Bifocal soft contact lenses as a possible myopia control treatment: a case report involving identical twins
Article first published online: 28 JUN 2008
© 2007 The Authors. Journal compilation © 2007 Optometrists Association Australia
Clinical and Experimental Optometry
Volume 91, Issue 4, pages 394–399, July 2008
How to Cite
Aller, T. A. and Wildsoet, C. (2008), Bifocal soft contact lenses as a possible myopia control treatment: a case report involving identical twins. Clinical and Experimental Optometry, 91: 394–399. doi: 10.1111/j.1444-0938.2007.00230.x
- Issue published online: 28 JUN 2008
- Article first published online: 28 JUN 2008
- Submitted: 2 April 2007Revised: 17 July 2007Accepted for publication: 24 July 2007
Vol. 91, Issue 5, 479, Article first published online: 10 AUG 2008
- children's vision;
- contact lenses;
Background: Several studies have suggested that bifocal and progressive spectacles can reduce progression of myopia in esophoric children. This study compared myopic progression with bifocal (BSCL) and single vision soft contact lenses (SVSCL) in identical twins with near point esophoria.
Methods: Two 12-year-old myopic girls were randomly assigned to wear either BSCL or SVSCL for one year using a double-masked design. Both twins then wore BSCLs for another year. Ocular measurements included cycloplegic and manifest refractions, corneal curvature and axial length. Distance and near phorias were measured through distance corrections and near associated phorias, with both types of contact lenses.
Results: Through their SVSCLs, both children exhibited near associated esophorias, which were neutralised by the BSCLs. The child wearing SVSCLs over the first year showed significant myopic progression, increasing -1.19 D (binocular average), while the child wearing BSCLs showed no progression (+0.13 D). The latter child showed limited progression (-0.28 D) over the second year, while switching from SVSCLs to BSCLs arrested progression in the other child (+0.44 D after one year). Axial length data were consistent with the refractive findings; the child exhibiting more myopia at the end of the first 12 months of the study had longer eyes (by 0.64 mm) than her sister, although their corneas also had steepened more (by 0.44 D compared to 0.18 D). The children showed similar, small increases in eye size over the second year when both wore BSCLs (binocular averages: 0.05, 0.09 mm, respectively).
Conclusion: The apparent inhibitory effect of BSCLs on myopic progression reported in this twin study argues for further study of their efficacy as a control treatment for myopes with near esophoria.