Purpose
To correlate different optic nerve head (ONH) parameters measurements obtained by enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT) with visual field status in glaucomatous patients.
Methods
We prospectively enrolled glaucomatous patients, glaucomatous suspects and healthy controls. Exclusion criteria: significant media opacity or other ocular disease. All participants underwent EDI-OCT (SD-OCT; Spectralis®, Wavelength: 870nm; Heidelberg Engineering Co., Heidelberg, Germany) and visual field assessment using the Humphrey Visual Field Analyzer (24-2; SITA-Standard). These ONH parameters were evaluated: lamina cribrosa (LC) and pre-laminar neural tissue thicknesses (PLNTT) and cup depth (CD). Two independent examiners assessed EDI-OCT images (poor quality images were not included in the analysis). Each ONH parameter was compared among groups using analysis of covariance. Multiple regression analysis was used to investigate the correlation between each ONH parameter and the visual field mean deviation index (MD).
Results
A total of 25 eyes of 25 patients were included. Glaucomatous patients (and suspects) were significantly older than controls (p=0.013; Table 1). Although the LC was thinner in glaucomatous patients (mean, 271.2 μm) compared to controls (mean, 310.3 μm), these differences did not reach statistical significance (p=0.42; Figure 1). PLNTT was significantly reduced in glaucomatous patients (mean, 188.2 μm) compared to controls (mean, 523.6 μm; p<0.01; Figure 2). As expected, DC was deeper in glaucomatous patients (mean, 610.9 μm) compared to controls (mean, 286.2 μm; p=0.04; Figure 3). Although there was a trend for a significant correlation between LC thickness and visual field MD (eyes with thinner LC having a worse MD; Figure 4) this association did not reach statistical significance (R2=0.13, p=0.16). There was no significant correlation between PLNTT and visual field MD (R2=0.06, p=0.37).
Conclusions
Using the EDI method to evaluate deep ONH structures in vivo, we found a significant reduction in PLNTT in glaucomatous patients. In addition, there was a trend for LC thinning in these eyes and for a significant correlation between LC thickness and visual field status. Our data suggest the hypothesis that laminar and pre-laminar tissues involvement are associated with visual field loss in glaucomatous patients.
Keywords: 627 optic disc •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)