Stress wave amplitudes during laser surgery of the cornea

Ophthalmology. 2001 Jun;108(6):1070-4. doi: 10.1016/s0161-6420(01)00570-x.


Purpose: To determine the stress wave amplitudes generated during photoablation of the cornea using an argon fluoride excimer laser.

Design: Experimental study using porcine eyes.

Methods: Profiles of the stress wave amplitudes and enucleated human eyes along the axis of symmetry of porcine eyes and enucleated human eyes were measured using a miniature piezoelectric transducer. The ablation parameters, fluence, and ablation diameters were varied within the range of clinical application.

Main outcome measures: Stress wave amplitudes generated during photoablation.

Results: The stress waves pass through a pressure focus located in the posterior lens and anterior vitreous, where amplitudes of up to 100 atm were measured with a 6-mm or larger ablation zone. Posterior to this focus, the stress wave amplitudes rapidly decrease to less than 10 atm at the retinal site. Small diameter excimer laser spots (< or =1.5 mm) produce a declining stress wave with no pressure focus at the lens and anterior vitreous.

Conclusions: Stress waves may be potentially hazardous to anterior structures of the human eye, including the corneal endothelium, lens and anterior vitreous face. They peak at the lens and vitreous with a broad beam, but not with small spot laser ablation. At posterior retinal and subretinal structures, they may be considered harmless.

MeSH terms

  • Animals
  • Cornea / surgery*
  • Corneal Diseases / etiology*
  • Eye Enucleation
  • Humans
  • Keratomileusis, Laser In Situ / adverse effects*
  • Lasers, Excimer
  • Photorefractive Keratectomy / adverse effects*
  • Stress, Physiological / etiology*
  • Swine
  • Vibration*