The Battle of the Blur: DIMS Lenses vs Orthokeratology in the Myopia Wars

By The Biomedical Observer

Somewhere in the world right now, a child is squinting at a whiteboard. In another classroom, a kid is sitting in the front row not because they're eager to learn, but because they literally cannot see the board from anywhere else. Welcome to the global myopia epidemic, and let me tell you - we're losing.

By 2050, projections suggest roughly half of humanity will be myopic. That's nearly 5 billion people who can't see the forest OR the trees without optical correction. If myopia were a stock, you'd be shorting everything else.

But here's the thing: we're not just sitting around accepting our blurry fate. Two technologies are duking it out in the arena of myopia control - DIMS spectacle lenses and orthokeratology. And a fascinating clinical trial (NCT05134935) is asking the question every parent of a nearsighted kid wants answered: which one actually works better?

The Myopia Problem is Worse Than You Think

Let's talk numbers. In East Asian countries like Hong Kong, Taiwan, and Singapore, myopia prevalence among young adults is hitting 80-90%. This isn't just an inconvenience requiring glasses - high myopia significantly increases the risk of serious eye conditions like retinal detachment, glaucoma, and macular degeneration later in life.

The eyeball of a myopic person is essentially too long. Light focuses in front of the retina instead of on it, hence the blur. And here's the kicker: once your eyeball elongates, it doesn't un-elongate. The growth is permanent. Every millimeter of extra axial length matters.

This is why myopia control - actively slowing the progression of nearsightedness in children - has become one of the hottest topics in optometry. We're not just correcting vision anymore; we're trying to prevent eyeballs from growing into little stretched-out footballs.

DIMS Lenses: The Fancy Glasses Approach

DIMS stands for Defocus Incorporated Multiple Segments. It's a spectacle lens that looks mostly normal but contains something clever in its design. Around the central clear zone that corrects your vision for distance, there's a honeycomb-like arrangement of tiny segments that create myopic defocus - essentially, slightly blurred zones that the eye's peripheral retina experiences.

Why would you deliberately blur part of someone's vision? Because of something called the "peripheral defocus theory" of myopia progression. Research suggests that when the peripheral retina experiences hyperopic defocus (focused behind the retina), it sends signals that encourage the eye to keep growing. Myopic defocus (focused in front of the retina) appears to do the opposite - it tells the eye to slow down.

The DIMS lens has those multiple segments providing +3.50 diopters of myopic defocus. It's like having tiny speed bumps around your visual field that whisper "stop growing" to your eyeball. Poetic, isn't it?

The results from Hong Kong's original 2-year randomized controlled trial were impressive: 183 Chinese children aged 8-13 showed 52% slower myopia progression in the DIMS group compared to single vision lenses. Axial elongation - the actual stretching of the eyeball - was reduced by 62%. That's not incremental; that's substantial.

Orthokeratology: The Overnight Reshaping Miracle

Ortho-K, as the cool kids call it, takes a completely different approach. These are specially designed rigid contact lenses worn overnight that physically reshape the cornea while you sleep. You wake up, pop them out, and - voila - you can see clearly all day without any glasses or contacts.

Yes, it sounds like witchcraft. But it's actually just mechanics.

The lenses gently flatten the central cornea and steepen the peripheral zones. This reshaping corrects your myopia for daytime activities AND creates that magical myopic peripheral defocus that appears to slow eye growth. Two birds, one sleepy stone.

Orthokeratology has been around since the 1960s, though modern iterations are far more sophisticated and predictable. Studies show it can reduce myopia progression by about 50-60% - roughly comparable to DIMS lenses.

The Head-to-Head: What NCT05134935 Wants to Know

The clinical trial we're talking about directly compares these two interventions. It's a noninferiority study, which in clinical trial speak means: "We think the newer thing (DIMS) is at least as good as the established thing (orthokeratology), and we're going to prove it."

The study uses axial length as the primary outcome - the actual elongation of the eyeball measured at 18 months. This is the money measurement, the one that really matters for long-term eye health. They're using linear mixed-effects models (fancy statistics for handling repeated measurements over time) and will report both intention-to-treat and per-protocol analyses.

Why does this comparison matter? Because DIMS lenses and orthokeratology have very different practical profiles:

DIMS lenses: You wear glasses. That's it. No contact lens care, no solutions, no risk of corneal infections from sleeping in contacts. For young children or anyone who finds contact lens handling challenging, this is huge.

Orthokeratology: No daytime correction needed. Kids can play sports, swim, do whatever without glasses or contacts in the way. But it requires diligent overnight lens wear, proper hygiene, and carries a small but real risk of microbial keratitis if lenses aren't cared for properly.

Parents face this choice constantly: convenience vs. intervention complexity. If DIMS can match orthokeratology's efficacy, it becomes an incredibly compelling option for many families.

The Science of Growing Eyeballs

Here's what's wild about all this: we still don't fully understand exactly why these interventions work. The peripheral defocus theory is our best hypothesis, but the eye is a complex biological system. There are probably multiple mechanisms at play.

What we do know is that both DIMS and orthokeratology induce myopic defocus in the peripheral retina, and both slow axial elongation. Recent research has even shown that DIMS lens wearers show increased choroidal thickness - the blood vessel layer behind the retina - which may be part of the protective mechanism.

The Hong Kong 6-year follow-up study on DIMS lenses showed something particularly encouraging: there was no rebound effect after stopping treatment. The myopia control benefits persisted. Children who wore DIMS for 6 years maintained the slower progression rate throughout, with no evidence that their eyes suddenly "caught up" when they switched to regular glasses.

What About Combining Treatments?

Some researchers are going full send on myopia control by combining interventions. Studies have shown that adding low-dose atropine (0.01%) to DIMS lens wear can reduce axial elongation by up to 72% compared to single vision lenses. That's getting into "almost stopped" territory.

Atropine is a muscarinic antagonist that somehow (we're still figuring out the details) independently slows myopia progression. Combining it with optical interventions like DIMS or orthokeratology might be the future of aggressive myopia management - throwing everything we have at the problem.

The Bottom Line for Parents and Clinicians

If you're a parent of a myopic child, here's what you should know:

1. Doing nothing is the wrong choice. Letting myopia progress unchecked while a child is still growing is accepting unnecessary risk for their future eye health.

2. Both DIMS and orthokeratology work. The question of which works "better" is still being investigated, and the answer may be that they're roughly equivalent for most kids.

3. The choice often comes down to lifestyle. Does your child want glasses or overnight contacts? Can they handle contact lens hygiene? Do they play water sports?

4. Treatment should continue as long as possible. Myopia typically stabilizes in late adolescence, so several years of intervention may be needed.

The NCT05134935 trial will give us better evidence to guide these decisions. In the meantime, the good news is that we have options - real, proven options - for fighting back against the myopia epidemic.

Our grandchildren may live in a world where progressive myopia is largely preventable. And honestly? That future looks pretty clear to me.

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References:

1. Lam CSY, et al. Defocus Incorporated Multiple Segments (DIMS) spectacle lenses slow myopia progression: a 2-year randomised clinical trial. Br J Ophthalmol. 2020;104(3):363-368. DOI: 10.1136/bjophthalmol-2018-313739

2. Lam CSY, et al. Long-term myopia control effect and safety in children wearing DIMS spectacle lenses for 6 years. Sci Rep. 2023;13:5475. DOI: 10.1038/s41598-023-32700-7

3. Chen Y, et al. Comparison of myopic control between orthokeratology and DIMS lenses: A meta-analysis. Int J Med Sci. 2024;21:1329-1338.

4. Clinical trial registration: NCT05134935

   

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Disclaimer: This blog post is for informational purposes only and does not constitute medical advice. Clinical trials are ongoing research studies - consult with healthcare providers for medical decisions. The views expressed are those of the author and do not represent endorsement of any specific products or treatments. Images and graphics are for illustrative purposes only and do not depict actual medical devices, procedures, mechanisms, or research findings from the referenced studies.