Purchase this article with an account.
A.K. Hsieh, S. Fraser–Bell, M. Ying–Lai, R. Varma; Retinal Nerve Fiber Layer Asymmetry: A Useful Parameter in Assessment of Early Glaucoma . Invest. Ophthalmol. Vis. Sci. 2005;46(13):2521.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
PURPOSE: To describe the asymmetry in the retinal nerve fiber layer thickness (RNFL) in normals and compare it to a sample of patients with early glaucomatous optic nerve damage. Methods: Seven hundred and twenty four participants underwent a complete examination including measurement of visual acuity, intraocular pressure by applanation, stereoscopic disc photographs, Humphrey visual field tests, and STRATUS OCT measured RNFL in both eyes. Fast RNFL scans performed by the STRATUS OCT consisting of three consecutive measurements of the peripapillary RNFL with diameter of 3.46 mm centered around the optic disc were performed on both eyes of all participants. RNFL asymmetry was defined as the difference in RNFL between the right and left eye of the same person. The overall RNFL asymmetry and the quadrantic RNFL asymmetry and its relationship to age, gender, and refractive error were evaluated using analysis of variance (ANOVA), t tests, and multiple regression analyses respectively. Overall RNFL asymmetry and the quadrantic RNFL asymmetry between normal persons and patients with early glaucomatous optic nerve damage were compared using t–tests. Results: 687 normal persons and 37 patients with early glaucomatous damage were included in the study. The normal persons had a mean age of 51.5 years, a mean IOP of 14.45 mmHg, a mean C/D of 0.32 and an average MD of –1.27. In normals the mean (+ s.d.) overall RNFL asymmetry was 4.5 (+ 3.7) microns and the mean quadrantic asymmetry were 7.1±5.9, 9.9±7.9, 10.8±8.5, 9.3±8.2 microns in the temporal, superior, nasal, inferior quadrants respectively. Patients with early glaucoma had a mean age of 57.6 years, a mean IOP of 19.5 mmHg , a mean C/D of 0.48 and an average MD of –2.26. The mean asymmetry in overall RNFL was 6.4± 6.9 microns. The mean quadrantic asymmetry were 7.7±6.7, 14.8±13.1, 12.1±8.8, 11.5±12 microns in the in the temporal, superior, nasal, inferior quadrants respectively. There were no consistent associations between RNFL asymmetry and age, gender, axial length, or spherical equivalent refractive error. The asymmetry in the superior RNFL was 48% greater in early glaucomatous patients compared to normal persons and these differences were statistically significant (p<0.03). Conclusions: Asymmetry in the STRATUS OCT measured RNFL may be an early sign of glaucomatous optic nerve damage. The clinical utility of this parameter in the management of patients with glaucoma should be further evaluated.
This PDF is available to Subscribers Only