Predicting Myopia Onset and progression (PreMO): an evidence-based risk
indicator for eye care practitioners.
Stratification of a child’s risk for developing myopia can be undertaken using the PreMO risk indicator. The risk indicator provides
advice and guidance for children and their parents on the likelihood of future myopia and provides a structure with which to discuss
strategies to delay onset (Part 1). For myopic children, the indicator can be used in combination with professional judgement toselect evidence-based management options (Part 2). Because the PreMO is derived primarily from NICER Study outcomes, it isbest suited for use with primary school children of white ethnicity living in the UK.

Part 1: Risk Indicator- stratifying risk of future myopia
To determine child’s risk of myopia you will need the following information:
1.) Age of the child (years) 2.) Parental history of myopia 3.) Cycloplegic refractive error (using spherical equivalent refraction [SER]) *4.) Axial Length **Use either Table 1a for children 6-8 years OR Table 1b for children 9-10 years to calculate your patient’s ‘Risk Score’. The colour coding
used in the tables relates to the evidence-derived risk of remaining emmetropic (green), or becoming myopic by approximately 10 (red),13 (orange), or 16 (yellow) years of age and corresponds to the management in Table 1c.

6-8-Year-Old Children

Table 1a: Assessing risk of myopia development
Risk factor for myopia development
Genetic
1. Parental
Neither parent myopic
myopiaOne parent myopic
Two parents myopic
Refractive

Score assigned
023

2. Cycloplegic
SER *Greater than +1.00D+0.75D to +1.00DLess than +0.75D0233.
Axial Length **Less than 22.93mm
22.94mm to 23.11mm
23.12mm to 23.18mm
23.19 mm or greater

012
3Risk Score (0-9)*If cycloplegic SER is not available use these
non-cycloplegic estimations for risk scores 2
Non cycloplegic SER (D)Greater than +0.75
0+0.325 to +0.75
2Less than +0.325
3**If axial length is unavailable, use these estimations for risk score from average
K (mm) & SER (D)Cycloplegic SER (D)-0.25

0.00 or+0.25+0.50 or+0.75+1.00 or+1.25+1.50 or+1.75K(mm)7.4 or less
7.5
7.6
7.7
7.8
7.9013333002333001233000123000012

8.0 or greater

3333

3

9-10-Year-Old ChildrenTable 1b: Assessing risk of myopia development
Risk factor for myopia development
Genetic
1.
Neither parent myopic
Parental
One parent myopic
myopiaTwo parents myopic
Refractive

Score assigned
012

2.
Cycloplegic
SER *Greater than +0.875D+0.375D to +0.875D
Less than +0.375D

012

3. Axial
Length **Less than 23.33mm
23.33mm to 23.61mm
23.62 mm or greater

012Risk Score (0-6)* If cycloplegic SER is not available use these
non-cycloplegic estimations for risk scores 2
Non cycloplegic SER (D)Greater than +0.625
0+0.125 to +0.625
1Less than +0.125
2** If axial length is unavailable, use these estimations for risk score from average
K (mm) & SER (D)Cycloplegic SER (D)0.00 or+0.50 or+1.00 or+1.50 or-0.25+0.25+0.75
+1.25
+1.75
K(mm)
7.6 or less
000007.711000
7.821
1007.9221
108.0
222118.1
222218.2 or greater
22222* Result of autorefraction (or retinoscopy) >20 minutes after instillation of 1% Cyclopentolate HCl. Use the result from the least hyperopic eye/most emmetropic eye.
Use the conversion table for non-cycloplegic subjective refraction results if cycloplegic refraction values are not available. Cycloplegic refraction is encouraged to determine the risk score more accurately.
** If you do not have access to axial length measures use the conversion table to estimate the axial length risk score based on SER (D) and mean anterior corneal radius of curvature (K, mm).

Interpreting the Risk Score
Table 1c: Predicted risk of myopia development and suggested management and advice
Evidence-Informed Management
Score
Use the ‘Risk Score’ calculated in Table 1a or 1b to indicate the child’s risk of
becoming myopic, the age at which myopia is likely to develop and thesuggested recall schedule and management advice from Table 1c.
RE-TEST INTERVAL: The suggested recall for patients at moderate to high riskof developing myopia by 10 or 13 years of age is one year until at least 13years of age1,4 in the absence of emergent signs/symptoms, significant existing
astigmatism and/or anisometropia or a pre-existing binocular vision anomaly.
ADVICE: All patients who are ‘at risk’ of myopia development (Risk Score >1)should receive evidence-informed environmental and lifestyle advice including
promoting spending increased time outdoors (>40 mins per day) anddecreasing time spent on near activities e.g. smart phones and computers.
The higher the score, the higher the risk of future myopia and of myopia
occurring at an earlier age. Earlier onset is likely to result in higher
magnitudes of myopia long-term.1 This information can be relayed toparents to highlight their child’s relative risk and stress the importance ofregular eye examinations and adherence to environmental and lifestyleadvice.

Risk of myopia
development

Predicted refractive
outcomeManagement
Suggested
recall †0

LITTLE/NO RISK

Likely to remain
emmetropic

2 years

1-3

LOW RISK

4-6

MODERATE RISK

7-9

HIGH RISK

Likely to be myopic
by 16 years
Likely to be myopic
by 13 years
Likely to be myopic
by 10 years

1 yearAdviceLittle/No riskof myopia
development
Environment& lifestylemodifications‡† In the absence of emergent signs or symptoms during recall period or presence of significant refractive error (hyperopia,anisometropia or astigmatism) or binocular vision anomaly‡ With advice on implementation of environmental modifications and lifestyle advice (e.g. increasing time spent outdoors >40 mins
per day, decreasing time spent on near activities e.g. smart phones and computers) 5Part 2: Management of myopia progression if child becomes myopic >6 years of age.
Use Tables 2a and 2b below in conjunction with your clinical judgment to determine the most appropriate recall interval and patient
advice dependent on refractive status, age and rate of progression of cycloplegic refractive error (using SER).
To determine an evidence-based management and recall schedule for myopic children you will need:1.) Cycloplegic SER result from two or more successive eye examinations 2.) An estimate of annual progression in SER

Annual progression of SER can be calculated using the following formula: Annual Progression (D) = SER2-SER1/Years between tests
Table 2a: Myopia management and suggested recall schedule
Risk of myopic progression
DemographicRefractive1.
Age of child2.
Annual progression
in SER (D)Evidence-Informed Management

Score assigned
13 years old or more

0Less than 13 years
old1Less than 0.50D

00.50D or more

1

Risk Score (0-2)

Use the ‘Risk Score’ calculated in Table 2a to indicate the child’s risk ofmyopic progression and the suggested recall schedule and management
advice from Table 2b.
RE-TEST INTERVAL: The suggested recall for patients at risk of myopic
progression is one year until at least 13 years of age in the absence ofemergent signs/symptoms, significant existing astigmatism and/or
anisometropia or a pre-existing binocular vision anomaly. If the child isless than 13 years of age and has shown an annual myopic progression of>0.50D, they are at risk of fast myopic progression and should bereviewed in six months. Table 2a can be used at subsequent review to re-evaluate the future risk of progression.

ADVICE: The optometrist should discuss myopia control strategies withpatients who are at moderate to high risk of myopia progression (score 1or 2).**
Where the risk of myopia progression is identified as ‘Little/No Risk’,this should be considered in the context of the child’s current
environment/lifestyle. Risk of progression should be re-evaluated atsubsequent review.

Table 2b: Predicted risk of myopia progression and suggested management and advice
Score

Risk of myopia progression &predicted refractive outcome

Management
Suggested recall *Advice0

LITTLE/NO RISK2 years

1

MODERATE RISK

Low risk of myopic
progression
Discuss myopia control
strategies **2

HIGH RISK

Stable/Slow progression of myopia
Low magnitude of myopia long-term
Moderate progression of myopia
Moderate magnitude of myopia longterm
Fast progression of myopia
High magnitude of myopia long-term

1 year6 months* in the absence of symptoms, significant refractive error (hyperopia, anisometropia or astigmatism) or BV anomaly** if within practitioners’ level of clinical competency and in line with the College of Optometrists ‘Myopia Management Guidance for Optometrists’REFERENCES

The PreMO Risk Indicator has been developed primarily from the NICER Study research. Supporting references are included below:
McCullough, SJ., Adamson, G., Breslin, KMM., McClelland, J.F., Doyle, LA., Saunders, KJ. (2020) Axial Growth and Refractive Change in White European Children andYoung Adults: Predictive Factors for Myopia, Scientific Reports, 10(15189)
Morgan PB, McCullough SJ & Saunders KJ. Estimation of ocular axial length from conventional optometric measures. Cont Lens Anterior Eye 2020; 43(1):18-20.
Doherty SE, Doyle LA, McCullough SJ, Saunders KJ. (2019) Comparison of retinoscopy results with and without 1% cyclopentolate in school-aged children, Ophthalmic
Physiol Opt; 39(4):272-281.
McCullough SJ, O’Donoghue L & Saunders KJ. Six Year Refractive Change among White Children and Young Adults: Evidence for Significant Increase in Myopia
among White UK Children. PLoS One 2016; 11(1): e0146332. doi: 10.137/journal.pone.0146332.
Guan H, Yu NN, Wang H, Boswell M et al. Impact of various types of near work and time spent outdoors at different times of day on visual acuity and refractive error
among Chinese school-going children. PLoS One 2019; 14(4): e0215827. doi: 10.1371/journal.pone.0215827. eCollection 2019.
Huang HM, Chang DST & Wu PC. The Association between Near Work Activities and Myopia in Children – A Systematic Review and Meta-Analysis. PLoS One 2015; 10(10): e0140419. doi: 10.137/journal.pone.0140419..
Xiong S, Sandaridurg P, Naduvilath T et al. Time spent in outdoor activities in relation to myopia prevention and control: a meta-analysis and systematic review. ActaOphthalmol 2017; 95:551-6.
The College of Optometrists, 2019. Guidance for Optometrists: Myopia Management. [online] Available at < https://www.college-optometrists.org/uploads/assets/25f80829-6cf1-44aa-a6b56fe20d215f48/Myopia-management-guidance-for-optometrists.pdf> [Accessed 18 September 2020].

O’Donoghue L, Kapetanankis VV, McClelland JF et al. Risk Factors for Childhood Myopia: Findings From the NICER Study. Invest Ophthalmol Vis Sci 2015; 56(3): 152430.
Ruiz-Pomeda AR & Villa-Collar C. Slowing the Progression of Myopia in Children with the MiSight Contact Lens: A Narrative Review of the Evidence. Ophthalmol Ther2020; doi: 10.1007/s40123-020-00298-y
11 Chamberlain P, Peixoto-de-Matos SC, Logan NS et al. A 3-year randomized clinical trial of MiSight lenses for myopia control. Optom Vis Sci 2019; 96(8): 556-67.