Purchase this article with an account.
Hamid Hosseini, Jay Riddle, Gina Lee, Elena Bitrian, Naveed Nilforushasn, Laurence Rahardjanoto, Joseph Caprioli, Kouros Nouri-Mahdavi; Older Age and Longer Axial Length are Associated with Lower Signal Strength on Spectral-Domain OCT. Invest. Ophthalmol. Vis. Sci. 2011;52(14):1028.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To determine factors affecting signal strength (SS) with spectral-domain optical coherence tomography (SD-OCT).
Eighty-three eyes of 47 subjects from the UCLA OCT Imaging Study were included. Open-angle glaucoma patients, glaucoma suspects or normal subjects meeting the following criteria were prospectively enrolled: reliable fields with MD >-15.0 dB, spherical refractive error <8 D and astigmatism <3 D, and no prior glaucoma surgery. Eligible patients underwent a full eye exam including biometry with IOLMaster, and disc and retinal nerve fiber layer (RNFL) OCT imaging (Optic disc Cube 200x200, Cirrus OCT) by a single technician. Linear regression analyses correcting for the correlation of the two eyes of the same subject were performed to determine factors influencing SS on OCT images.
Average (± SD) mean deviation was -2.7 ± 3.4 dB. Signal strength ranged from 6 to 10 (mean ± SD: 8.1 ± 0.81). On univariate analyses, older age (p <0.001), longer axial length (p=0.006), thinner central corneal thickness (CCT; p=0.063), higher intraocular pressure (p=0.064), and steeper average keratometry (p=0.072) were predictive of a lower SS. Only age (p<0.001), axial length (p=0.005), and average keratometry (p=0.032) were associated with a lower SS on multivariate analyses. Severity of glaucoma as determined by mean deviation was not a predictive factor for a poorer SS on univariate or multivariate analyses (p= 0.517 and 0.634, respectively).The effect of age did not change after reanalyzing data from eyes with visual acuity better than or equal to 20/25 (46 eyes; p=0.009 for age).
Older age, longer axial length and, to a lesser extent, steeper corneal curvature are the major determinants for lower image quality with SD-OCT. The age influence seems to be only partially related to media opacity. This finding has clinical implications since lower SS has been associated with thinner RNFL measurements.
This PDF is available to Subscribers Only