Clinical Practice

SER is the international standard formula that combines sphere and cylinder into a single number to express myopia severity:

The IMI (International Myopia Institute) 2019 white paper recommends SER as the standard for all myopia research. This enables direct comparison across studies, treatment efficacies, and populations.

In MiyoLab, every sphere and cylinder value entered is automatically converted to SER. All progression calculations, BHVI projections, and treatment efficacy analyses are based on this value.

IMI 2019 myopia classification:

• Emmetropic / pre-myopic: SER > −0.50 D
• Mild myopia: −0.50 D ≥ SER > −3.00 D
• Moderate myopia: −3.00 D ≥ SER > −6.00 D
• High myopia: SER ≤ −6.00 D

Measurements taken while accommodation (the focusing reflex) is active in children may overestimate myopia. The gold standard is autorefraction performed after temporarily paralyzing accommodation with a cycloplegic agent (typically cyclopentolate 1%).

MiyoLab asks you to record the measurement method (cycloplegic / non-cycloplegic / subjective) on entry. Non-cycloplegic measurements are automatically adjusted with a correction factor, and only same-method measurements are compared in progression analysis. The clinical decision support system warns when method inconsistency is detected.

The IMI 2021 Clinical Management Guidelines strongly recommend cycloplegic refraction for myopia diagnosis and monitoring in children.

The foundation of myopia management is accurately measuring the rate of progression. MiyoLab calculates annual progression rate (D/year) from each patient's SER measurements across multiple time points using ordinary least squares (OLS) linear regression.

Calculated metrics: annual progression rate (D/year), R² value (model fit), confidence interval, standard error, and data quality score. Data with R² > 0.80 is classified as "reliable", 0.50–0.80 as "moderate", and < 0.50 as "low reliability".

Progression rate is compared against BHVI age-specific expected rates (Donovan et al. 2012 meta-analysis). Patients progressing faster than expected are flagged as "fast progressors" and trigger treatment initiation/modification recommendations.

Implausible progression rates (e.g., > −2.0 D/year or large positive shifts) are automatically flagged as implausible and data entry review is recommended.

BHVI (Brien Holden Vision Institute) Model

The model also accounts for treatment efficacy, compliance rates, rebound effect, and inter-individual variability to produce prognosis projections up to age 18. Shown with confidence band (±1 SD).

Myopia risk is multifactorial. MiyoLab combines lifestyle, genetic, and clinical data to calculate a composite risk score from 0–100:

• Parental myopia: 0, 1, or 2 myopic parents (Morgan et al. 2012; 1 parent: 1.25×, 2 parents: 1.60× risk multiplier)
• Outdoor time: < 1 hour/day = high risk, ≥ 2 hours = protective (He et al. 2015, Rose et al. 2008)
• Screen / near work time: > 3 hours/day of near work increases risk (Huang et al. 2015)
• Current myopia level and progression rate
• Axial length and AL/CR ratio
• Onset age: Early onset (< 8 years) carries higher risk of ultimate myopia
• Ethnicity: East Asian children have 2-3× higher prevalence (IMI 2021)

The risk score is used by the clinical decision support system as a treatment initiation threshold and is recalculated with every measurement update.

MiyoLab's CDS engine, based on IMI 2021 Clinical Management Guidelines, continuously monitors over 12 clinical parameters and generates recommendations at three levels:

• Info: Monitoring notes, e.g. "Axial length above 75th centile, 6-month follow-up recommended"
• Warning: Requires attention, e.g. "Progression rate 1.5× above BHVI expectation, treatment modification should be considered"
• Critical: Urgent intervention, e.g. "AL > 26 mm + rapid progression: pathological myopia risk, retinal examination recommended"

Does the difference between two measurements reflect a real change, or just measurement error? MCID (Minimal Clinically Important Difference) makes this distinction.