Why would you schedule an in-person eye exam when you could get one online, in your pajamas, without leaving home?
As online eye exams, eyeglass, and contact lens orders become more common, it's natural to get excited about the ease and the lower cost of virtual interactions. But according to the National Eye Institute and John A. Moran Eye Center optometrist, Brandon J. Dahl, OD, FAAO, nothing replaces regular exams by an eye care professional.
"The biggest difference between online and in-person exams is that the online version completely ignores the overall health aspect of the eyes," says Dahl. "You may think your eyes are healthy, but a comprehensive dilated exam (with pupils enlarged with eye drops)—during which a doctor looks at the back of your eye—is the only way to be sure. Dilation allows us to detect some critical issues, even before your physician sees the signs. For example, changes in the blood vessels in your eyes can reveal high cholesterol, high blood pressure, or the onset of diabetes. Many eye diseases that can lead to blindness—including glaucoma, age-related macular degeneration, and diabetic retinopathy—have no early symptoms, so early detection through the eyes is key."
Precise Prescriptions More Likely in Person
In addition to examining eyes, optometrists and ophthalmologists evaluate your vision with a variety of tools calibrated to measure things like eye pressure and peripheral vision (high eye pressure and loss of peripheral vision can signal risk factors for glaucoma).
"When it comes to vision testing—also called refraction—online exams don't necessarily take into account your eyes internal focusing system. So if you're not at the right distance from the screen, and the chart isn't properly calibrated, the online exam can significantly 'over prescribe.' Those too-strong prescriptions can lead to headaches, eye strain, and fatigue," notes Dahl.
What's Included in a Thorough Eye Exam?
In-person eye exams leave nothing to chance as optometrists and ophthalmologists perform several tests beyond evaluating your retina.
Eye muscle tests evaluate the muscles that control eye movement. Your eye doctor may have you follow a moving object, such as a pen or small light with your eyes while checking for muscle weakness or poor control or coordination.
Visual acuity testing measures how clearly you see. It's the standard eye chart test where you read down the rows of letters.
Refraction assessments determine the lens prescription that will give you the sharpest, most comfortable vision. Your doctor may use a computerized refractor or a technique called retinoscopy—using a hand-held light to measure refractive errors. Finally, a manifest refraction—when the doctor places different lenses in front of your eyes and asks which is better—fine-tunes everything.
Tonometry, either with a puff of air or anesthetic eye drops, measures the fluid pressure inside your eye to help detect glaucoma.
"Eye exams are as important as any other kind of regular exam," says Dahl. "Your optometrist or ophthalmologists will let you know how often you should have your eyes checked, depending on your age and other health factors—but the bottom line is, you need to show up, in person."