Cornea - ARVO

ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group - Corneacontrols. This suggests that IVCM of the corneal sub-basal nerveplexus may be a more sensitive indicator of peripheral nervedegeneration in type 1 vs. type 2 DM.Commercial Relationships: Maxwell Stem, None; MuniraHussain, None; Melody Chan, None; Stephanie J. Chiu, DukeUniversity (P); Pratul Srinivasan, None; Jeffrey M. Sundstrom,None; Thomas W. Gardner, Kalvista (C), Aerpio (C), Akebia (C),Penn State University (P); Sina Farsiu, Duke University (P); RodicaPop-Busui, None; Roni M. Shtein, NoneSupport: This research was supported by the Michigan DiabetesResearch & Training Center funded by NIH P60DK020572 from theNational Institute of Diabetes and Digestive and Kidney Diseases(RMS); American Diabetes Association-Merck (MS); JuvenileDiabetes Research Foundation (TWG); Taubman Institute (TWG);Research to Prevent Blindness (TWG); NIH Grant 1R01EY022691-01 (SF); NIH Grant R01 HL102334 (RP)Program Number: 2605 Poster Board Number: D0405Presentation Time: 2:45 PM - 4:30 PMRepeatability of peripheral (near-limbal) corneal thicknessmeasurements of Pentacam Scheimpflug corneal topographyRaul Martin 1 , Sven Jonuscheit 2, 3 , Michael J. Doughty 2 , Ana del RioSan Cristóbal 1 , Lisa J. Mackintosh 2 , David MacTaggart 2 , MichaelHiscock 2 . 1 Optometry Research Group, IOBA Eye Institute,Valladolid, Spain; 2 Vision Sciences, Department of Life Sciences,Glasgow Caledonian University, Glasgow, United Kingdom;3 Diabetes Research Group, Institute for Applied Health Research,Glasgow Caledonian University, Glasgow, United Kingdom.Purpose: To assess the repeatability of peripheral corneal thickness(CT) measurements along the horizontal meridian as close to thelimbus as possible in healthy eyes with Scheimpflug topographyPentacam.Methods: CT was measured in 63 corneas of 63 healthy subjects ateleven corneal locations nominally 1 mm apart along the horizontalmeridian with Scheimpflug topography Pentacam. Two consecutiveScheimpflug scans were performed in quick succession to determinethe repeatability of the pachymetry values measured in each corneallocation up to 5 mm away from the corneal apex. Ocular assessmentsalso included habitual visual acuity, slit-lamp biomicroscopy, andoptical coherence tomography. To rule out corneal endotheliopathynon-contact specular microscopy was performed. Descriptivestatistics were generated. The repeatability was determined byassessing absolute differences between measurement 1 and 2. Therelative difference was then calculated and expressed as the ratio ofthe absolute difference to the central CT. A variant of Bland-Altmananalysis was carried out to determine the effect of the overallmagnitude of CT on the differences between pachymetrymeasurements.Results: The mean [SD] age was 27 [7] years. CT increasedprogressively and asymmetrically from the corneal center to theperiphery. Mean CT (µm) at the temporal 5 mm location was 771[49] and 823 [53] at the corresponding nasal location; central CT was558 [33]. Peripheral CT repeatability, based on absolute differences(microns) between 2 measurements was 2.41 [13.41] temporally and-1.03 [15.39] nasally, both at 5 mm away from the corneal apex.These values decreased to just 0.27 [5.33] for central CT. Thisdifference in repeatability between peripheral and central locationswas not statistically significant (p=0.918 Kruskal-Wallis ANOVA,nasal and temporal). Regression analyses indicate that differencesbetween measurements (repeatability) were not dependent on theabsolute thickness values (p=0.978; r= 0.10).Conclusions: Pentacam shows excellent repeatability not only forcentral pachymetry measurements near the corneal apex, but also forperipheral measurements close to the corneal limbus 5 mm awayfrom the corneal centre in normal eyes. The results provide evidenceof the utility of Pentacam assessment of the peripheral cornea inextended contact lens wear and surgical procedures.Commercial Relationships: Raul Martin, None; Sven Jonuscheit,Santander UK plc (F); Michael J. Doughty, None; Ana del Rio SanCristóbal, None; Lisa J. Mackintosh, Santander UK plc (F); DavidMacTaggart, Santander UK PLC (F); Michael Hiscock, NoneSupport: Jose Castillejo Program, Spanish Ministry of EducationProgram Number: 2606 Poster Board Number: D0406Presentation Time: 2:45 PM - 4:30 PMComparison of corneal shape and ocular aberrations in eyes withforme fruste keratoconus to that of normal corneaRyotaro Ueki 1, 2 , Naoyuki Maeda 1 , Mutsumi Fuchihata 1 , ShizukaKoh 1 , Takashi Kitaoka 2 , Kohji Nishida 1 . 1 Ophthalmology, OsakaUniv School of Medicine, Osaka-Shi, Japan; 2 Ophthalmology,Nagasaki Univ School of Medicine, Nagasaki-Shi, Japan.Purpose: Forme fruste keratoconus (FFK) is defined as a corneawhich has no abnormal findings by slit-lamp examinations andPlacido-based corneal topography, and is the fellow eye of a patientwith clinical keratoconus. FFK has recently gained a lot of attentionbecause it is the borderline condition between keratoconus suspectand normal cornea. The purpose of this study was to compare thecorneal shape and ocular aberrations of eyes with FFK to that ofnormal corneas.Methods: We studied 38 eyes with FFK and 50 eyes with normalcorneas. The corneal thickness and location of thinnest point, Belin-Ambrósio enhanced ectasia Display (BAD) parameters, Df, Db, Dp,Dt, Da, and D, and corneal coma aberrations (anterior, posterior andtotal cornea) for a 4 mm diameter were obtained with a rotatingScheimpflug camera (Pentacam HR, OCULUS Optikgeräte GmbH,Germany). The ocular spherical aberration (C4,0) and comaaberration (C3,1 and C3,-1) for a 4 mm diameter were obtained by anaberrometer (KR-1W, Topcon Corp., Japan). Multiple logisticregression analyses and the receiver operating characteristic (ROC)analyses were performed on these data to determine whether the twogroups can be differentiated.Results: Multiple logistic regression analyses showed the BADparameter D, the anterior corneal coma, and the total corneal comawere significant variables for differentiating FFK group from thenormal group (P