Visual Psychophysics / Physiological Optics - ARVO

ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group – Visual Psychophysics / Physiological Opticsdamage to cells; 2) optical microscopy of the scleral tissue, clearedwith a 40% glucose solution after laser irradiation; and 3) mechanicalinstrument probing to simulate the insertion of PSI implants.Results: Optical microscopy of cleared sclera showed explicitsubsurface disruption when irradiated with microjoule-energy pulsesat 1030nm wavelength. The efficacy of tissue separation wasdemonstrated by inserting a 1mm-wide blunt probe along tunnels of3-4mm length. Histological assessment continued to showimprovement in accuracy and consistency of the ablated tissue planeas the irradiation parameters were refined.Conclusions: Given the challenges that scleral tissue presents as anoptical medium, our preliminary parametric trials of scleralsubsurface femtosecond laser ablation on ex-vivo porcine areencouraging. These early results suggest that currently availablerefractive femtolaser platforms might be adapted for the creation ofPSI tunnels. In-vivo animal experiments are necessary to assess theclinical viability of the procedure.Commercial Relationships: Aghapi mordovanakis, Refocus Group(F); Larry Baitch, Refocus Group (E)Support: Support from Refocus Group (Dallas, TX)Program Number: 4279 Poster Board Number: B0316Presentation Time: 8:30 AM - 10:15 AMElectro-optic lens for correction of presbyopiaGuoqiang Li, Thomas F. Mauger. Depts of Ophthal and Vis Sci andECE, Ohio State University, Columbus, OH.Purpose: A large population on the planet needs correction of nearvision with aging. To overcome the disadvantages of the existingeyeglasses for correction of presbyopia based on area division, it isvery attractive to develop tunable electro-optic lens with highimaging quality and large aperture. In this technique, the power canbe continuously adjusted by a small voltage across the wholeaperture.Methods: By incorporating nanotechnology and cost-effectivemicrofabrication technology, we have designed and fabricatedtunable liquid crystal lenses with large aperture and large tunablerange needed for correction of presbyopia. To our knowledge, this isthe first demonstration of such a powerful device. The nanoparticlesdoped in the liquid crystals provide excellent alignment of the liquidcrystals and this property eliminates the alignment layer on thesurface of the microsturctured element.Results: We have designed and fabricated a tunable liquid crystallens with large aperture (over 20 mm), large tunable range (over 3diopters) and low driving voltage. The lens shows high opticalquality. These lenses have been used to build the prototypes ofadaptive spectacles and visual simulator. Vision test results will beshown.Conclusions: The electro-optic tunable lenses with large aperture andlarge tunable range are promising for vision correction and visionassessment.Model eye imaging. Left, adaptive lens off; right, adaptive lens on.Commercial Relationships: Guoqiang Li, The Ohio StateUniversity (E); Thomas F. Mauger, NoneSupport: NIH/NEI grant R01 EY020641Program Number: 4280 Poster Board Number: B0317Presentation Time: 8:30 AM - 10:15 AMTolerance to astigmatism with a small aperture corneal inlayAbhiram S. Vilupuru 1 , Juan Tabernero 2 , Pablo Artal 2 . 1 R&D,AcuFocus, Inc, Irvine, CA; 2 Universidad de Murcia, Murcia, Spain.Purpose: Small aperture corneal inlays are used to extend depth offocus in presbyopic patients. Visual outcomes depend on residualrefractive error. While the impact of defocus was already studied(Tabernero & Artal, JCRS, 2011), we expanded their study toinvestigate how much uncorrected astigmatism can be tolerated witha small aperture corneal inlay.Methods: We developed 20 computational eye models using datafrom corneal topography, ocular axial lengths and wavefrontaberrations taken in 20 healthy presbyopic subjects (mean age 59years, standard deviation 7 years). The axial length was adjusted torender all eyes to be at best focus (emmetropia). A small aperture of1.6 mm of diameter was placed at the corneal plane. The pupil of theeye was set to 3 mm of diameter. Astigmatism was induced in stepsof 0.25 D (axis 90°) by placing a cylindrical lens at 15 mm from thecorneal axis and then the eye’s modulation transfer function (formonochromatic light of 550 nm) was obtained for every eye from 0 Dup to 3 D of induced astigmatism. The spatial frequency thatcorresponded to a modulation value of 0.2 (along the orthogonaldirection to the axis of the astigmatism) was used as an image qualitymetric and calculated in every eye with and without the smallaperture.Results: With the small aperture implanted in the cornea, the cut-offfrequencies increased significantly for all values of inducedastigmatism. On average for the 20 eyes, if 1 D of astigmatismremained uncorrected for a pupil diameter of 3 mm (whichcorresponds to a 0.2 cut-off frequency of 0.22 decimal visual acuityunits) then the equivalent value with the small aperture inlayimplanted is obtained at 1.9 D (i.e. an increasing of 0.9 D of toleranceto astigmatism). For a different uncorrected threshold value ofastigmatism, for instance to 0.5 D, then the tolerance with the smallaperture would double up to 1 D. Since the inlay is actually anannulus (external diameter of 3.8 mm), this tolerance would be lowerin those subjects with pupil diameters significantly larger than 4 mm.Conclusions: The retinal image quality in eyes implanted with asmall aperture corneal inlay to extend depth of focus is affected bythe remaining uncorrected astigmatism. Although there is anindividual variability due to the particular eye’s aberrations, thepresence of the small aperture approximately doubles the typicaltolerance to astigmatism.Commercial Relationships: Abhiram S. Vilupuru, AcuFocus (E);Juan Tabernero, None; Pablo Artal, AMO (C), Voptica SL (P),Voptica SL (I), AMO (F), Calhoun Vision (F), Calhoun Vision (C),AcuFocus (C)Support: FIS2010-14926 CSD2007-00013 4524/GERM/06Program Number: 4281 Poster Board Number: B0318Presentation Time: 8:30 AM - 10:15 AMDistribution of Achromatizing Pupil Positions and First PurkinjeReflections in a Normal PopulationSilvestre Manzanera 1 , Juan Tabernero 1 , Antonio Benito 1 , Abhiram S.Vilupuru 2 , Pedro M. Prieto 1 , Pablo Artal 1 . 1 Laboratorio de Optica,University of Murcia, Murcia, Spain; 2 R&D, AcuFocus, Irvine, CA.©2013, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permissionto reproduce any abstract, contact the ARVO Office at arvo@arvo.org.