Myopia management has become an increasingly important part of eyecare as the prevalence of myopia continues to rise worldwide.1 Much of the recent conversation has focused on optical strategies designed to slow axial elongation. However, refractive correction alone does not always tell the full story.
In clinical practice, evaluating how the eyes work together, particularly during sustained near work, can provide additional insight when managing patients with developing or progressing myopia. As patients spend more time reading, studying, and using digital devices, the functional performance of the visual system becomes increasingly relevant.
Binocular vision assessment can help clinicians better understand how accommodative demand and eye coordination interact with the visual environment in which myopia develops.
The growing prevalence of myopia
Myopia has become a significant global public health concern. Current projections estimate that nearly 50% of the world's population may be myopic by 2050, with approximately 10% developing high myopia.1 Higher levels of myopia are associated with increased lifetime risk of retinal detachment, myopic maculopathy, glaucoma, and other vision threatening complications.1
Because of these risks, the focus of eyecare has shifted from simply correcting refractive error to slowing myopia progression. Modern treatment strategies including orthokeratology (ortho-K), multifocal contact lenses, and myopia control spectacle lenses that aim to influence retinal myopia defocus in order to reduce the stimulus for axial elongation.2 At the same time, visual behavior and binocular vision function may influence how patients respond to these treatments.
A brief overview of binocular vision
Binocular vision refers to the coordinated interaction between accommodation, vergence, and sensory fusion that allows both eyes to work together efficiently.3 These systems support clear, single, and comfortable vision during both distance and near tasks.
As visual demands increase with sustained reading, computer use, and digital device exposure, binocular vision function becomes increasingly important. Sustained near work requires accurate accommodation and stable vergence control.3
When these systems function efficiently, visual tasks can be maintained with minimal strain; however, when they do not, patients may experience symptoms such as eyestrain, headaches, blurred vision, or reduced visual endurance.4
Because individuals with progressing myopia often spend significant time engaged in near activities, evaluating binocular vision can provide useful clinical context beyond refractive error alone.
Diagnosis: Evaluating binocular vision
A comprehensive examination should include targeted assessment of binocular vision function.
Several clinical tests can help evaluate how efficiently the visual system manages near demand:5
- Cover testing at distance and near
- Near point of convergence (NPC)
- Positive and negative fusional vergence ranges
- Accommodative amplitude and facility
- Measurement of accommodative lag such as MEM retinoscopy
Each of these findings provides insight into how the visual system is functioning under near demand and can directly influence management decisions. For example, a receded near point of convergence or reduced convergence ability at near may indicate difficulty sustaining convergence, which can increase visual strain during near work.5
In addition, reduced accommodative facility or amplitude may suggest that the patient is struggling to meet sustained accommodative demand.3 Elevated accommodative lag is particularly relevant in myopia management, as it has been associated with hyperopic retinal defocus during near tasks.3
Identifying these patterns allows the clinician to move beyond refractive correction alone and consider how binocular vision function may be contributing to both symptoms and progression risk.
Clinical observation from practice
In my practice, cycloplegic refraction is routinely performed for new patients when clinically appropriate. This often reveals refractive findings that are not apparent during manifest refraction alone. In our patient population, more than 50% of children demonstrate at least 1.00D of latent hyperopia under cycloplegia, and approximately 25% demonstrate more than 2.00D.
Recognizing latent hyperopia is clinically important because uncorrected hyperopic refractive error can increase accommodative demand throughout the day, including during sustained near work.5 When latent hyperopia is not identified, the visual system may compensate through increased accommodative effort during near tasks which may contribute to accommodative lag and the presence of hyperopic retinal defocus.5
In busy clinical settings, clinicians may rely primarily on manifest refraction when evaluating refractive error. However, without cycloplegic assessment, latent hyperopia may go undetected.
Understanding pseudomyopia
Pseudomyopia occurs when a patient appears myopic on manifest refraction but demonstrates less myopia under cycloplegia, which is typically driven by excessive or sustained accommodation.6 Clinically, this distinction matters. Without cycloplegic confirmation, these patients may be over-minused, increasing accommodative demand and contributing to visual symptoms.6
In practice, pseudo-myopia may represent an early or functional stage in myopia development rather than a fixed refractive state. Identifying it allows the clinician to shift focus from simply prescribing more minus to addressing underlying accommodative and binocular vision demands.
The relationship between binocular vision and myopia progression
The relationship between binocular vision and myopia development continues to be studied. One area of interest is accommodative lag. When accommodation is insufficient during near work, the focal plane may fall behind the retina resulting in hyperopic retinal defocus.3
Experimental and clinical research suggests that hyperopic retinal defocus may act as a stimulus for axial elongation.7 Although accommodative lag alone does not cause myopia it may contribute to the visual environment in which myopia develops or progresses.3
Vergence stability may also influence visual comfort during sustained near tasks. Individuals with reduced fusional reserves or poorly compensated phorias may experience greater visual stress during prolonged near work.8
Moreover, conditions such as convergence insufficiency or accommodative dysfunction may not directly cause myopia, but they can increase visual stress during sustained near work.9 This increased demand may contribute to behaviors such as reduced working distance or prolonged near effort, which may influence the visual environment associated with myopia progression.8
Addressing these dysfunctions can improve visual comfort and may support better adherence to myopia management strategies.
Integrating binocular vision into myopia management
Most contemporary myopia control strategies aim to introduce controlled myopic retinal defocus in order to slow axial elongation.7 However, evaluating how the visual system performs during near tasks can provide additional clinical insight.
While optical treatments such as orthokeratology, multifocal contact lenses, and myopia control spectacle lenses aim to influence retinal defocus, understanding binocular vision function can provide additional insight into how patients tolerate and adapt to these interventions.
For example, patients with reduced accommodative function or binocular instability may initially struggle with certain optical designs that alter retinal defocus.7 In these cases, addressing the underlying binocular vision issue first—or concurrently—may improve adaptation and overall treatment success.
Top management strategies for binocular vision dysfunction include:3
- Vision therapy when indicated, such as in patients with symptomatic binocular vision dysfunction, including:
- Convergence insufficiency
- Accommodative dysfunction
- Reduced vergence ranges that impact visual comfort and performance during near tasks
- Near addition lenses in selected cases
- Counseling regarding working distance and visual ergonomics, which could include:
- Maintaining an appropriate reading distance (typically at least 30 to 40cm)
- Avoiding very close working distances for prolonged periods of time
- Encouraging regular breaks during sustained near work (ex., 20-20-20 rule)
- Being mindful of posture and screen positioning to reduce visual and accommodative strain
- Encouraging outdoor activity when appropriate
Key takeaways
- Myopia management extends beyond correcting refractive error alone
- Binocular vision involves accommodation vergence and sensory fusion
- Evaluating accommodative lag and vergence function can provide useful clinical insight3
- Cycloplegic refraction may reveal latent hyperopia that increases accommodative demand5
- Addressing binocular vision issues may improve comfort and treatment adherence in myopia management3
