Dean A. VanNasdale

The Ohio State University

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Ann E. Elsner

Indiana University Bloomington

Benno L. Petrig

Penn Presbyterian Medical Center

Masahiro Miura

Tokyo Medical University Ibaraki Medical Center

Stephen A. Burns

Indiana University Bloomington

Anke Weber

Center for Systems Biology Dresden

B. P. Haggerty

Multnomah County Health Department

Bryan P. Haggerty

Indiana University Bloomington

A. E. Elsner

Indiana University Bloomington

Yanming Zhao

China University of Geosciences (Beijing)

Toco Yuen Ping Chui

New York Eye and Ear Infirmary

Cooperative Institutions

Indiana University Bloomington

The Ohio State University

SUNY College of Optometry

Indiana University

Fundação Armando Alvares Penteado

Indiana University – Purdue University Indianapolis

Harvard University

Smith-Kettlewell Eye Research Institute

Aeon Imaging (United States)

Massachusetts Eye and Ear Infirmary

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Foveal Curvature and Asymmetry Assessed Using Optical Coherence Tomography

Optometry and Vision Science (2017)

Dean A. VanNasdale Amanda Eilerman Aaron B. Zimmerman Nicky Lai Keith A. Ramsey

The aims of this study were to use cross-sectional optical coherence tomography imaging and custom curve fitting software to evaluate and model the foveal curvature as a spherical surface and to compare the radius of curvature in the horizontal and vertical meridians and test the sensitivity of this technique to anticipated meridional differences.Six 30-degree foveal-centered radial optical coherence tomography cross-section scans were acquired in the right eye of 20 clinically normal subjects. Cross sections were manually segmented, and custom curve fitting software was used to determine foveal pit radius of curvature using the central 500, 1000, and 1500 μm of the foveal contour. Radius of curvature was compared across different fitting distances. Root mean square error was used to determine goodness of fit. The radius of curvature was compared between the horizontal and vertical meridians for each fitting distance.There radius of curvature was significantly different when comparing each of the three fitting distances (P < .01 for each comparison). The average radii of curvature were 970 μm (95% confidence interval [CI], 913 to 1028 μm), 1386 μm (95% CI, 1339 to 1439 μm), and 2121 μm (95% CI, 2066 to 2183) for the 500-, 1000-, and 1500-μm fitting distances, respectively. Root mean square error was also significantly different when comparing each fitting distance (P < .01 for each comparison). The average root mean square errors were 2.48 μm (95% CI, 2.41 to 2.53 μm), 6.22 μm (95% CI, 5.77 to 6.60 μm), and 13.82 μm (95% CI, 12.93 to 14.58 μm) for the 500-, 1000-, and 1500-μm fitting distances, respectively. The radius of curvature between the horizontal and vertical meridian radii was statistically different only in the 1000- and 1500-μm fitting distances (P < .01 for each), with the horizontal meridian being flatter than the vertical.The foveal contour can be modeled as a sphere with low curve fitting error over a limited distance and capable of detecting subtle foveal contour differences between meridians.

Radius of curvature

Root mean square

10.1097/opx.0000000000001084

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Citations (1)

Mueller matrix retinal imager with optimized polarization conditions

Optics Express (2008)

K. Twietmeyer Russell A. Chipman Ann E. Elsner Yanming Zhao Dean A. VanNasdale

A new Mueller matrix polarimeter was used to image the retinas of normal subjects. Light from a linearly polarized 780 nm laser was passed through a system of variable retarders and scanned across the retina. Light returned from the eye passed through a second system of retarders and a polarizing beamsplitter to two confocal detection channels. Optimization of the polarimetric data reduction matrix was via a condition number metric. The accuracy and repeatability of polarization parameter measurements were within +/- 5%. The magnitudes and orientations of retardance and diattenuation, plus depolarization, were measured over 15 degrees of retina for 15 normal eyes.

Mueller calculus

Polarimeter

Beam splitter

Repeatability

10.1364/oe.16.021339

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Citations (99)

Henle Fiber Layer Phase Retardation Changes Associated With Age-Related Macular Degeneration

Investigative Ophthalmology & Visual Science (2014)

Dean A. VanNasdale Ann E. Elsner Todd Peabody Kimberly D. Kohne Victor E. Malinovsky

Purpose.: To quantify and compare phase retardation amplitude and regularity associated with the Henle fiber layer (HFL) between nonexudative AMD patients and age-matched controls using scanning laser polarimetry (SLP) imaging. Methods.: A scanning laser polarimeter was used to collect 15 × 15° macular-centered images in 25 patients with nonexudative AMD and 25 age-matched controls. Raw image data were used to compute macular phase retardation maps associated with the HFL. Consecutive, annular regions of interest from 0.5 to 3.0° eccentricity, centered on the fovea, were used to generate intensity profiles from phase retardation data and analyzed with two complementary techniques: a normalized second harmonic frequency (2f) of the fast Fourier Transform (FFT) analysis and a curve fitting analysis using a 2f sine function. Paired t-tests were used to compare the normalized 2f FFT magnitude at each eccentricity between the two groups, the eccentricity that yielded the maximum normalized 2f FFT between paired individuals across the two groups, and curve fitting RMS error at each eccentricity between the two groups. Results.: Normalized 2f FFT components were lower in the AMD group at each eccentricity, with no difference between the two groups in the maximum normalized 2f FFT component eccentricity. The root-mean-square (RMS) error from curve fitting was significantly higher in the AMD group. Conclusions.: Phase retardation changes in the central macula indicate loss and/or structural alterations to central cone photoreceptors in nonexudative AMD patients. Scanning laser polarimetry imaging is a noninvasive method for quantifying cone photoreceptor changes associated with central macular disease.

Eccentricity (behavior)

10.1167/iovs.14-14459

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Citations (9)

Retinal Birefringence in Normal Eyes and in Exudative Eye Disease

Investigative Ophthalmology & Visual Science (2007)

Ann E. Elsner Dean A. VanNasdale B. P. Haggerty Boris Hansel Yanming Zhao

Source

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Accounting for Image Grading Criteria in Minimally Trained Telemedicine Graders

Matthias Müller Andreas Elsner Dean A. VanNasdale Victor E. Malinovsky Todd Peabody

Grading (engineering)

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Imaging polarimetry of macular disease

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2008)

Masahiro Miura Ann E. Elsner Benno L. Petrig Dean A. VanNasdale Yanming Zhao

Polarization properties of the human eye have long been used to study the tissues of the human retina, as well as to improve retinal imaging, and several new technologies using polarized light are in use or under development.^1-8 The most typical polarimetry technique in ophthalmology clinic is a scanning laser polarimetry for the glaucoma diagnosis.^1,2 In the original conceptualization, the thickness of the retinal nerve fiber layer is estimated using the birefringent component of light returning from the ocular fundus. More recently, customized software to analyze data from scanning laser polarimetry was developed to investigate the polarization properties of the macular disease.^5-8 In this study, we analyzed macular disease with imaging polarimetry, which provides a method for the noninvasive assessment of macular disease.

Scanning laser polarimetry

Fundus (uterus)

10.1117/12.761406

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Determination of foveal location using scanning laser polarimetry

Journal of Vision (2009)

Dean A. VanNasdale Ann E. Elsner Anke Weber Masahiro Miura B. P. Haggerty

The fovea is the retinal location responsible for our most acute vision. There are several methods used to localize the fovea, but the fovea is not always easily identifiable. Landmarks used to determine the foveal location are variable in normal subjects and localization becomes even more difficult in instances of retinal disease. In normal subjects, the photoreceptor axons that make up the Henle fiber layer are cylindrical and the radial orientation of these fibers is centered on the fovea. The Henle fiber layer exhibits form birefringence, which predictably changes polarized light in scanning laser polarimetry imaging. In this study 3 graders were able to repeatably identify the fovea in 35 normal subjects using near infrared image types with differing polarization content. There was little intra‐grader, inter‐grader, and inter‐image variability in the graded foveal position for 5 of the 6 image types examined, with accuracy sufficient for clinical purposes. This study demonstrates that scanning laser polarimetry imaging can localize the fovea by using structural properties inherent in the central macula.

Scanning laser polarimetry

Fovea centralis

10.1167/9.3.21

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Citations (20)

Foveal Localization and Polarimetric Image Comparisons Between Age-Related Macular Degeneration and Normals

Dean A. VanNasdale A. E. Elsner Anke Weber Masahiro Miura B. P. Haggerty

Degeneration (medical)

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Polarization Variability in Age-related Macular Degeneration

Optometry and Vision Science (2018)

Dean A. VanNasdale Ann E. Elsner Victor E. Malinovsky Todd Peabody Kimberly D. Kohne

Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss. Complementary imaging techniques can be used to better characterize and quantify pathological changes associated with AMD. By assessing specific light-tissue interactions, polarization-sensitive imaging can be used to detect tissue disruption early in the disease process.

10.1097/opx.0000000000001197

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Citations (6)

Semi-Automatic OCT Segmentation of Nine Retinal Layers

Liang Zhao Ann E. Elsner Chris Clark Toco Yuen Ping Chui Joel A. Papay

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Citations (5)