This document provides an overview of myopia, including its definition, global epidemiology, risk factors, management options, and the importance of controlling axial length growth. It discusses that myopia prevalence is increasing globally and poses lifelong risks. Risk factors for increased myopia progression include younger age, family history, near work, ethnicity, and binocular vision issues. The document reviews behavioral, optical, and pharmacological management strategies and their effectiveness, noting that controlling axial length growth through approaches like orthokeratology and atropine is key to managing myopia progression.

1. MYOPIA
CONTROL
assignment
SUBMITTED BY: SRIJANA LAMICHHANE
4TH
YEAR, B.OPTOM
Maharajgunj Medical
campus, TUTH , IOM

2. Myopia control
Table of contents
• Introduction of myopia
• Global epidemiology of myopia
• Why myopia control is necessary?
• Risk factors of myopia
• Why axial length control is crucial for the control of myopia?
• Management options for Myopia
Introduction of myopia
It is a type of refractive error (not diseases) in which the parallel rays of light coming from infinity comes to focus in
front of the retina when accommodation is minimum or near rest. Myopia is a significant global public health and
socioeconomic problem. Myopia can be characterized as refractive or axial, although a continuum of the two types
exists. In refractive myopia the overall refractive power of the eyes as determined by cornea and crystalline lens
power is excessive in relation to an eye of normal axial length. A single mm change in curvature of cornea changes
6D of refractive power. Axial myopia is the result of an excessive elongation of the eye with respective to its
refractive components. In axial myopia, 1mm of axial length change gives 3D of refractive error change.
There are several classifications of myopia but according to Curtin (1985) classification, myopia is divided into
following groups.
1. Simple or physiological myopia (less than -3D) with usually no funduschanges.
2. Intermediate myopia (- 3 to -5D), in which temporal crescents are present.
3. High or pathological myopia (-6D or more) due to excessive axial elongation and is associated with posterior
segment anomalies
High Myopia is a condition in which the mean spherical equivalent objective refractive error is ≥ −6.00 D or axial
length is ≥ 26 mm in either eye
Global epidemiology
High myopia is one of the leading causes of low vision in the world. There is higher prevalence in Asian countries, but
it is estimated that 1% of the global population exhibits high myopia. According to published studies, the prevalence
of myopia is highest in East Asia, where China, Japan, the Republic of Korea and Singapore have a prevalence of
approximately 50%, and lower in Australia, Europe and north and South America. It is estimated myopia and high
myopia will affect 52% (4949 million) and 10.0% (925 million), respectively, of the world’s population by 2050
Why myopia control is necessary?
It is commonly understood that myopia prevalence is growing globally. By 2050, it is predicted that half of the
world’s population - five billion people - will be myopic, with nearly one billion at risk of myopia related ocular
pathology. high myopia is strongly linked to higher risk of cataract, retinal detachment and myopic maculopathy, and
increasing rates of vision impairment and blindness due to the latter are already evident in Asian countries.
The myopia control imperative is understanding that even -1.00D of myopia carries an additional lifelong risk of
posterior subcapsular cataract (PSCC), retinal detachment (RD) and myopic maculopathy (MM). A convincing case

3. has been previously made by pediatric ophthalmologist Ian Flitcroft that the delineation of physiological and
pathological myopia is not valid, as the term ‘physiological’ implies that there is a level of myopia which could be
considered ‘safe’ in comparison to emmetropia. Using odds ratios, which describe the increased risk of a condition
over a reference of 1 (this being the risk of emmetropia), the table below summarizes Flitcroft’s data which shows
that even 1D of myopia doubles the risk of MM and PSCC, and triples the risk of RD compared to the emmetrope. At
3D of myopia, the risk of PSCC triples, with the risk of RD and MM being nine times that of the emmetrope. Higher
levels of myopia bring more eye-watering risks
Risk factor of myopia
Myopia is etiologically heterogenous. Myopia development and progression is multifactorial. Assessing the risk
factor for early onset and progression is more crucial in the selection of most appropriate intervention for myopia
control.
Identifying the pre-myope
There are four key principles for assessing risk of myopia onset:
Family history – one myopic parent increases risk by three-fold, while two myopic parents doubles this risk again
Visual environment – less than 90 minutes a day spent outdoors increases risk, especially if combined with more
than 3 hours a day spent on near work activities (outside of school time)
Binocular vision – Children with higher accommodative convergence (AC/A) ratios, typically seen with esophoria,
have an increased risk of myopia development within one year of over 20 times. Accommodative lag may also be a
risk factor but there is conjecture. Intermittent exotropia has also been associated with onset of myopia.
Current refraction – the most significant risk factor of this lot for future myopia is if a child exhibits 0.50D or less
of manifest hyperopia at age 6-7. This risk is independent of family history and visual environment.
In addition to this, the fastest rate of refractive change in myopic children occurs in the year prior to onset, so the
child who is less hyperopic than age normal should be closely monitored, especially if concurrent risk factors are
evident.
Identifying the myopia progressor
Age - the younger a child becomes myopic, the faster they will progress, with children 7 years of age progressing by
at least 1D per year with this halving by age 11-12.
Family history - children with two myopic parents have been shown to be the fastest progressors in single vision
spectacle and atropine corrections, and children with one myopic parent progress less than the former but more
than the child without such family history.

4. Visual environment – near work at less than 20cm working distance and durations of longer than 45 minutes have
been linked with more myopia progression.
Ethnicity - Asian ethnicity has been linked to faster myopia progression
Binocular vision – watch for esophoria, accommodative lag and intermittent exotropia. In myopia control studies
of progressive addition spectacle lenses (PAL), children with esophoria in single vision spectacle control groups were
found to progress more quickly, and children with a larger baseline accommodative lag in the PAL groups showed
statistically greater treatment effect. Children with lower baseline accommodative amplitude have shown a greater
myopia control response to orthokeratology contact lens wear compared to normal accommodators. Finally, while
the effect of controlling IXT on controlling myopia has not yet been studied, 50% of children with intermittent
exotropia (IXT) are myopic by age 10 and 90% by age 20.
Why axial length control is crucial for the control of myopia?
Ultimately the myopia control is the control of axial length. Tiedeman and colleagues from the Netherlands
evaluated the prevalence of lifelong visual impairment (6/12 or less) with increasing axial length, using data from
over 10,000 Dutch people with an average age of 61 years – an axial length of 24-26mm was used as the referent.
Axial length of 26-28mm doubled the risk of visual impairment by age 60, while 28-30mm increased the risk by 11
times and an axial length of 30mm or more by 25 times. The prevalence of visual impairment by age 75 for the
longest eyeballs (over 30mm) was 90%. Between 26-30mm axial length, the likelihood of being visually impaired by
age 75 was around 25%, with the difference between shorter (26-28mm) and longer (28-30mm) eyes being the age
of onset – the person with longer eyeballs is likely to suffer visual impairment for a longer duration of their life.
Summarized in the table below, this is sobering data and provides the clear message to both patients and parents
that controlling axial elongation also controls lifelong risk of visual impairment.
Treatment options for the control of myopia
• Assess the risk of myopia
• Behavioral management
• Optical management
• Pharmacological management
• Asses and manage binocular vision
ASSESS THE RISK OF MYOPIA
We should always assess the risk of myopia even a 1D myopia can results in a lifelong risk of PSCC, retinal
detachment and myopic maculopathy.
There should be regular eye examination of the people who are at a greater risk of myopic complications.
The child who are less hyperopic at the age of 6-7 yrs. should undergo regular follow-up eye examination.

5. BEHAVIORAL MANAGEMENT
In this management option, it is mainly concerned with the change in behavior and attitude.
Behavioral management includes:
• Time spent outdoors
• Less near work
Time spent outdoors and less near work
Outdoor light exposure during childhood is the most critical known modifiable risk factor for myopia. Outdoor light
exposure prevents or delays the onset of myopia and may slow progression. (Ho et al., 2019) The protective effect of
being outside is currently explained by high light intensity triggering the release of retinal dopamine, an ocular
growth inhibitor that inhibits myopic development. (Ramamurthy et al, 2015) Another potential explanation is that
pupils are more constricted outdoors, causing a greater depth of field and less image blur, resulting in less myopic
stimulus. (Flitcroft 2012)
. In animal studies, higher light levels greatly retarded form- deprivation myopia a reaction which is abolished by
dopamine antagonists
The role of chromaticity (red and blue) and ultraviolet (UV) light is still uncertain, Also, vitamin D levels to degree
of myopia change is very small.
Rudnicka et al. (2016) found that children living in predominantly urban environments have 2.6 times the risk of
myopia compared to children living in rural environments.
Potential explanations include:
more congested environment,
greater emphasis on education,
- more near-vision work &
- fewer outdoor activities
The clinical culmination is that at least 90 minutes of average outdoor time per day for children is beneficial
with less near work and working distance. UV protection is important and must be balanced with the visual
and retinal stimulation provided by bright natural light
20-20-2 rule for myopia control
20-20-2 Rule, proposed by Prof. Caroline Klaver, MD, PhD, and her co-researchers at the Erasmus University Myopia
Research Group in Rotterdam, Netherlands, is more effective in reducing the incidence of myopia and possibly
slowing progression. (Klaver et al, 2020) What is the 20-20-2 Rule? After 20 minutes of close work, children should
gaze at objects in the distance for at least 20 seconds, and they should be outside intermittently for at least 2 hours
per day.

6. Optical Management
Optical management includes the use of appropriate concave lens to correct the myopia. But the management
should also control the progression of myopia and its onset. Various spectacles, contact lens design have been
studied in the control of myopia progression. All the treatment options should be individualized and must be
evidence based. For the individual patient, there could be one primary driver to myopia progression and
development I.e. genetics, environment, peripheral refraction, accommodation or it could be a combination.
• Spectacles lenses
• Contact lenses
• Orthokeratology
Spectacles lenses
Studies have shown that single vision lenses (SVL) is ineffective in the control of myopia progression. So, most
investigated spectacles lens design for the control of myopia progression are Progressive addition lenses (PAL),
Bifocal lenses, and Prismatic bifocal (bifocal lenses with BI Prism).
New spectacle lens technology for myopia control is on the horizon -the award-winning Defocus incorporated
multiple segments (DIMS) spectacle lenses, developed at the Hongkong polytechnic university, has just been
released in Asia.
PAL, Bifocal and prismatic bifocal lenses
PAL and bifocal spectacle lenses have shown reasonable research results for myopia control. Spectacles lenses are
the first line of treatment we usually prescribe for myopia contralesionally, it is also an important adjunct treatment
in soft contact lens wearers as a backup correction and also in case where atropine is being prescribed as a first line
of treatment.
PAL studies for myopia control show negligible results when single adds are applied to all children, however when
applied to children with esophoria and accommodative lag, the results become more impressive at 30-40% efficacy.
Cheng et all’s study investigated a standard bifocal with +1.50 Add, and the same add with the 3BI prism in each eye.
After three years of wear, they found a moderate myopia control effect around 35% for axial length and 50% for
refractive change. the study incorporated children with orthophoria and exophoria in their baseline SVL. They found
minimal effect in esophoric children, and when analyzed by accommodative lag, both bifocal types show similar
effect in children with high accommodative lag (over 1D), but found better results with prismatic bifocal in children
with low accommodative lag.
So, which to pick in practice?
Esophoria and high accommodative lag: PAL
Orthophoria, exophria or normal accommodation (lag<1D): bifocal or prismatic bifocal
DIMS LENSES
The DIMS lens has a 10 mm clear central optical zone with the distance correction, and then is covered with +3.50
lens lets with regions of the distance correctio in between the lenslets.the intended result is that wherever a child
looks in the lens, they’ll experience 50%of retinal focus being their distance correction, and 50% of the +3.50 Add.
These lenses look like the single vision lens but could work more like a contact lens because a newly published two-
year study with these lenses have shown 50% refractive control and 60% axial length control.

7. Contact lenses
Numerous studies have concluded that the SV soft contact lens and conventional GP (not OK) lenses didn’t show
promising results in the control of myopia progression.
Contact lens options appear to be the most consistent, with multifocal soft contact lenses and OrthoK offering
around 50% efficacy for controlling both refractive and axial length in myopia.
Multifocal soft CL
Although they come in many designs, only center-distance designs have been formally investigated in the context of
myopia control. In these designs, the peripheral region of the lens has relatively more positive (plus) power,
incorporated as a gradual increase toward the periphery (progressive design) or presented in distinct zones
(concentric ring design). The lens design is reflected in the labeling: bifocal, MF, gradient, progressive, or positive
spherical aberration–inducing lenses. In most cases, the lenses are intended to provide clear distance vision, while
imposing myopic defocus on the more peripheral retina as a putative stimulus to slow eye growth. Based on sample
size–weighted averages, the eight trials published over the 2011 to 2016 period showed a 38.0% slowing of myopia
progression and a 37.9% slowing of axial elongation with MF soft contact lens interventions. Interestingly, concentric
ring designs showed better control over axial elongation than progressive designs (44.4% versus 31.6%), whereas
their effects on myopia progression were similar (36.3% versus 36.4%).
accommodative responses to near tasks were consistent with accommodation being driven by the center-distance
zone of the MF lenses, the implication being that accommodative lags would have been minimally affected.
However, two other studies reported positive benefits on accommodative errors in the presence of MF soft contact
lenses (i.e., decreased accommodative lags and accommodative leads)
Orthokeratology (OK)
OK, also known as corneal reshaping therapy, involves reshaping of the cornea to reduce myopic refractive errors.
OK has proven to be effective in slowing myopia progression. OK also has been shown to induce relative myopic
shifts in peripheral refractive errors in all meridians, consistent with the most popular hypothesis for this myopia
control effect.
Individual studies and meta-analyses have shown a 40–60% reduction in the rate of myopia progression with ortho-k
lenses compared with controls using SVL spectacles
In a meta-analysis by Sun et al., the combined results showed
-a mean AL reduction of 0.27 mm (95% CI: 0.22, 0.32) after 2 years, corresponding to a 45% reduction in myopic
progression
Younger children (aged 7–8 years) with faster myopic progression (>1.0 D/year) might benefit more benefits were
noted even in partially corrected children with high myopia However, studies show that the efficacy may decrease
over time, especially after 4–5 years, and a potential “rebound” after discontinuation, especially in children under 14
years.
Pharmacological management
Atropine is a non-specific muscarinic acetylcholine receptor antagonist initially thought to work by blocking
accommodation. this theory has since been disproved in animal studies. Its exact mechanism is still unknown, but it
is thought to work through muscarinic or non-muscarinic pathways either in the retina or in the Bruch’s membrane.
Atropine has a strong dose-dependent inhibitory effect of myopia progression. The initial high doses of atropine (i.e.,
0.5% or 1.0%) slowed myopia progression by more than 70% over 1–2 years. However, lower doses (0.1% or less)
can also slow myopia by 30–60%, and may be associated with fewer side effects (pupil dilation, glare or blur).

8. Various studies are done on the pharmacological treatment of myopia with atropine and still there are many studies
currently underway, among them ATOM 1 and ATOM 2 study shows the most promising results.
ATOM 1 study (atropine in the treatment of myopia)
• Parallel-group, placebo-controlled, randomized, double-maskedstudy
• Conducted in Singapore
• Included 400 children aged 6-12 years (mean age 9.2years)
• With moderate myopia (-1.00 D to -6.00 D, mean -3.50D)
• For 3 yrs. (2-yrs treatment period and 1-yr washoutperiod)
• The treatment group received atropine 1% at bed time in one eye and no treatment in the othereye
RESULTS
• Over 2 yrs., there was a 77% reduction in the mean progression of myopia (progression of-1.20 D+/-0.69 in
the placebo group and -0.28D +/- 0.92 in the atropinegroup)
• There was also a strong correlation with reduction in axial length in the atropinegroup
• there were no severe adverse effects associated with atropine eyedrops
• At 3 yrs., a significant rebound was seen for both the myopia progression and axial elongation after cessation
of atropine 1% for 1 yr.
ATOM 2 study
Conducted shortly after ATOM 1 study
Aim: To compare the safety and efficacy of 3 lower doses of
atropine (0.5%, 0.1%, and 0.01%)
• Double-masked, randomized, controlled trial
• Included 400 children
• Age: 6-12 years
• Myopia worse than -2.00 D
• Children were randomized to receive either 0.5% atropine (n=161), 0.1% (n=155), or 0.01%(n=84)
• Both eyes were treated
• This was a 5-yr study that included 2 yrs. of treatment, 1 yr. of washout, and 2 yrs. where treatment was
restarted in children who continued to progress
• These children were retreated with only 1 dose of atropine
• The results showed a dose-related response with atropine and myopiaprogression
• But these differences were clinically small (-0.30 +/0.60 D for 0.5%, -3.8 +/- 0.60 D for 0.1%, and -4.9 +/- 0.63
D for 0.01%)
Conclusion from both studies
• 0.01% atropine has similar efficacy compared to the higher concn
of 0.1% and0.5%.
• Side effects with atropine 0.01% were minimal compared to the 2 higherconcn
• Negligible effect on accommodation
• No effect on near VA in the 0.01% group (mean value of 20/20,J1)
• During the washout period, children in the 0.01% atropine group had minimal rebound (-0.87 +/- 0.52 D in
the 0.5% group, -0.68 +/- 0.45 D in the 0.1% group,and -0.28 +/- 0.33 D in the 0.01% group, P<0.01)
• No rebound seen for axial length in the 0.01%group
The lower myopia progression in the 0.01% group persisted during phase 3, with overall myopia progression and
change in axial elongation being the lowest in this group at the end of 5 yrs. The low dose of atropine is clinically
palatable, appearing to have negligible side effects profile compared to higher concentration

9. Recently another study lower concentration Atropine for myopia progression (LAMP) with one-year study showing
efficacy with different concentration of atropine was published.
• LAMP study
• A randomized, double blinded, placebo-controlled trial of 0.05%,0.025% and 0.01%atropine
• Amied to evaluate the efficacy and safety of low concentration ofatropine
• Study time period was 1 year
• Enrolled 438 children aged 4to 12 years with myopia of at least -1.0D and astigmatism of -2.5 D or less
• Participants were randomly assigned in a 1:1:1:1 ratio to receive 0.05%, 0.025%, and 0.01% atropine eye
drops, or placebo eye drop, respectively, once nightly to both eyes for 1year
• Cycloplegic refraction, axial length (AL), accommodation amplitude, pupil diameter, and best-corrected
visual acuity were measured at baseline, 2 weeks, 4 months, 8 months, and 12 months. Visual Function
Questionnaire was administered at the 1-yearvisit.
Results:
• After 1 year, the mean SE change was −0.27±0.61 D, −0.46±0.45 D, −0.59±0.61 D, and −0.81±0.53 D in the
0.05%, 0.025%, and 0.01% atropine groups, and placebo groups, respectively ( P <0.001), with a respective
mean increase in AL of 0.20±0.25 mm, 0.29±0.20 mm, 0.36±0.29 mm, and 0.41±0.22 mm ( P < 0.001)
• Visual acuity and vision-related quality of life were not affected in eachgroup
• This study concluded that 0.025 % will have 30% AL control and 0.05% have around 50% controleffect.
• 0.05% atropine was most effective in controlling SE progression and AL elongation over a period of 1 year.

10. At the end there is infographics to help select the myopia control strategies from spectacle lens, multifocal contact
lens, orthokeratology and atropine options taking binocular vision under consideration and also have a chart for
gauging success
This infographic is taken from myopia profile online learning website

11. References:
1. Holden BA, Jong M, Davis S et al. Nearly 1 billion myopes at risk of myopia-related sight-threatening conditions by
2050 - time to act now. Clin Exp Optom. 2015;98:491-3.
2. Flitcroft DI. The complex interactions of retinal, optical and environmental factors in myopia aetiology. Prog Retin Eye
Res. 2012;31:622-60.
3. Rose KA et al. Outdoor activity reduces the prevalence of myopia in children. Ophthalmology. 2007;15:1279-85.
4. Cheng D, Woo GC, Schmid KL. Bifocal lens control of myopic progression in children. Clin Exp Optom 2011;94:24-32
5. Chua W-H, Balakrishnan V, Chan Y-H et al. Atropine for the treatment of childhood myopia. Ophthalmol.
2006;113:2285–91.
6. Chia A, Chua W-H, Cheung Y-B et al. Atropine for the treatment of childhood myopia: safety and efficacy of 0.5%,
0.1%, and 0.01% doses (Atropine for the Treatment of Myopia 2). Ophthalmol 2012;119:347–54.
7. Chia A, Lu Q-S, Tan D. Five-Year Clinical Trial on Atropine for the Treatment of Myopia 2: Myopia Control with
Atropine 0.01% Eyedrops. Ophthalmol 2016; 123;391-9.
8. Bullimore M, Berntsen D. Low-dose atropine for myopia control: considering all the data. JAMA Ophthalmol
2018;136:303
9. https://www.myopiaprofile.com