Abstract
Purpose :
Quantitative evaluation of optical properties of tissues in the normal optic nerve head (ONH) are demonstrated by using multifunctional Jones-matrix optical coherence tomography (JM-OCT). The optical properties include degree of polarization uniformity (DOPU), local birefringence (LB), correlation-based OCT-angiography (OCA), scattering intensity (OCT intensity), and OCT-signal attenuation coefficient (AC). The statistical interrelationship among tissues and optical parameters are investigated. The interrelationship among the optical parameters, age and refractive error are also examined.
Methods :
The left ONH of five healthy male subjects with ages ranging from 26 to 56 (mean ± SD, 36.8 ± 11.6) were scanned using 1.0-µm JM-OCT over a 3 mm x 3 mm transversal range at 100,000 A-scans/s. For each subject, tomograms of all of the optical parameters listed above were obtained. From horizontal B-scans of scattering intensity at the center of the ONH, the regions of the prelamina (PL), lamina cribrosa (LC), nasal and temporal peripapillary sclera (NPPS and TPPS) were manually delineated. Pearson’s correlations of the mean values among each region and each parameter are computed. Correlations of parameters with age and refractive error (in diopter) are also computed.
Results :
Table 1 summarizes the correlations. The AC at PL has a strong negative correlation with the OCA at LC (r = -0.94, p = 0.016, row-a), which may indicate that high scattering in the PL is associated with low flow in the LC. The DOPU at LC has a significant, strong negative correlation with age (r = -0.90, p = 0.036, row-b). Possible causes include accumulation of deposit or melanin with age in the LC. Although it was insignificant (p = 0.055), strong correlation was found between birefringence at LC and refractive error (r = 0.87, row-e). The other significant correlations were summarized in Table 1. In addition, the AC image shows a significant improvement in LC-PL contrast than the OCT intensity image (Welch's two sample t-test, one-tailed, p = 0.0022).
Conclusions :
The present analysis shows significant interrelationships among ONH tissues, its optical contrasts, age, and refractive error. These results suggest that quantitative JM-OCT can be useful for the investigation of the ONH. In comparison to scattering OCT, attenuation imaging would provide better quantitative assessment.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.