Volumetric imaging of inner retina with adaptive optics spectraldomain optical coherence tomography

Yan Zhang, Barry Cense, Ravi Jonnal, Weihua Gao, Steve Jones, Scot Olivier, Donald T. Miller

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

Adaptive optics (AO) coupled with ultra-fast spectral-domain optical coherence tomography (SD-OCT) has achieved the necessary 3D resolution, sensitivity, and speed for imaging the microscopic retina at the cellular level. While this technology has been rigorously applied to evaluating the 3D morphology of cone photoreceptors, similar detailed studies of cell-sized structures in the inner retina have yet to be undertaken. In this paper, we improve the technical performance of our AO ultrafast SD-OCT and investigate its use for imaging the microscopic inner retina, in particular the nerve fiber layer (NFL) and retinal capillary network. To maximize lateral resolution within the inner retina, focus was controlled with a high stroke, 37-actuator bimorph mirror (AOptix) that also served as the wavefront corrector of the AO. The AO system operated at a closed-loop rate of 25 Hz. The SD-OCT sub-system consisted of a superluminescent diode (λ= 842 nm, Δλ= 50 nm) and a 512 pixel line scan charge-coupled device (CCD) that acquired 72,000 A-scans/sec. Three different B-scan lengths (36, 60, and 120 A-scans/B-scan), which correspond to B-scan exposure durations of 0.5, 0.83, and 1.67 ms, were evaluated to determine the maximum B-scan length that could be tolerated without noticeable loss in image quality due to eye motion in the well fixated eye. Additional technical improvements included sub-pixel registration to remove instrument error and axial registration of the volume images. Small volume images were acquired at 2 and 7 degrees retinal eccentricity with focus systematically shifted through the retina. Small capillaries, some approaching the smallest in the human eye, were readily detected with AO SD-OCT. Appearance of the nerve fiber layer varied noticeably with depth. The most inner portion (presumably the inner limiting membrane) appeared as a thin irregular surface with little characteristic speckle noise. Within the NFL, complex striation patterns (presumably NFL bundles) were observed throughout the entire thickness with pattern density highest in the inner portion (∼15 μm) and large corrugations (̃35 μm) at the interface with the ganglion cell layer below. Speckle noise was significant throughout the NFL.

Original languageEnglish (US)
Title of host publicationOphthalmic Technologies XVII
Volume6426
DOIs
StatePublished - Aug 31 2007
Externally publishedYes
EventOphthalmic Technologies XVII - San Jose, CA, United States
Duration: Jan 20 2007Jan 23 2007

Other

OtherOphthalmic Technologies XVII
CountryUnited States
CitySan Jose, CA
Period1/20/071/23/07

Keywords

  • Adaptive optics
  • Capillaries
  • Eye
  • Nerve fiber bundles
  • Optical coherence tomography
  • Retina
  • Spectroscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology Nuclear Medicine and imaging

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  • Cite this

    Zhang, Y., Cense, B., Jonnal, R., Gao, W., Jones, S., Olivier, S., & Miller, D. T. (2007). Volumetric imaging of inner retina with adaptive optics spectraldomain optical coherence tomography. In Ophthalmic Technologies XVII (Vol. 6426). [64261P] https://doi.org/10.1117/12.701960