Page 167 - July-August 2020

The strategies available are ACTIVITY QUESTIONS Average time spent per day
classified in three broad categories:
Optical, Pharmacological, and Less than 1-2 2-3 more than
hours
1 hour
3 hours
hours
environmental/behavioural. 13
1. School homework/reading    
I. OPTICAL INTERVENTION: 2. Mobile Phone    
Earlier, it was assumed that under 3. Using computer    
correction of myopia reduces myopia 4. Watching T.V/videos/DVD    
progression, but studies have found
that the opposite is true – it rather 5. Drawing/painting/writing    
increases myopia progression . So 6. Playing chess or other    
10
full correction of myopia has been board games
suggested. Use of bifocals and PALs 7. Playing musical    
has been proposed based on the instruments
lag of accommodation theory. The 8. Out of door leisure
aim is to compensate the reduced activities (walking, riding,    
accommodative response during backyard)
near work and reduce the retinal 9. Outdoor sports (cricket,    
blur. However, studies suggest football, golf etc)
13
that the reduction of myopia 10. Indoor sports (table    
progression by these methods were tennis, swimming etc)
clinically insignificant (<0.25D). 11, 11. Other recreational
12 Soft spherical contact lens were activities    
believed to increase peripheral Check list to identify children who have higher risk of myopia progression.
hyperopic defocus due to negative *the red box indicated higher risk and more the number of columns with
spherical aberration in negative red boxes means immediate intervention
power. Unfortunately, there is no
13
evidence that soft spherical contact
lens leads to either slower or faster imposing peripheral myopic defocus ORTHOKERATOLOGY
myopia progression. Multifocal on peripheral retina as a stimulus
13
or bifocal soft contact lens have to slow myopia progression. The Orthokeratology is an optical
5
emerged in the spotlight for myopia effectiveness of these lens for correction mainly for correcting low-
control. Studies suggest the use myopia control is stated to be as to-moderate myopia with benefit of
of central distance designs with good as 38%. This option can be potential reduction in the progression
9
higher add produces better results. seen in children with higher amount of myopia. Orthokeratology is the
14
The lenses are designed to provide of refractive error or also if they have temporary reduction of myopia by
clear central distance vision while large amount of cylinder. using specially designed reverse
geometry ortho-k lens which are
FIG 4: CORRECTION OF PERIPHERAL HYPEROPIC DEFOCUS BY ORTHO-K LENS worn overnight. It produces clear
vision without the aid of glasses
in daytime. These lenses were
initially created for vision correction
in myopia. Later, it was found to
be effective in reducing myopia
progression too.
Working: Rigid lenses with high
oxygen permeability are designed to
work overnight resulting in central
cornea flattening and mid-peripheral
steepening. Unlike Lasik it is a

JULY-AUG 2020 | 163 Myopia