Myopia Control

Question 1

how can spectacle lenses help for myopia control?

Answer 1

• undermining makes it worse

- multifocals offer some benefit

Question 2

what were the names of the 2 large scale PAL trials?

Answer 2

• Edwards et al. (2002)

- COMET (Gwiazda et al. 2003)

Question 3

Edwards et al. (2002) study showed:

Answer 3

-single vision: -1.26 D
-PALs= -1.12 D
treatment effect= 11%

Question 4

COMET (Gwiazda et al. 2003) study showed:

Answer 4

-single vision: -1.48 D
PALs= -1.28 D
treatment effect= 13%

Question 5

study design (participants, random groups) on Executive bifocals study (Cheng et al. 2010)

Answer 5

• randomized clinical trial of 135 myopic Chinese Candian children
• randomly assigned to: single vision lenses, +1.50D executive bifocals, or +1.50D executive with 3pd base-in segment

Question 6

results of on Executive bifocals study (Cheng et al. 2010)

Answer 6

-single vision: -1.56D
-bifocal: -0.96D
-prism bifocal: -0.70D
treatment effect on bifocal= 31% and on prism bifocal= 34%

Question 7

myopia progression at 2 years in the ATOM1 (N=400) study

Answer 7

0. 28 in 1% group

1. 20D in placebo group

Question 8

mean myopic progression at 2 years in ATOM2 study (N=400) of different concentrations

Answer 8

0. 30 D in 0.5% group
1. 38 D in 0.1% group
2. 49 D in 0.01% group

Question 9

how does atropine work to control myopia?

Answer 9

• action on muscarinic receptors in retina
• atropine is non-selective muscarinic antagonist
• selective muscarinic antagonist could target M1 receptors in retina

Question 10

what did the Pirenzepine study show?

Answer 10

• selective anti-muscarinic
• one year randomized trial of 174 children
• 51% effect
• but side effects of stinging, pupil dilation, and short term blurring

Question 11

design of RGP lenses: the CLAMP study

Answer 11

• 3 year randomized masked clinical trial
• 116 children aged 8-11 years randomized to RGPs or soft lenses
• run in period to limit drop out

Question 12

how does Orthokeratology work for myopia control?

Answer 12

• temporary reduction in myopia
• corneal reshaping, corneal refractive therapy, vision shaping treatment
• produced by flat-fitting rigid contact lenses

Question 13

how does Ortho-K work?

Answer 13

• reverse geometry lens designs
• secondary curve steeper than base curve
• computer-assisted videokeratography
• highly gas permeable materials
• potential for overnight wear

Question 14

ortho-K study (Cho et al. 2005) showed

Answer 14

corneal reshaping 0.29 +/- 0.27mm
spectacle wearers 0.54 =/- 0.27mm
(46% effect size)

Question 15

ortho-K study (Walline et al. 2009) showed

Answer 15

56% effect size

Question 16

in 1997, the “accommodative lag theory” mechanism for myopia and control stated that:

Answer 16

• under-accommodation during near work
• image focused behind retina at fovea
• relative hyperopia stimulates eye growth
• treat with plus at near: bifocals, PALs

Question 17

in 2017, the “peripheral refraction theory” mechanism for myopia and control stated that:

Answer 17

• shorter off-axis eye length
• image focused behind retina in periphery
• relative hyperopia stimulates eye growth
• treat with plus in periphery

Question 18

why do we care about peripheral refractive errors?

Answer 18

• refractive development regulated by visual feedback
• fovea not essential for vision-dependent growth
• when conflicting signals exist peripheral signals can dominate central
• peripheral optical errors can alter central refractive development

Question 19

what are some clinical methods for putting plus in the periphery?

Answer 19

• corneal reshaping with ortho-k
• contact lenses with small optical zone
• spectacle lenses with add in all meridians

Question 20

what study showed how contact lenses with small optical zone worked? what were the results?

Answer 20

• results from Brien Holden Vision Institute
• 34% reduction in progression of myopia relative to spectacle comparison group
• 33% reduction in axial elongation

Question 21

what study showed how spectacle lenses with add in all meridians worked? what were the results?

Answer 21

• results from Brien Holden Vision Institute
• 15% reduction in progression compared to control group
• 30% reduction in younger children with at least one myopic parent