Page 166 - July-August 2020

mobiles phones. Similarly, children
with one or both myopic parents
also have higher risk of developing
6
myopia. Some studies have found
that children who favour outdoor
activities and less near activities are
2.5 times less likely to be myopic. 6

CONTROL OF MYOPIA
PROGRESSION
With the threat of increasing
numbers and degree of myopia it is
vital to control myopia progression.
There is currently no technique
that can stop its progression, but
a number of treatment strategies
FIG 2: REPRESENTATION OF MECHANICAL TENSION THEORY
have been put forward to decrease
the progression of myopia. These
8
short period of accommodation. It elongation . It has been supported
suggests that contraction of ciliary by studies which show significant interventions to decrease the
muscle following accommodation reduction in myopia progression progression are very important as
leads to forward and inward pulling with treatment that corrects the they can save one from potential
of choroid thus resulting in ciliary- peripheral hyperopic defocus (like vision threatening complications that
Choroidal tension which reaches orthokeratology, central distance may arise from high myopia.
a critical point where proportional multifocal soft contact lens). 9
expansion of eye is not possible. This HIGH MYOPIA INCREASES
restricts the equatorial growth of FACTORS RELATED TO THE RISK FOR VISION
eye due to which the circumference PROGRESSION OF MYOPIA THREATENING
of the sclera decreases resulting in Various factors have been COMPLICATIONS LIKE
a more prolate shape of the eye. associated with the progression RETINAL AND VITREOUS
Ultimately the growth axial length of of myopia – these factors can be DETACHMENTS,
eye accelerates resulting in myopia genetic, environmental, or visual CATARACTS, GLAUCOMA,
progression (fig 2) 7 factors. Studies have found that AND MYOPIC MACULAR

PERIPHERAL HYPEROPIC progress of myopia is rapid in DEGENERATIONS BY
DEFOCUS THEORY children who spend more time on MANY FOLDS
near work like reading, writing, using
This is a popular and widely
accepted theory currently. As per this
theory, the lens induced hyperopic
defocus (fig 3) which occurs during
myopia plays a significant role in
providing stimulus for elongation
of eyeball and thus progression of
myopia . The peripheral hyperopic
5
defocus first sends out Choroidal
thinning signals which along with
collagen/scleral shell softening
events allows the peripheral retina
to better align itself. This peripheral
retina stretching then pulls the fovea
back along with it, resulting in axial FIG 3: PERIPHERAL HYPEROPIC DEFOCUS

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