Faculty Collaboration Database

The reliability of parafoveal cone density measurements. Br J Ophthalmol 2014 Aug;98(8):1126-31

Date

05/24/2014

Pubmed ID

24855115

Pubmed Central ID

PMC4112420

DOI

10.1136/bjophthalmol-2013-304823

Scopus ID

2-s2.0-84905117685 (requires institutional sign-in at Scopus site)   33 Citations

Abstract

BACKGROUND: Adaptive optics scanning light ophthalmoscopy (AOSLO) enables direct visualisation of the cone mosaic, with metrics such as cone density and cell spacing used to assess the integrity or health of the mosaic. Here we examined the interobserver and inter-instrument reliability of cone density measurements.

METHODS: For the interobserver reliability study, 30 subjects with no vision-limiting pathology were imaged. Three image sequences were acquired at a single parafoveal location and aligned to ensure that the three images were from the same retinal location. Ten observers used a semiautomated algorithm to identify the cones in each image, and this was repeated three times for each image. To assess inter-instrument reliability, 20 subjects were imaged at eight parafoveal locations on one AOSLO, followed by the same set of locations on the second AOSLO. A single observer manually aligned the pairs of images and used the semiautomated algorithm to identify the cones in each image.

RESULTS: Based on a factorial study design model and a variance components model, the interobserver study's largest contribution to variability was the subject (95.72%) while the observer's contribution was only 1.03%. For the inter-instrument study, an average cone density intraclass correlation coefficient (ICC) of between 0.931 and 0.975 was calculated.

CONCLUSIONS: With the AOSLOs used here, reliable cone density measurements can be obtained between observers and between instruments. Additional work is needed to determine how these results vary with differences in image quality.

Author List

Liu BS, Tarima S, Visotcky A, Pechauer A, Cooper RF, Landsem L, Wilk MA, Godara P, Makhijani V, Sulai YN, Syed N, Yasumura G, Garg AK, Pennesi ME, Lujan BJ, Dubra A, Duncan JL, Carroll J

Authors

Joseph J. Carroll PhD Director, Professor in the Ophthalmology and Visual Sciences department at Medical College of Wisconsin
Robert 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
Alexis M. Visotcky Biostatistician III in the Institute for Health and Equity department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adult
Cell Count
Female
Fovea Centralis
Humans
Linear Models
Male
Middle Aged
Observer Variation
Ophthalmoscopes
Ophthalmoscopy
Pattern Recognition, Automated
Reproducibility of Results
Retinal Cone Photoreceptor Cells
Retinal Diseases
Young Adult