![]() Dual focus (DF) lenses for myopia control in children are designed to introduce myopic defocus. Conversely, introduction of myopic defocus can slow eye growth and may counteract the grow signal from simultaneously present hyperopic defocus. Purpose: Hyperopic defocus can accelerate eye growth in young eyes. Title: Dual Focus Contact Lenses induce Myopic Defocus in Children during Near ViewingĪuthors: Dawn Meyer, Viswa Ramasubramanian, Nicola S Logan, Susie Jones, Matt Jaskulski, Martin Rickert, Arthur Bradley, Baskar Arumugam, Paul Chamberlain, Pete S Kollbaum The dual focus lens did not alter accommodative behaviour compared to single vision. This indicates that the +2D myopic defocus in the treatment zones successfully removed hyperopic defocus and introduced myopic defocus in the foveal image.This lead to an increase in myopic defocus from 18% to 40% The dual focus lens reduced the percentage of hyperopic defocus in the foveal region from 50% to 28% over these target distances. ![]() However, the +2D myopic defocus shifted the mean defocus in the treatment zone from hyperopia (+0.75D) to myopia (-1.00D) at near (50cm to 20cm) With dual focus contact lenses, children accommodated similarly in the pupil centre.During near viewing, children fit with single vision contact lenses accommodated to achieve approximate focus in the pupil centre but experienced up to 2D of hyperopic defocus in the pupil margin (due to increasing levels of negative spherical aberration and accommodative lag).A pyramidal aberrometer was used to obtain wavefront measurements along the visual axis while subjects accommodated bilaterally to high contrast letter stimuli (20/40 equivalent) at 6 target vergences (viewing distances from 4m to 20cm). Myopic children aged 14-18 years (n=17) who had completed 3 or 6 years of wearing a dual focus contact lens (MiSight 1 day) were fit bilaterally with a dual focus and a single vision contact lens. This abstract examined the optical impact of a dual focus contact lens during near viewing in a sample of children being treated with a dual focus lens. This has been postulated as a theory for the myopia control efficacy of contact lenses and glasses that use positive lenses to induce hyperopic defocus. It is well established that hyperopic defocus can act as a stimulus for eye growth in young eyes, while myopic defocus may generate signals to inhibit eye growth.
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