his peripheral vision, he presses a button on a handheld device. Different locations within a given region of the visual field are tested until the threshold, or the stimulus intensity seen 50% of the time, is seen at each test location.
IOL Master – non-contact optical instrument, which provides eye measurements used to determine the proper IOL (intra-ocular lens) to be implanted during cataract surgery.
Optical Coherence Tomography (OCT) – measures the reflection of laser light much like an ultrasound measures the reflection of sound, can directly measure the thickness of the nerve fiber layer and create a three dimensional representation of the optic nerve. OCT has been shown to be clinically useful for evaluation of vitroretinal disease (such as macular holes, macular edema, age-related macular degeneration, epiretinal membranes) and glaucoma.
Pachymetry – measures the thickness of your cornea (the clear window at the front of the eye). A probe called a pachymeter is gently placed on the cornea to measure its thickness. Pachymetry can help in glaucoma diagnosis, because corneal thickness has the potential to influence eye pressure readings. With this measurement, your doctor can better understand your IOP reading and develop a treatment plan that is right for you. The procedure takes only about a minute to measure both eyes.
Visual Evoked Potential (VEP) Vision Testing – VEP is a painless, safe, non-invasive vision test used to objectively measure neurological responses of the entire visual pathway from the eyes to the vision center of the brain. This technology has been demonstrated to aid in the diagnosis and treatment of many disorders including amblyopia, brain injury, stroke, multiple sclerosis, and other vision-related issues such as glaucoma. The results will provide comprehensive information to assist your doctor in better planning your treatment (if needed) and monitoring the effects.
The testing time may vary depending on what tests your doctor orders. Relaxation is an important part of the test, you must sit still. It is best for your hair and face to be clean, dry, and free of any gels, sprays or oils. The technician will attach three small sensory pads to your head using a washable gel material. You will be seated in front of a screen and asked to stare at the center. The screen will display different size patterns that quickly reverse. One eye may be covered while the other eye is tested. A computer records your response.
If you have a seizure disorder (epilepsy), notify your technician before beginning the exam.