Optimal image sample size for corneal nerve morphometry

Vagenas, Dimitrios, Pritchard, Nicola, Edwards, Katie, Shahidi, Ayda M., Sampson, Geoff, Russell, Anthony, Malik, Rayaz A., & Efron, Nathan (2012) Optimal image sample size for corneal nerve morphometry. Optometry and Vision Science, 89(5), pp. 812-817.

View at publisher


Purpose Arbitrary numbers of corneal confocal microscopy images have been used for analysis of corneal subbasal nerve parameters under the implicit assumption that these are a representative sample of the central corneal nerve plexus. The purpose of this study is to present a technique for quantifying the number of random central corneal images required to achieve an acceptable level of accuracy in the measurement of corneal nerve fiber length and branch density.

Methods Every possible combination of 2 to 16 images (where 16 was deemed the true mean) of the central corneal subbasal nerve plexus, not overlapping by more than 20%, were assessed for nerve fiber length and branch density in 20 subjects with type 2 diabetes and varying degrees of functional nerve deficit. Mean ratios were calculated to allow comparisons between and within subjects.

Results In assessing nerve branch density, eight randomly chosen images not overlapping by more than 20% produced an average that was within 30% of the true mean 95% of the time. A similar sampling strategy of five images was 13% within the true mean 80% of the time for corneal nerve fiber length.

Conclusions The “sample combination analysis” presented here can be used to determine the sample size required for a desired level of accuracy of quantification of corneal subbasal nerve parameters. This technique may have applications in other biological sampling studies.

Impact and interest:

27 citations in Scopus
Search Google Scholar™
27 citations in Web of Science®

Citation counts are sourced monthly from Scopus and Web of Science® citation databases.

These databases contain citations from different subsets of available publications and different time periods and thus the citation count from each is usually different. Some works are not in either database and no count is displayed. Scopus includes citations from articles published in 1996 onwards, and Web of Science® generally from 1980 onwards.

Citations counts from the Google Scholar™ indexing service can be viewed at the linked Google Scholar™ search.

ID Code: 54153
Item Type: Journal Article
Refereed: Yes
Keywords: corneal confocal microscopy, sampling methodology, corneal nerves, daibetes
DOI: 10.1097/OPX.0b013e31824ee8c9
ISSN: 1040-5488
Subjects: Australian and New Zealand Standard Research Classification > MATHEMATICAL SCIENCES (010000) > STATISTICS (010400) > Biostatistics (010402)
Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300)
Divisions: Current > Institutes > Institute of Health and Biomedical Innovation
Deposited On: 15 Oct 2012 01:28
Last Modified: 12 Jun 2013 15:13

Export: EndNote | Dublin Core | BibTeX

Repository Staff Only: item control page