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Flashcards in Myopia Control Deck (21):
1

how can spectacle lenses help for myopia control?

-undermining makes it worse
-multifocals offer some benefit

2

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

-Edwards et al. (2002)
-COMET (Gwiazda et al. 2003)

3

Edwards et al. (2002) study showed:

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

4

COMET (Gwiazda et al. 2003) study showed:

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

5

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

-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

6

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

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

7

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

0.28 in 1% group
1.20D in placebo group

8

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

0.30 D in 0.5% group
0.38 D in 0.1% group
0.49 D in 0.01% group

9

how does atropine work to control myopia?

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

10

what did the Pirenzepine study show?

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

11

design of RGP lenses: the CLAMP study

-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

12

how does Orthokeratology work for myopia control?

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

13

how does Ortho-K work?

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

14

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

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

15

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

56% effect size

16

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

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

17

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

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

18

why do we care about peripheral refractive errors?

-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

19

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

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

20

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

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

21

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

-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