Myopia progression varies with age and severity of myopia

Objective To investigate annual myopia progression in individuals from South Indian states across different age groups, and its association with age of onset and severity of myopia. Methods This retrospective study included the data of 6984 myopes (range: 1-30 years), who visited at least twice to LV Prasad Eye Institute and on whom a standard retinoscopy technique was performed to determine refractive error. Based on spherical equivalent (SE) refractive error, individuals were classified into mild, moderate, high and severe myopic groups. Myopia progression was calculated as difference between SE at 1-year follow-up visit and at baseline. To determine the age-specific myopia progression, individuals were further categorized as myopes who are at least 15 years or younger and those who are above 15. Results The mean annual progression of myopia was influenced by both the age group (p < 0.001) and severity type of myopia (p < 0.001). The overall mean myopia progression ranged from -0.07 +/- 0.02 D (standard error) to -0.51 +/- 0.02 D across different age groups with maximum change in refractive error noted in children aged 6-10 years and the least in adults aged 26-30 years. Myopia progression was greater in severe myopes, followed by high, moderate, mild myopes and in individuals aged <= 15 years compared to those aged >15 years (-0.45 +/- 0.01 vs. 0.14 +/- 0.01, p < 0.001). Severe myopes alone had similar annual myopia progression rate irrespective of age (i.e <= 15 and >15 years, p = 0.71). Early onset of myopia was associated with high myopia in adulthood. Conclusion The magnitude of myopia progression in children from South Indian states is comparable to that of Caucasians and Chinese. The greater progression in 'severe myopes' across different age groups emphasize the need for regular follow-ups, monitoring axial lengths, and anti-myopia strategies to control myopia progression irrespective of the age and degree of myopia.