Do You Really Need Dilation at Every Eye Exam?
-Experts disagree on who needs it and when. Here’s what the evidence suggests.
The New York Times | By Michelle Crouch
August 20, 2024
Perhaps the most unpleasant part of an eye exam is when the doctor squeezes in the dreaded drops to dilate your pupils. They sting your eyes, blur your vision and leave you squinting at screens for hours. As you blink back tears, it’s natural to wonder: Is this really necessary?
There’s no question that getting your eyes dilated can help providers catch glaucoma, macular degeneration and many other diseases. But there’s a surprising debate over who actually needs it done, and how often.
The American Optometric Association recommends that all adults have a dilated eye exam every year, even if they have no vision problems. But the guidance from the American Academy of Ophthalmology is entirely different: That group says most young, healthy adults don’t need annual dilated exams.
“This is such a hot-button issue,” said Dr. Roy Chuck, an ophthalmologist at Montefiore Einstein in New York and the director of quality of care for the American Academy of Ophthalmology. “It’s confusing, because you’re hearing different things from different doctors.”
We asked experts on both sides of the debate about the benefits and downsides of dilation.
How does dilation work?
Dilation enlarges your pupil to give your eye doctor a wider and clearer view of the retina, optic nerve and blood vessels in the back of your eye, said Dr. Andrew Morgenstern, director of the American Optometric Association’s clinical resources group.
“Looking without dilation is like looking into a room through a keyhole,” Dr. Morgenstern said. “With dilation, it’s like looking with the door open.”
Dilation can help a provider diagnose hundreds of conditions, including some that aren’t vision-related, such as high blood pressure, autoimmune diseases and cancer.
Who needs a dilated exam, and when?
Eye experts all agree that dilated eye exams are crucial for patients who are experiencing symptoms such as floaters, flashes of light, eye pain, double vision or a dramatic change in vision. These can be signs of an issue that threatens your sight, such as glaucoma, macular degeneration, diabetic retinopathy or a detached retina.
Experts also generally agree that it’s important to get a dilated exam every year or every other year if you have certain risk factors. These include having diabetes, high blood pressure, being older than 55, or having a family history of eye disease.
Beyond that, the recommendations of optometrists and ophthalmologists diverge.
To understand the debate, it’s helpful to know the differences between the two types of eye providers: Optometrists hold doctor of optometry degrees and are trained to perform eye exams, prescribe corrective lenses and diagnose and manage certain eye conditions. Ophthalmologists, who have medical degrees, perform most eye surgeries and handle more complex medical conditions.
The American Optometric Association began recommending annual dilated exams for all patients in 2023. Dr. Steven Reed, the association’s president, said this helps providers detect problems sooner.
“Saying ‘Can I skip dilation?’ is kind of like going to dentist and saying, ‘Can I just open my mouth a little bit?’” Dr. Reed said.
Dr. Morgenstern, who helped write the new optometry guidelines, added that rising rates of type 2 diabetes and glaucoma, along with an aging population at risk of falls from cataracts, were key considerations. Glaucoma, a major cause of irreversible blindness in the United States, can start to damage your eyes years before you notice symptoms.
“We are seeing diseases at younger and younger rates every single year,” Dr. Morgenstern said.
Ophthalmologists agree that eye exams are important, but many argue that yearly dilation is not necessary for most younger adults with no symptoms or risk factors.
Instead, the American Academy of Ophthalmology has said that everyone should have at least one dilated eye exam in their 20s and two in their 30s. When you turn 40, you should get a base line exam that your doctor can use to track changes over time, followed by more frequent dilated checkups according to your provider’s advice.
Your 40s are “a pivotal time, when some of the eye diseases start showing early signs,” said Dr. Andrew Iwach, an ophthalmologist at the Glaucoma Center of San Francisco and an academy spokesperson. Dr. Iwach said the ophthalmology guidelines aim to find a balanced approach that takes into account the frequency of eye diseases at different ages.
So, what does the research show?
For something as widely recommended as dilated eye exams, there’s relatively little research on their benefits and risks for young, asymptomatic patients.
Dr. Morgenstern noted that no studies have compared the benefits of having a dilated eye exam every year versus having one every two, three or five years. In its recommendation, the optometry association acknowledged “a gap in the evidence,” but Dr. Morgenstern said the consensus was that the best way to prevent serious eye problems was with early detection.
Ophthalmologists point to research that suggests dilation rarely uncovers significant issues in asymptomatic patients. In a 1998 analysis of 1,094 patients with no symptoms or risk factors, eye exams identified potentially concerning eye issues in only 30 patients. Nearly all of those issues could have been detected without dilation, the authors said. And a 2014 study that followed 592 older patients for 10 years found that while 34 patients developed eye conditions that required treatment, all but one had symptoms at the time of diagnosis.
“What the evidence does show is that our ability to find things is not that great until the later ages,” said Dr. Chuck, who helped write the ophthalmology guidelines.
The U.S. Preventive Services Task Force, an independent expert panel, hasn’t weighed in on dilation specifically, but said in 2022 there wasn’t enough evidence to back routine glaucoma screening in adults aged 40 and older.
More recent research has focused on the promise of retinal imaging devices, which photograph the inside of the eye. Some doctors now offer the technology as an alternative to dilation and even market “no dilation” exams. While this imaging can be useful, experts said it can’t fully replace dilation.
Health insurers typically pay only for dilated eye exams to detect suspected disease, but most vision plans cover the cost of an annual eye exam, with or without dilation.
For patients who don’t have risk factors or symptoms, the choice comes down to whether the inconvenience of dilation outweighs the reassurance that, in rare cases, it might detect an issue.
Beyond the temporary effects, “there’s no harm in doing a complete dilated exam,” Dr. Chuck acknowledged. But if “everything is totally fine [and] you have no family history, just know that the chances that you’ll find anything are just extremely low.”
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