How delaying the onset of myopia can influence the final refraction

Paper title: Final Level of Myopia versus Age of Onset: Effect of Race and Age at Final Refraction

Authors: Mark Bullimore (1), Noel Brennan (2)

1. University of Houston
2. Johnson & Johnson Vision

Date: May 2022

Reference:   ARVO Meeting 2022, Denver

This abstract explored the effect of race and the age of myopia onset on final recorded myopic correction.

The authors analyzed data from seven studies; two prospective studies from East Asia which examined myopic progression as a function of age of onset, two retrospective studies from India and the Netherlands which assessed myopia progression and two cross-sectional studies from Argentina and the UK.  The seventh study was from Finland which followed subjects into adulthood which used the age when joining the study as the age of onset).

The age of myopia onset was plotted as a slope against the final level of myopia.

• The slopes demonstrated an increase in myopia for each increasing year of age.
• In East Asia, an increase of 0.97 and 0.68D per year was found for 11 and 17yr olds, respectively. 
• In Finland, the slope showed a change of 0.87D per year
• The studies from India, the Netherlands, Argentina and the UKs showed flatter slopes (between 0.23 to 0.35D increase per year)

For each year myopia is delayed, the final myopic refraction would be between 0.23D and 0.97D less, depending on the country.

• For those in East Asia, delaying the onset of myopia by 1yr could reduce the final level myopia by approximately 0.75D. This is comparable to several years using current myopia control options
• For non-East Asians, there would be a benefit in delaying onset of myopia, even if it was by a smaller degree
• For the subjects in Europe, increased age was associated with higher myopia. This could be suggestive of adult myopia progression.

If the onset of myopia could be delayed, even by just one year, it could provide similar savings in myopia to longer periods with current myopia control options.

Eyecare practitioners should be aware of the importance of prevention of myopia as well as the treatment.

The study from Finland had a similar slope to those from East Asia and was the steepest slope for the studies from Europe. However, the age of joining the study was as a substitute for the age of onset and so for some subjects, this may not have been accurate. Further research could confirm how much difference this makes to the progression slopes.

Title: Final Level of Myopia versus Age of Onset: Effect of Race and Age at Final Refraction

Authors: Mark Bullimore, Noel Brennan

Purpose: Myopia severity has a profound impact on visual impairment in later life. A patient's final level of myopia may be lowered by myopia control, but also by delaying onset. Here we evaluate the influence of age of onset on the final recorded level of myopia.

Methods: Data were extracted from the following reports:

● two prospective cohort studies of myopia progression in East Asia where final recorded level of myopia is presented as a function of age of onset (Chua et al., 2016; Hu et al., 2020)

● two retrospective studies of myopia progression in India and the Netherlands (Verkicharla et al., 2004; Polling et al., 2021)

● two cross-sectional studies in Argentina and the UK (Iribarren et al., 2004; Williams et al., 2013).

For the above, age of onset was based on self-report of age at first spectacle prescription and the midpoint was used for all age ranges.

A seventh set of data comprised Finnish subjects originally recruited for a clinical trial and followed into adulthood (Parssinen et al., 2019). Subjects were divided into five groups according to age at recruitment which was used as a surrogate for age of onset.

Results: Figure 1 shows the final recorded level of myopia as a function of age of onset for the seven studies. Figure 1A shows data for the two East Asian studies. The myopia level is different because the reference ages are 11 and 17 years. The slopes are 0.97 and 0.68 D/year, meaning that each year later age of onset is associated with 0.97 or 0.68 D less myopia at the final refraction. Figure 1B shows data for the five non-East Asian studies. For four studies the slopes are substantially flatter, with slopes between 0.23 and 0.35 D/year. In contrast, the slope for the Finnish study was 0.87 D. Among subjects of European descent, increasing age of final refraction tended to be associated with higher levels of myopia.

Conclusions: Among East Asians, delaying onset of myopia by just one year has potential to lower the final level myopia by 0.75 D or more-equivalent to multiple years of myopia control with existing modalities. The benefit is lower, but meaningful, among non-East Asians. The trend linking age of final refraction with final myopia level suggests ongoing adult progression.

Layman Abstract: Delaying onset of myopia by just one year has a similar benefit to multiple years of myopia control with existing modalities. In other words, an ounce of prevention is worth a pound of cure.

[Link to abstract]