Evaluating Descriptive Metrics of the Human Cone Mosaic. Invest Ophthalmol Vis Sci 2016 Jun 01;57(7):2992-3001
Date
06/09/2016Pubmed ID
27273598Pubmed Central ID
PMC4898203DOI
10.1167/iovs.16-19072Scopus ID
2-s2.0-84973380341 (requires institutional sign-in at Scopus site) 91 CitationsAbstract
PURPOSE: To evaluate how metrics used to describe the cone mosaic change in response to simulated photoreceptor undersampling (i.e., cell loss or misidentification).
METHODS: Using an adaptive optics ophthalmoscope, we acquired images of the cone mosaic from the center of fixation to 10° along the temporal, superior, inferior, and nasal meridians in 20 healthy subjects. Regions of interest (n = 1780) were extracted at regular intervals along each meridian. Cone mosaic geometry was assessed using a variety of metrics - density, density recovery profile distance (DRPD), nearest neighbor distance (NND), intercell distance (ICD), farthest neighbor distance (FND), percentage of six-sided Voronoi cells, nearest neighbor regularity (NNR), number of neighbors regularity (NoNR), and Voronoi cell area regularity (VCAR). The "performance" of each metric was evaluated by determining the level of simulated loss necessary to obtain 80% statistical power.
RESULTS: Of the metrics assessed, NND and DRPD were the least sensitive to undersampling, classifying mosaics that lost 50% of their coordinates as indistinguishable from normal. The NoNR was the most sensitive, detecting a significant deviation from normal with only a 10% cell loss.
CONCLUSIONS: The robustness of cone spacing metrics makes them unsuitable for reliably detecting small deviations from normal or for tracking small changes in the mosaic over time. In contrast, regularity metrics are more sensitive to diffuse loss and, therefore, better suited for detecting such changes, provided the fraction of misidentified cells is minimal. Combining metrics with a variety of sensitivities may provide a more complete picture of the integrity of the photoreceptor mosaic.
Author List
Cooper RF, Wilk MA, Tarima S, Carroll JAuthors
Joseph J. Carroll PhD Director, Professor in the Ophthalmology and Visual Sciences department at Medical College of WisconsinRobert F. Cooper Ph.D Assistant Professor in the Biomedical Engineering department at Marquette University
Sergey S. Tarima PhD Associate Professor in the Institute for Health and Equity department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AdultCell Count
Female
Humans
Male
Ophthalmoscopes
Ophthalmoscopy
Optics and Photonics
Pattern Recognition, Automated
Retinal Cone Photoreceptor Cells
