Decreasing Peripheral Hyperopia With Distance-centre Relatively-plus Powered Periphery Contact Lenses Reduced The Rate Of Progress Of Myopia: A 5 Year Vision Crc Study

Abstract

Purpose: : To determine whether reducing peripheral hyperopic defocus using distance-centre relatively-plus peripheral power contact lenses slows the rate of progress of myopia.

Methods: : In Phase 1, 40 children aged 8 to 14 years with myopia -0.50 to -4.00 D and cylinder ≤0.75D were randomised to wear soft contact lenses that were either a Test Lens (TL) with relatively narrow central optical zone (2.3mm) with back vertex power to correct the child’s distance vision and a relatively plus (+1.50D) peripheral optical zone, or, a single vision Control Lens (CL) in the same material and monitored for 43±4 months. In Phase 2, the remaining subjects wore TLs in both eyes for a further 2 years. Refractive error (RE) (cycloplegic autorefraction) and axial length (AL) (partial coherence interferometry) were measured 6 monthly. Differences in progression of RE and AL were compared using quadratic fits of a linear mixed model after adjusting for age, gender and ethnicity based on an intent-to-treat principle. Progression within Phase 2 was analyzed using % change relative to Phase 2 baselines.

Results: : 40 children entered; 27, 20 and 16 completed 36±1 and 43±3 months (Phase 1) and 67 ± 3 months (after Phase 2) respectively. The changes in Phase 1 in RE with TCL v CCL were -0.37 ± 0.43D v -0.59 ± 0.32 D; -0.61 ± 0.30D v -0.99 ± 0.46; -0.80 ± 0.37D v -1.31± 0.60D and -0.99 ± 0.58D v -1.63 ± 0.66D at 12, 24, 36 and 43 months respectively. The changes in AL with TCL v CCL were 0.12 ± 0.12 mm v 0.21 ± 0.10mm; 0.22 ± 0.15mm v 0.39 ± 0.17mm; 0.29 ± 0.19mm v 0.53 ± 0.26mm and 0.41 ± 0.24mm v 0.67 ± 0.29mm at 12, 24, 36 and 43 months respectively. The slopes of change in RE and AL over 43 months were significantly less for TCL than CCL (p<0.0001). TCL also reduced LCVA by 0.12 Log MAR units (p=0.021). The slopes for the percent rate of progression for both Phase 1 groups refitted with TCL in Phase 2 were not different (p=0.211 for RE and p=0.796 for AL).

Conclusions: : The peripheral plus design lenses slowed rate of progress of myopia by 39% and axial elongation by 41% over 43 months. When both TL and CL groups from Phase 1 were fitted with TLs in Phase 2 they showed similar % rates of progression. The small sized optic related decrement in central vision with TCL can be avoided by increasing the central optic zone size (Holden et al 2010 ARVO abstract E 2220).

Clinical Trial: : http://www.anzctr.org.au ACTRN12611001148965

Keywords: contact lens • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • myopia