Abstract
Purpose: :
Advanced imaging systems such as optical coherence tomography (OCT) can objectively measure both retinal nerve fiber layer (RNFL) thickness and optic disc contour. We aim to estimate the diagnostic accuracy of the Stratus OCT for glaucoma screening in high risk populations.
Methods: :
In a prospective cross-sectional study, 333 volunteer participants with risk factors for glaucoma underwent imaging of the optic nerve and peripapillary RNFL 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 predictive values and positive and negative likelihood ratios of the RNFL and optic disc parameters were calculated.
Results: :
After excluding 30 eyes due to missing data and 99 eyes due to poor scan quality, the data of 209 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/disk area ratio) and RNFL 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% (CI 92%-98%), positive predictive value of 33% (CI 11%-65%), negative predictive value of 99% (CI 96%-100%), a positive likelihood ratio of 17.08 (CI 7.06-41.4) and a negative likelihood ratio of 0.35 (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.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • nerve fiber layer