The American Optometric Association recommends that both children and adults have their eyes checked at least once every two years. If you notice changes in your vision or if you are at risk for vision problems, annual eye examinations are recommended. There are various tools and methods available to check your vision. For more information or to schedule an appointment, please contact our office today.
Comprehensive Eye Exams
Comprehensive eye examinations are an important part of any preventative health care plan. The reality is that many eye conditions do not present obvious symptoms; people are often unaware that a problem exists until it is too late. Regular diagnostic testing and treatment of eye conditions is essential to maintaining eye health and visual acuity for both adults and children.
What is a comprehensive eye exam?
A comprehensive eye exam is designed to evaluate vision and the health of your eyes. Eye doctors use a combination of tests and procedures during these exams. The tests can be simple, like reading an eye chart, or they can be complex, like undergoing a slit-lamp examination. The tests are painless but extremely effective.
Reasons for undergoing a comprehensive eye exam
Comprehensive eye examinations focus on the overall health of the eye as well as the accuracy of vision. School-age children are urged to undergo comprehensive eye exams every year. Of course, school screenings take place to determine if a child has "good" vision; however, these tests do not examine the health of the eyes as a whole. The best way to ensure that your children do not develop a vision-related learning disorder is to schedule comprehensive eye examinations for them annually.
Comprehensive eye exams for adults are just as important. The risk of developing certain eye diseases only increases with age. Comprehensive eye exams allow physicians to screen for everything from glaucoma to diabetes, multiple sclerosis, and macular degeneration.
Performing comprehensive eye exams
Comprehensive eye examinations can take an hour or more, depending on the number and nature of tests required. Here are just a few of the different vision tests and screenings that are commonly performed during a comprehensive eye exam:
- Patient medical history
- Visual acuity testing and eye charts
- Color blindness test
- Cover test (to test how eyes work together)
- Retinoscopy and refraction (to measure eyeglass prescription)
- Slit-lamp exam (to gauge the health of eyes)
- Glaucoma test (intraocular pressure test)
- Pupil dilation
- Visual field test
Even if you do not think you are having any vision problems, you should schedule regular comprehensive eye examinations to catch any issues in their early stages.
Glaucoma Testing (Eye Pressure Test)
Glaucoma is a common eye condition characterized by a buildup of fluid in the eye. When the passages in the eye that drain excess fluid become clogged, the pressure from the fluid can damage the optic nerve. If left untreated, glaucoma can eventually lead to complete vision loss. In fact, glaucoma is one of the leading causes of blindness in the United States.
Vision Screening Using the Snellen Eye Chart
A vision screening can be performed using the Snellen eye chart to measures your visual acuity. This is usually one of the first tests performed during a routine eye exam. The Snellen eye chart, which was first developed in 1862 by Dutch ophthalmologist Hermann Snellen, sets a standard for what an individual with normal vision can see at a distance of 20 feet. The chart consists of eleven lines of block letters. The first line has one very large letter and in each line that follows the letters decrease in size with multiple letters on each line.
Why is vision screening performed?
The Snellen eye chart is used during a vision screening to determine whether prescription lenses are needed to improve your vision. While this screening is an initial part of a routine eye exam, the test may also be performed outside the optometrist's office. For instance, you must pass a vision screening test at the DMV when applying for or renewing your driver's license.
How a vision screening is performed
During a vision screening, you will typically be asked to sit or stand 20 feet away from the eye chart. In instances where the optometrist's office is not 20 feet long, the chart may be located behind you and a mirror may be placed on the opposite wall to simulate a distance of 20 feet. The optometrist will then ask you to cover one eye and read the letters on the chart aloud beginning at the top and working your way to the bottom. The test will be performed again with the other eye covered and then with both eyes uncovered.
The smallest row of letters that you can see clearly will indicate your visual acuity. Numbers on the side of the chart indicate how many feet away a person with normal acuity could be to read that line on the chart. For instance, if you can read the line labeled 20/40, you need to be at a distance of 20 feet to read something that individuals with a normal visual acuity could read from 40 feet away.
If you are having difficulty seeing, your optometrist can perform a vision screening with the Snellen eye chart to determine if you need prescription lenses or a change in your prescription. Further tests may also be required to confirm the specific prescription needed to help you achieve clear vision. Contact your optometrist today to schedule an appointment.
Refractive errors, including nearsightedness, farsightedness, and astigmatism, are the main eye conditions that send people to the optometrist.
What is a refraction?
A refraction test is performed by an optometrist during an eye exam to determine the refractive condition of the eye and the corrective lens prescription needed to compensate for any refractive errors.
Why is refraction important?
Refraction testing is performed during an eye exam if a patient is unable to see clearly and needs corrective lenses. Retinoscopy is often performed first to confirm the type of refractive errors causing vision problems. A refraction is then performed to determine the lens power needed to compensate for refractive errors so that light comes to a sharp focus on the retina. This information is used then to prescribe corrective lenses, such as eyeglasses and contacts. For patients interested in contact lenses, a contact lens fitting may be required as well.
How refraction testing is performed
An optometrist performs refraction using a mechanical device called a phoropter, which consists of several different lenses. Using the phoropter, the optometrist places lenses of various powers in front of your eyes while you look through the lenses at an eye chart. The optometrist then uses either a hand-held tool called a retinoscope or a computerized instrument to measure how each of the lenses focus the light in order to determine which lens power is needed to compensate for your refractive errors.
During the examination, the optometrist may also ask you which lens helps you to see the eye chart more clearly. For patients who are unable to respond, the optometrist may use eye drops to dilate the eyes before the procedure. This prevents the eyes from changing focus and can help the optometrist in determining the most appropriate lens prescription.
If you have noticed a change in your vision, you may be in need of a new prescription and can benefit from refraction testing. Schedule an appointment with your optometrist today to have your vision checked.
What is glaucoma testing?
Increased pressure in the eye is a sign of glaucoma, therefore one of the first and most important screening tests used to diagnose glaucoma is an intraocular eye pressure test, or tonometry.
Tonometry determines the amount of fluid pressure in the eye by measuring the tone and firmness of the surface of the eye. The test is conducted with an applanation tonometer or an air puff tonometer. The tonometer calculates intraocular pressure by measuring the eye's resistance to pressure or a puff of air. Patients with high intraocular pressure may be at risk for glaucoma and will be subjected to further testing, including a test for optic nerve damage.
Reasons for administering glaucoma tests
There is no cure for glaucoma, therefore early detection is critical. Glaucoma does not present any visible symptoms until vision loss has already started to occur. That means the only way to preserve vision is to undergo regular glaucoma screening tests. Though there are a variety of tests that can be used to help diagnose glaucoma, the intraocular eye test is an excellent first screening test that is quick and painless.
Performing glaucoma tests
The gold standard of glaucoma testing is the intraocular eye pressure test, or tonometry test.
The first type of tonometry test is the non-contact "puff of air" test. During this test, you place your chin on a chin rest and focus on a light inside a machine. The doctor directs a small puff of air at the open eye, and the machine calculates intraocular pressure based on the eye's resistance to the air.
The second type of tonometry test requires contact but is slightly more accurate. You are given numbing eye drops that contain a dye that glows under light. You are then asked to stare straight ahead while the doctor uses the tonometer to gently make contact with the surface of your eye. The test is painless and takes just a few seconds.
A glaucoma test should be part of your regularly scheduled eye examinations.
Regular eye exams are an important way of monitoring the health of your eyes. An essential component of any thorough eye exam is a pupil dilation test.
Pupil dilation tests are not uncomfortable, but some patients consider them a nuisance because the visual effects of the eye drops used to dilate the pupils last for several hours. However, dilation testing is a critical part of an eye exam because it gives eye doctors a clear view of the retina, optic nerve, and blood vessels in the back of the eye.
What is pupil dilation?
A pupil dilation test is an eye exam that is used to evaluate the health of the retina and the light-sensitive tissue at the back of the eye. The only way to get a clear view of the back of the eye is to dilate (enlarge) the pupils. This allows more light to enter the eye without pupils constricting. After pupils have been dilated, the doctor is able to see a much greater area at the back of the eye.
Why we dilate your eyes
Eye dilation is incorporated into routine eye exams because it gives doctors the chance to detect eye diseases and conditions at their earliest stages. Pupil dilation allows physicians to see all the way to the back of your eye. This area of the eye includes the retina, the optic nerve, and many important blood vessels. Pupil dilation can reveal any problems with these parts of the eye and can also reveal evidence of general health issues.
Here are just a few of the diseases and conditions that can be diagnosed with the help of pupil dilation:
- Macular degeneration
- Retinal detachment
- Infectious diseases
Performing pupil dilation tests
To begin the test, the doctor will place dilating drops in your eye. The drops take about 20-30 minutes to take effect. When pupils are completely dilated, the doctor will shine a light in your eye. Normally the pupil would contract, but the drops force the pupil to stay open and allow more light to pass through to the retina.
During a pupil dilation test, doctors examine the optic nerve, retina, and the blood vessels in the back of your eye. Changes to the optic nerve, retina, and blood vessels from one visit to the next can be a sign of eye disease. Pupil dilation tests can also help doctors recognize early signs of other health conditions, including hypertension, diabetes, and high cholesterol.
If you are having trouble with your vision, be sure to schedule a comprehensive eye exam with an optometrist.
Slit Lamp Examination
A slit-lamp examination is often performed by an optometrist during a routine eye exam. The procedure involves the use of an instrument called a slit-lamp, which provides a three-dimensional view of the eye. While the exam usually focuses on the structures in the front part of the eye, such as the cornea, iris and vitreous gel, it can also be used to examine the optic nerve and retina which are located at the back of the eye.
Why is a slit lamp examination important?
An optometrist will perform a slit-lamp examination to check for any abnormalities of the eye caused by injury or infection and to diagnose conditions including cataracts, dry eye syndrome, keratoconus, diabetic retinopathy, Fuchs' dystrophy, uveitis, glaucoma, retinal detachment and macular degeneration. In patients who have already been diagnosed with a condition such as glaucoma or macular degeneration, slit-lamp exams may be performed to monitor the disorder.
How a slit lamp examination is performed
During the procedure, the patient will be asked to sit facing the slit-lamp and keep their head still by resting their chin upon the chin rest attached to the instrument and placing their forehead against the head support. The optometrist will then shine a thin, bright light into the eye and look through the magnified lens to examine the front structures of the eye. In some cases, fluorescein eye drops may be administered. These drops are yellow in color and temporarily stain the tear film on the surface of the eye which can make it easier to detect corneal injuries and other abnormalities.
If structures in the back of the eye such as the retina or optic nerve need to be examined, the optometrist will typically administer eye drops to dilate the pupils. It will take about 15 to 20 minutes for the eyes to dilate, but once they're dilated the slit lamp procedure can be performed again, this time to examine the back of the eye. The eyes will remain sensitive to light for a few hours after being dilated, so sunglasses should be worn outside. Patients may also want to arrange for someone else to drive them home after the procedure.
If you suspect you have an eye condition or are due for a routine eye exam, contact your optometrist today to schedule an appointment.
Visual Field Testing
When doctors refer to your field of vision, they are talking about how much you can see around you, including your side vision. The visual field test is designed to check for loss of side vision and diagnose eye problems and visual abnormalities.
These are basic visual field testing methods:
Moving target tests: During this test, lighted targets are moved from beyond your peripheral vision toward the center of your visual field. As soon as you recognize the target, you press an indicator button.
Fixed targets: Objects appear suddenly rather than moving from the side to the center of your vision. When a target appears, you press the indicator button.
Reasons for visual field testing
Countless eye and brain disorders can cause visual field abnormalities and blind spots in the field of vision.
Visual field testing is used to detect all of the following conditions and disorders:
- Central or peripheral retinal disease
- Ptosis (drooping eyelid)
- Optic nerve disease
- Macular degeneration
- Toxicity from certain medications
- Brain tumors
- Brain injury or swelling
Performing visual field tests
Visual field tests are performed on one eye at a time, with one eye temporarily covered to avoid errors. The tests can be done on a dark screen or on a wall using an instrument called a perimeter. Patients are asked to sit facing the testing instrument and look straight-ahead at a fixed spot. Lighted objects are introduced into the field of vision at different locations and varying intensities. Patients are instructed to push a button when they first see the target. The tests are simply and stress-free.
Your field of vision will be checked during a routine eye examination. If it has been two or more years since your last comprehensive eye examination, contact your optometrist today.
Color Blindness Testing
Color blindness is not actually a form of blindness; it is a deficiency in how a person sees color. People with color blindness have a hard time distinguishing between certain colors, including red and green, and blue and yellow.
Color blindness is hereditary, but it can also be acquired from eye diseases, toxins, and drugs. Individuals with mild color blindness may never even realize that they have a problem seeing colors. The good news is that color blindness can be detected at an early age with routine eye exams.
What is a color blindness test?
Color blindness tests are designed to detect a person's ability to distinguish colors. The tests consist of a series of color plates containing numbers or symbols hidden within a background of colored dots. Both inherited and acquired color blindness can be diagnosed with these simple screening tests. Even preschool age children can take these tests.
Why is color blindness testing important?
Color blindness tests are performed to screen school age children for color vision deficiencies and to screen job applicants for fields that require color perception (including law enforcement, truck driving, and the military).
While color blindness may seem like a harmless condition, it can cause serious problems for young children. Many learning materials in the classroom rely heavily on a child's color perception. It is important for parents and teachers to be aware of a child's color blindness so they can learn to plan lessons and homework accordingly.
Performing color blindness tests
Color blindness testing is a relatively straightforward process. The tests simply check a person's ability to distinguish colors. One of the most popular tests is the Ishihara color test, which is a series of images with colored spots. In each image, there is a figure or number embedded within the spots in a slightly different color. People with normal color perception can easily identify the number.
Testing is slightly different for young children. Rather than numbers, color blindness tests for children feature symbols and shapes like squares and circles.
If you are concerned that you or your child is having problems seeing colors properly, schedule a color blindness test.
Your eyes need to work together as a team in order to see clearly. Part of any comprehensive eye examination will include a test to determine how well your eyes are functioning together. The simplest and most common way to check eye alignment and how your eyes work as a pair is with a cover test.
What is a cover test?
A cover test is an eye exam that determines if a patient has any ocular deviation. Essentially, the test is measuring eye alignment and trying to figure out whether one eye is working harder than the other is. During a cover test, one eye is covered while the other eye focuses on an object within the room. The test is repeated for both eyes at distances close-up and far away.
Cover tests allow eye doctors to observe how much each eye has to move after being uncovered in order to focus on an object. If eye alignment is outside of the normal limits treatment may be necessary.
Reasons for administering cover tests
Cover tests can be used to detect eye turn, or strabismus; a condition where the eyes are not properly aligned. Eventually, strabismus can lead to amblyopia (lazy eye), as well as poor depth perception and problems with binocular vision.
Cover tests are part of all comprehensive eye examinations given to young children because they are at a higher risk of developing problems with eye alignment. Amblyopia is currently the leading cause of vision loss in children.
Performing cover tests
There are two types of cover tests performed during eye examinations: the unilateral cover test and the alternating cover test.
During the unilateral cover test, you are asked to focus on a distant object while the doctor covers each of your eyes in turn. If either of the uncovered eyes has to move to focus on the object, this may be evidence of strabismus.
The second part of the exam is the alternating cover test. You are asked to focus on an object while the eye cover is switched from one eye to the other. If the doctor detects eye movement after the eye cover is removed, this is an indication of phoria. A significant amount of phoria can lead to eyestrain and/or double vision.
If you are experiencing vision problems, be sure to schedule a comprehensive exam with your eye doctor.