Keeping myopia away: The importance of maintaining hyperopic reserve in premyopia.

Myopia has emerged as a major global public health challenge, with the prevalence of myopia among children increasing exponentially over the past two decades. Emerging evidence, however, indicates that delaying the onset of myopia through early intervention during the premyopic stage may be more impactful than attempting to control myopic progression after onset. Central to this prevention strategy is the concept of the hyperopic reserve, the physiological hyperopia present in early childhood that functions as a protective buffer against the development of myopia. This narrative review examines the definition and clinical significance of hyperopic reserve in identifying children at risk for myopia (premyopia), as well as evidence-based intervention strategies aimed at preserving this reserve. The recommended safety threshold for hyperopic reserve is +1.00 D before age 12 years. Recommended strategies include behavioral interventions, such as increasing outdoor time and implementing regular breaks during near work. Long-term monitoring and regular follow-up are crucial for identifying high-risk groups associated with factors such as insufficient outdoor time, prolonged near work (including screen time and cram school attendance), parental myopia, younger age with lower baseline hyperopia reserve, rapid myopia shift >0.5 D/year, and rapid axial length elongation >0.2 mm/year. Pharmacological or optical therapies may be considered for high-risk children. By understanding and maintaining hyperopic reserve during the critical premyopic stage, eye care practitioners can shift the clinical paradigm from myopia control to myopia prevention, thereby potentially reducing both the incidence and severity of myopia in future generations.