Abstract
Abstract: :
Purpose:To determine the relationship between Retinal Nerve Fiber Layer Thickness(RNFLT) and disc area in normal human eyes. Methods:A complete Ophthalmologic examination, including automated perimetry, Optical Coherence Tomography (OCT) and optic disc image analysis were performed on a population based sample of participants from the Los Angeles Latino Eye Study. OCT scanning consisted of three peripapillary circular scans with a diameter of 3;4 mm to obtain the average RNFLT. A linear vertical Scan through the superior and inferior optic disc poles was performed to measure the superior and inferior RNFLT at the disc margin. The Topcon Image Analyzer was used to measure the disc area. The disc area was corrected using the Littmann Equation. Data were analyzed using linear regression analyses to determine the relationship between disc area and superior, inferior and average peripapillary RNFLT. Results:182 normal eyes of 182 participants were studied. All participants had no evidence of ocular disease. The mean age of the participants was 51;2 (+-9)years.After adjusting for age and gender, the superior and average RNFLT was inversely related to disc area (r2= 0.06, p= 0.008; r2=0.11, p < 0.0001 respectively). The inferior RNFLT was not related to disc area (r2= 0.02, p=0.34). Conclusion:Since disc size is correlated with RNFLT, it is important to adjust for disc size when obtaining RNFLT measurements. Also this observation suggests that OCT scan diameters should be proporcional to disc size when obtaining standardized RNFLT measurements.
Keywords: 498 optic disc • 430 imaging/image analysis: clinical • 432 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)