Myopia study confirms US is also on the slippery slope

The recent release of findings from a study that was launched in 2003 and whose clinical assessments ended in 2011, confirms that the so-called ‘myopia epidic’ is not an Asia/Asian probl as some thought, rather it is a world probl and the United States is not expt, albeit occupying a trailing position relative to the prevalence in Asia, especially East Asia.
The Multi-Ethnic Pediatric Eye Disease Study (MEPEDS) originated from the Pediatric Eye Disease Study Group at the Doheny Eye Institute and the Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles (USC[LA]) and was the subject after launch of a descriptive paper in Ophthalmic Epidiology in 2006 (Varma et al., 2006).
The project cost almost US$1.2 million which was funded by a National Institutes of Health grant. A mber of that study group who would be familiar to many Australian conference goers is Prof Susan Cotter who is now a staff mber of the Marshall B. Ketchum University’s Southern California College of Optometry (formerly SCCO). In 2014, the Doheny Eye Institute separated from USC(LA) and realigned itself with the UC(LA) instead. MEPEDS’ hosting institute is now the USC Eye Institute in Los Angeles.
The objectives of the study were to:
– Estimate age and ethnicity-specific prevalence of strabismus, amblyopia, and refractive error;
– Evaluate the association of selected risk factors with those ocular disorders; and
– Evaluate the association of ocular conditions on limitations in health-related functional status in a population-based sample of 12,000 children aged 6-72 months from four ethnic groups: African-American, Asian-American, Hispanics/Latinos, and non-Hispanic White.
Each eligible child underwent a free eye examination along with an interview with their parent(s) often at their home. That interview included an assessment of dographic, behavioural, biological, and ocular risk factors as well as the health-related functional status of the child.
The ophthalmic assessment included: fixation preference testing, VA, stereoacuity, axial length measurent, a cycloplegic refraction, keratometry, eye alignment, and an examination of both anterior and posterior segments.
In a news release from USC dated 22 January 2016, the study findings were highlighted. Childhood myopia incidence was increasing at an “alarming pace” (their description) confirming a global trend.
The release claimed that MEPEDS was the largest study of childhood eye disease ever undertaken in the US and it confirmed that myopia among American children has more than doubled in the last 50 years.
It admitted that its findings echoed those anating from Asia where up to 90% or more of children now have some degree of myopia diagnosed whereas 60 years ago that figure was more like 10-20%. The incidence of myopia was greatest (in order) in: African Americans, Asian-Americans, Hispanic/Latinos, and non-Hispanic whites.
In a telephone interview played on EyeWire TV (10 February 2016 – www.eyewiretoday.com/tv/), lead author, project and USCEI director, Prof Rohit Varma, stated that, apart from genetic influences, certain environmental and behavioural influences were involved.
Specifically, he nominated the amount of outdoor activity/exposure to daylight and the amount of near work, especially involving the use of screen devices by the very young, as causes for concern (or simply, too much screen time and not enough sunlight – see the USC news release).
Those claims mirror the findings of many similar studies carried out in various parts of the world. He raised the possibility of re-examining the same cohort of children (MEPEDS) at some time in the future to monitor progress and the effect, if any, of interventions that might be applied as a result of the study’s findings.
To date, some 20 acadic papers on all aspects of the study have been published. It is possible that confirming the US myopia probl so convincingly, may have some beneficial flow-on effects on the number and ambition of studies of the probl carried out in the US and elsewhere. Any such increase can only enhance human knowledge of the topic and improve the likelihood of finding a universal solution to it, if one exists.