paediatric optometry week 8- myopia management

Why is it important to manage myopia?

- myopia prevalence is increasing

- being a high myope is a risk factor for other conditions

What is classed as a low myope?

-0.50 to 3D

What is classed as a moderate myope?

-3 to 5 D

What is classed as a high myope?

-5.00D+

What are the different classifications of myopia?

- physiological - this can be split into early onset and late onset. it stabilises in adulthood.

- pathological

What is early onset myopia?

childhood - early teens

genetic

What is late onset myopia?

late teens - adulthood

environmental factors

What is pathological myopia?

- leads to retinal and choroidal degeneration due to excessive elongation of the eye

- myopia macular degeneration, cataract, glaucoma, retinal detachment

2050 myopia

-4-5 billion with myopia

- 1 billion with high myopia

What does a lenstar do

Predicts myopia chance based on

Prescription

Age

Axial

Males vs females high myopia

- males with high axial length more likely to have high myopia than females

What is a meaningful decrease of myopia in myopia management

40% decrease

Single vision spectacles and myopia management

- once thought that under correction was ideal management

-studies found no change when undercorrected by 0.50

- studies found -.0.25 decrease when undercorrected by 0.75

Single vision treatment disadvantages

- blurred vision if not fully corrected

-small change of rx does not justify the treatment

What are the different methods of myopia management?

- single vision spectacles

- bifocals/ multifocal spectacles

- defocus incorporated multiple segments

- multifocal contact lenses

- orthokeratology

- pharmacological

- environmental

How do multifocal spectacles help manage myopia?

- distance portion allows clear vision at distance

- near portion is to eliminate or reduce accommodative error which may lead to myopia progression

- has a small effect on myopia progression, maximum effect is usually over the first year and then it tends to reduce thereafter

Do multifocal contact lenses help with myopia management?

- studies have shwon a greater reduction in myopia progression compared to spectacles

- studies also shows that higher adds work better than medium ones

- more research needed for long term effects. Need to consider other effects CLs have on eyes

What are Misight contact lenses?

- disposable CL

- Currently available as myopia management treatment in the UK

What is DIMS?

Defocus incorporated multiple segments

- similar to multifocal CLs but in spectacle lens form

- two designs on UK market: HOYA miyosmart & Essilor stellest

Hoya lens myopia progression

Less myopia progression those over 10

Found from 2 year Study

What is important for dims lens

What is the Essilor stellest design?

- 11 lenslet rings

- 9mm central portion

What is orthokeratology?

The overnight use of RGP contact lenses to temporarily reduce myopia during the day. Approved for -0.5 to 6 D of myopia.

The lens is fitted at a base curve flatter than the corneal curvature.

works to eliminate peripheral hyperopic defocus

research suggests that it is effective at treating myopia progression over a prolonged period

What is important for orthokeratology

Compliance

To allow lens to be continuously flattened to reduce peripheral hyperopic blur

What are some risks that can come with orthokeratology?

- microbial keratitis

- corneal staining/ lens binding

- corneal thinning

Orthokeratology oxygen transmission

Over 125 , which is sufficient

Oth

What are the contraindications of orthokeratology?

- >4.50D myopia

- >2.00D with the rule astigmatism

- high myopes presenting with low peripheral eccentricities

- corneas flatter than 8.65 mm or steeper than 7.50mm against the rule or oblique astigmatism of greater than 0.75D

- residual astigmatism greater than 0.50D

- keratoconus

- large pupils

- those with a prior history of poor compliance

- those with unrealistic expectations expecting a permanent cure

- unmotivated for CL wear

- poor response to overnight trial

What does long term success of orthokeratology depend on?

- proper fitting of lenses

- compliance

- regular reviews

- appropriate intervention to complications

what drugs can be used as pharmacological myopia management?

- atropine

- pirezepine

What is atropine?

- non selective anti muscarinic

- high affinity to M1-M5 receptors in pupillary sphincter and ciliary muscle

- results in mydriasis and cycloplegia

- lower dose of atropine reduce these effects

What dose has been shown to be most effective at reducing myopia progression?

low dose (0.01%)

- as effective as 0.5% and 0.1% but has fewer side effects

What is the CHAMP study?

- childhood atropine for myopia progression study

- to evaluate the efficacy and safety of low dose atropine eye drops to reduce the progression of myopia in UK children

- children ages 6 to 12 years >0.50D of myopia

- 5 year trial in total

Champ study participants

Uk and Ireland

289

Atropine 0.p1% to placebo ratio = 2

5 year trial

What is pirenzepine?

- selective anti muscarinic

- high affinity for M1 and M4 receptors

- less likely to cause mydriasis and cycloplegia

- has been shown to reduce myopia progression but lack of commercial availability has limited its use

What is the environmental management for myopia?

- association between near work and myopia onset

- particularly in countries where western education has been relatively recently introduced

- more time spent outdoors can limit progression of myopia

What is the preferred method to monitor progression of myopia?

- axial length

- cycloplegic autorefraction and keratometry can be used to provide an estimate of axial length

What are the risk factors of myopia?

- having parents with myopia

- east Asian ethnic origin

- spending limited time outside and being heavily engaged in activities using near vision

What can the results of myopia managemen depend on?

- age of onset of myopia

- age when starting myopia management

- compliance with treatment

- amount of near work and outdoor activity