An investigation of CO2 laser scleral buckling using moiré interferometry.
OBJECTIVE
To demonstrate suitability of moiré interferometry to assess and quantify laser-induced shrinkage of scleral collagen for buckling procedures.


METHODS
Scleral buckling of human cadaver eyes was investigated using a Coherent Ultrapulse CO2 laser. Projection moiré interferometry was employed to determine the out-of plane displacement produced by laser exposure, and in-situ optical microscopy of reference markers on the eye was used to measure in-plane shrinkage.


RESULTS
Measurements based on moiré interferometry allow a three dimensional view of shape changes in the eye surface as laser treatment proceeds. Out-of-plane displacement reaches up to 1.5 mm with a single laser spot exposure. In-plane shrinkage reached a maximum of around 30%, which is similar to that reported by Sasoh et al (Ophthalmic Surg Lasers. 1998;29:410) for a Tm:YAG laser.


CONCLUSIONS
The moiré technique is found to be suitable for quantifying the effects of CO2 laser scleral shrinkage and buckling. This can be further developed to provide a standardized method for experimental investigations of other laser sources for scleral shrinkage.
Maswadi
Saher M
SM
Department of Physics, University of Hull, United Kingdom.
Dyer
Peter E
PE
Verma
Dinesh
D
Jalabi
Wadah
W
Dave
Dinesh
D
D002102:Cadaver; D002245:Carbon Dioxide; D004867:Equipment Design; D006801:Humans; D021621:Imaging, Three-Dimensional; D007368:Interferometry / Q000295:instrumentation / Q000379:methods*; D053685:Laser Therapy / Q000295:instrumentation; D015903:Moire Topography / Q000295:instrumentation; D012590:Sclera / Q000473:pathology; D012591:Scleral Buckling / Q000295:instrumentation
D002245:Carbon Dioxide