Everyone remembers seeing the big “E” at the eye doctor’s office. Sit in the chair, look into the device and tell them which lenses provide the most clarity. It’s quick and painless. But if it has been a few years since visiting the office, there might be some questions about the process. Let’s talk about eye health exams. These routine tests are provided by both optometrists and ophthalmologists. Contact wearers need them in order to update annual prescriptions and, besides ensuring better vision, these infrequent trips help check for preventable eye diseases, as well as tumors and anomalies in the brain and systemic diseases like diabetes and high blood pressure.
What is an eye health exam?
Eye health exams are an important part of routine body maintenance. These painless procedures help with the earlier detection of eye disease, result in clearer vision and, sometimes, result in snazzy new contact lenses. They also offer patients a chance to talk with doctors about eye health issues. This is especially important for those who experience discomfort and problems with vision. During these exams, doctors examine the health of the eyes and, for those who require vision correction, determine the prescription that best serves the patient’s needs.
These exams are not just for glasses. Eye health exams allow doctors to make recommendations for contact lenses as well. Eye care professionals provide reliable information about eye care and can offer basic demonstrations on contact usage.
List of Eye Exam Tests
- Visual Acuity Testing
- Color Testing
- Depth Perception Testing
- Muscle Testing
- Pupil Testing
- Eye Pressure Testing (tonometry)
- Slit Lamp Examination
- Visual Field Testing
- Pupil Dilation
- Contact Lens Fitting and Evaluation
Visual Acuity Testing
These common tests occur at most eye health exams. Most people know the “Snellen” Chart as the one with the big “E” on top. This tool determines how well someone is able to see, also referred to as their visual acuity. This tests their ability to read letters, without squinting, from a distance of 20 feet. Those with normal, good vision have an acuity of 20/20.
Color Blindness Testing
This test determines your ability to distinguish subtle color difference and helps to detect hereditary color vision deficiencies. This test can also detect eye health problems that may affect color vision.
Depth Perception Testing
This test measures your stereopsis, or depth perception. The process usually involves viewing images made up of dots or pictures, sometimes through special glasses. This determines how well someone can see in three dimensions. It also helps to detect eye diseases such as amblyopia, strabismus, suppression, and stereopsis
This test is done to let your doctor determine how well your eyes work together and if there is any muscle imbalance that may cause one or both eyes to want to not point straight. Muscle testing also helps to be sure that all of your eye muscles and nerves work well together. Eye muscle tests require very few tools. The doctor asks the patient to follow an object across six different positions, expose weakness in muscles.
Pupil testing is usually done with a small bright flash light. The eye care professional shines a penlight over one eye at a time and looks for pupil dilation and contraction.
This test uses a computerized instrument to measure how light focuses through the eye and gives the doctor a preliminary measure of your prescription.
This test also helps the doctor determine your prescription by measuring what lenses it takes to focus light perfectly on the back of your eye.
Eye Pressure Testing (tonometry)
The pressure inside the eye is very important to measure, because high pressures can be one risk factor for glaucoma, a potentially blinding eye condition. The eye pressure is measured one of several different ways. Doctors will sometimes use a computerized instrument that blows a gentle puff of air in the eye to measure the pressure. The pressure can also be measured with various other handheld devices that gently touch the surface of the eye to measure the pressure. The doctor may also use an instrument that is attached to the microscope and uses dye in the eye and a blue light to check the pressure.
The refraction test determines the ideal prescription for the patient. During this test, the patient is given something to look at (usually the Snellen chart or something similar) and asked to determine their best vision from a series of options. The patient looks through the phoroptor, deciding between two lenses at a time. This is the part of the exam when you can expect to hear “one or two” and “three or four” over and over again. The eye care professional uses the patient’s choices to determine which, if any, prescription is needed.
Slit Lamp Examination
Your doctor will use a high powered microscope called a slit lamp to thoroughly examine the structures on the outside of the eye under magnification. The doctor will also use a strong lens to focus on the structures inside of the eye. During this test, you will comfortably place your chin on the chin rest of the slit lamp while the doctor shines a bright light toward the eye.
Visual Field Testing
Visual Field Testing
These tests measure your peripheral vision. Peripheral tests are given by having the patient looked in a fixed forward direction, then introducing images from behind and to the sides of their eyes. This measures how well the patient can see at the edges of their vision as they focus on a point directly ahead. Visual field testing may also be done with an automated instrument that presents lights or other targets and asks you to click a button when you see them like a video game. Peripheral tests can help discover glaucoma damage as well as neurological problems.
Your doctor will likely need to put drops in your eyes that enlarge the size of the pupil in order to get a wider view into the inside of the eye. It takes about 20 minutes for the drops to work, and then the doctor will examine the structures inside the eye with a special headset mounted microscope and with the slit lamp. Pupil dilation will make it a little harder to focus at near and will make you more sensitive to bright light, but is a very important test to provide the most thorough examination of the health of the eyes.
Depending on the examination findings, your doctor may order further testing such as photographs of the inside of your eyes, scanning images of the layers of the retina, or other diagnostic testing as needed.
Contact Lens Fitting and Evaluation
Contact lenses come in many different shapes, sizes and materials. For patients who are interested in wearing contact lenses, the doctor will need to perform extra measurements to be sure that the most appropriate lenses are fit on the eye. This will usually involve actually placing the lens on the eye and evaluating the way the lens sits on the eye surface and moves with a blink. Contact lens evaluations are important even if you have worn contacts for many years to be sure that the lenses are still providing for optimal eye health.
Who needs an eye exam (and how often)?
It’s important for everyone to have their eyes checked, but there are guidelines about how frequently this needs to happen. Children will need their first exam at 6 months and again at age 3 and then before starting school. An eye examination can be a fun experience for children. School aged children should have an eye examination every year because during this formative time, the eyes develop quickly and prescriptions can change fast.
Adults who wear contact lenses or who have a family or personal history of eye problems should continue to have eye examinations every year. If there is no history of any problems with the eyes, adults between the ages of 20 and 40 should schedule a routine eye examination at least every two years. After age 40, the eyes start to change significantly, and there is a greater risk of eye disease. Adults over age 40 should see an eye doctor every year.
Eye health examinations with your eye doctor help to maintain healthy eyes and vision as we age. They can uncover many eye ailments such as glaucoma, cataracts, and macular degeneration, and can even detect systemic health problems such as diabetes, high blood pressure, high cholesterol and stroke. Many of these issues can be treated when discovered early.