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Ablation smoothness as a function of excimer laser delivery system
Journal of Cataract and Refractive Surgery
|July 1, 1996
Summary
Galvanometric scanning excimer laser systems create significantly smoother ablation profiles compared to iris diaphragm systems. This technology offers superior surface smoothness for ophthalmic procedures.
Area of Science:
- Ophthalmology
- Laser Technology
- Surface Metrology
Background:
- Excimer laser refractive surgery aims for precise tissue ablation.
- Different laser delivery systems exist, impacting ablation profile quality.
- Surface smoothness is critical for optimal visual outcomes.
Purpose of the Study:
- To quantitatively compare the ablation profiles of three excimer laser delivery systems.
- To determine which system yields the smoothest ablation surface.
- To inform selection of laser technology for refractive surgery.
Main Methods:
- Excimer laser myopic ablations were performed on PMMA test blanks.
- Three delivery systems were tested: iris diaphragm (no homogenizer), iris diaphragm (with homogenizer), and galvanometric scanning.
- Surface smoothness was measured using a scanning white-light interferometer (RMS, peak-to-valley, arithmetic average).
Main Results:
- Galvanometric scanning systems produced smoother ablations (approx. 3x smoother by RMS) than iris diaphragm with homogenizer (P=.01).
- Iris diaphragm with homogenizer systems were approx. 2x smoother than iris diaphragm without homogenizer (P=.03).
- Galvanometric scanning demonstrated superior surface smoothness.
Conclusions:
- Galvanometric scanning delivery systems offer significantly smoother ablation profiles.
- This smoother profile is advantageous for ophthalmic laser procedures.
- The findings support galvanometric scanning as a preferred technology for precise excimer laser ablation.