Learn About Eye Exams and What to Expect

Understanding the Purpose of Eye Exams

An eye exam is a medical evaluation performed by an eye care professional to assess your vision and the overall health of your eyes. Unlike a simple vision screening at a school or workplace, a comprehensive eye exam involves multiple tests and measurements designed to detect problems ranging from refractive errors like nearsightedness to serious conditions like glaucoma or diabetic retinopathy.

According to the American Academy of Ophthalmology, about 93 million Americans are at high risk for vision loss, yet only half visit an eye care professional annually. Regular eye exams can detect diseases in their early stages when treatment is most effective. For example, glaucoma often has no symptoms in its early phases, but an eye exam can identify increased eye pressure before permanent vision damage occurs.

Eye exams serve multiple purposes beyond checking whether you need glasses or contacts. They can reveal signs of systemic diseases like diabetes, high blood pressure, and high cholesterol—conditions that often show symptoms in the eyes before other parts of the body. An eye care professional examining the back of your eye can see blood vessels and nerve tissue, providing a unique window into your overall health.

There are three main types of eye care professionals: optometrists, ophthalmologists, and opticians. Optometrists perform eye exams and can prescribe glasses and contacts but are not medical doctors. Ophthalmologists are medical doctors who can perform eye exams, prescribe corrective lenses, and perform eye surgery. Opticians fill prescriptions for eyeglasses and contact lenses but do not perform eye exams.

Practical Takeaway: Schedule an eye exam at least once every two years, or annually if you have existing eye conditions, diabetes, or are over age 60. Bring a list of current medications to your appointment, as some drugs can affect your vision or eye health.

What Happens During a Standard Eye Exam

A typical eye exam follows a structured sequence of tests designed to evaluate different aspects of your vision and eye health. The entire appointment usually takes 30 to 60 minutes, depending on the complexity of your case and whether dilating drops are used.

The exam typically begins with a review of your medical history and chief complaints. You'll be asked about any vision problems you've noticed, family history of eye diseases, current medications, and general health conditions. This information helps the eye care professional focus on areas of concern specific to your situation.

Next comes the visual acuity test, commonly known as the eye chart test. You'll read letters of decreasing size from a chart positioned 20 feet away. The results are expressed as a fraction, such as 20/20 vision. A result of 20/40 means you can see at 20 feet what a person with normal vision sees at 40 feet. About 35% of American adults have some form of refractive error, meaning their eyes don't focus light properly on the retina.

The automated refraction test uses a machine called a phoropter to measure how light bends as it passes through your eye. This test determines whether you have myopia (nearsightedness), hyperopia (farsightedness), astigmatism (blurred vision at all distances), or presbyopia (age-related difficulty focusing on near objects). The eye care professional may then perform a manual refraction, asking you to compare different lens options to determine your most comfortable prescription.

Additional standard tests include eye alignment and movement tests to ensure both eyes work together properly, and tonometry to measure the fluid pressure inside your eyes. A slit lamp examination uses a specialized microscope to examine the front structures of your eye, including the cornea, iris, and lens. Dilated eye exams involve putting drops in your eyes to enlarge your pupils, allowing the professional to see the retina and optic nerve at the back of your eye more clearly.

Practical Takeaway: Arrange transportation if you'll have dilating drops used, as they can blur your vision and increase light sensitivity for several hours. Wear comfortable clothing and plan to spend at least 45 minutes at the appointment.

Advanced Testing and When It May Be Recommended

Beyond the standard eye exam components, eye care professionals may recommend additional tests based on your individual circumstances, age, symptoms, or risk factors. These advanced tests provide detailed information about specific eye structures and can help diagnose complex conditions.

Optical coherence tomography (OCT) is a non-invasive imaging test that creates detailed cross-sectional images of the retina and optic nerve. This test is particularly useful for diagnosing age-related macular degeneration, diabetic retinopathy, and glaucoma. The test takes only a few minutes and requires no dilation or contact with the eye.

Visual field testing measures your peripheral vision—what you can see to the sides while looking straight ahead. This test is important for detecting glaucoma, which often damages peripheral vision first. During the test, you'll sit at a machine and indicate when you see small flashes of light in your visual field. The results create a map showing areas of normal and reduced vision.

Fundus photography involves taking a photograph of the back of your eye to document the appearance of the retina and optic nerve. These images serve as a baseline for comparison during future exams and can help detect changes over time. This is especially valuable for people with diabetes or a family history of macular degeneration.

Pachymetry measures the thickness of your cornea, which is important in assessing glaucoma risk. A thinner cornea may indicate higher eye pressure readings, while a thicker cornea may suggest lower readings than actual. Corneal topography maps the surface shape of your cornea and can detect irregularities like keratoconus or help determine if you're a candidate for contact lenses.

Amsler grid testing involves looking at a grid pattern to detect early signs of macular degeneration. People at risk for this condition may be given a grid to use at home and instructed to report any changes in how the grid appears, such as wavy lines or missing areas.

Practical Takeaway: Ask your eye care professional which advanced tests are recommended for your situation and why. Understanding the purpose of each test helps you make informed decisions about your eye care.

How Often You Should Have Eye Exams

The frequency of eye exams depends on your age, health status, and risk factors. General guidelines provide a framework, but your eye care professional may recommend different intervals based on your individual needs.

For adults aged 18 to 60 with no known eye problems or risk factors, the American Academy of Ophthalmology suggests an eye exam every two years. However, if you have existing eye conditions, diabetes, high blood pressure, or a family history of eye disease, annual exams are recommended. Adults over age 60 should have eye exams every year, as the risk of age-related eye diseases increases significantly.

Children's eyes change rapidly during development, making regular exams crucial for detecting problems that could affect learning and development. The American Optometric Association recommends that children have their first comprehensive eye exam at six months of age, another at three years, and then yearly before starting school and annually throughout school years.

People with diabetes should have dilated eye exams at least once yearly, or more frequently if any signs of diabetic retinopathy are detected. According to the Centers for Disease Control and Prevention, about 1 in 3 people with diabetes develop diabetic retinopathy, a condition that can cause vision loss if left untreated. Early detection through regular eye exams is critical.

If you wear contact lenses, you typically need an eye exam at least annually to update your prescription and assess the health of your corneas. People with glaucoma, macular degeneration, cataracts, or other chronic eye conditions require more frequent monitoring—sometimes as often as every three months depending on disease severity and treatment.

Risk factors that warrant more frequent exams include family history of glaucoma or macular degeneration, elevated eye pressure, African American or Hispanic descent (higher glaucoma risk), previous eye surgery or injury, and use of medications that can affect vision such as corticosteroids or certain psychiatric medications.

Practical Takeaway: Schedule your next eye exam based on your current health status and risk factors rather than assuming a standard interval applies to you. Discuss with your eye care professional the timing of your next appointment before leaving your current visit.