Defocus Spectacle Lenses: How Special Glasses Help Slow Childhood Myopia

Author: Dr Val Phua
Estimated reading time: 23 minutes

Defocus spectacle lenses are specially designed glasses that correct a child’s blurred distance vision while also helping to slow the progression of myopia.

Unlike ordinary single-vision spectacles, these lenses contain additional optical zones or lenslets around a clear central viewing area.

The central part provides the child’s full distance prescription.

The surrounding treatment areas create controlled optical signals intended to reduce excessive elongation of the eye.

Defocus spectacle lenses may be described as:

Myopia-control spectacles
Myopic-defocus spectacles
Lenslet spectacles
Peripheral-defocus spectacles
Multiple-segment spectacles
Myopia-management glasses

Different products use different optical designs.

Examples include:

Defocus Incorporated Multiple Segments, or DIMS
Highly aspherical lenslets
Slightly aspherical lenslets
Cylindrical annular refractive elements
Dual-index aspherical lenslets
Diffusion-optics designs
Other proprietary segmental or annular treatment patterns

These designs should not be assumed to be equivalent.

They differ in:

Lenslet shape
Treatment power
Central clear-zone size
Arrangement of optical elements
Amount and distribution of myopic defocus
Effect on retinal image contrast
Clinical-trial evidence
Prescription range
Adaptation
Recommended fitting

Modern lenslet-based spectacles have demonstrated meaningful reductions in childhood refractive progression and axial elongation compared with ordinary single-vision glasses. A 2025 meta-analysis of 23 randomised trials found that advanced myopia-control spectacle lenses reduced average axial elongation by approximately 0.15 millimetres and refractive progression by approximately 0.31 dioptres relative to single-vision spectacles, although the effect varied considerably between designs.

Defocus spectacles do not:

Reverse myopia already present
Shorten an elongated eye permanently
Guarantee that myopia will stop
Remove the need for follow-up
Protect against every future myopia-related complication
Work equally well in every child

They aim to slow additional progression.

A child will usually still require glasses after starting treatment, but the final prescription may be lower than it would have been without myopia control.

The central message for parents is:

Defocus spectacle lenses combine clear vision with a myopia-control signal. They are among the safest and most practical first-line options for many children, but their effectiveness depends on the specific lens design, accurate fitting, consistent wear and regular monitoring of refraction and axial length.

The Quick Answer

What Are Defocus Spectacle Lenses?

Defocus spectacle lenses are glasses containing:

A clear distance-correction zone
Surrounding treatment zones that alter how light is focused on parts of the retina

The child sees through the central prescription while the additional optical areas provide signals intended to slow excessive eye growth.

How Are They Different from Ordinary Glasses?

Ordinary single-vision glasses use essentially the same distance prescription across most of the lens.

They make vision clear but generally do not provide a strong myopia-control effect.

Defocus lenses combine:

Full correction of the child’s myopia
Additional optical elements designed specifically for myopia control

Do They Actually Work?

Yes, several designs are supported by randomised clinical trials.

In the original two-year DIMS trial:

Myopia progressed by approximately −0.41 D in the DIMS group.
Myopia progressed by approximately −0.85 D in the single-vision group.
Axial elongation was approximately 0.21 mm with DIMS.
Axial elongation was approximately 0.55 mm with single-vision glasses.

This corresponded to approximately 52% less refractive progression and 62% less axial elongation in that study population.

In a two-year trial of highly aspherical lenslets, the highly aspherical design reduced progression relative to single-vision lenses by approximately:

0.80 D
0.35 mm of axial elongation

Children wearing the lenses for at least 12 hours daily experienced a larger average treatment effect.

These percentages should not be treated as guaranteed results for an individual child.

Do They Cure Myopia?

No.

They correct the current prescription and slow further progression.

If the child removes the spectacles, the existing myopia remains.

How Long Must They Be Worn?

Myopia-control spectacles are generally intended for full-time daytime wear.

This commonly means wearing them for:

School
Homework
Reading
Screen use
Outdoor activities
Ordinary daily life

Clinical-trial data with highly aspherical lenslets showed a greater average effect among children wearing the lenses for at least 12 hours per day.

Are They Safe?

They are generally considered low-risk because:

They do not touch the eye.
They do not require medication.
They carry no contact-lens infection risk.
Their optical effects stop when the glasses are removed.

Some children notice:

Peripheral blur
A swimming sensation
Distortion
Glare
Awareness of the lenslets
Mild difficulty on stairs
A short adaptation period

Most children in clinical trials adapted successfully without serious ocular adverse events.

Who May Benefit?

They may be considered for children who:

Have established myopia
Are still progressing
Developed myopia at a young age
Have increasing axial length
Cannot or do not want to use contact lenses
Prefer to avoid eye drops
Have sufficient spectacle prescription within the product range
Can wear the glasses consistently

Why Childhood Myopia Should Be Controlled

Myopia Is Usually Caused by Eye Elongation

In most children with progressive myopia, the eye becomes longer than its ideal optical length.

Light from distant objects is then focused in front of the retina instead of directly on it.

The spectacle prescription becomes increasingly negative as the eye elongates.

Why Does Axial Length Matter?

Increasing axial length stretches the structures at the back of the eye.

Higher degrees of myopia are associated with greater lifetime risks of:

Retinal tear
Retinal detachment
Myopic macular degeneration
Myopic choroidal neovascularisation
Glaucoma
Cataract
Myopic traction maculopathy

Myopia-control treatment therefore aims to reduce the child’s cumulative axial elongation rather than merely reduce the thickness of future spectacle lenses.

Why Not Wait Until the Prescription Becomes High?

Younger children commonly progress faster and have more years during which their eyes may continue growing.

Waiting until the child reaches high myopia loses an opportunity to reduce earlier progression.

A child does not need to reach:

−3.00 D
−5.00 D
−6.00 D

before treatment is discussed.

Ordinary Single-Vision Glasses

Single-vision spectacles provide clear central vision.

They remain appropriate when:

The child is not progressing
A myopia-control design is not available or suitable
The prescription is outside a particular product range
Myopia-control treatment is declined
Another treatment provides the control signal

However, ordinary single-vision spectacles generally do not slow axial elongation sufficiently to be considered a primary myopia-control treatment.

How Defocus Spectacle Lenses Work

The Eye Responds to Retinal Focus

The retina does more than detect an image.

It also participates in signals that regulate the growth of the eye.

When light is focused in different positions relative to the retina, the eye may receive different growth signals.

Broadly:

Light focusing behind the retina is called hyperopic defocus.
Light focusing in front of the retina is called myopic defocus.

Animal and human research suggests that retinal regions can respond to local defocus and that myopic defocus may help reduce signals encouraging axial elongation.

Clear Vision and Treatment Defocus Occur Together

A defocus spectacle lens attempts to provide two optical effects simultaneously:

Central Correction

The child’s full myopic prescription focuses distant light onto the central retina.

This provides clear vision for:

Classroom work
Reading the board
Walking
Sport
Everyday activities

Treatment Signal

The surrounding segments or lenslets add positive power or alter retinal contrast.

This creates a treatment image in addition to the clear image.

The child’s brain generally continues to use the clear central image for vision while the retina is exposed to the treatment signal.

Why Not Simply Give Weaker Glasses?

Deliberately undercorrecting myopia creates general blur rather than a carefully controlled treatment pattern.

Undercorrection:

Reduces distance clarity
May interfere with school and safety
Does not reliably slow myopia
Has sometimes been associated with faster progression

Defocus lenses provide the full central prescription while delivering a separate treatment signal.

Does the Child See Multiple Images?

The lens creates more than one optical focus, but most children do not report seeing distinct duplicated images.

Possible early experiences include:

Slight blur outside the central zone
Awareness of movement
Reduced peripheral clarity
Mild distortion when moving the head
Awareness of small lens structures under certain lighting

Neural adaptation and changes in eye and head movement usually reduce these symptoms.

Main Types of Myopia-Control Spectacle Lenses

DIMS Spectacle Lenses

What Does DIMS Mean?

DIMS stands for Defocus Incorporated Multiple Segments.

The lens contains:

A central clear zone providing the full distance prescription
A surrounding treatment zone containing many small positive-powered segments

The segments produce simultaneous myopic defocus while the central area maintains clear vision.

What Did the Original DIMS Trial Show?

The two-year randomised trial enrolled 183 children aged eight to thirteen years.

Compared with single-vision lenses, DIMS reduced average:

Refractive progression by approximately 0.44 D
Axial elongation by approximately 0.34 mm

Approximately 21.5% of the children wearing DIMS had no measurable refractive progression during the two-year study, compared with 7.4% wearing single-vision lenses.

Does DIMS Work Outside East Asia?

A two-year UK study included children aged five to fifteen years.

The study did not use a concurrently randomised single-vision control group, but compared observed axial growth with age- and ethnicity-matched expected untreated progression.

Children wearing DIMS showed meaningfully slower axial elongation, with 91% growing more slowly than the published untreated average. Visual function remained good and symptoms were generally infrequent.

These results support usefulness in more diverse populations, although trial designs and comparison methods differ.

Is There Long-Term Evidence?

A six-year extension of the original DIMS study reported sustained myopia control and no clear evidence of rebound after treatment stopped.

However, the extension did not maintain the original randomised comparison throughout all six years, so long-term estimates are less certain than the initial two-year results.

Highly Aspherical Lenslet Spectacles

What Are Aspherical Lenslets?

These lenses contain multiple small lenslets whose optical power changes across each lenslet rather than remaining uniform.

The lenslets are arranged around a central clear zone.

Their combined optics are intended to create a three-dimensional volume of myopic defocus in front of the retina.

Highly Versus Slightly Aspherical Lenslets

A randomised trial compared:

Highly aspherical lenslets
Slightly aspherical lenslets
Single-vision lenses

After one year, the highly aspherical design produced greater average control than the slightly aspherical design.

Relative to single-vision lenses, the highly aspherical design reduced:

Refractive progression by approximately 0.53 D
Axial elongation by approximately 0.23 mm

The slightly aspherical design produced smaller but still significant average effects.

After two years, the highly aspherical design remained more effective than the slightly aspherical design.

This demonstrates an important principle:

Two lenses may both contain lenslets while producing different treatment effects because lenslet geometry and optical power matter.

Does Wearing Time Matter?

Yes.

In the two-year study, children wearing highly aspherical lenslet spectacles for at least 12 hours daily had larger average reductions in:

Refractive progression
Axial elongation

than the overall study group.

Is There Long-Term Evidence?

A five-year follow-up reported continued efficacy among children remaining in highly aspherical lenslet spectacles.

The long-term control comparison was extrapolated mathematically rather than observed in a continuing single-vision control group, so the results support durability but do not carry the same evidential strength as a five-year randomised trial.

Cylindrical Annular Refractive Elements

What Are CARE Lenses?

CARE lenses contain cylindrical annular refractive elements surrounding a clear central zone.

The elements are arranged to produce a controlled blur or defocus signal while maintaining central distance vision.

Different versions may use:

Different central-zone diameters
Different treatment powers
Different distributions of the annular elements

What Does the Evidence Show?

In a two-year multicentre randomised trial involving children aged six to thirteen years:

Single-vision lenses produced approximately −1.15 D of progression and 0.59 mm of axial elongation.
One CARE design produced approximately −0.73 D and 0.40 mm.
A second CARE design produced approximately −0.80 D and 0.44 mm.

Compared with single-vision lenses, the adjusted axial-length differences were approximately:

0.20 mm for CARE
0.17 mm for CARE S

Both treatment designs significantly slowed progression, with no statistically significant difference between the two CARE versions.

Earlier one-year CARE research found a smaller average effect, illustrating that results may vary between:

Lens versions
Trial populations
Central-zone dimensions
Treatment powers
Wearing behaviour
Study design

Dual-Index Aspherical Lenslets

A Singapore randomised trial assessed spectacle lenses using dual-index aspherical lenslets in children aged eight to thirteen years.

After one year, compared with single-vision lenses:

Axial elongation was approximately 0.18 mm lower.
Refractive progression was approximately 0.26 D lower.
The axial-length effect was larger in younger children.
All participants adapted within approximately three to four days.
Best-corrected distance vision remained comparable between groups.

This supports the use of other lenslet technologies but also reinforces that efficacy should be assessed product by product.

Diffusion Optics Technology

How Is Diffusion Optics Different?

Diffusion-optics lenses do not rely only on conventional positive-powered lenslets.

They use microscopic diffusing elements intended to reduce retinal contrast signals that may contribute to myopia development.

The child still has a clear central prescription, but the surrounding lens structure modifies contrast rather than creating the same form of discrete positive defocus used by DIMS or lenslet designs.

What Does the Evidence Show?

The CYPRESS study was a multicentre randomised trial involving North American children aged six to ten years.

At twelve months, one diffusion-optics design significantly reduced axial elongation and refractive progression compared with single-vision control lenses.

A four-year follow-up reported sustained statistically significant differences, although the absolute treatment effect was more modest than that reported in some lenslet trials. The design of the study also changed after the initial randomised phase.

Diffusion optics should therefore be understood as a distinct treatment approach rather than another name for all defocus lenses.

Other Emerging Designs

Other studied or developing spectacle designs include:

Diversified segmental defocus patterns
Annular microstructure lenses
Dual-index lenslets
Full-field defocus designs
Maximised-asphericity lenslets
Novel central and peripheral treatment-zone arrangements

Some have encouraging one-year results.

For example, a Singapore trial of dual-index aspherical lenslets and a separate trial of a novel defocus design both reported less axial elongation than single-vision spectacles.

However, parents should not assume that a lens is proven merely because it contains:

Dots
Rings
Segments
Lenslets
A “myopia-control” label

Useful questions include:

Has this exact design undergone a randomised clinical trial?
How long was the trial?
Was axial length measured?
Was cycloplegic refraction used?
What ages and prescriptions were studied?
Was there a concurrent single-vision control group?
Was the study independently replicated?
Is there longer-term follow-up?
Were visual symptoms and adverse events reported?

Do All Defocus Spectacle Lenses Work Equally Well?

No.

A 2025 meta-analysis found that microlens or lenslet-based designs produced stronger average effects than older non-microlens peripheral-defocus designs.

At 24 months, microlens designs were associated with approximately:

0.51 D less refractive progression
0.29 mm less axial elongation

than single-vision spectacles in the pooled analysis.

Older non-microlens peripheral-defocus designs did not demonstrate a similarly consistent effect.

A separate randomised-trial meta-analysis found that highly aspherical lenslets and DIMS were among the better-supported spectacle designs, while several other lens types produced smaller or more variable effects.

Why Product-Specific Evidence Matters

Two lenses may look similar but differ in:

Lenslet power
Asphericity
Density
Diameter
Arrangement
Central clear-zone size
Retinal image quality
Treatment-zone coverage during eye movement

The term “defocus lens” describes a broad category rather than one standard treatment.

Understanding Treatment Percentages

Relative Effect

Suppose the control group elongates by 0.50 mm and the treated group by 0.25 mm.

The relative reduction is 50%.

Absolute Effect

The absolute difference is 0.25 mm.

Why Percentages Cannot Be Compared Directly

Consider two studies:

Study A

Control elongation: 0.60 mm
Treatment elongation: 0.30 mm
Relative reduction: 50%
Absolute difference: 0.30 mm

Study B

Control elongation: 0.20 mm
Treatment elongation: 0.10 mm
Relative reduction: 50%
Absolute difference: 0.10 mm

Both report 50%, but the absolute differences are not the same.

Why Control Groups Progress Differently

Control progression is influenced by:

Age
Ethnicity
Baseline prescription
Parental myopia
Outdoor time
Educational environment
Study location
Follow-up duration
Seasonal effects
Previous treatment

Parents should not rank products solely by advertising percentages drawn from unrelated studies.

What Outcome Matters Most?

Important outcomes include:

Change in cycloplegic refraction
Change in axial length
Clear vision
Comfort
Wearing time
Safety
Long-term adherence

A lens that performs well in a trial but remains unworn in the child’s school bag provides little benefit.

Which Children Are Suitable?

Children with Progressive Myopia

Defocus spectacle lenses are commonly considered when:

Myopia is established
The prescription is becoming more negative
Axial length is increasing
The child is young
The child has a strong family history
There is concern about future high myopia

Newly Diagnosed Myopia

Treatment may begin at the first diagnosis of myopia rather than waiting for documented rapid progression, particularly when the child:

Is young
Has myopic parents
Already has moderate myopia
Has a long axial length for age
Has a sibling with high myopia

The clinician should confirm that the prescription represents true myopia, often using cycloplegic refraction.

Younger Children

Spectacle-based treatment is particularly attractive for younger children because it avoids:

Contact-lens insertion
Overnight lens wear
Contact-lens infection risk
Daily eye drops

Younger children may also have more potential years of future progression and therefore more to gain from early treatment.

Children with Astigmatism

Many defocus spectacle designs can incorporate astigmatism correction.

The available cylinder range varies between products.

Children with:

High astigmatism
Oblique astigmatism
Irregular astigmatism
Keratoconus
Corneal scarring

may require additional assessment.

A child with increasing or unusual astigmatism may need corneal topography rather than simply a stronger spectacle prescription.

Anisometropia

Anisometropia means that the two eyes have different prescriptions.

Some defocus lenses can be prescribed independently for each eye.

However, a significant difference between the eyes raises additional concerns, including:

Amblyopia
Unequal visual development
Different axial lengths
Different progression rates
Reduced binocular vision

The myopia-control plan should address both visual development and progression.

High Myopia

Children with high myopia may still benefit from slowing additional progression.

Suitability depends on:

Product power range
Lens thickness
Frame size
Visual quality
Astigmatism
Axial length
Retinal health

High myopia does not mean that treatment is too late.

Even partial reduction of further elongation may remain valuable.

Premyopia

Premyopia describes a child who is not yet myopic but is at increased risk because of:

Little remaining hyperopia for age
Rapid refractive change
Increasing axial length
Myopic parents
Early age
Strong family history

Recent trials have investigated lenslet or segmental-defocus spectacles before myopia begins.

Some one-year studies reported less myopia onset or axial elongation in at-risk children.

However:

Long-term evidence remains limited.
Definitions of premyopia vary.
The child does not yet require a distance myopia prescription.
Routine preventive spectacle treatment is not established for every at-risk child.

Outdoor time and careful monitoring remain the most broadly accepted first strategies for non-myopic children.

When Might Defocus Spectacles Be Unsuitable?

They may be unsuitable or require modification when:

The child refuses spectacles
The prescription lies outside the product’s range
Frame fit cannot be maintained
Visual symptoms remain unacceptable
The child has severe developmental or sensory intolerance
Significant strabismus or amblyopia requires another optical plan
The cornea is irregular
There is unexplained reduced vision
The child repeatedly looks over or beneath the lenses
Progression continues despite good adherence

How Are the Lenses Prescribed?

Step 1: Confirm the Prescription

The assessment may include:

Unaided visual acuity
Corrected visual acuity
Cycloplegic refraction
Subjective refraction in cooperative children
Eye-alignment testing
Ocular-health examination

Cycloplegia is particularly important when:

The child is young
The prescription is inconsistent
Pseudomyopia is suspected
The child has strabismus
Myopia appears to have progressed unusually quickly

Step 2: Measure Axial Length

Axial length provides a structural baseline.

It helps determine whether the eye is:

Elongating
Stable
Responding to treatment
Growing faster than expected for age

The spectacle prescription and axial length should be interpreted together.

Step 3: Choose the Lens Design

Selection may consider:

Age
Prescription
Astigmatism
Previous progression
Frame size
Visual needs
Available evidence
Cost
Child and parent preference
Whether atropine may also be used

Step 4: Select the Frame

A good frame should:

Fit securely
Remain centred
Avoid sliding down
Provide sufficient lens depth
Be comfortable behind the ears
Sit at an appropriate distance from the eyes
Allow the child to look through the intended optical zones

A frame that repeatedly slips may reduce visual comfort and treatment-zone exposure.

Step 5: Take Accurate Measurements

Depending on the lens design, the dispenser may measure:

Monocular pupil distance
Fitting height
Frame dimensions
Vertex distance
Pantoscopic angle
Frame wrap
Pupil position

Accurate centration is especially important because the central clear zone should align appropriately with the child’s habitual gaze.

Step 6: Check the Finished Spectacles

The clinician or optician should verify:

Prescription
Optical-centre placement
Fitting height
Frame stability
Visual acuity
Comfort
Head posture
Whether the child looks over the frame

Why Frame Fit Matters

The Child Moves Their Eyes Through Different Zones

During normal vision, children look:

Straight ahead
Down to read
Sideways
Up at a board
Through the lens periphery while walking

A lens is designed with the expectation that these movements expose the retina to both:

Clear correction
Treatment optics

A Slipping Frame Changes Alignment

When a frame slides down:

The child may look through the wrong zone.
The central correction may no longer align optimally.
The child may look over the top.
Peripheral distortion may become more noticeable.
Treatment exposure may become inconsistent.

Children Grow

Frames that fitted well six months earlier may become:

Too narrow
Too low
Crooked
Loose
Uncomfortable

Fit should be checked at each review and whenever the child reports visual difficulty.

How Long Does Adaptation Take?

Many children adapt within:

Several hours
A few days
Approximately one to two weeks

A Singapore trial of dual-index aspherical lenslets reported adaptation within three to four days.

In DIMS and highly aspherical lenslet studies, most children maintained normal distance and near visual function after adaptation.

Possible Early Symptoms

Children may initially report:

Peripheral blur
A swimming feeling
Distortion when moving the head
Difficulty locating steps
Awareness of the treatment pattern
Glare or halos
Mild headache
Eye strain
Reduced confidence during sport

These symptoms commonly improve.

When Should the Child Be Rechecked Early?

Arrange review when:

Symptoms remain significant beyond the expected adaptation period.
The child refuses to wear the glasses.
The child repeatedly removes them at school.
The child trips or feels unsafe.
Vision is not clear centrally.
One eye sees worse than the other.
Headaches are persistent.
The frame slips.
The lenses appear incorrectly centred.
The prescription may be inaccurate.

Persistent symptoms should not simply be dismissed as poor cooperation.

Do Defocus Lenses Affect Reading?

They are designed to provide useful near as well as distance vision.

Children commonly look down through part of the treatment area while reading.

Most clinical trials have not found clinically significant long-term impairment of:

Near visual acuity
Accommodation
Stereoacuity
Near eye alignment

with DIMS or highly aspherical lenslet designs.

Some children may initially notice:

Reduced peripheral clarity
Slower page scanning
Awareness of blur when shifting gaze

Reading posture and frame fit should be checked.

Do They Affect Night Vision?

Some children may notice:

Halos
Glare
Peripheral blur
Reduced low-contrast clarity

particularly:

At night
In dim lighting
With large pupils
During fast movement

Highly aspherical lenslet studies found small initial reductions in selected low-contrast or dim-light visual measures, but these generally did not produce significant long-term functional problems.

Can Children Play Sport in Them?

Yes, for many sports.

Consider:

Impact-resistant lens material
Secure sports straps
A suitable frame
Eye protection
Whether the sport permits spectacles
Peripheral adaptation

For high-impact sports, prescription sports goggles may be safer.

A separate ordinary sports frame may provide vision but may not provide the same myopia-control treatment during the hours it is worn.

Can They Be Worn Outdoors?

Yes.

Outdoor time remains important even when the child uses myopia-control spectacles.

Options may include:

Clear lenses
Photochromic lenses
Clip-on sun protection
Prescription sunglasses when compatible with the treatment plan
A hat

The child should not remove the glasses simply to obtain more outdoor light unless specifically advised.

Do Blue-Light Filters Improve Myopia Control?

No convincing evidence shows that an ordinary blue-light coating adds a meaningful myopia-control effect.

The treatment comes from the lens’s specialised optical design, not from a routine blue-light filter.

Blue-light coatings should not be confused with:

Defocus lenslets
Diffusion optics
Myopia-control treatment zones

Can the Lenses Be Photochromic?

This depends on:

Product availability
Lens material
Prescription
Manufacturer specifications

A photochromic treatment may improve outdoor comfort, particularly for a child using atropine.

It should not alter the intended geometry or manufacture of the myopia-control design.

Must the Lenses Be Worn Full Time?

Consistent daytime wear is generally recommended.

Possible exceptions include:

Bathing
Sleeping
Selected contact sports
Swimming
Activities where spectacle wear is unsafe

Why Wearing Time Matters

The treatment signal is delivered only while the child looks through the lenses.

If the spectacles are worn only for:

School
Television
Seeing the board

the child may lose many treatment hours during:

Homework
Reading
Screen use
Outdoor activity
Weekends

Clinical trials of aspherical lenslets found a stronger treatment response with longer daily wear.

Should the Child Remove Them for Near Work?

Usually no.

Modern myopia-control spectacle lenses are generally intended to be worn during both:

Distance vision
Near work

Removing them for reading may:

Reduce treatment time
Produce blur or poor posture
Encourage closer viewing
Undermine full-time adaptation

Follow the prescribing clinician’s specific instructions.

How Are the Lenses Monitored?

Initial Follow-Up

An early review may assess:

Central visual acuity
Adaptation
Frame fit
Wearing time
Head posture
Symptoms
Lens position

Six-Monthly Myopia Reviews

Children receiving active myopia-control treatment are commonly reviewed approximately every six months.

Assessment may include:

Visual acuity
Cycloplegic or appropriate refraction
Axial length
Eye alignment
Lens condition
Frame fit
Wearing time
Outdoor habits
Near-work habits
Ocular health

Why Measure Axial Length?

A stable spectacle prescription does not always mean that eye growth has stopped.

Changes in:

Cornea
Natural lens
Choroid
Accommodation

may partly conceal axial elongation.

Axial length helps identify whether the eye is continuing to grow structurally.

What Counts as Successful Treatment?

Success does not always mean zero progression.

A useful response may include:

Less progression than before treatment
Less axial elongation than expected for age
Avoidance of rapid progression
Reduced likelihood of high myopia
Good vision
Good adherence
Acceptable comfort

What if Myopia Still Progresses?

Progression does not automatically prove that the lens has failed.

First assess:

Is the child wearing the glasses consistently?
Is the frame correctly fitted?
Is the prescription accurate?
Was refraction performed appropriately?
Is axial-length measurement reliable?
Has the child entered a rapid growth phase?
Is the child particularly young?
Has the lens become scratched or damaged?
Is the child looking over the frame?
Was progression unusually rapid before treatment?

When May Treatment Be Intensified?

Possible options include:

Improving frame fit
Increasing wearing time
Replacing damaged lenses
Updating the prescription
Changing to another evidence-supported spectacle design
Adding atropine
Changing to contact-lens treatment
Using orthokeratology
Selected combination treatment

Defocus Spectacles and Atropine

Can They Be Used Together?

Yes.

Atropine and defocus spectacles use different treatment approaches:

Atropine provides a pharmacological signal.
The spectacles provide an optical signal.

Combination treatment may be considered when:

The child is very young
Myopia began early
Progression is rapid
Axial elongation remains excessive
One treatment alone is insufficient
The child has a strong family history of high myopia

Is Combination Treatment Always Better?

Not necessarily.

Evidence is still developing, and results vary according to:

Atropine concentration
Spectacle design
Age
Previous treatment response
Adherence
Study design

A European observational comparison found that DIMS, atropine and combined treatment all slowed progression, but the non-randomised design prevents firm conclusions about which strategy was superior.

More recent real-world data also suggest benefit from combined atropine and lenslet spectacles in selected fast progressors, but treatment should still be individualised.

A Central European randomised trial found that DIMS produced less one-year axial elongation than 0.01% atropine alone. This comparison does not establish that DIMS is superior to higher atropine concentrations or to every atropine regimen.

When Should Atropine Be Added?

Possible reasons include:

Progression remains faster than expected.
The child’s axial length continues increasing substantially.
Myopia started at a very young age.
The child is approaching high myopia.
Wearing time cannot be increased further.
The family wants stronger control without contact lenses.

The concentration should be selected according to:

Expected efficacy
Light sensitivity
Near-vision effects
Age
Previous response
Local availability
Clinician judgement

Defocus Spectacles Versus Other Treatments

Versus Ordinary Glasses

Defocus spectacles offer:

Similar convenience
Better myopia-control evidence
Full correction of vision

They may cost more and require more precise fitting.

Versus Atropine

Defocus spectacles:

Correct the prescription
Avoid medication
Carry no pharmacological side effects

Atropine:

Does not depend on frame alignment
Can be combined with any suitable optical correction
May provide strong control at appropriate concentrations
May cause light sensitivity and near blur

Versus Dual-Focus Soft Contact Lenses

Defocus spectacles:

Do not touch the eye
Require less hygiene
Are often suitable for younger children

Soft contact lenses:

Provide freedom from spectacles
May be preferred for sport
Require handling and corneal follow-up
Carry a small risk of infection

Versus Orthokeratology

Defocus spectacles:

Are worn during the day
Avoid overnight contact-lens wear
Have no corneal-infection risk

Orthokeratology:

Provides clear unaided daytime vision
Requires rigid lenses during sleep
Requires topography and careful hygiene
Has an established myopia-control effect

Is One Option More Effective?

Average treatment effects overlap.

The best option depends on:

Age
Prescription
Axial length
Progression rate
Corneal health
Lifestyle
Adherence
Side-effect tolerance
Family preference

A treatment that is slightly stronger in a trial may perform worse in practice when the child cannot use it consistently.

When Should Treatment Start?

Treatment may be considered when:

Myopia is first confirmed
Progression is documented
Axial length is increasing
The child is young
Risk factors predict substantial future progression

There is no requirement to wait until the prescription changes by exactly −0.50 D or −1.00 D.

How Long Should the Child Continue?

Treatment often continues for several years.

Stopping may be considered when:

The child is older
Refraction has remained stable
Axial growth has slowed
Pubertal growth is largely complete
The child’s risk profile has decreased
Stability has been demonstrated over more than one visit

Myopia may continue progressing through adolescence and occasionally into early adulthood.

Is There Rebound After Stopping?

The six-year DIMS extension did not identify clear rebound after discontinuation.

However:

Long-term cessation data remain limited.
Evidence differs between designs.
The child’s natural myopia progression may continue.
Stopping the lens removes the optical treatment signal.

Children should be monitored after changing to ordinary spectacles.

Can an Older Sibling Reuse the Lenses?

No.

The lenses are personalised according to:

Prescription
Pupil distance
Fitting height
Frame
Optical alignment

Even when the prescription appears similar, another child should not use them.

When Must They Be Replaced?

Replacement may be required when:

The prescription changes
The lenses are scratched
The frame no longer fits
The optical centres are misaligned
The frame is bent
The treatment areas are damaged
The child’s face has grown
Vision has deteriorated

Can Scratches Affect Treatment?

Significant scratches may affect:

Vision
Contrast
Glare
Comfort
Use of the treatment zones

The lenses should be inspected during follow-up.

Caring for Myopia-Control Spectacles

Children should:

Use both hands to remove them.
Store them in a hard case.
Rinse dust before wiping.
Use a suitable microfibre cloth.
Avoid placing lenses face-down.
Avoid excessive heat.
Avoid leaving them in a hot car.
Attend for frame adjustment when slipping develops.

Common Myths

“They Are Just Expensive Ordinary Glasses”

False.

Evidence-supported designs contain specific optical structures tested for myopia control.

“Every Lens with Dots or Rings Works”

False.

The exact optical design and supporting clinical evidence matter.

“The Child Will See Hundreds of Images”

Usually false.

Most children perceive one useful central image and adapt to the additional optics.

“The Lenslets Damage the Retina”

There is no evidence that established spectacle lenslets damage the retina through ordinary wear.

They redirect light rather than delivering high-powered radiation.

“The Glasses Permanently Reshape the Eye”

False.

They aim to slow future elongation.

“The Prescription Will Become Lower”

Not necessarily.

The expected outcome is slower worsening.

“The Child Should Remove Them to Read”

Usually false.

They are commonly intended for full-time use.

“Wearing Them Only at School Is Enough”

Less wearing time means less treatment exposure.

“The Strongest-Looking Lens Must Work Best”

False.

Appearance does not reveal the retinal treatment effect.

“All Lenslet Designs Are Equivalent”

False.

Clinical trials show different effects between optical designs.

“Frame Fit Is Only Cosmetic”

False.

Centration and stability influence how the child uses the lens.

“Axial Length Does Not Need to Be Measured”

Refraction alone may not show the complete structural response.

“If the Prescription Changes, the Treatment Has Failed”

False.

Treatment usually slows progression rather than stopping it completely.

“The Child Can Stop at Age Twelve”

Not automatically.

Myopia often continues through adolescence.

“Outdoor Time Is No Longer Needed”

False.

Outdoor activity remains beneficial for general health and may reduce environmental myopia risk.

“Blue-Light Coating Provides the Myopia Control”

False.

The treatment comes from the specialised optical design.

Frequently Asked Questions

Which Defocus Spectacle Lens Is Best?

No design is universally best.

The choice depends on:

Evidence
Age
Prescription
Astigmatism
Availability
Fit
Visual comfort
Cost
Response

DIMS and highly aspherical lenslets currently have among the most mature clinical evidence, while CARE, dual-index and other designs have expanding trial support.

Are Defocus Glasses Better Than Atropine?

They are different treatments.

A Central European randomised trial found less one-year axial elongation with DIMS than with 0.01% atropine, but this does not compare DIMS with stronger atropine concentrations.

Can a Five-Year-Old Wear Them?

Potentially.

Suitability depends on:

Confirmed myopia
Product availability
Prescription range
Frame size
Cooperation
Visual development
Ability to wear spectacles consistently

Are They Suitable for Teenagers?

Yes, particularly when myopia is still progressing.

Contact lenses or orthokeratology may also be discussed according to lifestyle.

Do They Work for High Myopia?

They may slow additional progression if the prescription lies within the product’s range.

Can They Correct Astigmatism?

Many designs can include cylinder correction.

Product limits differ.

Can They Treat Lazy Eye?

They may provide the necessary optical prescription, but amblyopia treatment may also require:

Full-time glasses
Patching
Atropine penalisation
Strabismus management

Amblyopia and myopia control are separate objectives.

Can They Correct an Eye Turn?

They may improve alignment when the turn is influenced by refractive error.

They are not a general treatment for every form of strabismus.

Will My Child Notice the Lenslets?

The structures may be visible when the spectacles are held at an angle.

Most children do not remain constantly aware of them during ordinary vision.

How Quickly Should My Child Adapt?

Many children adapt within a few days.

Allow approximately one to two weeks unless symptoms are severe.

Should the Glasses Be Worn During Screen Time?

Usually yes.

Should They Be Worn Outdoors?

Yes.

Can My Child Swim in Them?

Ordinary spectacles are generally impractical for swimming.

Prescription swimming goggles may be used, but they do not necessarily provide myopia-control optics.

Can They Be Used for Football or Tennis?

Often yes, with:

A secure frame
Sports strap
Impact-resistant lenses
Appropriate eye protection

Why Does the Frame Need a Larger Lens?

Some designs require sufficient lens area to include:

The central clear zone
The surrounding treatment zone

An excessively shallow frame may compromise the intended design or reduce useful treatment exposure.

What if the Child Looks Over the Glasses?

The frame should be adjusted or changed.

Looking over the lens removes both:

Clear correction
Myopia-control treatment

What if One Eye Progresses Faster?

The clinician should check:

Prescription accuracy
Axial length
Visual acuity
Amblyopia
Adherence
Eye health
Lens centration

Each eye may require a different prescription.

How Often Should the Glasses Be Changed?

There is no fixed six-month replacement rule.

They should be changed when:

The prescription meaningfully changes
The frame no longer fits
The lenses are damaged
Visual acuity declines
The optical alignment is no longer appropriate

What if Myopia Progresses by −0.50 D?

The result should be interpreted according to:

Age
Axial-length change
Pretreatment rate
Wearing time
Time interval
Measurement method

It may represent partial control rather than failure.

Can Atropine Be Added Later?

Yes.

Can the Child Change to Orthokeratology Later?

Yes, if:

Corneal shape is suitable
Hygiene is reliable
The child and family understand overnight-lens risks

Does the Lens Stop Working as the Child Gets Older?

The biological response may change with age.

Older children naturally tend to progress more slowly, but treatment may still be useful while growth continues.

Can the Child Use an Old Pair as a Spare?

An old pair may be used briefly only when:

The prescription remains reasonably appropriate
The frame still fits
The lenses are intact

The treating clinician should advise whether it is an acceptable backup.

When to Seek Earlier Eye Assessment

Defocus spectacle lenses do not usually cause eye disease.

Seek earlier assessment when the child develops:

Sudden loss of vision
New distortion
Severe headache with neurological symptoms
Sudden double vision
A new eye turn
Eye pain
Marked redness
Light sensitivity
Flashes
A sudden shower of floaters
A curtain or shadow
Eye trauma

Persistent central blur while wearing the new glasses also requires review.

A Parent’s Defocus-Spectacle Checklist

Before Starting

Has true myopia been confirmed?
Was cycloplegic refraction performed when appropriate?
Was axial length measured?
How quickly has the prescription changed?
What is the child’s age-related risk?
Is the cornea healthy?
Is there significant astigmatism?
Is amblyopia present?
Is an eye turn present?
Is the product supported by clinical trials?

Choosing the Lens

What optical design does it use?
What ages and prescriptions were studied?
How long was the main trial?
Was axial length measured?
How large was the absolute treatment effect?
Are long-term data available?
Is this exact product available in the required prescription?
Can it include the child’s astigmatism?

Frame Fitting

Does the frame sit securely?
Is the central zone aligned with each pupil?
Is the lens deep enough?
Does the frame slide?
Does the child look over the top?
Are the temples and bridge comfortable?

Wearing the Lenses

Are they worn throughout the day?
Are they worn for homework?
Are they worn during screen use?
Are they worn outdoors?
Is a sports alternative needed?
Is the child reporting distortion or headaches?

Follow-Up

Has visual acuity remained clear?
Has axial length changed?
Has the prescription progressed?
Is progression slower than before treatment?
Is the frame still correctly centred?
Are the lenses scratched?
Is atropine needed?
Should another treatment be considered?

The Bottom Line

Defocus spectacle lenses are specially designed glasses that:

Correct the child’s myopia
Provide a simultaneous myopia-control optical signal
Aim to slow further axial elongation
Avoid medication and contact-lens wear

The main evidence-supported designs include:

DIMS
Highly aspherical lenslets
CARE
Dual-index aspherical lenslets
Diffusion optics
Other emerging segmental or lenslet systems

DIMS and highly aspherical lenslet spectacles have demonstrated substantial average reductions in refractive progression and axial elongation in randomised trials.

CARE, dual-index aspherical lenslets and diffusion-optics designs also have clinical-trial evidence, although the size and maturity of the evidence differ.

Not all myopia-control spectacles are equivalent.

The treatment effect depends on:

Exact optical design
Age
Baseline myopia
Axial length
Progression risk
Frame fit
Wearing time
Individual biological response

Parents should not select lenses solely according to:

Advertising percentages
Lens appearance
Price
The word “defocus”
Recommendations intended for another child

Accurate fitting and full-time wear matter.

Children should usually wear the lenses during:

School
Reading
Homework
Screen use
Outdoor activity
Normal daily life

The child should be reviewed regularly using:

Visual acuity
Refraction
Axial length
Frame assessment
Wearing-time review
Ocular-health examination

If progression remains excessive, the plan may be adjusted by:

Improving fit or wearing time
Updating the prescription
Changing lens design
Adding atropine
Moving to another optical treatment
Using combination therapy

The most important message is:

Defocus spectacle lenses are not simply glasses with a different appearance. Evidence-supported designs use carefully engineered optics to provide clear vision while reducing signals that encourage excessive eye growth. They are a practical, low-risk myopia-control option for many children, but successful treatment requires the right lens, accurate fitting, consistent wear and objective follow-up.

References

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