Genetic information alone may one day be enough to determine the risk of myopia in children aged zero to six, according to researchers who say this would obviate the need for cycloplegic autorefraction. However, the accuracy of polygenic risk scores (PRSs) is not yet good enough to warrant their use in clinical practice.
Neema Ghorbani Mojarrad and colleagues at the University of Bradford in Bradford, UK set out to examine whether genetic information alone can identify children at risk of myopia development and whether including a child’s genetic predisposition to educational attainment is associated with improved genetic prediction of the risk of myopia.
Currently, the best predictor of risk of myopia is believed to be a low hyperopic refractive error at an age before myopia typically manifests. This is measured using cycloplegic autorefraction screening using eye drops to temporarily paralyse the muscles that help focus the eye. The approach is resource and time expensive. Additionally, Mr Mojarrad wrote, “As the transition from moderate to low hyperopia may be part of the process of myopia development, cycloplegic autorefraction screening may detect children too late if the aim is to instigate a prophylactic intervention”.
The researchers followed an established, effective four step process to develop their PRSs, and having done so, concluded that it would be possible to categorise a sample of children into three groups: a group at low risk of myopia and high myopia development); a high-risk group, who are at three-fold to five-fold increased risk; and a very high-risk who are at five-fold to six-fold increased risk.
a personalised medicine approach to detecting children at risk of myopia is now feasible, although currently the accuracy of PRSs is not yet good enough
They wrote, “The latter two groups may benefit most from an intervention to reduce the incidence of myopia, such as time outdoors, or to reduce the rate of myopia progression, such as orthokeratologic or atropine treatment… However, as no prophylactic treatment intervention is currently available for preventing incident myopia (other than the advice for children to spend more time outdoors), this advantage is currently likely to be of academic interest rather than sufficient to recommend any change in clinical practice.”
“Sensitivity and specificity did not reach the levels obtainable using cycloplegic autorefraction (AUC = 0.67 vs 0.87); however, genetic prediction offers the advantages of not requiring the use of eye drops and specialist clinical assessment and could be used to detect children who would benefit from interventions to prevent incident myopia (eg, more time outdoors) as well as to slow myopia progression. Incorporating genetic information capturing aspects of future educational attainment was found to be associated with improved accuracy of the PRS in predicting myopia, although the gain was modest. This work suggests that a personalised medicine approach to detecting children at risk of myopia is now feasible, although currently the accuracy of PRSs is not yet good enough to warrant their use in clinical practice.”
The findings were published in JAMA Ophthalmology (2020; 138Ci):7-13).
