Incidence and Progression of Myopia in Early Adulthood

Abstract

IMPORTANCE Myopia incidence and progression has been described extensively in children. However, few data exist regarding myopia incidence and progression in early adulthood.OBJECTIVE To describe the 8-year incidence of myopia and change in ocular biometry in young adults and their association with the known risk factors for childhood myopia. DESIGN, SETTING, AND PARTICIPANTSThe Raine Study is a prospective single-center cohort study. Baseline and follow-up eye assessments were conducted from January 2010 to August 2012 and from March 2018 to March 2020. The data were analyzed from June to July 2021. A total of 1328 participants attended the baseline assessment, and 813 participants attended the follow-up assessment. Refractive information from both visits was available for 701 participants. Participants with keratoconus, previous corneal surgery, or recent orthokeratology wear were excluded.EXPOSURES Participants' eyes were examined at ages 20 years (baseline) and 28 years. MAIN OUTCOMES AND MEASURES Incidence of myopia and high myopia; change in spherical equivalent (SE) and axial length (AL).RESULTS A total of 516 (261 male [50.6%]) and 698 (349 male [50.0%]) participants without myopia or high myopia at baseline, respectively, were included in the incidences analyses, while 691 participants (339 male [49%]) were included in the progression analysis. The 8-year myopia and high myopia incidence were 14.0% (95% CI, 11.5%-17.4%) and 0.7% (95% CI, 0.3%-1.2%), respectively. A myopic shift (of 0.50 diopters [D] or greater in at least 1 eye) occurred in 261 participants (37.8%). Statistical significance was found in longitudinal changes in SE (−0.04 D per year; P < .001), AL (0.02 mm per year; P <.001), and lens thickness (0.02 mm per year; P < .001). Incident myopia was associated with self-reported East Asian vs White race (odds ratio [OR], 6.13; 95% CI, 1.06-35.25; P = .04), female vs male sex (OR, 1.81; 95% CI, 1.02-3.22; P = .04), smaller conjunctival ultraviolet autofluorescence area (per 10-mm 2 decrease, indicating less sun exposure; OR, 9.86; 95% CI, 9.76-9.97; P = <.009), and parental myopia (per parent; OR, 1.57; 95% CI, 1.03-2.38; P = <.05). Rates of myopia progression and axial elongation were faster in female participants (estimate: SE, 0.02 D per year; 95 % CI, 0.01-0.02 and AL, 0.007 mm per year, 95 % CI, 0.00.-0.011; P Յ .001) and those with parental myopia (estimate per parent: SE, 0.01 D per year; 95% CI, 0.00-0.02 and AL, 95% CI, 0.002-0.008; P Յ .001). Education level was not associated with myopia incidence or progression.CONCLUSIONS AND RELEVANCE These findings suggest myopia progression continues for more than one-third of adults during the third decade of life, albeit at lower rates than during childhood. The protective effects of time outdoors against myopia may continue into young adulthood.

Prevalence and Risk Factors of Myopia in Young Adults: Review of Findings From the Raine Study

“…We additionally found that women had higher odds of incident myopia (OR = 1.8) and double the progression rate compared to men (SphE and AL progression: women: −0.04D/year and 0.02 mm/year vs. men: −0.02D/year and 0.01 mm/year), after correcting for education and CUVAF area ( 14 ). Longitudinal studies in children have similarly noted that girls' myopia progressed faster than boys' ( 59 – 61 ), attributing this difference to pubertal growth spurts ( 62 ).…”

“…Across all participants, SphE progression, axial elongation, and lens thickening were also observed over the 8 years, at average rates of −0.041D/year, 0.02 mm/year, and 0.220 mm/year, respectively (all p < 0.001), although corneal curvature did not change over time ( 14 ). Based on these findings, it appears that myopia progression in young adults has a similar mechanism to that in children, i.e., driven by axial elongation.…”

“…Based on the International Myopia Institute definitions ( 13 ), 25.8% of the Raine Study participants had myopia at age 20 (spherical equivalent [SphE] ≤-0.50 D in either eye) ( 14 ), including 5.5% with SphE ≤-3.00 D and 1.5% with ≤-6.00 D (high myopia) ( 6 , 14 ).…”

“…With increased push to pursue tertiary and higher education, more individuals are likely to enroll in university. As myopia can start to develop and continue progressing in early adulthood ( 14 ), this may further drive the myopia epidemic. However, it is not prudent to discourage higher education as it contributes to individual wellbeing, economic growth, and advancements in science and technology.…”

“…In our study ( 14 ), we further tested the hypothesis that major risk factors of childhood myopia — parental myopia, less time spent outdoors, and higher education — are also associated with myopia progression in early adulthood. Indeed, for each parent with myopia, odds of incident myopia increased by 1.6 times, while SphE and AL progression rates were increased by 0.01D/year and 0.005 mm/year.…”