This document discusses myopia (nearsightedness), including its definition, causes, risk factors, prevalence, and interventions to reduce progression. It notes that myopia is highly prevalent worldwide and is influenced by both genetic and environmental factors like education level, time spent outdoors, and ambient lighting exposure. Current interventions discussed include increasing time outdoors, pharmacological options like atropine, and optical treatments, but there remains no definitive approach to halt progression.

1. Dr Haitham Al Mahrouqi
Oman Medical Specialty Board

2.  Section 1: The worldwide problem of myopia and theories regarding its
development.
 Section 2: Up to date interventions used to reduce the development and
progression of myopia.

4.  Five immediate priorities
 Cataract
 Trachoma
 Onchocerciasis
 Childhood blindness
 Refractive errors and low vision

7.  Myopia defined as > -1:
 6 years old: 0.5%
 12 years old: 5%
Lower in rural areas

8.  Conclusion: Family history of myopia and myopia at younger age
were predictors for progressive myopia in teenaged Omani children

9.  Cause
 Refractive
 Axial
 Age of onset
▪ Childhood: <7 years
▪ Juvenile onset (a.k.a school myopia): 7-14 years
(progresses 0.5D per year)
▪ Adult onset: >20 years

10.  Severity:
 Myopia
 High Myopia: Power > -6 or AL >26.5mm
 Pathological myopia (aka. Degenerative): Power > -8 or AL >32.5mm
OR better:
Pathological myopia is high myopia accompanied by characteristic
degenerative changes in the sclera, choroid, and retinal pigment
epithelium, with compromised visual function. (Duke-Elder, 1970)

12.  Glaucoma
 Cataract
 Retinal Detachment

13. Moriyama et al. 2011

14.  The most common eye disorder in the world that require
treatment
 Refractive wear
 Hospital visits to monitor or treat the disease and its sequelae
 Causes a lot of visual disability/productivity

15.  Lets review some theory
first

16. The process in the developing eye in which the refractive
power of the anterior segment and the axial length of the eye
adjust to reach emmetropia.
Ref: AAO BCSC2015 (volume No. 6 : Paediatric Ophthalmology
and Strabismus)

19. “if myopia presents before age 10
years, there is a higher risk of
eventual progression to myopia of
6.00 D or more”

20. Mild with the rule
astigmatism is normal.
However, not “against the
rule”

21.  Visual acuity:
 VEP studies show that 20/20 vision is reached as early as 6 months.
 Preferential looking (PL) studies show that 20/20 is reached between 3-5
years.
Discrepancy is probably due to the higher cortical processing required for
the PL vision test

22. GenesVs Environment

23.  Lets start with environmental factors

24. Morgan I, Rose K. How
genetic is school myopia?
Progress in Retinal and Eye
Research 2005;24(1):1-38.

25. Morgan I, Rose K. How genetic
is school myopia? Progress in
Retinal and Eye Research
2005;24(1):1-38.

26. (Morgan, 2005)

27.  Having higher education degrees/more intense education and
living in the city are associated with higher prevalence of myopia.
WHY??

28.  Hyperopic defocus
 Myopic defocus
 Form-deprivation Myopia

29.  Is accommodation “myopigenic”??
Lets find out!

30.  Australian schools, 2400, 12yr
old schoolers. (JP et.al 2008)
√
√

31. McBrain et al. 1993

32.  Hyperopic defocus
(accommodative lag)

33.  Having higher education/more intense education and living in the
city and is associated with higher prevalence of myopia.
WHY??
1) Near work especially close distance activities
What is living in the city got to do with myopia???

37.  Having higher education/more intense education and living in the city
and is associated with higher prevalence of myopia.
WHY??
1) Near work especially close distance activities
2) Decreased exposure to sunlight, high level ambient lighting.

38. - Twins studies
-
 Up to date analysis of the genetic basis of myopia is divided into two clusters of mutations:
 1) Mutations affecting the outer retinal layer involving the photoreceptors
 2) Mutations affecting the scleral ECM.
However, it seems that studies show that the environmental factors are stronger in school
myopia
Both parents myopic 50%
One parent myopic 30%
Non 10%
(Morgan , 2012)

39.  1) Mechanical tension theory
 2) Retinal blur (through
accommodative lag theory)
Brensten
et.al 2010

40. Section 2
Interventions to reduce the
development and progression of
myopia

41.  Three types:
 1) Outdoor interventions
 2) Pharmacological interventions
 3) Optical interventions

42.  2 RCTs underway
 “Children who spend more
time outdoors are less likely
to be, or to become myopic,
irrespective of how much
near work they do, or
whether their parents are
myopic”
 Uncertain if it reduces
progression
(French et al. 2013)

43.  Atropine
 Lowers progression
 Not through blocking
accommodation
 Side-effects: glare,
photophobia, reading blur,
rebound effect.
 Similar results with less
side-effects: Low dose
atropine 0.01%,
pirenzepine.

44.  Progressive additional &
peripheral hyperopic defocus
lenses: Little or no effect, and
effect is static
 Orthokeratology: Reshaping
the cornea overnight.
However, effects might not be
sustained
Microbial keratitis!

45.  Myopia is a huge public health problem
 Genes and environmental factors (near work and reduced
outdoor time) are aetiological factors
 Interventions:
 Primary prevention: Increased time outdoors and reduce near work
 Secondary prevention (reduce progression): Atropinization & ?optical

46.  Ashby R, Ohlendorf A, Schaeffel F.The Effect of Ambient Illuminance on the Development of Deprivation Myopia in Chicks.
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 Berntsen DA, Mutti DO, Zadnik K. Study ofTheories about Myopia Progression (STAMP) Design and Baseline Data. Optometry and
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 Duke-Elder S, Abrams D. Pathological refractive errors. In: Duke-Elder S, ed. Systems of ophthalmology. St. Louise: Mosby, 1970
 French AN, Ashby RS, Morgan IG, Rose KA.Time outdoors and the prevention of myopia. Experimental Eye Research 2013;114:58-68.
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 Ip JM, Saw S-M, Rose KA, Morgan IG, Kifley A,Wang JJ, et al. Role of Near Work in Myopia: Findings in a Sample of Australian School
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 McBrien NA, Moghaddam HO, Reeder AP. Atropine reduces experimental myopia and eye enlargement via a nonaccommodative
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 McCarthy CS, Megaw P, Devadas M, Morgan IG. Dopaminergic agents affect the ability of brief periods of normal vision to prevent
form-deprivation myopia. Exp Eye Res 2007;84(1):100-7.
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 Morgan IG, Ohno-Matsui K, Saw S-M. Myopia. The Lancet 2012;379(9827):1739-48.
 Moriyama M, Ohno-Matsui K, Hayashi K, Shimada N,YoshidaT,TokoroT, et al.Topographic analyses of shape of eyes with pathologic
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 Rose KA, Morgan IG, Ip J, Kifley A, Huynh S, SmithW, et al. Outdoor activity reduces the prevalence of myopia in children.
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