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J.L. Hougaard, B. Bengtsson, C. Ostenfeld, A. Heijl; Comparison of Retinal Nerve Fiber Layer Thickness Measurements Using Different Stratus–OCT Scan Protocols in Patients With Early Glaucoma . Invest. Ophthalmol. Vis. Sci. 2005;46(13):4817.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To compare the sensitivity and reproducibility of retinal nerve fiber layer thickness (RNFLT) measurements using different Stratus–Optical Coherence Tomography (OCT) scan protocols in patients with early glaucoma. Methods: A normal database, including one eye in each of 151 healthy subjects, was collected. In addition to a general eye examination all subjects underwent perimetry, fundus, disk, and RNFL photography. RNFLT was measured by the Stratus–OCT using a full circumpapillary scan with a diameter of 3.4 mm. RNFLT measurements were evaluated based on: (1) average values of three scans of the FAST RNFLT scan protocol with 256 A–scan density, (2) average values of three scans of the RNFLT scan protocol with 512 A–scan density, (3) the single best quality scan of the three scan RNFLT scan protocol with 512 A–scan density, and (4) the single best quality scan of the three scan RNFLT scan protocol with 256 A–scan density. Normal values and limits for full circle RNFLT was calculated for each of the four measurement protocols. The 95th and 99th percentiles defined the normal limits. These limits were evaluated in 56 eyes of 56 patients with early glaucoma. Sensitivity for each of the four RNFLT measurement protocols was determined at the predefined specificities of 95 % and 99 %. Reproducibility was calculated as the coefficient of variation. Results: The sensitivity for the four different OCT RNFLT protocols evaluated was almost the same, with a predefined specificity at 95% the sensitivity ranged from 87.5 to 89.3 %, and at 99 % specificity from 73.2 to 75%. The coefficient of variation was 5.3 % with measurement protocol (1), 3.0 % in (2), 4.2 % in (3), and 5.4 % in (4). Conclusions: We found no significant difference in the diagnostic ability between the four different peripapillary Stratus–OCT RNFLT protocols evaluated. The possibly better reproducibility of the RNFLT measurements of the 512 A–scan density scan protocol, suggests that such measurements might be superior to RNFLT measurements of scan protocols using a 256 A–scan density for follow–up.
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