Influence of Time Separation on Variability Estimates of Topographic Measurements with Confocal Scanning Laser Tomography

Chauhan, Balwantray C.; MacDonald, Corey A.

doi:10.1097/00061198-199506000-00008

Cited by 28 publications

(13 citation statements)

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“…In addition, longterm fluctuations of the normalized rim/disc area quotient in normal eyes have been reported, 25 while a comparable trend was noted in super pixel height measurements in healthy volunteers (P ¼ 0.14, N ¼ 10). 26 The larger biological variability in healthy subjects compared to glaucoma patients is an interesting finding. It has been found that long-and short-term fluctuations are characteristic of many physiological states, which can be explained by chaos theory principles.…”

Section: Discussionmentioning

confidence: 99%

Estimating the clinical usefulness of optic disc biometry for detecting glaucomatous change over time

Tangelder

Reus

Lemij

2005

Eye

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Purpose First, to determine the absolute measurement precision of scanning laser ophthalmoscopy (SLO) parameters, by expressing them as 95% limits of agreement (LA 95% ). Second, to propose a method for mathematically estimating the clinical ability of a parameter to monitor disease progression, expressed as the Discriminating Capacity Index (DCI). Methods We measured the optic disc of 14 healthy volunteers and 14 glaucoma patients. LA 95% -values were calculated from the average standard deviation of three measurements on the same day for repeatability, and three measurements on separate days within a 6-week period for reproducibility. We then calculated the DCI by dividing the measurement range by its LA 95% in healthy subjects and glaucoma patients separately. Thus, the DCI takes into account both the dynamic range of disease progression and the extent of measurement variance, providing an index of the possible clinical usefulness of a parameter. As the DCI is dimensionless it allows comparison across various parameters and across technologies.

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Section: Discussionmentioning

confidence: 99%

Estimating the clinical usefulness of optic disc biometry for detecting glaucomatous change over time

Tangelder

Reus

Lemij

2005

Eye

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“…Alternative estimates could have been derived from test-retest values in images from patients obtained several times over the same day or from a group of stable glaucoma population examined over a relatively short period. Evidence in normal subjects suggests that the test-retest variability estimates with these two approaches is comparable in normal subjects 38 ; however, more comprehensive study in patients with glaucoma is required. Permutation analyses of follow-up data where the order of examinations is randomized to simulate variability 19,15 has also been described for the this purpose.…”

Section: Discussionmentioning

confidence: 99%

Optic Disc Progression in Glaucoma: Comparison of Confocal Scanning Laser Tomography to Optic Disc Photographs in a Prospective Study

Chauhan

Hutchison

Artes

et al. 2009

Invest. Ophthalmol. Vis. Sci.

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“…For the normal subject group, the 20° × 20° scan field was selected to attain a wide range of normal Z profile signal width values. A minimum of seven series images were recorded, rather than three images recommended for clinical use,15 in order to gain a more realistic and reliable assessment of the inherent variability of the data 16. Scan depth and field were kept constant throughout repeated HRT image acquisition of a given eye.…”

Section: Methodsmentioning

confidence: 99%

Scanning laser tomography Z profile signal width as an objective index of macular retinal thickening

Hudson¹,

Flanagan

Turner

et al. 1998

British Journal of Ophthalmology

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Aims-(i)To evaluate the relation between retinal thickness and the Z profile signal width of a scanning laser tomographer in selected patients exhibiting clinically manifest and circumscribed macular retinal thickening; (ii) to compare the Z profile signal width values of a group of age similar normal subjects with those of the patients with macular retinal thickening; and (iii) to present the methodology underlying the Z profile signal width derivation. Methods-Three patients with the following conditions were selected: widespread diabetic macular oedema; localised diabetic macular oedema; and macular hole. The patients were selected because they exhibited clinically manifest and circumscribed macular retinal thickening. Patients underwent fundus photography and a clinical examination which included fundus biomicroscopy. Fourteen age similar normal subjects were also assessed. The Heidelberg retina tomograph (HRT) was utilised to acquire seven topographic images of each macula. Z profile signal width data were analysed using custom software. Signal width was measured at 50% of the maximum intensity. (Br J Ophthalmol 1998;82:121-130) Results-For

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Influence of Time Separation on Variability Estimates of Topographic Measurements with Confocal Scanning Laser Tomography

Cited by 28 publications

References 0 publications

Estimating the clinical usefulness of optic disc biometry for detecting glaucomatous change over time

Estimating the clinical usefulness of optic disc biometry for detecting glaucomatous change over time

Optic Disc Progression in Glaucoma: Comparison of Confocal Scanning Laser Tomography to Optic Disc Photographs in a Prospective Study

Scanning laser tomography Z profile signal width as an objective index of macular retinal thickening

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