Myopia can begin to develop, and continue to progress, during early adulthood, in contrast to previously held views that it tends to stabilise from teen years into early adulthood, according to a study from Lyons Eye Institute and University of Western Australia.
Published in JAMA Ophthalmology, the Raine study highlights the need for research into myopia controls for this age group across the general population.
The prospective single-centre cohort study observed 2,868 offspring of 2,900 pregnant women recruited from the King Edward Memorial Hospital in Western Australia from 1989 to 1991.
Participants undertook eye examinations at the 20-year follow-up (age 18 to 22 years) to attain a baseline and were invited to attend a further eye examination at the 28-year followup. Refractive information for 701 participants were available from both visits. The main outcomes and measures were for incidence of myopia and high myopia, change in spherical equivalent (SE) and axial length (AL).
Of the 701 participants, 14% who did not have myopia at 20 years-old had developed myopia by age 28. Spherical equivalent progressed by -0.04D per year on average, with 261 (37.8%) participants experiencing a myopia shift (0.05D or greater) in at least one eye over the eight years, including 152 with a myopia shift in both eyes. Myopia continued to progress in approximately one third of individuals during their twenties.
Myopia incidence was significantly associated with East Asian race relative to white participants, parental myopia, less sun exposure and female gender. Women had higher odds of myopia development than men, and more than twice the rate of myopia progression and axial elongation.
While observing an inverse association of increased sun exposure (quantified using conjunctival ultraviolet autoflourescence photography) with incident myopia, they reported a lack of association between ocular sun exposure and refractive measure change. This may have been because, although participants were exposed to outdoor lighting, they were more likely than children to wear hats and sunglasses that filter damaging ultraviolet arrays.
Although myopia studies of children often find an association between education and myopia, in this study, the level of education was not linked with myopia development or progression. Calling out the need for further exploration, the authors suggested that other lifestyle habits, biological or hormonal factors may mediate the age and sex interaction effect during childhood. The authors also noted crystalline lens thickening and axial elongation over the eight year period. With axial length strongly believed to increase the risk of myopia-related complications including retinal detachment, this was described as concerning.
“Myopia management strategies targeting control of axial elongation should therefore be considered in young adults exhibiting myopia progression,” they wrote.
This study is significant because although there have been many published studies on the incidence of myopia in children, there has been little exploration of the incidence of adult-onset of myopia. Additionally, participants were from the general population, whereas other studies of young adults have involved university students in their late teens or early twenties.
You can listen to an interview with the study author, Dr Samantha Lee, at: podcasts.apple.com/us/podcast/jama-ophthalmology-authorinterviews/id1227002916.
Reference
Lee SSYL, Lingham G, Sanfilippo PG, Hammond CJ, Saw SM, Guggenheim JA, Yazar S, Mackey DA. Incidence and Progression of Myopia in Early Adulthood. JAMA Ophthalmology. DOI:10.1001/jamaophthalmol.2021.5067
