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JA Goldsmith, S Radhakrishnan, V Westphal, D Huang, DK Dueker, AM Rollins, JA Izatt, SD Smith; Comparison of Optical Coherence Tomography and Ultrasound Biomicroscopy in Identifying Anatomically Narrow Angles . Invest. Ophthalmol. Vis. Sci. 2002;43(13):287.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To compare parameters measured by optical coherence tomography (OCT) and ultrasound biomicroscopy (UBM) of the anterior chamber angle, and their accuracy in classifying eyes with anatomically narrow angles. Methods: For this study, we used a prototype OCT instrument, which employs a longer wavelength (1.3 µm), and a scan speed of 4000 lines/second permitting video rate (8 frames/second), non-contact imaging of the anterior segment. Ophthalmic examination of 31 eyes of 28 subjects was performed, including gonioscopy by a glaucoma specialist. OCT and UBM were then performed, with 3 repeated images obtained in the nasal and temporal quadrants with each instrument. Computerized image analysis was used to quantify parameters of the anterior chamber angle from each modality. Results: Eight of 31 eyes were classified as having narrow angles (Shaffer grade ≤1). A strong correlation was found between gonioscopy grade and angle opening distance, angle recess area (ARA), and a new parameter we have defined, the trabecular iris space area (TISA) measured both by OCT and UBM (all p-values <0.0005). Both OCT and UBM showed excellent performance in classifying individuals with narrow angles. Areas under the receiver operating characteristic (ROC) curves for these parameters were all in the range of 0.91 to 0.99. Classification of eyes with narrow angles was most accurate by OCT using the ARA and TISA parameters (sensitivity=100%, specificity=95.7%). Conclusion: Parameters measured by OCT and UBM correlate strongly with gonioscopy. Classification of eyes with narrow angles was excellent with both modalities, but was better using parameters measured by OCT. The non-contact nature of OCT examination makes this a promising method for screening individuals at risk for narrow angle glaucoma.
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