Visual Psychophysics / Physiological Optics - ARVO

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ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group – Visual Psychophysics / Physiological OpticsGeorge Beiko, AMO (C); Patricia A. Piers, Abbott Medical Optics(E)Program Number: 854 Poster Board Number: B0078Presentation Time: 1:00 PM - 2:45 PMEvaluation of the Impact of Scatter in Pseudophakic Eyes withGlisteningsAnand Doraiswamy 1 , Edward DeHoog 2 . 1 Research andDevelopment, Advanced Vision Science Inc, Santa Barbara, CA;2 Optical Engineering & Analysis LLC, Grants Pass, OR.Purpose: To evaluate the impact of light scatter from glistenings inpseudophakic eye modelsMethods: A pseudophakic eye model is constructed in ZEMAXusing established eye models. The lens is optimized for apolychromatic MTF for field angles 0, 1.4 and 2 Degreescorresponding with Foveal vision. The modeling and evaluation ofscatter and image resolution (MTF) are performed for variousmaterials (hydrophobic acrylic, PMMA) for various size and grades(density) of glistenings, all under scotopic and photopic conditions.Results: Results from the evaluation demonstrate that light scatterincreases and MTF decreases with increase in glistening density forboth materials. The difference in index of refraction between thecavitations filled with water and the IOL material causes the scatter.As predicted by Mie theory as the relative difference between thescatterer and media increases the amount of scatter will increase. Sizeof glistenings/cavitations also plays a crucial role in the extent oflight scatter and loss of MTF. 2 micron sized glistenings were foundto more significant than 200 micron sized glistenings in influencingresolution of image.Conclusions: Incorporation of scatter metrics into a model eyeallows us to learn more about the impact of various phenomena onquality of vision. Mathematical modeling demonstrated thatglistening can have a significant effect on scatter and resolution ofimage. Smaller cavitations and larger density have a morepronounced effect on the MTF than larger cavitations and smallerdensity. The effect is more pronounce in higher index materials withglistenings. Further evaluation will focus on the effect of surfacehaze, and more importantly the role of neuroadaptation that maydepress the predicted outcomes in-vivo.Purpose: The purpose of the study is to combine the straylight levelsof IOLs measured with a method for small and a method for largeforward scatter position angles. The straylight levels were determinedfor intraocular lenses (IOLs) with different designs and materials.Methods: IOLs were measured on two different lab-based set-ups: 1)for forward scatter positions between 0.6 and 2 degrees 2) forforward scatter positions up to 30 degrees. In both cases the IOL wasplaced in a saline filled cuvette on an optical bench set-up. A CCDcamera was used to measure the line spread functions from which theangular dependent straylight parameters were then calculated. Thestraylight measured using the two methods were then combined inorder to determine the magnitude over the entire angular range.Using this method IOLs made from 4 different materials (2hydrophobic and 2 hydrophilic acrylics) and 3 different designs(spherical monofocal, aspheric monofocal and diffractive multifocal)were measured and compared. Additionally, the measured straylightlevels were compared to the levels published for a 20 and 70 year oldhuman crystalline lens.Results: All monofocal IOLs with the same type of optical designshow comparable straylight parameters, both for small and largeforward scatter angles.At a forward scatter angle of 2° the average value for the straylightparameter of diffractive multifocal lenses is 4.5. For an angle of 7.5°the average value for the same type of lenses is 1.2.Irrespective of material or design, the amount of straylight is reducedfor larger forward scatter angles. All IOLs have a straylightparameter of approximately 1.0 for angles of 10° and larger. For anangle larger than 7.5° all IOLs have a straylight level below that of a20-year old human crystalline lens.Conclusions: Straylight parameter results from both set-ups can becombined to determine the straylight profile of an IOL over anangular range from 0.6 to 30 degrees. IOL design has more influenceon the height of the straylight parameter than the IOL material does.IOL straylight parameters get smaller as the measurement anglesincrease. The straylight parameter of all IOLs measured isindependent of design parameters for angles larger than 10°.Commercial Relationships: Michelle Langeslag, AMO GroningenB.V. (E); Marrie Van der Mooren, AMO Groningen BV (E);Patricia A. Piers, Abbott Medical Optics (E); Luuk Franssen,AMO Groningen BV (E)Commercial Relationships: Anand Doraiswamy, Advanced VisionScience Inc. (E); Edward DeHoog, Advanced Vision Science (C)Program Number: 855 Poster Board Number: B0079Presentation Time: 1:00 PM - 2:45 PMIn vitro straylight levels for IOLs across forward scatter positionsup to 30 degreesMichelle Langeslag, Marrie Van der Mooren, Patricia A. Piers, LuukFranssen. Research, AMO Groningen BV, Groningen, Netherlands.Program Number: 856 Poster Board Number: B0080Presentation Time: 1:00 PM - 2:45 PMOptical simulation for sub-surface nano glisteningYoriko Takahashi 1 , Takushi Kawamorita 2 , Norihiro Mita 1 , NatsukoHatsusaka 1 , Eri Shibuya 1 , Eri Kubo 1 , Hiroshi Sasaki 1 .1 ophthalmology, Kanazawa Medical University, Ishikawa, Japan;2 Orthoptics and Visual Science, University School of Allied HealthSciences, Sagamihara, Japan.Purpose: To investigate the effect of sub-surface nanoglistening(SSNG)in hydrophobic acrylic intraocular lens (IOL) onirradiance, forward light scattering and imaging characteristics ofretina by optical simulation.Methods: To simulate the effect of SSNG we used optical designsoftware LightTools and CODE V (Synopsis) to evaluate the peakvalue of irradiance on retina, forward light scattering, and themodulation transfer function (MTF) with Liou-Brenann model eye(JOSA, 1997). The physicality and shape of IOL was set as acrylicIOL (SN60AT, Alcon). Ong et al (JCRS, 2012) found in explantedacrylic IOLs with severe SSNG, particles of diameter 150 nm locatedup to 60μm from the surface of the anterior and posterior side of theIOL at a volume ratio of SSNG particle, which corresponds to thedensity, of 0.05%. In the present optical simulation, particle diameter©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.
ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group – Visual Psychophysics / Physiological Opticsand volume ratios were set at 100 nm, 150 nm and 200 nm and 0%,0.05%, 0.1%, 0.2%, 0.5%,1.0%, 2.0%, 5.0% and 10.0%.Results: Peak value irradiance reduced with increased volume ratioand particle size of SSNG. At volume ratio 0.05%, peak values ofirradiance for SSNG particle diameters 100nm, 150nm and 200nmreduced by 0.7%, 1.8% and 2.9%, respectively, compared with thoseat volume ratio 0% (no SSNG). At volume ratio 0.1%, peak values ofirradiance for SSNG particle diameters 100nm, 150nm and 200nmreduced by 1.5%, 3.6% and 5.7%, respectively. Forward lightscattering increased with increased size of SSNG particle and volumeratio. MTF did not change with increased size of SSNG particle andvolume ratio.Conclusions: Although SSNG in this condition setting slightlyincreased forward scattering and reduced irradiance, there was noeffect on the characteristics of retinal imaging. These results suggestthat the effect of SSNG on visual function is very slight in eyeswithout severe retinal diseases.Commercial Relationships: Yoriko Takahashi, None; TakushiKawamorita, None; Norihiro Mita, None; Natsuko Hatsusaka,None; Eri Shibuya, None; Eri Kubo, None; Hiroshi Sasaki, Nonepredicted vs. measured change of acuity did not differ significantlyfrom 1 (α=0.05) for 2 of the 3 metrics: logNS (p=0.28, Fig.2) andlogVSX (p=0.13, Fig.3).Conclusions: One can confidently use logNS or logVSX to designwavefront guided corrections that minimize the impact of registrationuncertainty on visual acuity.218 Aberrations, Image Quality and Visual PerformanceMonday, May 06, 2013 8:30 AM-10:15 AMTCC LL 4/5 Paper SessionProgram #/Board # Range: 1279-1285Organizing Section: Visual Psychophysics / Physiological OpticsProgram Number: 1279Presentation Time: 8:30 AM - 8:45 AMOptical quality metrics predictive of visual acuity for the designof wavefront guided corrections in the presence of dynamicregistration uncertaintyYue Shi, Raymond A. Applegate, Ayeswarya Ravikumar, Harold E.Bedell. College of Optometry, University of Houston, Houston, TX.Purpose: When building a wavefront guided contact lens correctionfor highly aberrated eyes we would like to achieve the best visualacuity given dynamic registration uncertainty. To optimize the designof such a lens correction, it is useful to have optical quality metricsthat are highly correlated with and predictive of visual acuity. Thepurpose here is to find optical quality metrics that are highlycorrelated with and predictive of acuity given the unusual aberrationstructures generated by misalignment of wavefront guidedcorrections.Methods: Residual aberrations were generated by allowing 4correction designs (3 wavefront guided and 1 sphero-cylinder foreach eye) to undergo horizontal, vertical and rotary motion withrespect to 3 keratoconic eyes (KC) for 2 pupil sizes (4 and 5mm).Then 77 aberrations were selected based on their log visual Strehlwith the expectation that they would induce up to at least 5 lines lossof acuity [JOV, 12:1-13, 2012]. The point spread functions of theselected aberrations were convolved with unaberrated logMARacuity charts to generate blurred charts, which were presentedmonocularly to 3 normal chart-readers with 20/15 best correctedacuity. For each chart, visual acuity was measured up to 5th lettermissed through a 3 mm pupil placed conjugate and centered with thechart-reader’s dilated pupil. The measured change of acuity withrespect to the unaberrated chart was regressed against the changes ofacuity predicted by 29 optical quality metrics [JOV, 12:1-13, 2012].Results: Regression analysis revealed that only 3 of the 29 metrics(Fig.1) predicted change of measured logMAR acuity with acoefficient of determination (R 2 ) of at least 0.9: logNS (R 2 =0.96),logVSX (R 2 =0.96), and logVSMTF (R 2 =0.90). The slopes ofFig. 1: R 2 values of 29 metrics in the regressions.Fig. 2&3: Regressions of measured and predicted change of acuity bylogNS or logVSX. 3 data symbols: aberrations generated in 3 KCeyes. Error bars: 1 standard deviaiton of measeured change of acuityby 3 chart-readers.©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.
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