Photospallation: a new theory and mechanism for mid-infrared corneal ablations.
OBJECTIVE
A new mechanism for ablating corneal tissue is proposed, based on photospallation with short pulse mid-infrared (IR) laser radiation.


METHODS
By using a judicious combination of high absorption, short pulses, and low fluences, ablation with this process can potentially remove tissue in a highly localized manner with submicron collateral thermal damage characteristics similar to those achieved by excimer lasers. We provide a brief qualitative overview of aspects of the spallation process that distinguish it from the more familiar photoablation and photothermal mechanisms.


RESULTS
Results of preliminary parametric analysis based on one-dimensional models of thermoelastic expansion are summarized.


CONCLUSIONS
These preliminary calculations lend support to the conjecture that corneal tissue can be removed effectively with strongly absorbed nanosecond pulses from a mid-IR laser, using operational fluence levels of less than 200 mJ/cm2.
Hoffman
H J
HJ
IRVision, Inc., San Jose, CA 95131, USA.
Telfair
W B
WB
D003315:Cornea / Q000601:surgery*; D006801:Humans; D007259:Infrared Rays; D053685:Laser Therapy / Q000295:instrumentation / Q000379:methods*