Font Size: a A A

Screening for glaucoma in high risk populations using the Stratus optical coherence tomography

Posted on:2011-05-25Degree:M.ScType:Thesis
University:McGill University (Canada)Candidate:Li, GiseleFull Text:PDF
GTID:2444390002956566Subject:Ophthalmology
Abstract/Summary:
Background: Advanced imaging systems such as optical coherence tomography (OCT) can objectively measure both retinal nerve fiber layer thickness and optic disc contour. We aim to evaluate the validity of OCT for glaucoma screening in high risk populations.;Results: After excluding poor quality scans and missing data, the data of 210 right eyes were analyzed. Six right eyes had definitive glaucoma. Combining the best performing optic nerve head parameters (cup diameter or cup/disk vertical ratio or cup area) and nerve fiber layer parameters (superior average or inferior average or overall average) using AND-logic resulted in a sensitivity of 67% (95% confidence interval [CI], 24%-94%), specificity of 96% (95% CI, 92%-98%), positive likelihood ratio of 17.08 (95% CI, 7.06-41.4) and a negative likelihood ratio of 0.35 (95% CI, 0.11-1.08).;Conclusions: When adequate quality scans may be obtained, the Stratus has moderate sensitivity and high specificity for definitive glaucoma. Specificity is increased when parameters from both the optic nerve head and retinal nerve fiber layer scans are combined.;Methods: Three hundred thirty-three volunteer participants with risk factors for glaucoma underwent imaging of the optic nerve and peripapillary nerve fiber layer using the Stratus version of the OCT. Based on an ophthalmologic examination and frequency doubling perimetry, participants were classified into 4 categories: normal, possible glaucoma, probable glaucoma and definitive glaucoma. The sensitivities, specificities, positive and negative likelihood ratios of the retinal nerve fiber layer and optic disc parameters were calculated.
Keywords/Search Tags:Nerve fiber layer, Optic, Glaucoma, OCT, Risk, Stratus, Using, Parameters
Related items