Cornea - ARVO

ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group - Corneadepth (Figure 2). Whole porcine eyes were placed at the device’sfocal plane. Images from the side cameras were recorded at regularintervals after the application of RF solution.Results: Sequences of images recorded at regular intervals duringand after the application of RF solution showed increasedfluorescence at increased depths within the cornea. A focal planeangle of 18.2° to the apex of the eye was found to increase theuseable depth of field of the system by a factor of over 2.5.Conclusions: An advanced riboflavin dosimetry device is presented.The KXL-II system combines the use of UVA projection via a DMDwith side cameras that monitor riboflavin fluorescence in the cornea.The camera’s tilted focal plane relaxes the constraints on the systemsdepth of field. The DMD allows for rapid alternation betweenillumination profiles intended for cross-linking treatment and slitconfigurations intended for fluorescent dosimetry. With this device itmay be possible to respond and compensate to live dosimetryreadings as riboflavin is consumed and measured at various depthswithin the cornea. Real time dosimetry measurements will play asignificant role in determining the underlying mechanisms of cornealcross-linking and assist with the development of additional riboflavinformulations.Figure 1 Schematic of slit UVA illumination projected on to theCornea.topographer [Jongsma et al. OVS; 1998]. Three tasks were set. SinceESP requires instillation of fluorescein, the optimal combination ofthe fluorescein strips and the eye physiological solution that results inthe best quality of recorded images was assessed. Further, therepeatability of the instrument in measuring artificial and real eyesurfaces was studied. Finally, the new topographer was tested inclinical settings against traditional Placido disk topographer (E300,Medmont) for a range of normal, astigmatic, and highly aberratedeyes (post corneal grafts).Results: The best results in terms of highly resolved ESP imageshave been achieved with BIO GLO sterile strips (1 mg fluoresceinsodium) with Hial eye drops (0.4 mg/ml hialuronian sodium). Forartificial surfaces, the repeatability of instrument in a dynamic case,when operator manually focused the instrument, was very high whilethe accuracy of the instrument in terms of the RMS error was lessthan 10um but depended on the instrument-surface distance. Theworking distance was estimated at +/-250um from the best focalplane. For real eyes, the coverage area was routinely greater than16mm and often reached up to 20mm diameter. Single instillation offluorescein allowed acquisition from 3 to 20 measurements (taken inless than 30 second intervals). Repeatability, evaluated withrefractive spherical component over an 8 mm corneal diameter, washigh (differences less than 0.125 D). When tested against the E300topographer, ESP showed excellent repeatability for spherical power(in an 8 mm corneal diameter) but seemed to overestimate theastigmatic component, which seemed to depend on the instrument’sworking distance. For highly aberrated eyes, in situations where E300could not perform a valid measurement, the ESP was still performingwell.Conclusions: ESP has high potential clinical utility. It couldsubstitute the currently used videokeratoscopes and provide a newdiagnostic quality in those applications in which information oncorneoscleral topography is of essence.Commercial Relationships: D Robert Iskander, Eaglet Eye (F),Eaglet Eye (I)Support: Eaglet Eye - research grantFigure 2 Schematic showing side camera’s use of Sceimpflugprinciple. Focal plane intersects with measurement zone in cornea.Commercial Relationships: Marc D. Friedman, Avedro Inc (E);David B. Usher, Avedro Inc (E); Radha Pertaub, Avedro Inc (E);David Muller, Avedro Inc (E)Program Number: 533 Poster Board Number: B0170Presentation Time: 10:30 AM - 12:15 PMThe clinical utility of the Eye Surface ProfilerD Robert Iskander. Institute of Biomedical Engineering andInstrumentation, Wroclaw University of Technology, Wroclaw,Poland.Purpose: To evaluate the effectiveness of the Eye Surface Profiler inmeasuring the topography of the anterior eye surface.Methods: Eye Surface Profiler (ESP) is a newly developed corneaand sclera topographer that can measure up to 20mm of the anteriorsurface of the eye. It is an evolution of a wide field height eyeProgram Number: 534 Poster Board Number: B0171Presentation Time: 10:30 AM - 12:15 PMSubclinical Keratoconus Detection Based On PentacamScheimpflug Tomography IndicesPablo R. Ruisenor Vazquez 1, 2 , Marianella Delrivo 2 , FernandoFuentes Bonthoux 1, 2 , Tomás Pfortner 2 , Pablo Chiaradia 1 , JeremiasG. Galletti 1, 2 . 1 Ophthalmology Division, Hospital de Clínicas,University of Buenos Aires, Buenos Aires, Argentina; 2 ECOS(Clinical Ocular Studies) Laboratoy, Buenos Aires, Argentina.Purpose: To evaluate the diagnostic performance of corneal indicesprovided by the Pentacam tomograph for detecting subclinicalkeratoconus.Methods: Observational case series of 136 eyes from 136 healthysubjects in group 1 and 42 topographically-unremarkable eyes from42 keratoconic patients in group 2, evaluated with cornealtopography, aberrometry, and Scheimpflug tomography for Belin-Ambrosio D indices. For data analysis, Student's t test was used tocompare means and receiver operating characteristic (ROC) curveswere used to analyze the diagnostic performance of D indices forkeratoconus detection. The statistical significance criteria used was p