Optimal image sample size for corneal nerve morphometry

Dimitrios Vagenas, Nicola Pritchard, Katie Edwards, Ayda M. Shahidi, Geoff P. Sampson, Anthony W. Russell, Rayaz Malik, Nathan Efron

Research output: Contribution to journalArticle

55 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)812-817
Number of pages6
JournalOptometry and Vision Science
Volume89
Issue number5
DOIs
Publication statusPublished - May 2012
Externally publishedYes

Fingerprint

Nerve Fibers
Sample Size
Sampling Studies
Confocal Microscopy
Type 2 Diabetes Mellitus

Keywords

  • corneal confocal microscopy
  • corneal nerves
  • diabetes
  • sampling methodology

ASJC Scopus subject areas

  • Ophthalmology
  • Optometry
  • Medicine(all)

Cite this

Vagenas, D., Pritchard, N., Edwards, K., Shahidi, A. M., Sampson, G. P., Russell, A. W., ... Efron, N. (2012). Optimal image sample size for corneal nerve morphometry. Optometry and Vision Science, 89(5), 812-817. https://doi.org/10.1097/OPX.0b013e31824ee8c9

Optimal image sample size for corneal nerve morphometry. / Vagenas, Dimitrios; Pritchard, Nicola; Edwards, Katie; Shahidi, Ayda M.; Sampson, Geoff P.; Russell, Anthony W.; Malik, Rayaz; Efron, Nathan.

In: Optometry and Vision Science, Vol. 89, No. 5, 05.2012, p. 812-817.

Research output: Contribution to journalArticle

Vagenas, D, Pritchard, N, Edwards, K, Shahidi, AM, Sampson, GP, Russell, AW, Malik, R & Efron, N 2012, 'Optimal image sample size for corneal nerve morphometry', Optometry and Vision Science, vol. 89, no. 5, pp. 812-817. https://doi.org/10.1097/OPX.0b013e31824ee8c9
Vagenas D, Pritchard N, Edwards K, Shahidi AM, Sampson GP, Russell AW et al. Optimal image sample size for corneal nerve morphometry. Optometry and Vision Science. 2012 May;89(5):812-817. https://doi.org/10.1097/OPX.0b013e31824ee8c9
Vagenas, Dimitrios ; Pritchard, Nicola ; Edwards, Katie ; Shahidi, Ayda M. ; Sampson, Geoff P. ; Russell, Anthony W. ; Malik, Rayaz ; Efron, Nathan. / Optimal image sample size for corneal nerve morphometry. In: Optometry and Vision Science. 2012 ; Vol. 89, No. 5. pp. 812-817.
@article{5fbfd9fe306c47559707497e36092ef9,
title = "Optimal image sample size for corneal nerve morphometry",
abstract = "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.",
keywords = "corneal confocal microscopy, corneal nerves, diabetes, sampling methodology",
author = "Dimitrios Vagenas and Nicola Pritchard and Katie Edwards and Shahidi, {Ayda M.} and Sampson, {Geoff P.} and Russell, {Anthony W.} and Rayaz Malik and Nathan Efron",
year = "2012",
month = "5",
doi = "10.1097/OPX.0b013e31824ee8c9",
language = "English",
volume = "89",
pages = "812--817",
journal = "Optometry and Vision Science",
issn = "1040-5488",
publisher = "Lippincott Williams and Wilkins",
number = "5",

}

TY - JOUR

T1 - Optimal image sample size for corneal nerve morphometry

AU - Vagenas, Dimitrios

AU - Pritchard, Nicola

AU - Edwards, Katie

AU - Shahidi, Ayda M.

AU - Sampson, Geoff P.

AU - Russell, Anthony W.

AU - Malik, Rayaz

AU - Efron, Nathan

PY - 2012/5

Y1 - 2012/5

N2 - 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.

AB - 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.

KW - corneal confocal microscopy

KW - corneal nerves

KW - diabetes

KW - sampling methodology

UR - http://www.scopus.com/inward/record.url?scp=84861093523&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84861093523&partnerID=8YFLogxK

U2 - 10.1097/OPX.0b013e31824ee8c9

DO - 10.1097/OPX.0b013e31824ee8c9

M3 - Article

C2 - 22407254

AN - SCOPUS:84861093523

VL - 89

SP - 812

EP - 817

JO - Optometry and Vision Science

JF - Optometry and Vision Science

SN - 1040-5488

IS - 5

ER -