1. Common clinic scenarios
'Doctor, my son got new glasses last year — how did he gain another 100 degrees in just one year?'
'I saw something online called DIMS control lenses that supposedly stop myopia from worsening. Do they really work?'
'How does it compare to atropine or ortho-K? Is it actually right for my child?'
Pediatric myopia is extremely common in Taiwan. What parents worry about most isn't the current diopter number — it's 'will it keep getting worse and end up as high myopia? Will my child develop retinal problems later?' That's why myopia control has become a major clinic topic. DIMS (Defocus Incorporated Multiple Segments) is one optical approach in this category — a spectacle lens engineered to slow myopia progression.
In February 2026, American Journal of Ophthalmology published a systematic review and meta-analysis (Al-Shammari et al.) pooling 6 studies and 1224 children — moving the DIMS evidence base forward. This article digests that new paper into clinic-friendly language: what the evidence does and doesn't support, and what questions to bring to your child's ophthalmologist.
2. Bottom line: what you really need to know
30-second takeaways
- DIMS slows myopia progression and axial elongation in the first year — supported by consistent evidence (Al-Shammari 2026)
- Pooled analysis (6 studies, 1224 children): DIMS lenses preserved ~0.37 D more diopters and ~0.16 mm less axial elongation over 12 months (both P < .0001)
- Original 2-year RCT (Lam et al., 2020, BJO): DIMS produced ~52% less myopia progression and ~62% less axial elongation versus single-vision
- 'Slowing' is not 'stopping' — children still progress, just more slowly
- Suited for school-age children with progressing myopia; included children aged 8-12 years (mean ~10)
- Does not replace outdoor activity or regular eye exams — control lenses are an adjunct, not a panacea
- Long-term evidence is still accumulating — longest follow-up to date is 6 years (Lam et al., 2023, Sci Rep); the new meta-analysis only covers 12 months
- Whether to use should be decided by an ophthalmologist based on the individual child — not by online articles or marketing
3. Common parent Q&As
4. Why does childhood myopia need 'control'?
'Just wear glasses, why control it?' — a common parental question. But myopia is not merely about blurry vision.
① A rising global public-health issue
Myopia prevalence is rising. According to Holden et al. (Ophthalmology, 2016), about 30% of the global population is currently myopic, projected to reach nearly 50% by 2050. Asian school-age children have particularly high rates — myopia is now flagged by the WHO Global Initiative for the Elimination of Avoidable Blindness.
② High myopia raises the risk of sight-threatening complications
High myopia generally means > -6.00 D or axial length > 26 mm. Multiple epidemiologic studies show elevated risk of sight-threatening complications in high myopia:
- Retinal degeneration, retinal detachment (Saw et al., 2005; Cheng et al., 2013 in Hong Kong high-myope adolescents)
- Glaucoma (Xu et al., Ophthalmology, 2007: high myopia significantly associated with glaucoma)
- Myopic maculopathy
In short: controlling pediatric myopia is not just about avoiding thick glasses — it's about reducing the lifelong risk of these complications.
③ Why axial length matters more than diopter
Myopia is fundamentally excessive axial elongation. Once the axial length has grown, it doesn't shrink back. So 'myopia control' is essentially slowing axial elongation. This is why ophthalmologists emphasize axial length over diopter — axial length is an irreversible structural change and a more reliable efficacy indicator.
5. What is a DIMS lens? How does it work?
① In one sentence
DIMS is a spectacle lens whose center corrects refractive error (clear distance vision) while its periphery contains many microlens segments creating peripheral myopic defocus — a signal to the retina meaning 'no need to keep elongating'.
② Optical design
| Lens region | Design | Function |
|---|---|---|
| Central zone | Same as standard myopic correction (sphere or asphere) | Refractive correction; clear distance vision |
| Mid-peripheral annular region | Many microlens segments, each adding +3.50 D positive power | Generates peripheral myopic-defocus signal |
③ Proposed mechanism
The hypothesized mechanism:
- Central image stays clear (child sees normally)
- Peripheral image is shifted forward by microlenses, creating peripheral myopic defocus
- Retina detects this signal and relays it to the sclera
- Sclera slows further growth (scleral remodeling) → axial elongation slows
This mechanism has animal-model support and underlies many 'defocus-based' myopia-control methods (DIMS, ortho-K, dual-focus contact lenses). The 2026 meta-analysis observed consistent effects across Chinese, Italian, Malaysian and Turkish children — supporting a cross-ethnic mechanism (Al-Shammari 2026).
6. Does DIMS really work? Summary of evidence
① The 2020 original 2-year RCT
The foundational DIMS study is Lam et al., 2020, BJO — a double-masked randomized controlled trial:
- 2-year follow-up, DIMS vs single-vision
- 52% reduction in myopia progression in the DIMS group
- 62% reduction in axial elongation in the DIMS group
- This trial established DIMS in the myopia-control landscape and prompted subsequent multinational studies
② 6-year long-term follow-up
Lam et al., 2023 (Scientific Reports) reports the longest DIMS follow-up to date at 6 years. The 2026 meta-analysis cites this paper as evidence of continued safety and partial sustained benefit with ongoing wear. Specific long-term magnitudes should be referenced from the original article.
③ The 2026 meta-analysis: moving evidence forward
Al-Shammari et al., Am J Ophthalmol 2026, following PRISMA methodology, pooled 6 studies and 1224 children:
| Study | Country | Design | N (DIMS / SV) | Mean age |
|---|---|---|---|---|
| Akagun 2025 | Turkey | Retro cohort | 54 / 43 | 9.6 / 9.9 |
| Buzzonetti 2024 | Italy | Retro cohort | 40 / 40 | 11.5 / 11.2 |
| Chun 2025 | China | Retro real-world cohort | 489 / 156 | 8.8 / 8.8 |
| Li 2025 | China | RCT | 72 / 79 | 10.7 / 10.4 |
| Dardin 2024 | Malaysia | RCT | 20 / 18 | 9.6 / 9.5 |
| Zhang 2020 | China | RCT | 93 / 90 | 10.2 / 10.0 |
* 3 RCTs + 3 retrospective cohort studies; ~80% of children from Chinese populations.
④ 12-month primary outcomes
| Outcome | Mean difference vs single-vision | Statistical significance | Heterogeneity (I²) |
|---|---|---|---|
| Spherical equivalent (SER) | 0.37 D less progression (95% CI 0.22-0.51) | P < .0001 | 77% (high) |
| Axial elongation | 0.16 mm less elongation (95% CI 0.13-0.20) | P < .0001 | 41% (moderate) |
Heterogeneity (I² 77% for SER, 41% for axial length) reflects between-study variation in effect size. Leave-one-out sensitivity analyses by the authors showed conclusions stable when any single study was removed, supporting robustness.
⚠️ Honest read of the evidence strength
The 2026 meta-analysis represents moderate-strength evidence — directionally consistent and cross-ethnic, but with important limitations to keep in mind:
- Only 12-month follow-up — beyond-1-year durability and post-cessation rebound are uncertain
- ~80% Chinese — limited generalizability to Western or other Asian populations
- One large real-world cohort (Chun 2025, n=489) accounts for 40% of subjects — many had prior control treatment, potentially affecting pooled estimates
- Does not generalize to other defocus designs (H.A.L.T., CARE, EDOF spectacles are different)
- Wear-time compliance not consistently reported — daily hours significantly affect efficacy but were inconsistently documented
- 3 of 6 studies were retrospective (non-randomized) — selection bias possible
7. Who fits? Who may not?
① Subgroups with relatively better response
- School-age children with progressing myopia — included children mostly aged 8-12
- Shorter baseline axial length — 'earlier is better' before significant elongation
- Children > 10 years (Buzzonetti 2024 Italian study observed stronger response)
- Children who can wear full-time — studies generally required sustained daily wear
- Families committed to regular follow-up — axial-length and refraction monitoring is key
② Situations where DIMS may not be the right fit
- Adolescents with long-stable refraction — minimal benefit from progression control
- Poor compliance — frequent non-wear significantly undermines efficacy
- Coexisting strabismus, amblyopia, irregular astigmatism, etc. — requires individual ophthalmologic evaluation
- Already on stable myopia control — adding DIMS requires physician discussion
8. How does DIMS compare to other methods?
There are four major categories of pediatric myopia control. Each has its target population and limitations; decisions must be made with the ophthalmologist. This article does not directly compare efficacy percentages — study designs, populations, and follow-up periods vary substantially. The Cochrane 2023 living network meta-analysis (Lawrenson et al.) is the most comprehensive cross-method comparison available — discuss specifics with your doctor.
① Four-method overview table
| Method | Form | Best fit | Main limitations | Needs ophthalmologist |
|---|---|---|---|---|
| DIMS spectacles | Daytime glasses | School-age children, full-day compliance | Full-day wear required; 12-month evidence in this review | ✓ |
| Orthokeratology (OK lens) | Overnight rigid contact lens | Want daytime spectacle-freedom; parents can assist with cleaning | Contact-lens-related infection risk (e.g., microbial keratitis); strict hygiene required | ✓ |
| Low-dose atropine drops | Prescription eye drops at night | All ages; standalone or combined | Photophobia, mild near blur; possible rebound on cessation; prescription required | ✓ |
| Outdoor time (≥ 2 hr/day) | Lifestyle (no device/drug) | All children — beneficial for prevention and control | Requires school/family cooperation; not a substitute for devices or drugs | Routine follow-up advised |
* This table positions methods rather than ranks efficacy. Direct efficacy comparisons exceed this article's primary source; the Cochrane 2023 living review (Lawrenson et al.) offers the most complete cross-method synthesis.
② How to discuss 'which option' with the ophthalmologist
- Current refraction, axial length, progression rate — how much D/mm change in the past 12 months?
- Family myopia history — high-myope parents indicate higher progression risk
- Compliance capacity — can wear ≥ 10-12 hr/day? Drops? Ortho-K cleaning routine?
- Parental time and financial commitment — visit frequency, monitoring intensity, total cost differ across methods
- Child's lifestyle — sufficient outdoor time? Near-work hours?
9. What to watch during DIMS wear
① Wear and follow-up
- Studies generally required full-day wear — Dardin et al. 2024 (Malaysia RCT) specifically examined full-time-wear outcomes
- Regular follow-up — typically every 6 months with refraction and axial-length measurement
- Axial length is the key efficacy indicator — more stable and irreversible than refractive change, better reflects true progression
- If persistent discomfort (distance blur, edge wobble, headache) → return to ophthalmologist for re-check
② Daily habits matter just as much
Even with DIMS, these basic prevention habits remain essential:
- ≥ 2 hours of outdoor activity daily — outdoor light itself slows myopia progression; consistent recommendation in international guidelines
- Limit near-work duration — 5-10 min break every 30-40 min of close work
- Correct posture, adequate lighting, no reading in moving vehicles
- Adequate sleep — recent studies suggest a link between sleep duration and myopia progression
💡 Practical reminders
- DIMS is a brake pad, not a hard stop — progression continues, just more slowly
- Don't let DIMS become an excuse to skip lifestyle measures — outdoor time and near-work breaks still matter
- Track axial length, not just diopter — measured with optical biometers (e.g., IOL Master)
- Return if concerns arise — headache, discomfort, reluctance to wear → re-check, don't tough it out
10. Common myths
11. Advanced: for readers who want more depth
This section uses somewhat more technical language and suits medical students, residents, optometrists, and readers interested in methodology. General readers can stop at the previous section.
① The biological mechanism of DIMS (peripheral myopic defocus)
Animal studies (chick, tree shrew, primate) show direction-specific retinal responses to defocus signals:
- Myopic defocus (image focuses in front of retina) → signal toward inhibition of axial growth
- Hyperopic defocus (image focuses behind retina) → signal toward promotion of axial growth
In standard single-vision lenses, the peripheral focal plane tends to fall behind the retina — hypothesized as a myopiagenic signal. DIMS microlenses shift the peripheral focus in front of the retina (myopic defocus), reversing this signal direction. The downstream retinal signaling pathways and scleral-remodeling mechanisms remain active research areas.
② Why axial length is a more reliable endpoint than diopter
- Structure vs refraction: axial length is a direct structural change (irreversible); refraction is also influenced by cornea, lens, pupil
- Cycloplegia caveats: refraction measurement needs cycloplegia to relax accommodation; without it, accommodation creates error — especially in children with strong accommodation
- Optical biometers (IOL Master 700, Lenstar, Pentacam AXL) measure axial length with 0.01-0.02 mm precision — gold standard for pediatric myopia tracking
- The 2026 paper explicitly states: axial length is 'the most reliable indicator of treatment success', showing consistent reduction even when refractive changes were modest (Al-Shammari 2026)
③ Methodological notes on the meta-analysis
- Follows PRISMA 2020 reporting guideline
- Random-effects model for pooling; computed in R with metafor package
- Quality assessment: RCTs by ROB-2 (low / some concerns), retrospective cohorts by Newcastle-Ottawa Scale (7-8/9; weaker on comparability)
- Heterogeneity: tau² + I²; SER I² = 77%, primarily driven by Chun 2025 (real-world cohort with many children on prior control treatments, potentially underestimating pure DIMS effect)
- Sensitivity analysis: leave-one-out (removing each study sequentially); direction of pooled estimate unchanged → supports robustness
- Buzzonetti 2024 split analysis: subgrouped into < 10 and ≥ 10 years; shown as two data points in the forest plot
④ Ongoing research directions
The authors' suggested research priorities (Future Directions):
- Longer follow-up (> 2 years; including post-cessation changes)
- More population validation (Western, Southeast/South Asian)
- DIMS combined with low-dose atropine — theoretically synergistic, needs rigorous trials
- Dose-response of wear time — daily hours and efficacy
- Imaging tools (OCT, ocular biomechanics) to explain inter-individual response variation
- Larger RCTs to confirm effects and guide treatment by baseline risk
12. Taiwan NHI Coverage (April 2026)
Taiwan NHI coverage of the three main myopia-control methods:
| Method | NHI coverage | Conditions / notes |
|---|---|---|
| Low-dose Atropine eye drops (0.1 mg/mL) | ✅ Covered (since May 2023, updated Oct 2024) |
• Patients under 18 • Container ≥ 3.5 mL • 1 bottle per 4 weeks |
| DIMS spectacles | ❌ Self-pay | Spectacle lenses are optical accessories, not in NHI drug coverage. Price varies by brand/frame |
| Orthokeratology (OK lens) | ❌ Self-pay | Rigid contact lenses are medical devices, not in NHI drug coverage. Fitting + follow-up costs substantial |
💡 Practical reminder
- Low-dose atropine NHI coverage since 2023 is a major advance — previously self-pay (NT$ thousands per course); now eligible children can get NHI-covered prescriptions. Eligibility, dose, and combination decisions belong to your child's ophthalmologist
- DIMS and ortho-K remain self-pay — discuss cost and long-term feasibility with the ophthalmologist
- NHI rules update periodically; this article reflects April 2026 NHI drug regulations. Confirm at NHIA website
* Source: NHIA Drug Coverage Regulations, April 2026, Section 14.9.6 Atropine sulfate 0.1 mg/mL eye drops.
13. Summary: what you can do
If your child's myopia is progressing at ages 6-12: discuss DIMS suitability with the ophthalmologist, after a complete exam (refraction, axial length, binocular function, strabismus/amblyopia screening) — not based on ads or online articles alone.
After starting DIMS: follow up every 6 months — track axial length and refraction, comparing progression rate before vs after.
What DIMS cannot replace: ≥ 2 hr/day outdoor time, near-work breaks, screen-time control, correct posture, sufficient sleep. DIMS is an adjunct, not a substitute for basic habits.
What not to do alone: deciding to start/stop DIMS on your own; mixing myopia-control methods without supervision; buying unverified 'myopia control' products; comparing outcomes against other children across ages. Every child is different — treatment decisions should follow a complete ophthalmologic evaluation.
One final note on this 2026 paper: 12-month DIMS efficacy now has relatively consistent evidence, but long-term (> 1 year) durability, generalizability to Taiwanese children, and combination with other methods remain areas of ongoing investigation. Hopefully this digest equips you for a more substantive conversation at your child's next visit.
📚 HsiaoEye Pediatric Myopia Series
- 8 Pediatric Myopia Control Myths — Atropine, OK lens, control lenses, outdoor activity
- Are DIMS Lenses Effective? — 2026 meta-analysis, 0.37 D slowing/12 mo, optimal age (you are here)
- Monitoring: SER or Axial Length? — 2026 meta-analysis, 90/10 framework, disease-specific risk
References
- [本文主要來源] Al-Shammari YM, Alkandari SA, Al-Shammari RM, Al-Kurdi MA, Aljassar F. Defocus Incorporated Multiple Segments (DIMS) Spectacle Lenses Versus Single-Vision Lenses for Pediatric Myopia: A Systematic Review and Meta-Analysis. Am J Ophthalmol. 2026;286:90-97. doi:10.1016/j.ajo.2026.02.045
- [DIMS 原始 2 年 RCT] Lam CSY, Tang WC, Tse DYY, 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
- [DIMS 6 年長期數據] Lam CSY, Tang WC, Zhang HY, et al. Long-term myopia control effect and safety in children wearing DIMS spectacle lenses for 6 years. Sci Rep. 2023;13(1):5475. doi:10.1038/s41598-023-32700-7
- [Cochrane living network meta-analysis] Lawrenson JG, Shah R, Huntjens B, et al. Interventions for myopia control in children: a living systematic review and network meta-analysis. Cochrane Database Syst Rev. 2023;2(2):CD014758. doi:10.1002/14651858.CD014758.pub2
- [全球近視流行病學] Holden BA, Fricke TR, Wilson DA, et al. Global prevalence of myopia and high myopia and temporal trends from 2000 through 2050. Ophthalmology. 2016;123(5):1036-1042. doi:10.1016/j.ophtha.2016.01.006
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- [高度近視與青光眼] Xu L, Wang Y, Wang S, Wang Y, Jonas JB. High myopia and glaucoma susceptibility. Ophthalmology. 2007;114(2):216-220. doi:10.1016/j.ophtha.2006.06.050
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- [高度近視視網膜變化] Cheng SC, Lam CS, Yap MK. Prevalence of myopia-related retinal changes among 12-18 year old Hong Kong Chinese high myopes. Ophthalmic Physiol Opt. 2013;33(6):652-660. doi:10.1111/opo.12082
- [2026 meta-analysis 納入:Akagun 土耳其] Akagun N, Altiparmak UE. Defocus incorporated multiple segments spectacle lenses for myopia control: a retrospective study in a Turkish cohort. Ophthalmic Physiol Opt. 2025;45(5):1090-1097. doi:10.1111/opo.13527
- [2026 meta-analysis 納入:Buzzonetti 義大利] Buzzonetti L, Petroni S, Federici M, Valente P, Iarossi G. Effectiveness of defocus incorporated multiple segments in slowing myopia progression in pediatric patients as a function of age: three-year follow-up. Diseases. 2024;12(9):222. doi:10.3390/diseases12090222
- [2026 meta-analysis 納入:Chun 中國 real-world] Chun RKM, Wong KYQ, Lam CSY, et al. Real-world outcomes of defocus incorporated multiple segments lenses on retarding axial elongation in myopic children and adolescents. Front Med (Lausanne). 2024;11:1416286. doi:10.3389/fmed.2024.1416286
- [2026 meta-analysis 納入:Li 中國 RCT] Li X, Ma W, Song Y, Yap M, Liu L. Comparison of myopic progression and quality of life wearing either DIMS lenses or single-vision myopia correcting spectacles. J Ophthalmol. 2025;2025:9959251. doi:10.1155/joph/9959251
- [2026 meta-analysis 納入:Dardin 馬來西亞 RCT] Syed Mohd Dardin SF, Mohd-Ali B, Norazman FNN, et al. Effectiveness of defocus incorporated multiple segments (DIMS) lens in slowing myopia progression among Malay school children. IIUM Med J Malaysia. 2025;24(1):85-93. doi:10.31436/imjm.v23i04.2611
- [2026 meta-analysis 納入:Zhang 中國 RCT] Zhang HY, Lam CSY, Tang WC, Leung M, To CH. Defocus incorporated multiple segments spectacle lenses changed the relative peripheral refraction: a 2-year randomized clinical trial. Invest Ophthalmol Vis Sci. 2020;61(5):53. doi:10.1167/IOVS.61.5.53
