Orthokeratology for slowing myopic progression in a pair of identical twins

Ka Yin Chan, Sin Wan Cheung, Hie Hua Wong

Research output: Journal article publicationJournal articleAcademic researchpeer-review

17 Citations (Scopus)


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.
Original languageEnglish
Pages (from-to)116-119
Number of pages4
JournalContact Lens and Anterior Eye
Issue number2
Publication statusPublished - 1 Jan 2014


  • Axial length
  • Myopic control
  • Orthokeratology
  • Refractive errors
  • Twins

ASJC Scopus subject areas

  • Ophthalmology
  • Optometry


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