A novel analytical method using OCT to describe the corneoscleral junction.
OBJECTIVE
To develop and test a novel quantitative method of describing the corneoscleral junction, including metrics that reflect both the angle and the topography in this region of the ocular surface.


METHODS
Forty-eight neophyte subjects were recruited (16 Asian, 16 white, and 16 Latino). Optical coherence tomography images of the nasal, temporal, superior, and inferior quadrants in both eyes were taken. Custom image analysis software was written in Matlab to allow the observer to select a point defining the center of the junction, from which 20 concentric circles were automatically drawn. The surface of the junction in the image was automatically located by edge-detection routines, and the circles intersecting this edge defined a series of points in the Cartesian plane. A linear regression was fit to these points, and a set of metrics based on the regression residuals was calculated.


RESULTS
The sum of the squared orthogonalized residuals (SSRo) was the most repeatable metric and had the advantage of being unaffected by the orientation of the image. The SSRo was significantly greater in the nasal quadrant (p < 0.001), reflecting a more pronounced angle and/or rougher surface. The flattest and smoothest topography was found in the temporal quadrant. Whites had significantly higher SSRo than Asians and Latinos (p < 0.001).


CONCLUSIONS
This study presents a novel metric for characterizing the angle and topography of the corneoscleral junction using optical coherence tomography and establishes differences among quadrants and between ethnic groups.
*PhD †MA ‡OD, PhD, FAAO Clinical Research Center, School of Optometry (BT, ADG, MCL), Vision Science Group, (MCL), University of California, Berkeley, Berkeley, California; and Department of Computer and Information Science, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana (GT).
Bo
B
Tan
Andrew D
AD
Graham
Gavriil
G
Tsechpenakis
Meng C
MC
Lin
D000293:Adolescent; D000328:Adult; D001213:Asian; D003315:Cornea / Q000033:anatomy & histology*; D019781:Corneal Topography; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D016850:Limbus Corneae / Q000033:anatomy & histology*; D008297:Male; D015203:Reproducibility of Results; D012590:Sclera / Q000033:anatomy & histology*; D041623:Tomography, Optical Coherence / Q000379:methods*; D044465:White People; D055815:Young Adult