Dr. Yang Zhengfei's In-Depth Explanation: What's the Difference Between Defocus Lenses and Regular Glasses?

When children have regular checkups, isn’t the phrase parents dread hearing most: “Oh no, their prescription has increased again!”

In the clinical management of childhood myopia, many children with mild myopia can see their refractive status gradually stabilize and improve through standardized interventions, scientifically prescribed eyewear, and follow-up on home eye care.

Recently, Dr. Yang Zhengfei from Aier Eye Hospital in Dongguan shared a clinical case involving a 9-year-old girl. After one year of standardized management using a combination of defocus lenses, 0.01% atropine, and a systematic daily eye care regimen, the child’s refractive status showed overall stabilization and improvement.

Dr. Yang Zhengfei pointed out that this result fully demonstrates the advantages of a “personalized comprehensive prevention and control plan” in slowing the progression of myopia. However, she also emphasized:

“Currently, there are no authoritative clinical studies, either domestically or internationally, confirming that true myopia can be completely reversed. The favorable fluctuations in prescription observed in a small number of patients during clinical practice are mostly related to improvements in ocular accommodation, stabilization of refractive status, and a slowdown in axial length growth; this should not be equated with a ‘cure for myopia.’”

Many parents are curious: What exactly is the difference between defocus glasses—which help prevent and control myopia—and regular glasses? How should they be selected, worn, and replaced? Today, Dr. Yang Zhengfei addresses several topics of particular concern to parents, providing detailed answers.

Q1

What are defocus glasses? Why are they more expensive than regular glasses?

Many parents view defocus glasses as “regular glasses,” but in fact, their functions are entirely different.

Regular glasses: Primarily address the issue of “blurred vision” by focusing light onto the retina.

Defocus glasses: Not only ensure “clear vision,” but also help slow the progression of myopia.

Defocus glasses utilize a special optical design to alter the angle of light entering the eye, creating a myopic defocus signal in front of the retina, thereby inhibiting excessive axial length growth.

Q2

How should you choose a brand of defocus lenses? Does a higher price mean better quality?

With so many brands of defocus lenses on the market, many parents are torn: “Is more expensive always better? Which brand should I choose?”

Dr. Yang Zhengfei reminds us: The key to prevention and control lies in precise matching—the right fit is the best choice.

It’s like prescribing medicine: just because it’s imported doesn’t mean it’s necessarily better; the right treatment for the right condition is what matters. At Dongguan Aier, doctors focus on “parameters” rather than brands when selecting lenses:

First, they assess technical indications: Based on whether the child has hyperopia reserve and the rate of axial length growth, they determine which optical approach is suitable;

Next, they examine ocular biometric parameters: They analyze over a dozen data points, including corneal curvature, axial length, corneal diameter, and pupil size;

Finally, we consider visual function: We comprehensively evaluate accommodation and convergence functions to select the lenses that best match the child’s current eye conditions.

We adhere to “personalized fitting” and never blindly recommend brands—we choose what’s right, not what’s expensive.

Q3

When wearing defocus lenses, how much myopia progression is considered normal over six months?

Many parents get very anxious when they see a 25-degree increase on their eye exam report. In reality, what we need to look at is the “comparative data.”

Reference values: Generally speaking, a myopia progression of approximately 25–35 diopters over six months while wearing defocus lenses is considered a normal physiological fluctuation.

How to evaluate effectiveness: If a child previously progressed by 100 diopters annually but now progresses by only 50 diopters annually while wearing defocus lenses, this indicates that myopia control has been very successful! Do not worry simply because the “myopia hasn’t decreased.”

Q4

How often do defocus lenses need to be replaced?

Defocus lenses aren’t a one-time solution that lasts a lifetime. Generally, you should consider replacing them when any of the following three situations arise:

Lens wear: If the lens surface has noticeable scratches, scuffs, or is worn down, it will affect the accuracy of the defocus signal and must be replaced;

[Major Upgrade] One-Stop Myopia Prevention and Control Solution

To better serve families with children, Dongguan Aier Eye Hospital has launched its “Newly Upgraded Myopia Prevention and Control Program with Eyeglasses”:

This program integrates frame selection, custom lens fabrication, and regular follow-up examinations into a standardized package, delivering a “one-stop service.” Through a tiered technical assessment system, we can more easily match the most suitable prevention and control plan to each child based on their specific eye parameters.