Visual Psychophysics / Physiological Optics - ARVO

ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group – Visual Psychophysics / Physiological Opticscases acceptable frames of even the large field size may be difficultto obtain.Commercial Relationships: Ting Luo, None; Gang Huang, None;Toco Y. Chui, None; Stephen A. Burns, None536 Inner Retina and Blood VesselsThursday, May 09, 2013 10:30 AM-12:15 PMExhibit Hall Poster SessionProgram #/Board # Range: 6054-6066/B0065-B0077Organizing Section: Visual Psychophysics / Physiological OpticsProgram Number: 6054 Poster Board Number: B0065Presentation Time: 10:30 AM - 12:15 PMFuture Insights on an Ocular Hypertension Model in the WhiteLeghorn ChickenJennifer L. Choi 1 , Radouil T. Tzekov 2, 3 , Stacey S. Choi 1 . 1 NewEngland College of Optometry, Boston, MA; 2 The RoskampInstitute, Sarasota, FL; 3 Department of Ophthalmology, University ofSouth Florida, Tampa, FL.Purpose: While White Leghorn chicken (Gallus gallus domesticus)have been used to study physiological optical properties of the eyeand conditions such as myopia, there is a lack of in vivo studies thatlook at the potential of chicken as a model of ocular hypertension orglaucoma. When advanced imaging techniques are to be used in suchmodels, chicken have an advantage over rodents, having bigger eyeswith less optical aberrations. The induction of elevated IOP inchicken via anterior chamber injections of microbeads has thus beeninvestigated.Methods: Animals of both genders and varying ages (n=15:12-124days old) were subject to one of 12 combinations of anterior chamberinjections of microbeads: magnetic (4.5 µm) or non-magnetic (12µm) in one or both eyes with saline as a control. Intraocular pressure(IOP) was monitored frequently before and after injections withTonopen. In 4 out of the 17 animals A-scan ultrasound was used tomeasure ocular parameters including anterior chamber depth (ACD),lens thickness (LT), vitreous chamber depth (VCD), retinal thickness(RT) and choroidal thickness (ChT) pre and post all injections. Allbirds had isofluorane anesthesia prior to injections and ultrasound.Results: Elevation of IOP with maintenance of a clear visual axiswas successful in 2 out of 17 animals after two 70µL injections ofmagnetic microbeads (concentration 20x10 8 beads/mL). Animal#1943 was injected with 140x10 6 beads at age 51 days and with thesame amount two weeks later; 5 days later IOP was elevated 5 mmHg greater than the fellow eye for a period of 7 days. Animal #1975received an injection of 140x10 6 beads at age 99 days and 160x10 6beads at age of 110 days and an average elevation of 8mm Hg greaterthan the fellow eye was noted from day 4 to day 7 post secondinjection. In other animals injection of 98x10 6 magnetic beads at day40 and again at day 51 blocked the visual axis. Non-magneticmicrobeads (125x10 8 to 875x10 8 beads) did not elevate the IOP. Oneto 3 saline injections did not influence the growth rate of ocularparameters measured via ultrasound biometry.Conclusions: The White Leghorn chicken has potential for in vivostudies of ocular hypertension and/or glaucoma via magneticmicrobead anterior chamber injections. Studying the effects ofelevated IOP on the chicken retina over a longer time period isindicated. SD-OCT and Adaptive Optics imaging may shed furtherinsights.Commercial Relationships: Jennifer L. Choi, None; Radouil T.Tzekov, None; Stacey S. Choi, NoneSupport: NIH Grant EY007149Program Number: 6055 Poster Board Number: B0066Presentation Time: 10:30 AM - 12:15 PMDetection of flow velocity fluctuations associated with erythrocyteaggregation in diabetic retinopathy by using adaptive opticsscanning laser ophthalmoscopyAkihito Uji, Masanori Hangai, Sotaro Ooto, Shigeta Arichika,Tomoaki Murakami, Nagahisa Yoshimura. Ophthalmology, KyotoUniv Graduate Sch of Med, Kyoto City, Japan.Purpose: Adaptive Optics Scanning Laser Ophthalmoscopy (AO-SLO) has enabled noninvasive and direct monitoring of erythrocyteaggregates in the retinal capillaries. In this study, we quantified theblood flow velocity in the parafoveal capillaries of patients withdiabetic retinopathy (DR) by using the AO-SLO system prototypedeveloped by Canon Inc.Methods: Ten patients (mean age ± standard deviation [SD], 45.8 ±16.7 years) diagnosed with DR at Kyoto University Hospital (8patients with mild nonproliferative DR [NPDR], 2 patients withmoderate NPDR) and 8 control subjects without any history of ocularor systemic diseases (mean age, 34.6 ± 8.6 years) were recruited forthis study. AO-SLO videos were acquired from the temporal andnasal areas located 0.5° from the foveal center. The scan area of theretina was 1.4 × 2.8°, and scans were recorded for 4 seconds per areaat a frame rate of 64 Hz. Erythrocyte aggregates were detected as“dark tails” that were darker than the vessel shadows, and thevelocities of all the dark tails observed in both temporal and nasalareas were measured. In subjects whose pulse was measuredsimultaneously during the AO-SLO video recording, a relativecardiac cycle was assigned to each dark tail velocity in order toinvestigate the effect of cardiac pulsation on the velocities.Results: Vessels showing rapid changes in dark tail flow velocitywere noted in 6 DR patients, but these vessels were not detected innormal subjects. In these vessels, dark tail flow velocity wasextremely low and deformation of the trajectory of the dark tail flowwas depicted in the spatiotemporal image. Two such vessels werefound in 3 patients and 1 vessel was found in each of the remaining 3patients. The average velocity change in these vessels was 0.95 ±0.53 mm/s. Pulse was measured in 6 DR patients and 8 normalsubjects, and 220 dark tails were analyzed in total. The velocity of thedark tail in DR patients (1.45 ± 0.52 mm/s) was significantly higherthan that in normal subjects (1.33 ± 0.40 mm/s) (P < 0.05).Conclusions: The velocity of the dark tail in NPDR patients washigher than that in normal subjects. However, at the same time, therewere some vessels with extremely slow dark tail flow.Spatiotemporal images were useful in detecting rapid changes in darktail flow.Commercial Relationships: Akihito Uji, None; Masanori Hangai,Topcon (F), Canon (F), Nidek (C), Topcon (C); Sotaro Ooto, None;Shigeta Arichika, None; Tomoaki Murakami, None; NagahisaYoshimura, Canon (C), Canon (F), Nidek (C), Topcon (F),PCT/JP2011/073160 (P)Support: Innovative Techno-Hub for Integrated Medical BioimagingProgram Number: 6056 Poster Board Number: B0067Presentation Time: 10:30 AM - 12:15 PMAdaptive contrast enhancement in capillary shadow region ofAOSLO images using blood cell flow informationHiroshi Imamura 1 , Takashi Yuasa 1 , Hiraku Sonobe 1 , Akihito Uji 2 ,Sotaro Ooto 2 , Masanori Hangai 2 , Nagahisa Yoshimura 2 . 1 Canon Inc,Ohta-ku, Japan; 2 Ophthalmology, Kyoto University Graduate Schoolof Medicine, Kyoto City, Japan.Purpose: To improve visibility of photoreceptors in capillary shadowregion of AOSLO images using characteristics of temporal intensity©2013, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. 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