PURPOSE: To characterize preperimetric retinal nerve fiber layer (RNFL) defects on speckle noise-reduced spectral-domain optical coherence tomography (SD-OCT), and to determine whether detection of preperimetric RNFL defects can be improved by speckle noise reduction. PATIENTS AND METHODS: Thirty-two eyes of 32 patients with preperimetric glaucoma and 30 normal eyes of 30 volunteers underwent complete ophthalmic examinations and scanning by speckle noise-reduced SD-OCT (Spectralis), single-scan SD-OCT (RTVue-100), and single-scan time-domain (Stratus) OCT. RESULTS: All 40 RNFL defects identified by photography had angular widths <30 degrees and no disruption of RNFL reflectivity on Spectralis. Circumpapillary RNFL (cpRNFL) boundaries were accurately determined by Spectralis for 38 (95.0%) of the 40 defects, by RTVue-100 for 25 (62.5%), and by Stratus OCT for 23 (57.5%). Sensitivity for the detection of RNFL defects (cpRNFL thinning to <1% of normal for an age-matched database) was 15% for Stratus, 42.5% for RTVue, and 47.5% for Spectralis on sector maps and significantly higher for SD-OCT on temporal-superior-nasal-inferior-temporal (TSNIT) thickness graphs: RTVue-100 (57.5%; P=0.031) and Spectralis (90.0%; P=0.0001). On the basis of TSNIT thickness graphs, sensitivity for the detection of RNFL defects was significantly higher for Spectralis compared with RTVue-100 (P=0.001) and Stratus (P=0.0005). Spectralis TSNIT graphs were more sensitive (P=0.001) for glaucoma detection without significant reduction (P=0.125) in specificity compared with Spectralis sector maps. CONCLUSIONS: Our results suggest that accurate measurement of cpRNFL thickness by speckle noise-reduced SD-OCT and a comparison of the results with normative database using TSNIT graphs are required to improve the sensitivity for detecting preperimetric RNFL defects.
Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.