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P.J. Harasymowycz, D.G. Papamatheakis, M. Chagnon, A. Kamdeu Fansi; The Validity of Screening for Glaucomatous Optic Nerve Damage Using Confocal Scanning Laser Ophthalmoscopy (HRT II) in High Risk Populations . Invest. Ophthalmol. Vis. Sci. 2005;46(13):4800.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To evaluate whether confocal scanning laser ophthalmoscopy (HRT II) is a valid tool for the detection of glaucomatous optic nerve damage. Methods: This was a prospective, observational, cross–sectional, non–consecutive, populational study that took place in Montreal, Quebec, Canada and focused on "high risk" groups for open angle glaucoma (OAG) development. 303 subjects were enrolled during a six month period. Subjects underwent three tests: frequency doubling perimetry, HRTII, and a standard ophthalmologic examination, including gonioscopy, intraocular pressure–IOP, central corneal pachymetry–CCT, optic disc grading and fundoscopy. Outcomes measures included Likelihood Ratios (LR), sensitivities and specificities, as well as positive predictive values (PPV) of Moorefields regression analysis (MRA), Cup Shape Measure (CSM), Height Variation Contour (HVC) and Mean Retinal Nerve Fiber Layer Thickness (MRNFL). Glaucoma gold–standard and MRA test positive defininitions varied depending on wether "suspects" and/or "borderlines" were classified with "normals" or "glaucoma". Results: Of the original 303 patients examined, 21 (6.9%) were found to have glaucoma. 29 patients and an additional 13 single eyes were excluded from the statistical analysis. HRT II was successfully performed and of good quality in 531 of 604 eyes (88%). When MRA was compared to clinical based diagnosis, accordance was k=0.372, p<0.001. Best accordance was seen when "normals" where grouped with suspects in both clinical and MRA diagnosis (k=0.604, p<0.001). Depending on "gold–standard" and test positive definitions for glaucoma, specificity ranged from 87% to 97%, sensitivity from 25% to 100%, and PPV from 28% to 68%. CSM (p<0.001) and MRNFLT ( p<0.001) were smaller and the HVC (p=0.026) was less negative (greater) in "borderlines" compared to "normals" and in "out of normal limits" compared to "borderlines" and "normals", as defined by HRT II. CSM (p<0.001) and MRNFLT (p=0.01) were smaller in "glaucoma" compared to "suspects" and "normals" group, and "suspects" compared to "normals", as defined by clinical ecamination. Conclusions: This study suggests that a glaucoma screening program may be more effective in detecting POAG when targeting high risk populations. HRT II may prove to be a useful tool in detecting glaucomatous optic nerve damage, and could be used as part of a complete glaucoma screening protocol.
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