16. C X - Clinical Management of Myopia Flashcards
2008: Atropine seems to work but ..., risk of ... and rebound.
2016: ATOM2 → 0.01% atropine ..., better re-rebound.
2018: LAMP study → 0.01% atropine may not give ...
2021: LAMP study → 0.05% atropine ... 0.01%
2008: Atropine seems to work but too many side effects, risk of systemic toxicity and rebound.
2016: ATOM2 → 0.01% atropine almost no risk of side effects, better re-rebound.
2018: LAMP study → 0.01% atropine may not give statistically significant reduction in axial elongation
2021: LAMP study → 0.05% atropine twice as effective as 0.01%
What are the 9 baseline examination needed for myopia management?
- Clinical Hx
- Unaided vision
- Refraction + VA
- BV assessment
- Slit lamp examination + corneal topography
- Axial length
- Intraocular pressure
- Cycloplegic refraction
- Dilated retinal fundus examination + imaging
Exam structure of Myopia management px:
1. History:
* Assessment of risk including ..., ..., ..., ...
* POH including ... and ... if already myopic
2. Unaided vision/ ...
3. Assessment of Rx:
* ..., subjective Rx & ...
* ... for 1st time myope/ ...
4. ... measurements (where available)
5. ... profile to help decide best management options
6. ... to determine if OrthoK suitable & to rule out ...
7. ... & ... health exam
Exam structure of Myopia management px:
1. History:
* Assessment of risk including FOH, race, outdoor time, visual task
* POH including age of onset and rate of progression if already myopic
2. Unaided vision/ vision with existing correction
3. Assessment of Rx:
* Dry retinoscopy, subjective Rx & binocular blur function
* Cycloplegic refraction for 1st time myope/ large Rx change
4. Axial length measurements (where available)
5. BV profile to help decide best management options
6. Topography to determine if OrthoK suitable & to rule out keratoconus
7. Anterior & Posterior health exam
What are the 5 best predictors of myopia onset?
- Refractive error → more myopic than age normal e.g. < +0.25DS in a 6 year old or progression worse than 0.75D/year
- Parental myopia → one or both parents myopic
- Exessive near work
- Ethnicity → East Asian
- Limited outdoor time
What are the 4 factors that increases risk of myopia progression?
- Age → 9 year old or less
- Parental myopia → one or both parent myopic
- Refractive error → more myopic than age normal or progression worse than 0.75D/year
- Ethnicity → East Asian
Cycloplegic refractions are helpful to assess future risk of developing myopia when assessing non-myopes. Cycloplegic cut-offs for future risk of myopia:
6 yo → ...D
7-8 yo → ...D
9-10 yo → ...D
11 yo → ...
Cycloplegic refractions are helpful to assess future risk of developing myopia when assessing non-myopes. Cycloplegic cut-offs for future risk of myopia:
6 yo → +0.75D
7-8 yo → +0.50D
9-10 yo → +0.25D
11 yo → plano
Which is a better tool in monitoring myopia progression and in diagnosing myopia: Biometry or cycloplegic refraction?
Cycloplegic refraction is the best way to diagnose myopia. This is because axial length can vary between emmetropic individuals as the cornea and lens power in some can compensate for axial length.
Biometry is the best way to monitor myopia progression as it is more sensitivity in picking up and changes such that they are accurate up to 0.12D (0.04mm) compared to subjective refraction, which is only ± 0.50D accurate.
What is a PreMO risk indicator?
A predictor of the risk of future myopia according to age of the child, parental history of myopia, cycloplegic refraction and axial length. This creates a table for children 6-8 years old and another table for children 9-10 years old. This indicator is found to be more accurate in 9-10 years old. The colour coding used in the tables relates to the evidence-derived risk of remaining emmetropic in green, or becoming myopic by 10 in red, 13 in orange, and 16 in yellow.
Rank the most effective 3 big tiers of myopia management options.
- Most effective: OrthoK, 0.05% Atropine, MiSight, MiyoSmart/ Stellest
- Soft MF CLs (Biofinity, NaturalVue, SEED EDOF), 0.025% Atropine
- Least effective: Franklin’s bifocals with BI prism at near
What 3 factors should be considered when picking a myopia management option for your patient?
- Available parameters
- Px suitability to options
- Px attitudes
MiSight should be worn for at least ...days/week, minimum of ... hours each day for myopia management. The available parameters include:
* ... to ...DS in 0.25D steps
* ... to ...DS in 0.50D steps
* No ... options available
* Material: ... (...)
MiSight should be worn for at least 5-6days/week, minimum of 10 hours each day for myopia management. The available parameters include:
* -0.25 to -6.00DS in 0.25D steps
* -6.00 to -10.00DS in 0.50D steps
* No toric options available
* Material: omafilcon A (hydrogel)
What is the warranty guarantee for MiyoSmart lenses?
Rx warranty in first 6 months if prescription changes by ≥ 0.50D
Stellest (...) lenses have a ...mm diameter central clear zone. Treatment zone consist of ... of highly aspherical .... HALT design do not have a single ..., but instead create a .... Each of the ... features ... of the same power, with successive rings having different powers. Spaces between the rings of lenslets provide single vision correction.
Stellest (HALT) lenses have a 9mm diameter central clear zone. Treatment zone consist of 11 concentric rings of highly aspherical lenslets. HALT design do not have a single focal power, but instead create a volume of myopic defocus. Each of the 11 rings of lenslets features contiguous (touching) lenslets of the same power, with successive rings having different powers. Spaces between the rings of lenslets provide single vision correction.
Px eligibility of orthokeratology is dependent on px .... Only ... refraction is able to be corrected using OrthoK. The maximum spherical power is ...DS and the maximum cylindrical power is ...DC. Px also needs to have a stable and suitable ..., where ... axis are not suitable due to possible .... Px with ... are also not suitable. The ... at ...mm found in the map calculations is also an important factor, which measures how ... the ... is. Px must also be advise of proper ... and ... commitment.
Px eligibility of orthokeratology is dependent on px refraction. Only myopic refraction is able to be corrected using OrthoK. The maximum spherical power is -6.00DS and the maximum cylindrical power is -1.75DC. Px also needs to have a stable and suitable topography, where oblique axis are not suitable due to possible lens instability. Px with keratoconus are also not suitable. The sag diffferential at 8mm found in the map calculations is also an important factor, which measures how symmetrical the mid periphery cornea is. Px must also be advise of proper hygiene and care commitment.
Px attitude to CL wear is important to be considered before prescribing OrthoK. ... per 10,000 OrthoK px gets ... compared to ... per 10,000 daily disposable px. OrthoK Px with this infection are mostly children. With soft CLs wear, primary school age children have the ... events (... per 10,000 for ... yo). However, teenagers have ... events (... per 10,000 for ... yo). Quality of life ranking: ... > ... > ... However, OrthoK, MiSight and MiyoSmart introduces ..., where older px are more likely to reject. OrthoK is a good option when px are adverse to ... options.
Px attitude to CL wear is important to be considered before prescribing OrthoK. 7.7 per 10,000 OrthoK px gets microbial keratitis compared to 3.5 per 10,000 daily disposable px. OrthoK Px with this infection are mostly children. With soft CLs wear, primary school age children have the lowest risk of infiltrative events (97 per 10,000 for 8-11 yo). However, teenagers have very high rates of infiltrative events (335 per 10,000 for 13-17 yo). Quality of life ranking: OrthoK > Soft CL > glasses However, OrthoK, MiSight and MiyoSmart introduces higher order aberrations, where older px are more likely to reject. OrthoK is a good option when px are adverse to pharmacological options.
Some myopia management may impact binocular vision. This excludes ... CLs, ... spectacles. ... causes ~...Δ ... shift and ...-... reduction in lag. ... and ... may causes a similar .... ... may have an impact depending on concentration. 0.01% and 0.02% will have ... if baseline accommodation is normal; on average there may be a ...D reduction in amplitude of accommodation. 0.05% may result in about ...D reduction in amplitude of accommodation in ... or ... and ...D reduction in European eyes.
Some myopia management may impact binocular vision. This excludes MiSight CLs, MiyoSmart spectacles. OrthoK causes ~2Δ exophoric shift and 0.25-0.50 reduction in lag. Biofinity and NaturalVue may causes a similar esophoria shift. Atropine may have an impact depending on concentration. 0.01% and 0.02% will have minimal to no impact if baseline accommodation is normal; on average there may be a 1.5-1.6D reduction in amplitude of accommodation. 0.05% may result in about 2D reduction in amplitude of accommodation in darker irises or Asian eyes and 4D reduction in European eyes.
What are the side effects of dilute atropine?
- Photophobia
- N blur
- Periocular dermatitis
- Atopic facial eczema
Where can dilute atropine be obtained? What concentration can we do?
Dilute atropine can be compounded in any concentration. However, they may have variable stability based on pH and thus may change effectivity. There are only limited number of compounding pharmacies that can produce them. 0.01% can be found readily available in all pharmacies.
What are the contraindications for myopia control?
- Poor reliability/ compliance with review
- Atypical myopia → keratoconus, myopia D > age in years
- Reduced visual acuity → amblyopia
- Very high myopia
- Adults
Axial length us can be measured using the ..., which is originally used for planning .... ... scans are to be captured for each eye. Should aim for high ... ratio. The reproducibility between visits should be ± ...mm with quality scans.
Axial length us can be measured using the IOLMaster 500, which is originally used for planning cataracts surgery. 20 scans are to be captured for each eye. Should aim for high signal to noise ratio. The reproducibility between visits should be ± 0.04mm with quality scans.
Why is measuring axial length useful in myopia control?
- Plotting axial length against axial growth chart can be useful in assessing risk of future myopia onset
- Monitor success of a treatment e.g. if trending towards a higher percentile curve then more likely of incident myopia, or if myopic suggests sub-optimal treatment
Why does measuring axial length matter?
Axial length can be used as an absolute risk factor for lifetime visual impairment risk:
* <26mm 3.8%
* >26mm 25%
* >30mm 90%
What is normal axial elongation?
Average normal annual change in axial length without change in Rx:
* <10 years age: 0.1-0.2mm/year
* >10 years: 0.1mm/year slowing to minimal/ no change in teenage years
CLEERE study found that:
* fastest axial elongation was in the ... (~...mm/year)
* >...mm/year identified “fast progressors” SCORM study found regardless of age myopia onset occurred at absolute value
* ...mm for boys
* ...mm for girls
CLEERE study found that:
* fastest axial elongation was in the year prior to becoming myopic (~0.33mm/year)
* >0.22mm/year identified “fast progressors” SCORM study found regardless of age myopia onset occurred at absolute value
* 24.1mm for boys
* 23.7mm for girls
How does axial length change in myopes?
- Myopes tend to progress by ~0.3mm/year until age 10-11 years
- Slow to ~0.2mm/year in pre-teen and early teens
- Half stop axial elongation by age 16.3 years; 25mm for females and 25.5mm for males
- Males have around 0.5mm longer axial length than females, in both emmetropia and myopia
Cycloplegic assessment allows for an ... by controlling .... This can rule out accommodative ..., which is when px have intermittent ..., the accommodation induces myopia. Px with ... are px that are actually hyperopic, but present as myopic due to having .... In both cases, ... upon cycloplegia. Failure to cycloplegic can lead to ... and or an ....
Cycloplegic assessment allows for an accurate refractive estimate by controlling accommodation. This can rule out accommodative spasm, which is when px have intermittent ciliary contraction, the accommodation induces myopia. Px with pseudomyopia are px that are actually hyperopic, but present as myopic due to having near tonus. In both cases, myopia will disappear upon cycloplegia. Failure to cycloplegic can lead to misdiagnosis and or an incorrect refractive estimate.
What should be used in a cycloplegic refraction? What should not be used?
1.0% cyclopentolate (1 drop) → knocks out accommodation
1.0% tropicamide (2 drops) → significant residual accommodation (>1D) more likely in Asian children (7%)
What are the trends in peripheral retinal findings in highly myopic children ≤ 10yo?
30% peripheral retinal abnormalities
20% lattice degeneration
