Orthokeratology for slowing myopic progression in a pair of identical twins

Purpose: To compare the axial length elongation and change in refractive errors in a pair of identical twins wearing orthokeratology (ortho-k) and single vision lenses (SVLs), respectively. Case report: Identical Twin A and B, who were 8 years of age, with the same amount of near activities, were assigned to wear ortho-k and SVLs randomly and they were monitored for two years for myopic progression. Twin A and B were assigned to wear ortho-k and SVLs, respectively. Myopic progression was evaluated by the change in axial length and in refractive errors. A faster axial length elongation was observed in each eye of Twin B during the two-year study period. The overall change in axial length was 0.52 mm (OD) and 0.70 (OS) in Twin A and 0.77 mm (OD) and 0.82 mm (OS) in Twin B. In terms of cycloplegic refractive errors (SER), one month after ceasing lens wear (after completion of the two-year study), the increase (from baseline) were 11% (OD) and 48% (OS) in Twin A and 87% (OD) and 67% (OS) in Twin B. Conclusions: Ortho-k is more effective in controlling myopic progression in terms of axial elongation than wearing SVLs in this pair of identical twins. (C) 2013 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.