posted on 2013-12-06, 00:00authored byDaniel K. Roberts, Yongyi Yang, Ana S. Lukic, Jacob T. Wilensky, Miles N. Wernick
Purpose: To investigate near infrared iris transillumination (NIRit) imaging as a new
method to quantify pupil shape, size, and position because the imaging modality can
uniquely provide simultaneous information regarding iris structural details that influence
pupil characteristics and because exploration of related techniques could promote
discovery helpful to clinical research and care. Methods: Digital NIRit images of normal
and diseased eyes were used along with computer-assisted techniques to quantify four
primary pupil parameters, including pupil roundness (PR), pupil ovalness (PO), pupil
size (PS), and pupil eccentricity (PE). A combined measure of PR and PO was also
developed, i.e., the pupil circularity index (PCI). Repeatability of the measures was
studied and example analyses were performed. Results: Pupil measures could be
calculated for right eyes of 307 subjects (164 normal, 143 other), with <0.5% exclusions
due to image quality. Repeatability study did not show significant bias (P<0.05) for any
of the four primary measures. Example analyses could show age associated
differences in pupil shape (>50 year-olds had less regular pupils than <50-year-olds:
median PCI=0.009 vs 0.006; P<0.01), and that a group of pigment dispersion syndrome
subjects (N=27) had less regular pupils than a group of matched controls (PO=0.9966
vs. 0.9990; P<0.05). Conclusions: Digital NIRit imaging can provide novel, reliable,
and informative methods to quantify pupil characteristics while providing simultaneous
information about iris structure that may influence these parameters.
Funding
Grant NEI EY015604 (AL, YY, MNW).
History
Publisher Statement
Post print version of article may differ from published version. The definitive version is available through Slack at DOI: 10.3928/15428877-20120301-02