Effect of Dual-Focus Soft Contact Lens Wear on Axial Myopia Progression in Children
Nicola S. Anstice, BOptom, PhD; John R. Phillips, MCOptom, PhD
Department of Optometry and Vision Science, New Zealand National Eye Centre, The University of Auckland, New Zealand
Ophthalmology
Volume 118, Issue 6 , Pages 1152-1161, June 2011
In this study, dual focus lenses (center of the lens has the minus prescription surrounded by a concentric zone with a lowered prescription, in this case a reduction of 2 diopters), slowed the progression of myopia in comparison to the use of single vision lenses (lenses with only the full minus prescription).
From the abstract:
"Participants
"Participants
Forty children, 11–14 years old, with mean spherical equivalent refraction (SER) of −2.71±1.10 diopters (D).
Methods
Dual-Focus lenses had a central zone that corrected refractive error and concentric treatment zones that created 2.00 D of simultaneous myopic retinal defocus during distance and near viewing. Control was a single vision distance (SVD) lens with the same parameters but without treatment zones. Children wore a DF lens in 1 randomly assigned eye and an SVD lens in the fellow eye for 10 months (period 1). Lens assignment was then swapped between eyes, and lenses were worn for a further 10 months (period 2).
Main Outcome Measures
Primary outcome was change in SER measured by cycloplegic autorefraction over 10 months. Secondary outcome was a change in axial eye length (AXL) measured by partial coherence interferometry over 10 months. Accommodation wearing DF lenses was assessed using an open-field autorefractor.
Results
In period 1, the mean change in SER with DF lenses (−0.44±0.33 D) was less than with SVD lenses (−0.69±0.38 D; P < 0.001); mean increase in AXL was also less with DF lenses (0.11±0.09 mm) than with SVD lenses (0.22±0.10 mm; P < 0.001). In 70% of the children, myopia progression was reduced by 30% or more in the eye wearing the DF lens relative to that wearing the SVD lens. Similar reductions in myopia progression and axial eye elongation were also observed with DF lens wear during period 2. Visual acuity and contrast sensitivity with DF lenses were not significantly different than with SVD lenses. Accommodation to a target at 40 cm was driven through the central distance-correction zone of the DF lens.
Methods
Dual-Focus lenses had a central zone that corrected refractive error and concentric treatment zones that created 2.00 D of simultaneous myopic retinal defocus during distance and near viewing. Control was a single vision distance (SVD) lens with the same parameters but without treatment zones. Children wore a DF lens in 1 randomly assigned eye and an SVD lens in the fellow eye for 10 months (period 1). Lens assignment was then swapped between eyes, and lenses were worn for a further 10 months (period 2).
Main Outcome Measures
Primary outcome was change in SER measured by cycloplegic autorefraction over 10 months. Secondary outcome was a change in axial eye length (AXL) measured by partial coherence interferometry over 10 months. Accommodation wearing DF lenses was assessed using an open-field autorefractor.
Results
In period 1, the mean change in SER with DF lenses (−0.44±0.33 D) was less than with SVD lenses (−0.69±0.38 D; P < 0.001); mean increase in AXL was also less with DF lenses (0.11±0.09 mm) than with SVD lenses (0.22±0.10 mm; P < 0.001). In 70% of the children, myopia progression was reduced by 30% or more in the eye wearing the DF lens relative to that wearing the SVD lens. Similar reductions in myopia progression and axial eye elongation were also observed with DF lens wear during period 2. Visual acuity and contrast sensitivity with DF lenses were not significantly different than with SVD lenses. Accommodation to a target at 40 cm was driven through the central distance-correction zone of the DF lens.
Conclusions
Dual-Focus lenses provided normal acuity and contrast sensitivity and allowed accommodation to near targets. Myopia progression and eye elongation were reduced significantly in eyes wearing DF lenses. The data suggest that sustained myopic defocus, even when presented to the retina simultaneously with a clear image, can act to slow myopia progression without compromising visual function."
Link to the abstract:http://www.ophsource.org/periodicals/ophtha/article/S0161-6420(10)01154-1/abstract
Dual-Focus lenses provided normal acuity and contrast sensitivity and allowed accommodation to near targets. Myopia progression and eye elongation were reduced significantly in eyes wearing DF lenses. The data suggest that sustained myopic defocus, even when presented to the retina simultaneously with a clear image, can act to slow myopia progression without compromising visual function."
Link to the abstract:http://www.ophsource.org/periodicals/ophtha/article/S0161-6420(10)01154-1/abstract
