Visual Psychophysics / Physiological Optics - ARVO

ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group – Visual Psychophysics / Physiological Opticsinterfere with text preview and navigating to the next line. Mobilitydifficulty is associated with scotomas that could interfere withidentifying information below the line of sight.Commercial Relationships: Nicole C. Ross, None; Judith E.Goldstein, None; Robert W. Massof, NoneSupport: NEI grant EY012045 and MD 22 Lions Vision ResearchFoundation Postdoctoral Fellowship288 Refractive Errors, Myopia IMonday, May 06, 2013 2:45 PM-4:30 PMExhibit Hall Poster SessionProgram #/Board # Range: 2327-2343/B0286-B0302Organizing Section: Visual Psychophysics / Physiological OpticsProgram Number: 2327 Poster Board Number: B0286Presentation Time: 2:45 PM - 4:30 PMDaily interruptions to hyperopic defocus can reduce induced eyegrowth in marmosetsAlexandra Benavente-Perez, Ann Nour, Luying Yan, Keisha Roden,Kathleen Abarr, David Troilo. Biological Sciences, SUNY Collegeof Optometry, New York, NY.Purpose: To assess the effect that short daily interruptions toimposed hyperopic defocus have on the eye growth of marmosets,and to measure the effective refractive state during the interruptionperiod.Methods: A total of 20 marmosets were treated with -5D contactlenses on their right eyes for 12 weeks from the age of 10 weeks ofage (left eyes wore plano controls). On-axis vitreous chamber depth(VC) was measured after four (T4), eight (T8) and twelve weeks oftreatment (T12). Fifteen marmosets wore contact lenses continuouslyfor 9hrs/day and five had both contact lenses removed for 30minstwice/day (mid morning and mid afternoon) during the first four andlast four weeks of treatment. Vision during the interruptions wascontrolled by placing the marmoset in a primate chair at the center ofa 1m radius cylinder with videos of animal scenes projected on thewall. Noncyloplegic Rx was measured at 5min intervals using aninfrared video photorefractor (Power Refractor, MultiChannelSystem) while the marmosets were in the chair. Untreated marmosets(N=25) were used as controls.Results: At T4 the interocular difference in ocular growth rates in theinterrupted lens-reared group was smaller than in the continuous lensreared group (mean±SE exp-con: -0.3±1.3 vs +3.6±1.0 µm/day,p0.05).While inside the cylinder, the marmosets experienced an overallrelative myopic defocus of -2.07±0.63D during T4 that increased to -4.08±1.63 D during T12.Conclusions: Daily brief interruptions to imposed hyperopic defocusprevent the increased rate of ocular growth triggered by -5D contactlenses in marmosets. The effects were stronger when the interruptionshappened early during treatment than when the interruptions wereapplied to eyes that were already growing faster to compensate forimposed hyperopia.Commercial Relationships: Alexandra Benavente-Perez, None;Ann Nour, None; Luying Yan, None; Keisha Roden, None;Kathleen Abarr, None; David Troilo, NoneSupport: NIH R01 EY11228Program Number: 2328 Poster Board Number: B0287Presentation Time: 2:45 PM - 4:30 PMLuminance and Color Changes with Defocus Provide DifferentialCues For EmmetropizationMolly Fellows 1 , Gagan Kaur 2 , Ashley Tang 1 , Frances J. Rucker 1 .1 Biomedical Science & Disease, New England College of Optometry,Boston, MA; 2 Southern California College of Optometry, Fullerton,CA.Purpose: Factors that interfere with lens compensation areconsidered to interfere with emmetropization. We examine the effectsof color and luminance changes on lens compensation.Methods: Exp. 1: 5-7 day old chicks were exposed daily (9am-5pm)for three days, on consecutive weeks, to 2Hz sinusoidal, in-phase(LUM), modulated white light (619 nm + 515 nm + 460 nm; Mean680 lux) or to counterphase-modulated red/green light (R/G). Chickswore either a negative or a positive 7 D lens on alternate weeks.Exp. 2: 14 day old chicks were exposed daily (9am-5pm) for threedays to 2Hz sinusoidal, in-phase, modulated white light (619 nm +515 nm + 460 nm; Mean 850 lux) either with (+B) or without bluelight (-B). Chicks wore either a negative or positive 7 D lens on oneeye. Chicks wore no lenses in a control, no flicker condition.Chicks were kept in the dark overnight after exposures and otherwisein a brooder on a 12/12 hr light cycle between experiments. Relativechanges in the ocular components were measured with ultrasound(Exp.1) or with Lenstar (Exp. 2) and with a Hartinger refractometer.Results: Exp. 1: LUM flicker, but not R/G flicker, interfered withpositive lens compensation. There was a change in refraction in R/G(wk1: 4.93 ± 2.116 D; p=0.02) but not in LUM (wk1: 2.43 ± 2.68 D),despite a reduction in eye growth in all conditions (R/G: -196 ± 30μm; LUM: - 139 ± 24 μm; p