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M. Skaf, A.B. Bernardes, L.S. Melo, Jr, R.A. Costa, J.C. Castro, J.A. Cardillo; Assessment of Normal and Early Glaucomatous Retinal Nerve Fiber Layer Thickness Using a New Optical Coherence Tomography Approach . Invest. Ophthalmol. Vis. Sci. 2005;46(13):2520.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To perform an OCT–RNFL thickness assessment of 20 normal individuals and 20 patients with initial glaucomatous optic neuropathy utilizing an optimized measurement approach. Methods: After a complete ophthalmologic examination, twenty normal volunteers and twenty mild glaucomatous cases (patients with evident signs of glaucomatous optic neuropathy on the optic nerve head and RNFL, associated to ocular hypertension and/or typical visual field defects at the 24–2 Humphrey SITA test with a MD better than – 6.00 dB) were selected. One eye of each patient was studied. Sequential measurements of the RNFL thickness from disc margin up to 1400 µm in four radial sections (superotemporal, superonasal, inferonasal and inferotemporal) were performed. For both groups first circle was adjusted to the size of the optic disc and 3 scans were performed at this radius and at every 200 µm up to 1400 µm distance from the disc margin. A total of 24 concentric circles (3 scans per radius X 8 radii) were obtained from a single visit. From the thickness chart of each scan, selected points (64, 192, 320, and 448) were chosen to represent each radial section. The mean of the three RNFL thickness measurements obtained at the selected points of each set of three scans was used for statistical analysis. Results: The statistical analysis demonstrated a significant decrease of the RNFL thickness in the glaucomatous group at every distance from disc margin in the inferotemporal section (P<0.048), and in all sections at the disc margin (P ≤ 0.001). Comparing the mean overall thickness, glaucomatous patients had a significant smaller mean at every studied distance from the optic disc (P≤0.004). Differences between the overall mean at the disc margin of normal and glaucomatous patients were 41.2 µm (superotemporal), 56.5 µm (superonasal), 63.8 µm (inferonasal), and 43.8 µm (inferotemporal). Conclusions: This new sequential OCT–RNFL thickness analysis at regular distances from the disc margin demonstrated to be an efficient approach in differing normal and early glaucomatous cases, especially if inferotemporal section, disc margin measurements and overall mean are studied.
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