Retinal defocus in myopes wearing dual-focus zonal contact lenses

Purpose To evaluate the refractive impact of dual-focus (DF) myopia control contact lenses (CLs) on accommodating young myopic adults. Methods Phase 1: accommodative accuracy was assessed in 40 myopic participants. Phase 2: a subset of four subjects who demonstrated accurate accommodation and six who chronically underaccommodated were fitted with single vision (SV, Proclear 1 day) and centre-distance DF myopia control CLs (MiSight 1 day) with approximately +2.00 D of additional power in two surrounding annular zones. While binocularly viewing high contrast characters at 4.00, 1.00, 0.50, 0.33, 0.25 and 0.20 m, aberrometry data were captured across the central +/- 30 degrees of the horizontal retina. Local refractive errors were pooled for each area of the pupil covered by the central distance or first annular defocus zone of the DF CLs. Results In the good accommodator group fitted with SV CLs, accommodative lags were generally absent except at the closest viewing distance (mean errors: -0.09 +/- 0.22 D, -0.12 +/- 0.26 D, -0.05 +/- 0.37 D and +0.38 +/- 0.54 D for -2.00, -3.00, -4.00 and -5.00 D target vergences, respectively) but significantly larger in the poor accommodating participants (+0.81 +/- 0.21 D, +0.97 +/- 0.27 D, +1.18 +/- 0.39 D, +1.47 +/- 0.55 D). For most viewing distances, hyperopic defocus observed in the region of the pupil covered by the first annular zone was replaced with myopic defocus when fitted with the DF CLs. Myopic defocus created by the first annular region was present across the central 30 degrees of the retina. Conclusions Some young adult myopes chronically experience high levels of hyperopic defocus when viewing near targets, which was replaced by myopic defocus in the annular part of the pupil covered by the treatment zones when fitted with a centre-distance myopia control DF CL.

Automated summary

The study found that when using dual-focus myopia control contact lenses, some young myopic patients experienced high levels of hyperopic defocus when viewing near targets, which was replaced by myopic defocus in the annular part of the pupil covered by the treatment zones.