Technical Note: grading the vertical cup:disc ratio and the effect of scaling

Ruth Bennett; Paul G D Spry; Cecilia H Fenerty; Robert A Harper

doi:10.1111/j.1475-1313.2007.00510.x

Technical Note: grading the vertical cup:disc ratio and the effect of scaling

Ruth Bennett, Paul G D Spry, Cecilia H Fenerty, Robert A Harper

Research output: Contribution to journal › Article › peer-review

Abstract

PURPOSE: To evaluate the effect of scaling on sensitivity to change for grading the vertical cup:disc ratio (CDR).

METHODS: Vertical CDR was assessed by six observers (three ophthalmologists and three optometrists) on 43 stereo disc photographs. Repeated observations were made for both 0.1 and 0.05 interval scales. Paired differences were calculated for all observers and each observer separately. Mean and standard deviation of differences and agreement statistics were used to compare scales.

RESULTS: Five observers demonstrated a reduction in the spread of differences (mean difference 0.19 to 0.15) and all observers demonstrated a reduction in concordance using the finer scale (mean concordance 54% to 39%).

CONCLUSION: The use of a finer scale reduces test-retest variability and increases sensitivity to change when estimating the vertical CDR. Use of this scale does not require any additional resource and it may be easily implemented in routine clinical practice.

Original language	English
Pages (from-to)	619-25
Number of pages	7
Journal	Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists)
Volume	27
Issue number	6
DOIs	https://doi.org/10.1111/j.1475-1313.2007.00510.x
Publication status	Published - Nov 2007

Keywords

Clinical Competence
Confidence Intervals
Diagnostic Techniques, Ophthalmological
Glaucoma
Humans
Observer Variation
Optic Disk
Reproducibility of Results
Sensitivity and Specificity
Journal Article

Access to Document

10.1111/j.1475-1313.2007.00510.x

Cite this

@article{17ab4ee0b1ca4ed79b1ade527ed978b2,

title = "Technical Note: grading the vertical cup:disc ratio and the effect of scaling",

abstract = "PURPOSE: To evaluate the effect of scaling on sensitivity to change for grading the vertical cup:disc ratio (CDR).METHODS: Vertical CDR was assessed by six observers (three ophthalmologists and three optometrists) on 43 stereo disc photographs. Repeated observations were made for both 0.1 and 0.05 interval scales. Paired differences were calculated for all observers and each observer separately. Mean and standard deviation of differences and agreement statistics were used to compare scales.RESULTS: Five observers demonstrated a reduction in the spread of differences (mean difference 0.19 to 0.15) and all observers demonstrated a reduction in concordance using the finer scale (mean concordance 54% to 39%).CONCLUSION: The use of a finer scale reduces test-retest variability and increases sensitivity to change when estimating the vertical CDR. Use of this scale does not require any additional resource and it may be easily implemented in routine clinical practice.",

keywords = "Clinical Competence, Confidence Intervals, Diagnostic Techniques, Ophthalmological, Glaucoma, Humans, Observer Variation, Optic Disk, Reproducibility of Results, Sensitivity and Specificity, Journal Article",

author = "Ruth Bennett and Spry, {Paul G D} and Fenerty, {Cecilia H} and Harper, {Robert A}",

year = "2007",

month = nov,

doi = "10.1111/j.1475-1313.2007.00510.x",

language = "English",

volume = "27",

pages = "619--25",

journal = "Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists)",

issn = "0275-5408",

publisher = "John Wiley & Sons Ltd",

number = "6",

}

TY - JOUR

T1 - Technical Note

T2 - grading the vertical cup:disc ratio and the effect of scaling

AU - Bennett, Ruth

AU - Spry, Paul G D

AU - Fenerty, Cecilia H

AU - Harper, Robert A

PY - 2007/11

Y1 - 2007/11

N2 - PURPOSE: To evaluate the effect of scaling on sensitivity to change for grading the vertical cup:disc ratio (CDR).METHODS: Vertical CDR was assessed by six observers (three ophthalmologists and three optometrists) on 43 stereo disc photographs. Repeated observations were made for both 0.1 and 0.05 interval scales. Paired differences were calculated for all observers and each observer separately. Mean and standard deviation of differences and agreement statistics were used to compare scales.RESULTS: Five observers demonstrated a reduction in the spread of differences (mean difference 0.19 to 0.15) and all observers demonstrated a reduction in concordance using the finer scale (mean concordance 54% to 39%).CONCLUSION: The use of a finer scale reduces test-retest variability and increases sensitivity to change when estimating the vertical CDR. Use of this scale does not require any additional resource and it may be easily implemented in routine clinical practice.

AB - PURPOSE: To evaluate the effect of scaling on sensitivity to change for grading the vertical cup:disc ratio (CDR).METHODS: Vertical CDR was assessed by six observers (three ophthalmologists and three optometrists) on 43 stereo disc photographs. Repeated observations were made for both 0.1 and 0.05 interval scales. Paired differences were calculated for all observers and each observer separately. Mean and standard deviation of differences and agreement statistics were used to compare scales.RESULTS: Five observers demonstrated a reduction in the spread of differences (mean difference 0.19 to 0.15) and all observers demonstrated a reduction in concordance using the finer scale (mean concordance 54% to 39%).CONCLUSION: The use of a finer scale reduces test-retest variability and increases sensitivity to change when estimating the vertical CDR. Use of this scale does not require any additional resource and it may be easily implemented in routine clinical practice.

KW - Clinical Competence

KW - Confidence Intervals

KW - Diagnostic Techniques, Ophthalmological

KW - Glaucoma

KW - Humans

KW - Observer Variation

KW - Optic Disk

KW - Reproducibility of Results

KW - Sensitivity and Specificity

KW - Journal Article

U2 - 10.1111/j.1475-1313.2007.00510.x

DO - 10.1111/j.1475-1313.2007.00510.x

M3 - Article

C2 - 17956368

SN - 0275-5408

VL - 27

SP - 619

EP - 625

JO - Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists)

JF - Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists)

IS - 6

ER -

Technical Note: grading the vertical cup:disc ratio and the effect of scaling

Abstract

Keywords

Access to Document

Fingerprint

Cite this