is a progressive visual disorder that results poor distance
vision. If the myopia is severe, it will impair near vision
as well. Myopia is also known as "near-sighted" or "short-sighted."
In addition to weakening vision, it also changes the physical
structure of the eye. It can steepen the front surface of
the eye (cornea) and/or stretch the retina (axial elongation).
These changes increase the risk of future eye disease (see
The Dangers of Myopia). It is one of
the leading causes of blindness around the world and has a
direct association with retinal detachments and glaucoma.
definitely has a genetic link. However it is driven more by
the environmental stress of near work such as reading, studying,
computer use, hand games and the lack of outdoor time. In
fact, one theory of increasing myopia is that it is our eye’s
method of adapting to the demand of prolonged near work. It
takes less work for a myopic person to read. That's why we
call it "nearsighted". Humans before the Industrial Revolution
used their eyes predominantly for distance seeing. During
that period, the incidence of myopia was less than five percent.
In a recent study, researchers found that myopia has increased
66 percent in the United States from 1971 to 2004 (See Health
Issues: The Myopia Epidemic).
Dangers Of Myopia
and its progressive disorders can cause abnormal or adverse
ocular changes. High myopia may cause thinning and weakening
of the retina (the thin membrane at the back of the eye that
contains the rods and cones). Abnormal stretching or elongation
of the eye may pull on the vitreous (the gel substance that
fills the eye) which in turn pulls on the retina leading to
its detachment. A detached retina can lead to blindness. This
elongating process can also cause "lattice-like" holes to
occur in the peripheral retina. These holes can allow fluid
to seep under the retina-- lifting and detaching it. Again,
possibly leading to a permanent loss of sight.
to high myopic people are twice as likely to develop glaucoma.
(Mitchell 2000). Further, the detection of myopia is much
more difficult due to the deforming of the optic nerve head
as a result of ocular elongation. The optic nerve head is
one of the structures closely examined for changes due to
glaucoma. It is difficult to determine if the changes are
due to myopic stretching or glaucoma
Issues: The Myopia Epidemic
Health Organization (WHO) projects 2.5 billion nearsighted
people by year 2020. Approximately 80% of elementary students
in Singapore are myopic.
college students in China are nearsighted.
Institutes of Health reports that in 1972, the frequency
of myopia was 25% in U.S. individuals aged 12 to 54. By
2004, it had increased to 41.6%. (Roan,2010).
approximately 26% of all people living in the U.S. and
Europe were myopic.
of myopia in "hunter-gatherer" societies where children
perform little near work, is about 1%.
■Working at near distances can
result in the development of myopia
of school systems in cultures in which they did not previously
exist has resulted in greater incidence of myopia (Young et
dealing with intense near point activity lead to further myopic
development (Adams and McBrien 1992).
sectioned studies have found associations between near work
and myopia progression ( Saw et al., 1996; Saw et al 1999).
of 153 Singaporean children determined higher progression
rates for younger children and those with higher amounts of
myopia at the beginning of the study (Saw et al. 2000).
are especially susceptible to near work causing myopia (Goss,
adults ages 20-30 years have developed late onset of myopia
that has coincided with beginning intense near work and in
many cases, using a computer ( Sheedy, Shaw-McMinn, 2003).
■Myopia Development and Convergence
Esophoria is a risk factor in myopia development In children
Esphoria results in larger accommodative lag, resulting in
retinal blur (Goss and Rainey,1990)
is a condition where the eyes tend to turn inward excessively
when doing near tasks
■Myopia Development and Heridity
Orinda Longitudinal Study of Myopia (Zadnik, 1997). Children
become emmetropic as the eye's axial length increases and
the crystalline lens decreases in power. Parental history
of myopia is the predominant factor for myopic development
which is not due to myopic parents having an effect on near
■Myopia Development and Computers
(1988) reports myopic progression after 1 year of work on
computers. Toppel and Neuber (Thomson,2002) studied refractive
error change over 2 years as opposed to control group.
and Zadnik ( 1996) No compelling evidence that computers are
any more significant then reading in progressive myopia.
of California at Berkley(UCBSO Study,2002)– premature
myopia may result in children five to twelve years of age
doing computer work for more than two hours a day.
Yeow & Taylor demonstrated a transient myopia is common
effect of accommodative stress at the computer screen. The
authors also documented a myopia shift of .12D in a group
of computer users as compared to a control group. Transient
myopia changes have been shown objectively to result from
temporary changes in accommodation (Zheng,Yan et al,2008).
■ Myopia Development and Accommodation
Study, 2003) To prove or disprove the theory that children
with poor accommodative response may find progressive lenses
beneficial for slowing the progression of myopia. The Comet
Study was a randomized clinical trial designed to test the
effectiveness of plus lenses against the progression of myopia
in children. Progressive addition lenses (PALs), also called
"no-line bifocals" were used in the experimental group. After
three years, the study found practically no difference between
the group that wore the PALs versus the ones that wore standard
lenses for myopia.
■Myopia Developmentand Corneal
studies that address myopic progression and Ortho-K are Reim,
LORIC, CRAYON, SMART, MCOS and CRIMP.
(2003). Tom Reim OD,FOAA and colleagues first reported
the potential of myopia control in 2003 with a retrospective
study that reported that corneal reshaping experienced about
a sixty percent reduction in myopic progression.
(2005). The Longitudinal Orthokeratology Research in Children(LORIC)
study was conducted in Asia, and found a much slower rate
of myopia and axial elongation(47%) among young progressive
myopes who underwent corneal reshaping compared to those who
(2007). The Corneal Reshaping and Yearly Observation of
nearsightedness(CRAYON) study, conducted by Jeff Walline OD,FAAO
at Ohio State University, also found lower rates of myopia
progression and axial elongation(57%)(Walline, 2008).
in progress. Both the LORIC and CRAYON studies were small
in scale involving fewer then forty patients. The Stabilization
of Myopia by Accelerated Reshaping Technique(SMART) study,
a large scale(300 patient),five year longitudinal, multicenter
evaluation of the effectiveness of corneal reshaping for young
progressive myopes is now underway. First year results are
encouraging (Eiden et al,2009).
. Corneal reshaping inhibits myopia progression(CRIMP)
is a ten year retrospective study out of Australia that demonstrated
control of myopia progression over a ten year time frame.
Fully 70% of all participants in the corneal reshaping control
group did not progress in degree of myopia over the period
in progress. " The Myopia Control with Orthokeratology
contact lenses in Spain (MCOS) Study, in which continued documentation
of safety outcomes for corneal reshaping in a pediatric population
was evident by no changes in best-corrected visual acuity
or significant adverse health effects from ortho-k wear" (Gregory,2010).
Development-Thoughts: Nature vs Nurture
The Adolescent Myope- Excessive near point among adolescents
may lead to nearsightedness at an early age
genetic adaptation for survival may unwittingly lead to early
childhood myopia when the eyes instead of being used for distance
viewing are involved in excessive close work focusing. This
genetic adaptation is called emmetropization. The word emmetropization
means that the eye is going to the state of emmetropia, i.e.
to a state where proper focusing of distant objects can be
achieved with a relaxed focusing of the eyes. Emmetropization
is also used to describe the ability of the eye to adjust
the eye growth in length during development for optimal optical
imaging. Emmetropization in the sense of an adjustment of
the length of the eye to achieve proper vision when meeting
the needs of an individual, who would mostly use their vision
for distance viewing, is necessary when considering the individually
different optical parameters of the eye before emmetropization
takes place. Emmetropization has to be seen as a very smart
mechanism to balance for inborn optical differences and deficiencies.
In the history of human development both definitions matched,
because mostly the dominating viewing distance was the far
distance. Today, with often excessive near work, both definitions
of emmetropia are controversial: If the eye adjusts to the
dominating viewing distance it will often become not emmetropic,
and Myopia - nature
there a racial affinity towards myopia? In China, a 5% incidence
of myopia entering elementary school becomes 25% in 5th
grade and 90% incidence of myopia among college students.
Among Japanese, Korean and Jewish children myopia incidence
has increased dramatically over the last half century. Are
these changes due purely to genetics or are there cultural,
dietary or other environmental causes?
with Two Myopic Parents - nature
is the strongest single factor in predicting myopia for an
offspring. Is there a Myopia Gene? Is there a set of
special characteristics like esophoria ( eye over crossing
at close work), elongated eyes or steeper than normal corneas
that are passed on through the genetics?
User With Recent Onset Of Myopia- nurture
Eyes are poorly equipped to deal with extended hours in front
of a computer screen .
What is Computer Vision Syndrome (CVS)? It is
a multifaceted combination of eye and vision problems related
to near work experienced during or following computer use.
CVS affects up to 75% of computer users to some degree and
10 million eye doctor visits last year reported the
primary complaint was eyestrain coming from computer use.
This was not existent in 1970. While there is no direct correlation
between time spent on a computer and myopia the successful
student is often nearsighted.
Athlete- Spatial Awareness Factor - nuture
point to spatial awareness as a significant positive factor
in avoiding progressive myopia. Possible reasons maybe children
playing at sports are not in front of computers or reading
during that activity. It is also postulated that balance and
agility gained from sports may be significant development
that works against myopia.
P, Hourihan, F, Sanbach, J Wang, JJ The relationship between
glaucoma and myopia; the Blue Mountains Eye Study. Ophthalmology.
James E., Shaw-McMinn
, Peter G.,'Diagnosing and Treating Computer-Related Vision
Problems';; Butterworth-Heinemann, ©2003;
Yan,Liang Hu, Hao Chen,Fan Lu.Computer Vision Syndrome:
A widely spreading but largely unknown epidemic among
computer users. Journal Computers In Human Behavoir: Vol
24 Issue 5,September 2008: pp 2026-2042.
, Jane, Hyman, Leslie, Hussein, Mohamed, Everett, Donald,
Norton, Thomas, T.,Kurtz Daniel, Leske ,M. Christina,
Manny, Ruth, Marsh-Toutle,Wendy, Scheiman,Mitch and the
Comet Group. A Randomized Clinical Trial of Progressive
Addition Lensesversus single Vision Lenses on the Progression
of Myopia in Children. doi: 10.1167/10vs.02-0816 Invest
Ophthamol. Vis. Sci. April 2003 vol 44 no.4 1492-1500.
Pia. Computer Use and Visual problems in Children. University
of California Berkley School of Optometry Study. 2002.
Seang-Mei,Chua, Wei-Hua,Hong,Ching-Ye, Wu,Hui-Min,Chan,
Wai-Ying, Chia, Kee-Seng, Syone, Richard A., Tan,Donald.
Nearwork in Early Onset Myopia. Invest. Ophthalmol. Vis.
Sci. February 2002 Vol 42 No.2 332-339
and McBrien, N.A.(1992). Prevalence of myopia and myopic
progression in a population of clinical microscopists.
Optom. Vis. Sci. 69 467-473
K.,Mutti, DO, Friedman, NE, Adams, A.J., Initial Cross-Sectional
Results from the Orinda Longitudinal Study of Myopia.
Optom Vis Sci 1993 Sep;70(09):750-8
Jeffrey J..Slowing Myopia Progression with Lenses. www.clspectrum.com/article.aspx?article=100718.
Distance Vision is all a blur to more of us. www.latimes.com/news/nationworld/nation/la-sci-myopia15-2009dec15,0,6467519.story
et al. Prevalence, incidence, and progression of myopia
of school children in Hong Kong. Investigative Ophthalmology
Visual Sciences,2004 Apr;45(4) 1071-5
Gregory J. A Report from GSLS 2010. www.clspectrum.com/article.aspx?article=104222
S.B., Davis, R.L., Bennett, E.S., DeKinder, J.O.. The
Smart Study:Background,Rationale, and Baseline Results.
Contact Lens Specrum 2009;24;10:24-31
D, O; Zadnik, K. 1996. Is computer use a risk factor for
of the American Optometric Association.
Vol. 67, no. 9: 521-30.
T, Suzuki K. Changes in ocular refractive components and
development of myopia during seven years. Jpn J Ophthalmol
David W. Eye Problems and Visual Display Terminals-The
Facts and Fallacies. Ophthalmic and Physiological Optics
March 1998 Volume 18 Issue 2 111-19.
DA, Rainey BB. Relationship of accommodative response
and nearpoint phoria in a sample of myopic children. Optom
Vis Sci 1999 May;76(5):292-4.
Chong E. Near Esophoria is associated with high myopia.
Clinical and Experimental Optometry April 2009 Vol 83
Issue 2, 71-5.
NA, Adams DW, A longitudinal investigation of adult-onset
and adult progression of myopia in an occupational group.
Refractive and biometric findings. Invest ophthalmol Vis
Sci February 1997 Vol 38 no. 2 321-333.
Francis A. et al. 1969. The Transmission of Refractive
Errors within Eskimo Families. American Journal of Optometry
and Archives of the American Academy of Optometry 46(9)