Abstract
Purpose: In scanning photorefractive keratectomy, the corneal surface is reshaped by laser ablation with a scanning beam for the correction of myopia or astigmatism. A precise knowledge of the volume of corneal tissue removed by each laser pulse is necessary to be able to develop accurate ablation algorithms for scanning photorefractive keratectomy. The purpose of this study was to measure the ablation per pulse created on PMMA surfaces with a Q-switched frequency-quintupled Nd:YAG laser emitting at 213 nm. Methods: A frequency-quintupled Nd:YAG laser emitting at 213 nm with a pulse duration of 5 ns and a pulse energy of 1.2 to 1.5 mJ was used. The laser beam was focused on the surface of PMMA blocks and ablation craters were produced with 10, 50 and 100 pulses. The shape of the ablation craters was measured with an optical profilometer and compared with the beam profile measured with a laser beam diagnostic system. Results: The beam intensity distribution in the near-field consisted of two quasi-Gaussian peaks. The ablation craters contained two peaks. Assuming a Gaussian intensity distribution, the ablation per pulse in PMMA at 213 nm can be modeled by a parabolic function. Conclusions: Optical profilometry can be used to accurately measure the ablation per pulse and evaluate the homogeneity of the beam.
| Original language | English (US) |
|---|---|
| Title of host publication | Proceedings of SPIE - The International Society for Optical Engineering |
| Publisher | Society of Photo-Optical Instrumentation Engineers |
| Pages | 154-159 |
| Number of pages | 6 |
| Volume | 3591 |
| State | Published - 1999 |
| Event | Proceedings of the 1999 Ophthalmic Technologies IX - San Jose, CA, USA Duration: Jan 23 1999 → Jan 25 1999 |
Other
| Other | Proceedings of the 1999 Ophthalmic Technologies IX |
|---|---|
| City | San Jose, CA, USA |
| Period | 1/23/99 → 1/25/99 |
Fingerprint
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Condensed Matter Physics
Cite this
Scanning photorefractive keratectomy at 213 nm : PMMA ablations. / Manns, Fabrice; Rol, Pascal; Wosnitza, Martin; Maine, Patrick; Parel, Jean-Marie A.
Proceedings of SPIE - The International Society for Optical Engineering. Vol. 3591 Society of Photo-Optical Instrumentation Engineers, 1999. p. 154-159.Research output: Chapter in Book/Report/Conference proceeding › Chapter
}
TY - CHAP
T1 - Scanning photorefractive keratectomy at 213 nm
T2 - PMMA ablations
AU - Manns, Fabrice
AU - Rol, Pascal
AU - Wosnitza, Martin
AU - Maine, Patrick
AU - Parel, Jean-Marie A
PY - 1999
Y1 - 1999
N2 - Purpose: In scanning photorefractive keratectomy, the corneal surface is reshaped by laser ablation with a scanning beam for the correction of myopia or astigmatism. A precise knowledge of the volume of corneal tissue removed by each laser pulse is necessary to be able to develop accurate ablation algorithms for scanning photorefractive keratectomy. The purpose of this study was to measure the ablation per pulse created on PMMA surfaces with a Q-switched frequency-quintupled Nd:YAG laser emitting at 213 nm. Methods: A frequency-quintupled Nd:YAG laser emitting at 213 nm with a pulse duration of 5 ns and a pulse energy of 1.2 to 1.5 mJ was used. The laser beam was focused on the surface of PMMA blocks and ablation craters were produced with 10, 50 and 100 pulses. The shape of the ablation craters was measured with an optical profilometer and compared with the beam profile measured with a laser beam diagnostic system. Results: The beam intensity distribution in the near-field consisted of two quasi-Gaussian peaks. The ablation craters contained two peaks. Assuming a Gaussian intensity distribution, the ablation per pulse in PMMA at 213 nm can be modeled by a parabolic function. Conclusions: Optical profilometry can be used to accurately measure the ablation per pulse and evaluate the homogeneity of the beam.
AB - Purpose: In scanning photorefractive keratectomy, the corneal surface is reshaped by laser ablation with a scanning beam for the correction of myopia or astigmatism. A precise knowledge of the volume of corneal tissue removed by each laser pulse is necessary to be able to develop accurate ablation algorithms for scanning photorefractive keratectomy. The purpose of this study was to measure the ablation per pulse created on PMMA surfaces with a Q-switched frequency-quintupled Nd:YAG laser emitting at 213 nm. Methods: A frequency-quintupled Nd:YAG laser emitting at 213 nm with a pulse duration of 5 ns and a pulse energy of 1.2 to 1.5 mJ was used. The laser beam was focused on the surface of PMMA blocks and ablation craters were produced with 10, 50 and 100 pulses. The shape of the ablation craters was measured with an optical profilometer and compared with the beam profile measured with a laser beam diagnostic system. Results: The beam intensity distribution in the near-field consisted of two quasi-Gaussian peaks. The ablation craters contained two peaks. Assuming a Gaussian intensity distribution, the ablation per pulse in PMMA at 213 nm can be modeled by a parabolic function. Conclusions: Optical profilometry can be used to accurately measure the ablation per pulse and evaluate the homogeneity of the beam.
UR - http://www.scopus.com/inward/record.url?scp=0032681090&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032681090&partnerID=8YFLogxK
M3 - Chapter
VL - 3591
SP - 154
EP - 159
BT - Proceedings of SPIE - The International Society for Optical Engineering
PB - Society of Photo-Optical Instrumentation Engineers
ER -