Optical coherence tomography refraction and optical path length correction for image-guided corneal surgery.

Journal Article (Journal Article)

Optical coherence tomography (OCT) may be useful for guidance of ocular microsurgeries such as deep anterior lamellar keratoplasty (DALK), a form of corneal transplantation that requires delicate insertion of a needle into the stroma to approximately 90% of the corneal thickness. However, visualization of the true shape of the cornea and the surgical tool during surgery is impaired in raw OCT volumes due to both light refraction at the corneal boundaries, as well as geometrical optical path length distortion due to the group velocity of broadband OCT light in tissue. Therefore, uncorrected B-scans or volumes may not provide an accurate visualization suitable for reliable surgical guidance. In this article, we introduce a method to correct for both refraction and optical path length distortion in 3D in order to reconstruct corrected OCT B-scans in both natural corneas and corneas deformed by needle insertion. We delineate the separate roles of phase and group index in OCT image distortion correction, and introduce a method to estimate the phase index from the group index which is readily measured in samples. Using the measured group index and estimated phase index of human corneas at 1060 nm, we demonstrate quantitatively accurate geometric reconstructions of the true cornea and inserted needle shape during simulated DALK surgeries.

Full Text

Duke Authors

Cited Authors

  • Tian, Y; Draelos, M; McNabb, RP; Hauser, K; Kuo, AN; Izatt, JA

Published Date

  • September 1, 2022

Published In

Volume / Issue

  • 13 / 9

Start / End Page

  • 5035 - 5049

PubMed ID

  • 36187253

Pubmed Central ID

  • PMC9484446

International Standard Serial Number (ISSN)

  • 2156-7085

Digital Object Identifier (DOI)

  • 10.1364/BOE.464762

Language

  • eng

Conference Location

  • United States