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Brien A. Holden, Padmaja Sankaridurg, Percy Lazon, Arthur Ho, Earl L. Smith, III, Xiang Chen, Julia Lin, Thomas Naduvilath, Jian Ge; Central And Peripheral Visual Performance Of A Novel Contact Lens Designed To Control Progression Of Myopia. Invest. Ophthalmol. Vis. Sci. 2011;52(14):6518.
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We previously reported that a novel silicone hydrogel contact lens (CL) with a central aperture that corrects for foveal refractive error and a peripheral zone designed to reduce peripheral hyperopic defocus was able to slow the progression of myopia compared to spectacle wear. This study determined the central and peripheral visual performance of the novel CL compared to standard single vision CL (SVCL).
Central visual performance was assessed in a prospective clinical trial where 60 Chinese children (age 8-14 yrs; spherical equivalent ≤ -3.50D; cylinder < -0.75D) each wore either a novel CL or a SVCL. Peripheral visual performance was measured in another trial involving 20 children and adolescents with myopia -0.50 to -4.50D, cylinder <1.00D. At baseline, 6 & 12 months, central high and low contrast visual acuity (VA) was measured using LogMAR charts and contrast sensitivity (CS) with a FACTS chart. Peripheral VA & CS was measured at 30° nasal & temporal eccentricity at a single visit with VA measured using an electronic screen (Landolt’s C targets, LogMAR scale). Peripheral CS was measured by presenting either an annular sinusoidal grating at 2 cycles/° or a luminance-equivalent gray screen over two consecutive displays in a 4-alternative forced-choice task using a 3-down-1-up staircase technique. Differences between groups were analysed using linear mixed model and paired t-tests.
At all visits, there were no differences for high and low contrast VA and central CS between groups (p>0.05). A significant improvement was observed for peripheral VA at both 30° nasal & temporal eccentricity (mean difference: 0.33 and 0.30 respectively; equivalent to 3 line improvement, p<0.01). Additionally, CS improved at 30° temporal eccentricity (mean difference 0.31, p=0.008)
Centrally the visual performance of the novel CL was comparable to SVCL but peripheral VA & CS were improved. The improvement in peripheral vision is most likely due to a reduction in peripheral defocus. Such lenses clearly have the capability of correcting central vision without blur, slowing the progress of myopia due to reduction in peripheral hyperopia and enhancing peripheral vision - a relatively unique and beneficial combination of effects.
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