Visual Psychophysics / Physiological Optics - ARVO

ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group – Visual Psychophysics / Physiological Opticsoptical clarity of the +0.50D retinoscopic endpoint was alsocompared to an infinity endpoint using diverging light.Methods: A Copeland Optec 360 Streak Retinoscope (Fig. 1) wascalibrated for a 65cm retinoscopic working distance (RWD) andmarked for a +0.50D retinoscopic endpoint using +1.00D converginglight (CCR +050D ) and a infinity retinoscopic endpoint (∞) using -1.50D diverging light. Slide locks maintained the alignment of thecalibration line with the marked positions. The CCR +050D retinoscopictechnique uses the principles of conventional retinoscopy and doesn’trequire a fogging lens. With a phoropter, twenty-six normal andabnormal eyes of patients aged 11-77 with undilated pupils wereretinoscoped using the CCR +050D technique as they read the Snellenchart. The +0.50D endpoint was compared to the infinity endpoint byadding a +1.50D sphere and elevating the calibration line from the+0.50D position to the ∞ position with the thumb slide. A subjectiverefraction was performed and the results compared to the CCR +050Dmeasurements.Results: The mean differences and 95% confidence intervalsbetween the spherical equivalents (SE) and crossed cylinders (X/Cyl)of the CCR +050D endpoints and subjective refractions were: 0.03(-0.21to +0.21)D SE and 0.00(-0.21 to +0.21)D X/Cyl . The +0.50D pupillaryreflexes were brighter, sharper and easier to evaluate than the dullinfinity pupillary reflexes.Conclusions: The results indicate a high degree of accuracy for theCCR +050D technique in contrast to the accuracy/repeatability studiesof conventional retinoscopy. This is due to the calibrated visibleretinoscopic endpoint plus eliminating the fogging lens, the 0.50Dzone of doubt, the dull undetectable infinity endpoint, cycloplegicsand other disadvantages of conventional retinoscopy. Sinceretinoscopes are the only uncalibrated instruments used to measure arefractive error, they can produce different spherical measurementsand many cannot be calibrated. The clear CCR +050D endpoint shouldimprove the efficiency of the office and make retinoscopy easier toperform and teach.Ocular Refractive State In Fighting BullsJuan I Seva 1 , Manuel Sanes 1 , Francisco Martinez-Gomariz 1 , MatteoLo Sapio 2 , Juan M. Bueno 2 . 1 Facultad de Veterinaria, Universidad deMurcia, Murcia, Spain; 2 Laboratorio de Optica, Universidad deMurcia, Murcia, Spain.Purpose: Fighting bulls are bred free range on extensive farms undersimilar experimental conditions, well-defined manipulationprocedures and hardly human contact. Although they are geneticallyselected for a certain combination physical energy andaggressiveness, their behavior usually differs among animals duringbullfighting. It is believed that bulls present some lateral preferencesand sometimes they do not have a correct (near or far) vision. Weinvestigate whether differences in the ocular refractive state (RS)might be part of this lateralized visual processing.Methods: One-hundred and fifty eyes from 75 fighting bulls wereinvolved in the study. Animals were obtained from a localbullfighting arena. They were raised in different farms distributed allacross the country and ages ranged from 48 to 70 months. Enrolmentwas preceded by a veterinarian examination to rule out the presenceof any physical factor likely to interfere with the usual fighting. TheRS of each eye was assessed via streak retinoscopy with trial lensesin the horizontal meridian immediately after the regular bullfightingtook place. Before assessment we ensured the eyes kept their opticalproperties intact.Results: RS values varied between -1.25 and 2.5 D, with a mean of+0.65 D (SD=+/-0.80 D). Although both eyes were highly correlated(R=0.79), left eyes tend to be less ametropic. 8% of eyes (12/150)were myopic (refraction < -0.5 D). Anisometropia (difference in RSin a pair of eyes > 0.5 D) was detected in 35 animals (23%). RS wasnot correlated with either age or weight. No significant differences inRS among the animals coming from different farms were found.Conclusions: RS values of fighting bulls varied widely, althoughthey tend to be slightly hyperopic. This RS could explain theirbehavior when stimuli are presented at different locations, especiallyat short distances. Moreover, the existence of a certain degree ofanisometropy between pairs of eyes might be a factor contributing toa possible visual lateralization, and might help to understanddifferences in the behavior when the stimulus is presented in front ofan eye or the other.Commercial Relationships: Juan I Seva, None; Manuel Sanes,None; Francisco Martinez-Gomariz, None; Matteo Lo Sapio,None; Juan M. Bueno, NoneSupport: Ministerio de Edicación y Ciencia, Spain (grants FIS2009-06234-E)Fig. 1 Retinoscope calibrated for CCR +050D and infinity pupillaryreflexes and the RWD.Commercial Relationships: Clinton N. Sims, US 8,272,739 B2 (P),US 8,272,740 B2 (P)Program Number: 2343 Poster Board Number: B0302Presentation Time: 2:45 PM - 4:30 PM308 Binocular Vision and StereopsisTuesday, May 07, 2013 8:30 AM-10:15 AMTCC LL 4/5 Paper SessionProgram #/Board # Range: 2658-2664Organizing Section: Visual Psychophysics / Physiological OpticsProgram Number: 2658Presentation Time: 8:30 AM - 8:45 AMMechanisms underlying global stereopsis in fovea and peripheryRobert F. Hess, Nirel Witz. Ophthalmology, McGill University,Montreal, QC, Canada.Purpose: To better understand the mechanisms underlying globalstereopsis we examined the relationship between carrier luminancespatial frequency and modulator disparity spatial frequency.Methods: Thresholds for detecting global sinusoidal disparitycorrugations of equi-detectable spatially band-pass noise weremeasured as a function of modulator disparity spatial frequency for©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.