Nearsightedness (myopia) causes blurry vision when looking at distant objects. Approximately 33% of the population in the United States is nearsighted, and some Asian countries report that up to 80% of children are nearsighted. Several studies have examined a variety of methods (including eye drops, incomplete correction (known as 'undercorrection') of nearsightedness, multifocal lenses and contact lenses) to slow the worsening of nearsightedness.
In this review we included 23 clinical investigations of myopia treatments in children. Two studies investigated undercorrection of myopia; twelve studies investigated multifocal spectacles (progressive addition lenses (PALs) or bifocal spectacles); one study investigated bifocal soft contact lenses (BSCLs); one study investigated novel lenses designed to reduce peripheral hyperopic defocus (peripheral vision farsightedness) (i.e. lenses that help to focus peripheral vision as well as central vision); two studies investigated rigid gas permeable contact lenses (RGPCLs); and six studies investigated pharmaceutical eye drops (five of these studies were of anti-muscarinic medications). There was one study that evaluated both multifocal lenses and pharmaceutical eye drops. In all studies the interventions of interest were compared with each other, single vision lenses (SVLs) (spectacles), single vision soft contact lenses (SVSCLs) or placebo. The follow-up period was at least one year for all studies.
The largest positive effects for slowing myopia progression were exhibited by anti-muscarinic medications (eye drops), but they either cause light sensitivity or blurred near vision, and are not yet available for use. Multifocal spectacles including PALs and bifocal spectacles were found to yield a small slowing of myopia progression. Undercorrection of myopia was found to increase myopia progression slightly, while RGPCLs were found to have no evidence of effect on myopic eye growth.