Thermal lens measurements in the cornea.

Journal Article (Journal Article)

Q-switched pulses from a neodymium/YAG (yttrium-aluminium-garnet) laser were passed through corneal discs taken from the enucleated eyes of three baboons and four rabbits. The time course of heat dissipation following absorption of laser energy by the tissue was studied with the use of a second continuous wave laser beam acting as a probe. It was found that the absorption of each neodymium/YAG pulse created a transient divergent lens within the cornea as theoretical considerations predicted. The relaxation time that characterised the decay of this thermal lens for a 1/e laser beam diameter of 2.0 mm was found to be 2.3 +/- 0.1 s (mean +/- standard error for 12 separate groups of measurements). Our results show that Q-switched laser pulses passing through apparently unaffected transparent tissues can induce thermal lens effects which persist for several seconds. The optical transfer of each pulse in a stream will be identical only if enough time is left between pulses for the tissues to return to their initial state. Therefore, when such laser pulses sharply focused to perform high precision intraocular surgery are used, thermal lensing in the transparent ocular media must limit the rate at which pulses can be usefully delivered.

Full Text

Duke Authors

Cited Authors

  • Venkatesh, S; Guthrie, S; Cruickshank, FR; Bailey, RT; Foulds, WS; Lee, WR

Published Date

  • February 1985

Published In

Volume / Issue

  • 69 / 2

Start / End Page

  • 92 - 95

PubMed ID

  • 3838138

Pubmed Central ID

  • PMC1040531

International Standard Serial Number (ISSN)

  • 0007-1161

Digital Object Identifier (DOI)

  • 10.1136/bjo.69.2.92

Language

  • eng

Conference Location

  • England