Three-dimensional optic nerve head images using optical coherence tomography with a broad bandwidth, femtosecond, and mode-locked laser

Abstract

PurposeThe aim of this study was to demonstrate the fine laminar structure of the optic nerve head (ONH), in vivo, using a broad wavelength, ultra-high resolution, and optically coherent tomography (OCT) system.MethodsThis high-resolution OCT system, based on a 200 nm bandwidth spectrometer and an 8 femtosecond ultra-short, mode-locked, coherent laser light source, enabled in vivo cross-sectional ONH imaging with 2.0 μm axial resolution. A total of 300 optic disc B-scans, which consisted of 300 × 2048 pixels, were obtained in 10 μm steps. Three-dimensional images were rendered from these images to obtain n face images of the optic disc. Fundus photography, scanning laser ophthalmoscopy (SLO), and standard OCT were also performed for all subjects.ResultsThirty-six eyes of normal subjects and ten eyes of glaucoma patients with mean age of 40.0 ± 10.0 years were enrolled in this study. Sequential en face images, from the ONH surface to deeper layers, were reconstructed in 2.0 μm steps. Observation of the images indicated variations in the shape and arrangement of the lamina pores at different depths. Clear lamina pores were identified by this technique in 44 eyes, compared with the fundus camera (identified in six eyes), SLO (identified in 14 eyes), and standard OCT (identified in 24 eyes) (all comparisons, p < 0.001).ConclusionsThe fine structure of the ONH could be resolved in vivo using our OCT, providing improved imaging that can be used in research and clinical applications for a better characterization of the anatomical and pathological features associated with glaucoma.Electronic supplementary materialThe online version of this article (doi:10.1007/s00417-014-2870-5) contains supplementary material, which is available to authorized users.

Glaucomatous changes in lamina pores shape within the lamina cribrosa using wide bandwidth, femtosecond mode-locked laser OCT

“…Details of the current SD-OCT system have been described elsewhere. [ 17 – 19 , 21 , 22 ] In brief, it is an OCT system using an ultra-broadband Kerr lens ML Ti:Sapphire laser and wideband spectrometer. The spectral bandwidth of the light source was 200 nm full-width at half maximum (FWHM) at a central wavelength of 840 nm.…”

“…[ 17 , 18 ] Furthermore, the use of an ML coherent laser light source should allow us to obtain greater imaging depth and thin-slice en face imaging in the ONH than in the superluminescent diode light source, which is not a coherent light source in the strict sense. [ 17 , 19 ]…”

“…Using this system, which should be more suited for thin-slice LC imaging than existing commercially available spectral-domain (SD)-OCT instruments,[ 19 ] we conducted layer-by-layer analysis of the shape of the lamina pores within the LC to determine any potential correlation in the observed changes with glaucoma.…”

Vertical asymmetry of lamina cribrosa tilt angles using wide bandwidth, femtosecond mode-locked laser OCT; effect of myopia and glaucoma

“…The details of our SD-OCT system have been previously described elsewhere [11, 12, 14]. In brief, the OCT system used an ultra-broadband, Kerr lens, mode-locked (ML) Ti:sapphire laser, and a wide-band spectrometer.…”

“…High-resolution image acquisition enabled faster clearance of single-scanned images, resulting in substantially faster 3D image construction than that obtained with the standard commercial SD-OCT instruments that are currently available [11]. Using this system, we previously reported a novel indicator of LC tilt angles (LCTAs), which correlated with both glaucoma and refractive errors [12].…”