Visual Psychophysics / Physiological Optics - ARVO

ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group – Visual Psychophysics / Physiological Opticsproposed, the current designs only provide a modest range ofaccommodation in the best-case scenario. We describe here a newoptical design providing a wide-range of potential accommodationchange that could be incorporated in an IOL.Methods: The mechanical properties of the capsule and the zonulaare known to solely slightly change as the eye ages. The ciliarymuscle essentially maintains its function during the life span.Consequently, there is a possibility to use the accommodationapparatus to eventually transmit the subtle mechanical changes intoan IOL able for modulating its optical power. A family of opticaldesigns with a variable power, sensitive to small compression forceshas been devised. If incorporated within an IOL, power would changein response to small variations in their equatorial diameter. Regularmaterials available for standard IOL have been employed, as acrylicsand silicones.Results: The proposed design is a triplet-like optical structure thatproduces unprecedented gains between the equatorial compressionand the subsequent change in lens power. Some of the generated IOLmodels exhibit an increase in their power of up to 10 D onceimplanted in the eye. The gain is approximately 1 D/µm of equatorialcompression. The proposed IOL also permits the incorporation ofaspheric or toric surfaces for optimizing ocular spherical aberrationor correcting astigmatism. Chromatic aberration and ghost imagesanalysis have been also accomplished showing a similar performanceto monofocal standard IOLs currently available. The typical centralthickness of the triplet is 1 mm, showing an optical zone of 6 mm ofdiameter. These dimensions and the structure of the proposed hapticsmight allow the implantation of the IOL through a corneal incision of2-3 mm of diameter. The accurate control of the equatorial diameterof the accommodative IOL and its changes during accommodativeefforts can be solved by using a special intracapsular ring. Thedistribution of radial forces of the implanted IOL combined with thering showed an efficient mechanism to transmit the changes from theciliary muscle to the lens.Conclusions: A new triplet-type optical design in combination with acapsular ring for the precise control of its equatorial diameter mayhave the potential to restore accommodation after cataract surgery.Commercial Relationships: Enrique-Josua Fernandez, EP-101193(P), VOPTICA SL (P), VOPTICA SL (P), VOPTICAL SL (I),VOPTICAL SL (I); Pablo Artal, AMO (C), Voptica SL (P), VopticaSL (I), AMO (F), Calhoun Vision (F), Calhoun Vision (C), AcuFocus(C)Support: Ministerio de Ciencia e Innovación, Spain (grantsFIS2010-14926 and CSD2007-00013) and Fundación Séneca(Region de Murcia, Spain), grant 4524/GERM/06Program Number: 839 Poster Board Number: B0063Presentation Time: 1:00 PM - 2:45 PMOptical Ensemble Analysis of the Potential Optical Performanceof Aspheric Multifocal Toric IOLsHuawei Zhao. R & D, Abbott Medical Optics, Santa Ana, CA.Purpose: Contrast transfer is an important link betweenpseudophakic visual performance and intraocular lens (IOL) opticalperformance. This study uses previously validated optical ensembleanalysis (OEA, Zhao, Optics Letters) to compute pseudophakicoptical performance for acrylic aspheric IOLs with diffractivemultifocal anterior or posterior and toric on the accordingly oppositesurfaces.Methods: OEA is a Monte Carlo simulation using ZEMAX(ZEMAX Corporation, Bellevue, WA, USA) and a clinically-orientedeye model. MTF values are computed with different astigmatism,asphericity, pupil size, and IOL decentration, tilt and astigmaticorientation error. 600 eyes were simulated for two groups of asphericmultifocal toric IOLs: Group1 [aspheric-toric anterior and 4D-adddiffractive multifocal posterior surface; low refractive index (1.47)and chromatic dispersion (Abbe# = 55); full aspheric correction] andGroup 2 [aspheric apodized diffractive 3D-add anterior and toricposterior surface; high refractive index (1.55) and chromaticdispersion (Abbe# = 37); partial aspheric correction]. Three cylinderpowers were studied for each group (1.5, 2.25 and 3.0 D).Results: Ocular parameters in Groups1 and 2 agreed well withpublished clinical data and there were no statistically significantdifferences between groups (p>0.05). Ocular spherical aberration forGroup1 was statistically significantly lower than Group2.Pseudophakic optical performance declined consistently withincreasing astigmatic power in each of the two groups. Both IOLssignificantly reduced the ocular astigmatism (p0.05) and MTFs of far vision (p>0.05). MTFs of nearvision for Group1 were statistically significantly better than Group2(p