Visual Psychophysics / Physiological Optics - ARVO

ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group – Visual Psychophysics / Physiological OpticsErica L. Towle 1, 2 , Michelle T. Aaron 1 , Leon N. McLin 1 , Benjamin A.Rockwell 1 . 1 711 HPW/RHDO, Air Force Research Laboratory, FortSam Houston, TX; 2 Research Apprenticeship Program, NationalResearch Council, Washington, DC.Purpose: It has been hypothesized that slight heating (1 - 3°C) ofocular tissue with a near-infrared (NIR) laser could induce temporarychanges in visual function through an effect known as thermallensing. If these visual distortions could be safely induced andcontrolled, this technology would have potential as a new form ofdevice that can temporarily alter the visual field of the observer. Apreviously completed study concluded that it was possible to safelyand temporarily interrupt visual function using the thermal lensingeffect; however, little effort was made to measure the extent of theblurring in terms of changes to a subject’s visual acuity and contrastthreshold.Methods: Ten subjects were asked to identify the orientation of a50% contrast Landolt ring while being exposed to various lasersources co-aligned with the stimulus. Each exposure lasted 0.5seconds and was within the safety limits set by the AmericanConference of Government Industrial Hygienists. With eachexposure, the size of the target was increased (from 0 logMAR) untilthe subject was able to correctly identify the location direction of theLandolt ring. Once the target was correctly identified, the current andprevious acuity levels were repeated three times to refine thethreshold of acuity. This threshold under each laser condition (none,visible only, NIR only, combined visible and NIR) was then averagedacross three sessions (days) to account for any subject variability.Results: Results show that effects of a visible only exposuressignificantly alter the subject’s ability to see targets smaller than 0.25logMAR. NIR only exposures did not significantly change thesubject’s acuity. By combining two sources, the influence of the NIRon the visible obscuration was also observed to be negligible. Severalsubjects, however, were able to correctly identify when the NIR lightwas included in the exposure by a distinct “graying” or “loss ofcontrast” of the target.Conclusions: While the blurring effect of the thermal lens was notable to obscure the target on its own, evidence suggests that a distinctloss of contrast was induced during the experiments as a result of thethermal lens introduced in the eye. This loss of contrast has thepotential to reduce visual acuity of much finer targets (high resolutionGabors), and therefore, future experiments are planned to investigatethe change in an individual’s contrast acuity in the presence of athermal lens.Commercial Relationships: Erica L. Towle, None; Michelle T.Aaron, None; Leon N. McLin, None; Benjamin A. Rockwell, None136 IOL and Crystalline lensSunday, May 05, 2013 1:00 PM-2:45 PMExhibit Hall Poster SessionProgram #/Board # Range: 826-856/B0050-B0080Organizing Section: Visual Psychophysics / Physiological OpticsProgram Number: 826 Poster Board Number: B0050Presentation Time: 1:00 PM - 2:45 PMStraylight in Pseudophakes for Different Intraocular Lens TypesLuuk Franssen 1 , Marrie Van der Mooren 1 , Burkhard H. Dick 2 , UlrichMester 3 , Patricia A. Piers 1 . 1 R&D, AMO Groningen BV, Groningen,Netherlands; 2 Universitätsklinikum KnappschaftskrankenhausBochum, Bochum, Germany; 3 Augenzentrum im Medizeum,Saarbrücken, Germany.Purpose: To investigate the influence of intraocular lens (IOL)design and material on straylight in pseudophakes, and to investigatestraylight in cataract patients and pseudophakes at different scatterangles.Methods: Seventy-one eyes diagnosed for cataract were implantedwith either a monofocal (spherical acrylic (N=16), aspheric acrylic(N=17), aspheric silicone (N=13)) or multifocal (silicone diffractive(N=13), acrylic diffractive (N=12)) IOL. Intraocular straylight wasmeasured preoperatively and 1 week and 3 months postoperativelywith the C-Quant (Oculus), which measures at an average straylightangle of 7 degrees. In 29 eyes, straylight was also measured with anadapted C-Quant, which measures at an average angle of 3.5 degrees.Results: The average 3-month postoperative straylight values for the3 monofocal groups were not statistically significantly different(log(s) between 1.26 and 1.37 for 7 degrees, log(s) between 1.41 and1.45 for 3.5 degrees). For 7 degrees, the average value for themultifocal group (log(s)=1.32) was almost the same as for themonofocal group (log(s)=1.31). Also for 7 degrees, 80% of thepatients had a lower straylight value at 3 months postoperativelycompared to preoperatively. The 3.5 degree average results werehigher than the 7 degree results postoperatively (pseudophakes), butnot preoperatively (cataract patients).Conclusions: For the patients implanted with monofocal IOLs,design and material did not influence the average straylight valuepostoperatively. There was also no difference found between themultifocal and monofocal groups. Cataract patients tend to have adifferent angular straylight dependence than pseudophakes.Commercial Relationships: Luuk Franssen, AMO Groningen BV(E); Marrie Van der Mooren, AMO Groningen BV (E); BurkhardH. Dick, None; Ulrich Mester, None; Patricia A. Piers, AbbottMedical Optics (E)Program Number: 827 Poster Board Number: B0051Presentation Time: 1:00 PM - 2:45 PMBinocular through-focus image quality with variouscombinations of modified monovisionGuillaume Van Der Meer 1 , Pierre-Jean Pisella 1 , Richard Legras 2 .1 Univ Hospital of Tours, France, Tours, France; 2 CNRS, Orsay,France.Purpose: To evaluate the binocular through-focus (TF) subjectivevision with various combinations of modified monovision (iedifferent profile of spherical (SA4) and secondary spherical (SA6)aberration on each eye).Methods: We used a numerical eye model to calculate theappearance of an image (ie three 0.4 logMAR size high contrastletters) viewed thought an eye taking into account of the variation ofpupil size as a function of proximity (ie 4.7mm at distance vision to3.3mm at near vision). Images were calculated for variouscombinations of SA4 and SA6 (ie SA4-0.4μm, SA4+0.4μm, SA4-0.4μm and SA6+0.2μm, SA4+0.4μm and SA6-0.2μm) and for allproximities from -5-D to 5-D with a 0.125-D step. A 3D-NVIDIAvideo device was used to simulated binocular vision by projecting adifferent image on each eye with a 120Hz frequency. TF subjectivevision was evaluated by using a grading scale (ITU-R 500recommendation) by three subjects under monocular and binocularcondition for each tested conditions (ie various combination of thefive multifocal profiles).Results: Binocular TF curves followed the best monocular curve butthere was no binocular summation of quality of vision. Binocularinhibition was greater when the difference in subjective visionbetween each eye was important. Ocular dominance affected the levelof inhibition. We calculated area under the binocular curve (AUC) toevaluate subjective quality of vision and depth-of-focus. AUCincreased when adding spherical aberrations and can even bedoubled, compared to naked eye, with reverse profile of SA4 and©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.