Visual Psychophysics / Physiological Optics - ARVO

ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group – Visual Psychophysics / Physiological OpticsCommercial Relationships: Grace K. Han, Canon Inc. (F), OptosPLC (F); Jan Kristine T. Bayabo, None; Brandon J. Lujan,Genentech (C), Genentech (R), Genentech (F), Carl Zeiss Meditec,Inc (C), Avalanche Biotech (C), Regeneron (R), UC Berkeley (P);Jessica I. Morgan, Canon (F), Optos (F)Support: Earl and Brenda Shapiro Leber's Congenital AmaurosisResearch Initiative, Foundation Fighting Blindness, NIH K12EY017269, NIH EY019861, F.M. Kirby Foundation, Research toPrevent Blindness, Mackall Trust, Canon Inc.Berkeley (P); Shiri Zayit-Soudry, None; Reema Syed, None;Travis Porco, NIH NEI (F); Jan Kristine T. Bayabo, None; JosephCarroll, Imagine Eyes, Inc. (S); Austin Roorda, US Patent#6890076 (P), US Patent #7118216 (P), UC Berkeley (P); Jacque L.Duncan, NoneSupport: Foundation Fighting Blindness, Research to PreventBlindess, That Man May See, NEI Core Grant EY002162, NIH K12EY017269Clinical Trial: NCT00254605Program Number: 3436 Poster Board Number: C0157Presentation Time: 11:00 AM - 12:45 PMCorrelation of outer nuclear layer thickness with cone densityvalues in patients with retinitis pigmentosa and healthy subjectsMoreno Menghini 1 , Brandon J. Lujan 2 , Shiri Zayit-Soudry 1 , ReemaSyed 1 , Travis Porco 1 , Jan Kristine T. Bayabo 2 , Joseph Carroll 3 ,Austin Roorda 2 , Jacque L. Duncan 1 . 1 Ophthalmology, University ofCalifornia San Francisco, San Francisco, CA; 2 School of Optometry,University of California Berkeley, Berkeley, CA; 3 Ophthalmology,Medical College of Wisconsin, Milwaukee, MI.Purpose: Outer nuclear layer thickness (ONL) has been widely usedas a marker for photoreceptor numbers. However, some studies havenot shown a consistent correlation between ONL thickness and conedensity. Variability in ONL thickness measurements may beattributed to the inclusion of Henle’s fiber layer (HFL) when usingstandard optical coherence tomography (OCT) imaging techniques.The aim of our study is to compare ONL thickness using directionalOCT (D-OCT) with cone density values at identical retinal locationsin normals and retinitis pigmentosa (RP) patients.Methods: Cross-sectional analysis of images acquired with D-OCTand adaptive optics scanning laser ophthalmoscopy (AOSLO) fromnormals and RP patients. The D-OCT data sets were obtained using apreviously described method of varying the pupil entry position ofthe beam to reveal the HFL. Five retinal layers (ILM, OPL/HFLjunction, HFL/ONL junction, ELM and outer RPE border) weresegmented using Image J and MatLab® software. Multiple locationsalong the central horizontal meridian were selected on the AOSLOimages and compared with ONL thicknesses at identicaleccentricities. Cone density was analyzed in areas where conemosaics could unambiguously be identified and expressed ascones/degree2.Results: Mean age in our population was 40.5 in patients and 42.0years in normals. Average central retinal thickness was 240±25.0umand 234±12.8um, with an average ONL thickness at 1° eccentricity of47.2±8.8um and 46.0±3.7um in patients and in normals. Mean ONLthickness at 2° eccentricity was also comparable with 33.7±6.7um inRP patients and 33.7±7.1um in normals. Average cone densitiesmeasured at 1° eccentricity were 3718±1287 and 4313±541 forpatients and normals, respectively. At more eccentric locations (2°eccentricity) the values were 2646±531 and 2646±245. Combiningthe normal and patient images, ONL thickness was significantlycorrelated with cone density (Pearson’s correlation coefficient 0.74,95% CI 0.67, 0.82). The correlation between ONL+HFL values andcone density on the other hand was weaker (coefficient 0.59, 95% CI0.46, 0.78).Conclusions: ONL thickness measures correlated with cone densitymeasures in normals and RP patients, as measured using D-OCT.ONL thickness could be an easily obtainable indirect parameter torepresent cone density values both in diseased and healthyindividuals.Commercial Relationships: Moreno Menghini, None; Brandon J.Lujan, Genentech (C), Genentech (R), Genentech (F), Carl ZeissMeditec, Inc (C), Avalanche Biotech (C), Regeneron (R), UCProgram Number: 3437 Poster Board Number: C0158Presentation Time: 11:00 AM - 12:45 PMRepeatability of Cone Density Measurements in Healthy SubjectsUsing Commercially Available Flood-Illuminated AdaptiveOpticsShu Feng, Anupam K. Garg, Ambar Faridi, Jonathan D. Fay, HopeE. Titus, Travis B. Smith, Keith V. Michaels, Mark E. Pennesi. CaseyEye Institute, Oregon Health & Sciences University, Portland, OR.Purpose: To evaluate a commercially available flood-illuminatedadaptive optics camera for its repeatability in measuring the conemosaic and to determine average cone density among healthysubjectsMethods: We used the RTX1 flood-illuminated adaptive opticscamera (Imagine Eyes: Orsay, France) to image the cone mosaic in54 healthy subjects, ages 14 to 69 years. For each subject, a series of25 4°x4° retinal images were obtained. Using MosaicJ, these imageswere combined to create a retinal montage spanning a 12°x12° fieldof the central macula. Retinal montages were analyzed for regionaldifferences in cone density. Images were post processed in ImageJand cone counting was performed with a MATLAB algorithm. Todetermine repeatability of the device and montaging process, a subsetof 7 subjects ranging in age from 19 to 36 years were imaged on 3separate occasions. To assess the validity of automated cone countingfor each montage, automated cone counts were compared to manualcounts in sample retinal areas 2° and 4° temporal to the foveal center.Results: Image quality was excellent in most young subjects, butincreasingly variable in older subjects. Cones within 1.5° of thefoveal center could not be resolved with this camera. Angular densityof cones averaged 1587 ± 91 cones/degree 2 at 1.6° - 4.3° eccentricityand 1428 ± 64 cones/degree 2 between 4.3° and 5.4° eccentricity.When adjusted for axial length, cone density averaged 18,688 ± 2081cones/mm 2 between 1.6° and 4.3° and 16,763 ± 1669 cones/mm 2between 4.3° and 5.4°. Angular cone density between 1.6° and 4.3°decreased with age, but between 4.3° and 5.4° increased. Repeatedmeasurements of cone density in the same subject from separateimaging sessions resulted in an intraclass correlation coefficient of0.98 (p < 0.001, 95% CI: 0.93-1.00) between 1.6° and 4.3° and 0.95(p < 0.001, 95% CI: 0.83-0.99) between 4.3° and 5.4°. However,validity of the automated cone counting algorithm depended onimage quality, with poor quality images producing higher variability.Conclusions: Flood-illuminated adaptive optics providesmeasurements of cone density that are consistent with anatomicalstudies. Repeated measurements in a subset of younger subjectsresulted in very strong intraclass correction coefficients, whichindicate the system produced consistent measurements. However,challenges remain with older subjects.Commercial Relationships: Shu Feng, None; Anupam K. Garg,None; Ambar Faridi, None; Jonathan D. Fay, None; Hope E.Titus, None; Travis B. Smith, Pfizer, Inc. (F); Keith V. Michaels,Pfizer, Inc. (F); Mark E. Pennesi, Pfizer (F)Support: Research to Prevent Blindness (Unrestricted, CEI),Foundation Fighting Blindness (Pennesi CDA, CD-CL-0808-0469-©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.