Effect of Cataract and Pupil Size on Image Quality With Confocal Scanning Laser Ophthalmoscopy

Zangwill, Linda M.; Irak, Inci; Berry, Charles C.; Garden, Valerie; Lima, Marcia de Souza; Weinreb, Robert N.

doi:10.1001/archopht.1997.01100160153003

Cited by 60 publications

(28 citation statements)

References 16 publications

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“…Even if each image is made by many points, users prefer to employ standard parameters for each system and do not use all the available data. [13][14][15][16][17][18][19][20][21][22] To obtain parameter measurements, an outline had to be drawn around the outer optic disc edge and although this technique had a good reproducibility, the contour line position could change from one center to another. 10 The anatomical variability of normal ONH shape makes it difficult to differentiate normal from glaucomatous optic discs.…”

Section: Discussionmentioning

confidence: 99%

“…The accuracy and reproducibility of this instrument have previously been described in detail. [13][14][15][16][17][18][19][20][21][22] The HRT uses a scanning confocal laser imaging system, which produces a series of 32 confocal images of the back of the eye at consecutive focal planes, each 256 Â 256 pixels. This series is converted by further processing into a single 3-D topographic image.…”

Section: Optic Nerve Head Topographic Analysismentioning

confidence: 99%

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Detection of glaucomatous optic nerve head by using Heidelberg topographic maps

Iester

Zanini

Vittone

et al. 2006

Eye

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Section: Discussionmentioning

confidence: 99%

Section: Optic Nerve Head Topographic Analysismentioning

confidence: 99%

Detection of glaucomatous optic nerve head by using Heidelberg topographic maps

Iester

Zanini

Vittone

et al. 2006

Eye

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“…The patient's pupils were dilated before the examination because this has been reported to improve the quality of the HRT-II images. 24 Fourteen HRT parameters: the disc area; rim area; cup volume; cup area; cup/disc area ratio; rim volume; mean cup depth; vertical cup/disc area ratio; cup shape measure; maximum cup depth; reference height; height variation contour; retinal …”

Section: Optic Disc Measurements With Hrt-iimentioning

confidence: 99%

Correlation between morphology of optic disc determined by Heidelberg Retina Tomograph II and visual function in eyes with open-angle glaucoma

Omodaka

Nakazawa²,

Otomo³

et al. 2010

OPTH

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Purpose:To investigate the correlation between the morphology of the optic disc and the visual function of eyes with open-angle glaucoma (OAG). Patients and Methods: One hundred and three eyes of 76 patients with OAG were studied. The baseline optic disc morphology was used to classify the eyes into four types: focal ischemic type (FI), myopic glaucomatous type (MY), senile sclerotic type (SS), and generalized enlargement type (GE). The morphological parameters of the disc were determined by the Heidelberg Retina Tomograph II (HRT-II) and the visual function by the mean deviation (MD) of the Humphrey field analyzer. Results: Fourteen eyes were classified as the FI type; 52 as the MY type; 17 as the SS type; and 20 as the GE type. The highest correlation coefficients of HRT-II parameters to the MDs was the cup/disc area ratio (r = -0.27) for all groups, the vertical cup/disc ratio (r = -0.42) in the MY group, the maximum cup depth (r = 0.49) in the SS group, and the cup area (r = -0.70) in the GE group. However, none of the parameters was correlated in the FI group. Conclusions:The correlation between the HRT-II parameters and MDs was different for the four disc types. These findings suggest that a classification of optic disc morphology had a benefit for interpreting the measured values of HRT-II.

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“…The quality and variability of the images are associated with pupil size and density of nuclear and posterior subcapsular cataracts. 4,5 In addition, HRT measurements are influenced by acute changes in intraocular pressure 6,7 and even the cardiac cycle. 8 Current limitations of the technology include the need to outline the anterior scleral canal opening and a reference plane and stereometric parameters that are dependent upon this delineation.…”

Section: Heidelberg Retinal Tomographmentioning

confidence: 99%

Image analysis of optic nerve disease

Burgoyne¹

2004

Eye

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Existing methodologies for imaging the optic nerve head surface topography and measuring the retinal nerve fibre layer thickness include confocal scanning laser ophthalmoscopy (Heidelberg retinal tomograph), optical coherence tomography, and scanning laser polarimetry. For cross-sectional screening of patient populations, all three approaches have achieved sensitivities and specificities within the 60-80th percentile in various studies, with occasional specificities greater than 90% in select populations. Nevertheless, these methods are not likely to provide useful assistance for the experienced examiner at their present level of performance. For longitudinal change detection in individual patients, strategies for clinically specific change detection have been rigorously evaluated for confocal scanning laser tomography only. While these initial studies are encouraging, applying these algorithms in larger numbers of patients is now necessary. Future directions for these technologies are likely to include ultrahigh resolution optical coherence tomography, the use of neural network/machine learning classifiers to improve clinical decision-making, and the ability to evaluate the susceptibility of individual optic nerve heads to potential damage from a given level of intraocular pressure or systemic blood pressure. Definition of termsThere are at present two principal tasks for these imaging systems. First, cross-sectional screening, in which an eye is imaged initially with the intention of detecting the presence of glaucomatous optic nerve damage. Second, longitudinal change detection, in which an eye that is already known to be at risk is imaged on multiple occasions over time with the intention of detecting change or progressive damage. Current instruments Heidelberg retinal tomographThe Heidelberg retinal tomograph (HRT) is a confocal scanning laser ophthalmoscope (CSLO) that uses a 670 nm diode laser to obtain a series of two-dimensional optical section images of the ONH and peripapillary retina. A threedimensional topographic image of the ONH surface is then built from the series of 16-64 serial optical sections, when algorithms are used to find the surface at each of 256 Â 256 (HRT I) or 384 Â 384 (HRT II) pixels over a 10 or 151 field of view. The HRT II automatically captures three consecutive 151 images and from these generates a mean topographic image.To process images, the optic disc margin (anterior scleral canal opening) is defined by a contour line placed around the inner margin of the peripapillary scleral ring. The standard reference plane for volumetric parameter calculation is then automatically determined as 50 mm posterior to the mean peripapillary retinal height along the contour line between 350 and 3561; however, the reference plane

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Effect of Cataract and Pupil Size on Image Quality With Confocal Scanning Laser Ophthalmoscopy

Cited by 60 publications

References 16 publications

Detection of glaucomatous optic nerve head by using Heidelberg topographic maps

Detection of glaucomatous optic nerve head by using Heidelberg topographic maps

Correlation between morphology of optic disc determined by Heidelberg Retina Tomograph II and visual function in eyes with open-angle glaucoma

Image analysis of optic nerve disease

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