This presentation gives information about different myopia progression theories, reasons of increasing rate of myopia and it's available corrective measures.

1. MYOPIA PROGRESSION
• By Optom Pratiksha Patil &
• Optom Samiksha Prajapati
• M. Optom 1st Year

2. MYOPIA
• It is a type of refractive error in which
the parallel rays coming from infinity
comes to focus in front of the retina,
when accommodation is at rest.
• Total eye power is greater than 60 D

4. FACTORS EFFECTING MYOPIA
• Age
• Gender
• Genetic factors
• Ethnicity
• Environment and work related :Near work (Reading, High literacy,
accommodation)
• Race
• Under correction

5. AGE
• Congenital Myopia
• Youth-onset Myopia
• Early adult-onset Myopia
• Late adult-onset Myopia
BORISH CLINICAL REFRACTION Arch Ophthalmol. 2005;123(7):977-987. doi:10.1001/archopht.123.7.977

6. GENDER
• Progression of myopia tends to begin
and end early in Females.
Arch Ophthalmol. 2005;123(7):977-987. doi:10.1001/archopht.123.7.977

7. GENETIC FACTORS
• 39 genetic loci have been identified in the human genome which may be associated
with refractive error and myopia.
• The Sydney Myopia study found that the influence of one myopic parent was double
the risk of myopia while having two myopic parents increased that risk by eight
times.
https://www.opticianonline.net/cet-archive/184 (myopia part-1)

8. ETHNICITY
• High prevalence in Asian, Caucasians
and Hispanic
• Lower prevalence in White and
African-Americans
• Urban Vs Rural Population
Myopia is more common in urban
community than in rural community
Arch Ophthalmol. 2005;123(7):977-987. doi:10.1001/archopht.123.7.977
• BORISH CLINICAL REFRACTION

9. ENVIRONMENT AND WORK RELATED
• Evidence for a link between near work and myopia
progression continues to be reported in a wide range
of populations.
• Parssinen has shown that near work and short
reading distance are significantly corelated to
increased myopia progression.
• The Beijing eye pediatric eye study conducted in
15066 school children with mean age 13.2 +/- 3.4
years. This study reported that long reading
duration, shorter distance watching TV or computer,
dim reading illumination are significantly
associated with myopia. http://commons.pacificu.edu/opt

10. RACE

11. http://commons.pacificu.edu/opt

12. UNDER-CORRECTION
• Under correction of myopia produce
myopic defocus during distance
viewing has been reported to produce
an increase instead of a decrease in
myopia progression.

13. SEASONAL VARIATION
• More progression in winter ( December to March)
• Lesser progression in summer (June to September)

14. THEORIES AND PROGRESSION

15. • Theories and Progression
• Accommodation, IOP and Axial elongation
• Accommodative Lag Theory
• Mechanical tension Theory ( Role of Ciliary body and Choroid)
• Concept of Emmetropization at Near
• Role of EOM
• The Selection-Relaxation theory
• The effect of Blur
• Peripheral refraction

16. • Most commonly accepted theories used to explain how myopia progresses:

17. • Lag of Accommodation
• High lag of accommodation during near work causes foveal hyperopic retinal blur
• Induces an abnormal axial growth of the eye leading to myopia
• Myopes have a reduced accommodative response compared to emmetropes
• Treat myopic children with plus lenses for near work
• e.g. Bifocals and Progressive Addition Spectacles

19. • Mechanical Tension
• Eye responds to transient changes in axial length following short periods of
accommodation
• Contraction of the ciliary muscle following accommodation results in forward and
inward pulling of the choroid
• Ciliary-choroidal tension restricts the equatorial growth of the eye
• It decreases the circumference of the sclera leading to a more prolate eye shape and
ultimately to an elongation of the axial length

20. Schematic representation of the mechanical tension theory

21. • Peripheral Refraction
• Peripheral hyperopic defocus has been suggested to play a significant role in
development of myopia
• Several meta-analyses reported a significant reduction of myopia progression with
treatments that reduce peripheral hyperopic defocus (i.e. orthokeratology and centre-
distance multifocal soft contact lenses)

22. Schematic representation of the peripheral theory

23. HOW TO CONTROL MYOPIA???

25. • Myopia can be controlled by following measures:
1. Environmental Modification
2. Spectacles and Contact lenses
3. Pharmacological Therapies

26. 1. Environmental Modification
• Outdoor Activity
• Cocoa
• Use of amber filters

27. 2. Spectacles and Contact lenses
• Bifocal and Multi-focal glasses and
contact lenses
• Ortho-K lenses

30. 3. Pharmacological Therapies
• Anti-muscarine agents (Atropine 0.01%, Pirenzepine)
• Dopamine – by preventing myopic shift

31. • In rabbits injection of dopamine prevented the myopic shift and
vitreous chamber and axial elongation typically associated with
form deprivation myopia
( ref. Gao Q et al 2006 )

32. REFERENCE
• Myopia (3rd chapter) Primary Care Optometry
• Borish’s Clinical Refraction pg.no. 1443
• Study of theory about myopia progression (STAMP) vol-87, optom & Vn Science
• https://www.researchgate.net/publication/317762239_Theories_Behind_Myopia_Pro
gression
• http://commons.pacificu.edu/opt/14
• (https://www.brienholdenvision.org/privacystatement)
• Arch Ophthalmol. 2005;123(7):977-987. doi:10.1001/archopht.123.7.977
• https://www.opticianonline.net/cet-archive/184 (myopia part-1)

33. THANK U 