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Shrilekha Vedhakrishnan, Maria Vinas, Pilar Casado Moreno, Clara Benedi-Garcia, Carlos Dorronsoro, Susana Marcos; Vision with Multifocal contact lenses in Myopes and Presbyopes. Invest. Ophthalmol. Vis. Sci. 2020;61(7):551.
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© ARVO (1962-2015); The Authors (2016-present)
Multifocal contact lenses (MCLs), working under the principle of simultaneous vision are known solutions for Presbyopes, but they are also proposed to control the progression of Myopia. We evaluated visual performance with Center-Near design MCLs in Presbyopes and Myopes for different distances, viewing conditions and pupil diameters.
Measurements were performed in a group of 10 myopic subjects (MS, age: 24-27; SE: ±to-4.5D) and 5 presbyopes (PS, age: 47-58; SE:-2.75-+2.5D) on an Adaptive Optics system. All subjects were fitted with MCLs (three adds: LA: +1.25D; MA: +1.75D; HA: +2.5D), all with the same distance power (-2D). Residual defocus was corrected by a Badal System (BS). Decimal Visual Acuity (VA) was measured using an 8- Alternative Forced Choice procedure, tumbling E letter displayed on a CRT monitor (Visage, Cambridge research system), at different vergences (Far: 0D, Intermediate: +1.75D, Near: +2.50D). Measurements were performed both for paralyzed accommodation (PA, 5, 4 & 3 mm pupil), and natural accommodation (NA, natural pupil). Eye without the lens (NL) was measured as a control. The DOF was estimated as the dioptric range for which VA is 0.5 or better. The effect of the lens, addition, pupil diameter and accommodation was analyzed in the 2 study populations.
Under NA, VA with MCLs ranged from 1.13-1.07 (MS) and 0.95-0.8 (PS) for far, and 1.13-1.07 (MS) and 0.5-0.45 (PS) for near, decreasing by a factor of 1.18/1.09 (MS/PS) for the LA, 1.24/1.29 (MS/PS) for the MA and 1.22/1.21 (MS/PS) for the HA at far. Under PA, average VA values are 1.32 times lower than the NA values in MS and 1.05 times in PS for 5mm Pupil. The average RMS difference between the TFVA curves under NA and PA (7/5mm pupils) was 0.23/0.04 (MS/PS, NL), 0.21/0.03 (MS/PS, LA), 0.17/0.06 (MS/PS, MA), 0.13/0.03 (MS/PS, HA). DOF ranged from -3D/-2.5D (NL) to 1D/1D (HA) in YS (NA/PA) and from -2D/-1.5D (NL) to 1D/1D (HA) in PS (NA/PA).
MCLs decrease VA at far, both in young subjects and presbyopes, while increasing DOF(under paralyzed accommodation in both groups, and natural conditions in presbyopes). Both effects are proportional to the magnitude of the lens addition. In accommodating young subjects, MCLs do not seem to compromise on near acuity and they are maintained as the NoLens state.
This is a 2020 ARVO Annual Meeting abstract.
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