Work

Scoping Review of the Role of Accommodation and Binocular Coordination in Myopia Onset and Progression

Year: 2025

Type: article

Abstract: Background: The predominant theory, underlying most optical myopia control interventions, is that relative peripheral hyperopic defocus (RPHD) is a cause of myopia progression. However, interventions that reduce RPHD only slow myopia progression on average by ~50%, so other factors are likely to be involved. Objective: To explore the literature on accommodation and binocular coordination as possible factors in myopia development and progression. Methods: PubMed was searched for relevant keywords in September 2025. Non-human and non-English reports were excluded. Results: (1) Concerning myopia onset, the CLEERE study found changes in the interaction between accommodation and convergence (increasing AC/A ratio) from four years before myopia onset. This is thought to indicate compromised accommodation, supported by reduced positive relative accommodation before myopia onset in other longitudinal studies. (2) Regarding myopia progression, the magnitude of accommodative lag is not strongly correlated with rate of myopia progression. The validity of clinical measurements of accommodative lag has been questioned. Tests of eye alignment during near vision show a more convergent posture (esophoria) in some myopes around the time of myopia onset, probably secondary to increased AC/A ratio. If compromised accommodation and/or near esophoria are relevant to myopia progression, prescribing a near addition should be helpful. However, myopia control trials of bifocal and progressive addition lens spectacles show poor efficacy. Despite early indications of greater efficacy in cases with higher accommodative lag and/or near esophoria, poor treatment effects in this sub-group were subsequently found. Nonetheless, some individual cases with symptomatic convergence excess esophoria are likely to benefit from bifocal spectacles for symptomatic relief. Conclusion: Although accommodative dysfunction seems likely to play some role in myopia onset, accommodative and binocular factors are unlikely to be major causal factors in myopia progression. An additive risk factor risk-resilience model is presented and suggestions are made for further research. Plain Language Summary: Myopia (short-sightedness) has become much more common in recent years, and is predicted to affect half the world’s population by 2050. Treatments are available that slow the progression of myopia by approximately 50% on average, including special spectacle lenses, contact lenses, and eye drops. To better understand why these approaches are not 100% effective we need to know more about the various factors that may play a causal role in myopia. The purpose of this review is to assess the evidence for two such factors: the ability to focus close to (ocular accommodation) and to use the two eyes as a team (binocular coordination). The review reveals research that has found abnormalities in ocular accommodation several years before a child develops myopia. However, there is less evidence that myopia or binocular coordination play a role during myopia progression. A risk-resilience model of myopia is presented. This highlights various factors that may play a causal role in myopia and others that may protect some children against developing myopia. Keywords: myopia onset, myopia progression, accommodation, binocular vision, AC/A ratio, accommodative lag

Source: Clinical ophthalmology

DOI: 10.2147/opth.s567456

Authors: Bruce Evans, Rakhee Shah, Natalia Vlasak

Institutions: City, University of London, City St George's, University of London

Language: English

Topic: Ophthalmology and Visual Impairment Studies

Subfield: Epidemiology

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $2,320