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Randomized Controlled Trial
. 2021 May;41(3):523-531.
doi: 10.1111/opo.12812. Epub 2021 May 5.

Axial length targets for myopia control

Paul Chamberlain  1 , Percy Lazon de la Jara  1 , Baskar Arumugam  1 , Mark A Bullimore  2
Affiliations
Randomized Controlled Trial

Axial length targets for myopia control

Paul Chamberlain et al. Ophthalmic Physiol Opt. 2021 May.

Abstract

Purpose: Both emmetropic and myopic eyes elongate throughout childhood. The goals of this study were to compare axial elongation among untreated progressing myopes, progressing myopes treated with a myopia control contact lens and emmetropes, in order to place axial elongation in the context of normal eye growth in emmetropic children, and to consider whether normal physiological eye growth places limits on what might be achieved with myopia control.

Methods: Axial elongation data were taken from the 3-year randomised clinical trial of a myopia control dual-focus (MiSight® 1 day) contact lens. These were compared with data for myopic and emmetropic children in two large cohort studies: the Orinda Longitudinal Study of Myopia (OLSM) and the Singapore Cohort Study of the Risk Factors for Myopia (SCORM). Each study's published equations were used to calculate annual axial elongation. Four virtual cohorts-myopic and emmetropic for each model-were created, each with the same age distribution as the MiSight clinical trial subjects and the predicted cumulative elongation calculated at years 1, 2 and 3 for myopes and emmetropes using both the OLSM and SCORM models.

Results: The untreated control myopes in the MiSight clinical trial showed mean axial elongation over 3 years (0.62 mm) similar to the virtual cohorts based on the OLSM (0.70 mm) and SCORM (0.65 mm) models. The predicted 3-year axial elongation for the virtual cohorts of emmetropes was 0.24 mm for both the OLSM and SCORM models-similar to the mean 3-year elongation in MiSight-treated myopes (0.30 mm).

Conclusions: The 3-year elongation in MiSight-treated myopes approached that of virtual cohorts of emmetropes with the same age distribution. It is hypothesised that myopic axial elongation is superimposed on an underlying physiological axial elongation observed in emmetropic eyes, which reflects increases in body stature. We speculate that optically based myopia control treatments may minimise the myopic axial elongation but retain the underlying physiological elongation observed in emmetropic eyes.

Keywords: axial length; children; contact lenses; myopia; myopia control.

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Conflict of interest statement

Paul Chamberlain, Percy Lazon and Baskar Arumugam are employees of CooperVision. Mark Bullimore is a consultant for Alcon Research, Inc., Apellis, Inc., Arctic Vision, Inc., Ascpleix, Inc., CooperVision, Inc., Corneagen, Inc., Essilor International S.A.., Eyenovia, Inc., Genentech, Inc., Johnson & Johnson Vision, Inc., Presbia, Inc., and is the sole owner of Ridgevue Publishing, LLC, Ridgevue Technologies LLC, and Ridgevue Vision LLC. Preparation of this paper was supported by CooperVision, Inc.

Figures

Figure 1
Figure 1
Cumulative axial elongation (mm) for treated and control myopes in the MiSight clinical trial are compared to the virtual myopic and emmetropic cohorts developed using both the OLSM 7 and SCORM 37 models (see Methods). OLSM: Orinda Longitudinal Study of Myopia; SCORM: Singapore Cohort Study of the Risk Factors for Myopia.
See this image and copyright information in PMC

Comment in

  • Normative data for emmetropic and myopic eye growth in childhood.
    Saunders KJ, McCullough SJ. Saunders KJ, et al. Ophthalmic Physiol Opt. 2021 Nov;41(6):1382-1383. doi: 10.1111/opo.12873. Epub 2021 Aug 17. Ophthalmic Physiol Opt. 2021. PMID: 34402539 No abstract available.
  • Author's reply.
    Chamberlain P, Bullimore MA. Chamberlain P, et al. Ophthalmic Physiol Opt. 2021 Nov;41(6):1384. doi: 10.1111/opo.12872. Epub 2021 Aug 17. Ophthalmic Physiol Opt. 2021. PMID: 34402540 No abstract available.

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