Affiliation:
1. Rehabilitation Research Center, Department of Optometry, Iran University of Medical Sciences, Tehran, Iran
2. Department of Basic Sciences, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran
3. Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
Abstract
Purpose:
To determine the distribution, ocular, and systemic determinants of peripapillary retinal nerve fiber layer thickness (pRNFLT) using spectral-domain optical coherence tomography (SD-OCT) in an elderly population.
Methods:
This report is a part of the Tehran Geriatric Eye Study, a population-based cross-sectional study conducted in Tehran, the capital of Iran. The study population was all residents aged 60 years and above in Tehran. The sampling was performed using a multi-stage stratified random cluster sampling method. All study participants underwent ocular examination (including measurement of visual acuity, objective and subjective refraction, and slit-lamp biomicroscopy), anterior segment imaging using Pentacam HR, and ocular biometry using IOLMaster 500. The OCT imaging was performed for a random subsample (1307 individuals) using Spectralis SD-OCT.
Results:
Two thousand two hundred and forty-six eyes of 1189 individuals were analyzed for this report. Of these, 691 (58.1%) were female, and the mean age of the participants was 67.3 ± 5.9 years (60–94 years). The mean overall pRNFLT was 98.6 μ (95% confidence interval [CI]: 98.0–99.3). There was a statistically significant difference in pRNFLT between different quadrants; the highest and lowest mean pRNFLT was related to inferior and temporal quadrants, respectively (P < 0.001). The multiple generalized estimating equation model showed that older age (coefficient: −0.15 [95% CI: −0.24 to −0.06], P = 0.001), diabetes (coefficient: −1.69 [95% CI: −2.82 to −0.55], P = 0.004), and longer axial length (coefficient: −0.52 [95% CI: −0.83 to −0.22], P < 0.001) were significantly associated with a decreased overall pRNFLT. Higher body mass index was significantly related to an increased overall pRNFLT (coefficient: 0.19 [95% CI: 0.07 to 0.30], P = 0.002).
Conclusions:
The results of the present study can be used as a reference database for pRNFLT in the elderly population. Considering ocular and systemic determinants of pRNFLT is necessary for correct clinical interpretation of this parameter.