A new digital optic disc stereo camera: intraobserver and interobserver repeatability of optic disc measurements

Shuttleworth, G N; Khong, C H; Diamond, J P

doi:10.1136/bjo.84.4.403

Cited by 28 publications

(30 citation statements)

References 18 publications

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“…In a previous study, the intraobserver and interobserver repeatability of optic disc measurements was shown to compare favourably with ophthalmoscopic and stereophotographic methods of assessment of the optic disc 11. However, stereoscopic versus monoscopic assessments of the images were not performed.…”

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confidence: 98%

A comparison of stereoscopic and monoscopic evaluation of optic disc topography using a digital optic disc stereo camera

Parkin

2001

British Journal of Ophthalmology

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Aims-To compare stereophotographic and monophotographic optic disc assessments made using a digital optic disc stereo camera. Methods-Stereo digital optic disc photographs of 150 selected patients who had presented to a glaucoma clinic were assessed by two masked observers on separate occasions using (1) the stereophotographs and a stereoviewer, (2) a single image from the same stereopair. Results were analysed for both right and left eyes separately. 95% tolerance limits for change (TC) and intraclass correlation coeYcients (ICC) were calculated and a multivariate analysis using a general linear model for repeated measures was performed. Conclusions-This study using a digital stereo camera indicates that there may be little benefit of stereoscopic imaging over monoscopic imaging despite demonstrating small but inconsistent diVerences between both observers and methods. (Br J Ophthalmol 2001;85:1347-1351 The detection of early or progressive glaucomatous optic disc changes is essential in the optimum management of glaucoma patients. Despite the plethora of new technologies the accepted "gold standard" for optic disc assessment remains stereoscopic optic disc photography. Results-1-4 However, measurements rely on a subjective evaluation by the clinician and are subject to poor interobserver agreement. 5-10The Discam optic disc camera (Marcher Enterprises Ltd, Hereford) obtains digital monochromatic sequential stereophotographic images of the optic disc and the allied software allows the computation of a number of optic disc parameters. In a previous study, the intraobserver and interobserver repeatability of optic disc measurements was shown to compare favourably with ophthalmoscopic and stereophotographic methods of assessment of the optic disc.11 However, stereoscopic versus monoscopic assessments of the images were not performed.The aims of this study were to determine whether there were significant diVerences in intraobserver and interobserver repeatability of the computed optic disc parameters using monophotographic and stereophotographic images to determine the margins of the optic disc and optic cup. Materials and methodsStereophotographic digital images of patients presenting to a glaucoma clinic were acquired by two experienced operators following pharmacological mydriasis. The detailed method has been previously described. 11 The quality of the images were assessed by observer 2 (MC), on the basis of contrast, clarity, stereoscopic appearance, illumination, and excessive movement between the image pair. As this study did not aim to determine the clinical usefulness of the Discam, but purely to compare two methods of assessment, only high quality images were used for analysis in order to maximise any diVerences. Exclusion criteria were poor illumination of the disc, poor quality image, lens opacity, poor stereoimage (large shift on the screen between images of stereo pair) and optic discs of anomalous configuration (those which were tilted, colobomatous, or myopic). A total of 201 images (from a ...

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A comparison of stereoscopic and monoscopic evaluation of optic disc topography using a digital optic disc stereo camera

Parkin

2001

British Journal of Ophthalmology

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“…They reported intraobserver CV values of 1.5% to 4.0% (for disc and rim area), 5 4.0% (for LCDR), 1 and 9.5% to 14.2% (for horizontal, vertical, and area CDR). 6 In the current study, instead of evaluating intraobserver variability, in which the same observer evaluates the same stereo photograph multiple times, we studied the variability associated with evaluating multiple images of the same optic nerve taken short periods apart. The interrepeat CV in this study was 6.68%, which is slightly higher than the intraobserver CVs in 2 of the 3 previous reports.…”

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Variance Owing to Observer, Repeat Imaging, and Fundus Camera Type on Cup-to-disc Ratio Estimates by Stereo Planimetry

Kwon

Adix²,

Zimmerman³

et al. 2009

Journal of Glaucoma

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“…7 The Discam stereo fundus photocamera (Discam, Marcher enterprises, UK) only takes pictures in monochromatic quality and it is also rather expensive. 8,9 In our study, the quantitative parameters ONH size and c/d ratio have been evaluated significantly differently on 3D images. The ONH size was measured larger by 3D as compared with 2D measurements, but there were no significant differences either between the 'gold standard' compared with the answers of both groups or between the evaluations of residents versus ophthalmologists.…”

Section: Discussionmentioning

confidence: 99%

3D vs 2D qualitative and semiquantitative evaluation of the glaucomatous optic disc atrophy using computer-assisted stereophotography

Lehmann

Mardin

Martus

et al. 2007

Eye

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Background and purpose Real colour documentation of the optic nerve head (ONH) is one of the most important methods to identify the early progression of glaucomatous optic nerve damage. This study compares the qualitative and semiquantitative evaluation of ONH photographs, using a 3D time-multiplexing system and conventional 2D photography, visualised on a computer monitor. Patients and methods Stereophotographs of the ONH were converted by special software in a 3D file. The same images were shown in 2D and 3D to 22 subjects with different training grades (residents and ophthalmologists). The evaluation based on a standardised questionnaire, containing semiquantitative parameters of the ONH. A weighted score for quality of ONH assessment counted the correct answers of the observers to compare their evaluation in 2D to the one made in 3D. Results All of the observers achieved a significant better evaluation of the ONH with 3D than with 2D images. No significant differences were observed between both groups. Classification errors with respect to the 'gold standard' were lower for 3D measurements as compared with 2D measurements (P ¼ 0.007). No significant differences were observed between the gold standard and residents or ophthalmologists for the ONH size, but for the c/d ratio the stereoscopic images lead to better results. Conclusion This study showed a better evaluation of parameters associated with the glaucomatous ONH atrophy with 3D images

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A new digital optic disc stereo camera: intraobserver and interobserver repeatability of optic disc measurements

Cited by 28 publications

References 18 publications

A comparison of stereoscopic and monoscopic evaluation of optic disc topography using a digital optic disc stereo camera

A comparison of stereoscopic and monoscopic evaluation of optic disc topography using a digital optic disc stereo camera

Variance Owing to Observer, Repeat Imaging, and Fundus Camera Type on Cup-to-disc Ratio Estimates by Stereo Planimetry

3D vs 2D qualitative and semiquantitative evaluation of the glaucomatous optic disc atrophy using computer-assisted stereophotography

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