Myopia incidence and progression in young adults

Paper title: Incidence and Progression of Myopia in Early Adulthood

Authors: Samantha Sze-Yee Lee (1), Gareth Lingham (1, 2), Paul G. Sanfilippo (3), Christopher J. Hammond (4), Seang-Mei Saw (5, 6), Jeremy A. Guggenheim (7), Seyhan Yazar (8), David A. Mackey (1, 3, 9)

1. Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Perth, Australia
2. Centre for Eye Research Ireland, School of Physics, Clinical and Optometric Sciences, Technological University Dublin, Dublin, Ireland
3. Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
4. Department of Twin Research & Genetic Epidemiology, King's College London, London, United Kingdom
5. Singapore Eye Research Institute, Singapore
6. Yong Loo Lin School of Medicine, National University of Singapore, Singapore
7. School of Optometry and Vision Science, Cardiff University, Cardiff, United Kingdom
8. Garvan-Weizmann Centre for Cellular Genomics, Garvan Institute of Medical Research, Sydney, Australia
9. School of Medicine, Menzies Research Institute Tasmania, University of Tasmania, Hobart, Australia

Date: Jan 2022

Reference:  Lee SS, Lingham G, Sanfilippo PG, Hammond CJ, Saw SM, Guggenheim JA, Yazar S, Mackey DA. Incidence and Progression of Myopia in Early Adulthood. JAMA Ophthalmol. 2022 Feb 1;140(2):162-169.  (Link to abstract)

Myopia incidence and progression is well described in children; however, less is known about myopia incidence and progression in early adulthood. This prospective single-centre cohort study based in Western Australia described 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.

Baseline measurements were taken from 20 year olds (n=1328) and follow up measurements 8 years later (n=813). Refractive information from both visits was available for 701 participants. Data was gathered between 2010 and 2020 from a single site in Western Australia.

Results:

• The 8-year myopia and high myopia incidence were 14.0% and 0.7% respectively
• A myopic shift (of 0.50D or greater in at least 1 eye) occurred in 37.8% (n=26) of participants. This indicates over one third of participants experienced a myopic shift in their third decade of life.
• There was an average increase of 0.04D in myopia and 0.02mm in axial length per year over the 8 years 
• In those who showed myopia progression, the average myopic shift was -0.75D alongside 0.29mm axial elongation.
• Incident (newly onset) myopia was associated with self-reported East Asian vs White race, female vs male sex, smaller conjunctival ultraviolet autofluorescence area (indicating less sun exposure), and parental myopia
• Rates of myopia progression and axial elongation were faster in female participants and those with parental myopia 
• Education level was not associated with myopia incidence or progression. 

Two prior retrospective studies have indicated that around 20% of young adults in their 20s progress by at least 1D in that decade, with that data published in 2002 from a single site in the United States¹ and 2014 from a single site in Finland.² Newer data has been very much needed; this data indicates similar results to the older data in refractive progression but is the first to report changes in axial length.

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.

Clinically, this indicates that myopic patients in their third decade of life should be monitored for progression, and emmetropes should be monitored for the development of myopia - particularly those who are of East Asian ethnicity, female, with parental myopia and less time spent outdoors. For more clinical advice, read our article Adult myopia progression, and how to treat it.

Clinically, this advocates for active myopia management well into the third decade, however we require more research to explore this further. In addition, we need to learn which myopia control methods are most effective in our young adult populations. There is currently only very limited, case-series evidence for orthokeratology's propensity for adult myopia stabilization^3,4 and no randomized controlled trials. 

Interestingly, there was no significant association between highest level of education with rate of change in refractive measures. Instead, unmodifiable factors, such as race, sex and parental myopia had stronger associations with rate of refractive change than environmental factors. Further exploration is required to elucidate why level of education was not associated with rate of change.

Title: Incidence and Progression of Myopia in Early Adulthood

Authors: Samantha Sze-Yee Lee, Gareth Lingham, Paul G. Sanfilippo, Christopher J. Hammond, Seang-Mei Saw, Jeremy A. Guggenheim, Seyhan Yazar, David A. Mackey

Purpose: 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.

Methods: The 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.

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-mm² 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 ≤ .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 ≤ .001). Education level was not associated with myopia incidence or progression.

Conclusion: 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.

Abstract link is here