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Foveal Pit Curvature in a Normal Population

Eilerman, Amanda Louise
http://orcid.org/0000-0003-2498-270X
http://rave.ohiolink.edu/etdc/view?acc_num=osu1461109213

Abstract Details

2016, Master of Science, Ohio State University, Vision Science.
The purpose of this study is to determine whether a circular shape adequately describes the shape of the foveal pit, and if so, over what distance does this hold true. Another purpose of this study is to evaluate meridional symmetry within a normal fovea and compare radius of curvature between the horizontal and vertical meridians. The radius of curvature will also be compared to gender, axial length, and age. Previous studies have evaluated foveal pit shape and radius of curvature but using different techniques such as reflectometry, difference of Gaussians, and thickness measurements.1-4 Various studies have compared foveal characteristics to gender, axial length, and age.1-4 Many studies have also evaluated the underlying cellular organization and structure that define the fovea.5-9 The present study uses a novel curve fitting technique that is more direct and provides better visualization of the foveal curvature in more than one meridian. 22 normal subjects were imaged using the spectral domain optical coherence tomography (SDOCT, Heidelberg Engineering, Carlsbad, CA). All reported normal ocular health, and visual acuity was measured as clinically normal. Axial length measurements were also recorded. Twelve radial scans centered at the fovea were acquired from each eye. The images were exported into Photoshop (Adobe, San Jose, CA) and manually segmented. The line representing the internal limiting membrane was used for analysis in the custom curve fitting software (Matlab, Mathworks, Natick, MA). The circle was fit to the central 500 microns in a randomly selected eye of each of the 22 subjects. Linear regression was used to compare radius of curvature to axial length and age, and a paired t-test was used to compare radius of curvature between males and females. The circle was also fit to the central 500, 1000, and 1500 microns in the right eye of 10 of the 22 subjects. Paired t-tests were used to compare the horizontal and vertical meridian at each of the three locations in these 10 subjects. There was no significant association between radius of curvature in the horizontal or vertical meridian and axial length (R2=0.0378, R2=0.0264) or age (R2=0.0125, R2=0.0005) and no significant difference when compared between males and females (p=0.602, p=0.540). A circle fit to the central 500 microns demonstrated a good representation of foveal pit curvature in all subjects. The fit of the circle decreased with increased eccentricity at 1000 microns and even more so at 1500 microns in both meridians. The difference in radius of curvature between the horizontal and vertical meridians was significant at 1000 microns (p<0.0001) and 1500 microns (p<0.0001), with the horizontal meridian being flatter and having a larger radius of curvature than the vertical meridian. The difference in radius of curvature of the fovea with increased eccentricity corresponds to the foveal cone streak that has been documented by previous studies.5, 10 The custom curve fitting used in this study is a new, yet simple technique that is effective at evaluating meridional differences. Understanding normal foveal shape and curvature can help better understand deviations from normal and pathology.
Dean VanNasdale, OD, PhD (Advisor)
Nicky Lai, OD, MS (Committee Member)
Aaron Zimmerman, OD, MS (Committee Member)
78 p.
Health Sciences
Fovea; curve fitting

Recommended Citations

Citations

  • Eilerman, A. L. (2016). Foveal Pit Curvature in a Normal Population [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461109213

    APA Style (7th edition)

  • Eilerman, Amanda. Foveal Pit Curvature in a Normal Population. 2016. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1461109213.

    MLA Style (8th edition)

  • Eilerman, Amanda. "Foveal Pit Curvature in a Normal Population." Master's thesis, Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461109213

    Chicago Manual of Style (17th edition)

osu1461109213
1,012
© 2016, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.