TY - GEN
T1 - Evaluation of the smoothness and accuracy of scanning photorefractive keratectomy on PMMA by optical profilometry
AU - Manns, Fabrice
AU - Rol, Pascal O.
AU - Parel, Jean Marie
AU - Schmid, Armin
AU - Shen, Jin Hui
AU - Matsui, Takaaki
AU - Soderberg, Per G.M.D.
PY - 1996/1/1
Y1 - 1996/1/1
N2 - The smoothness and accuracy of PMMA ablations with a prototype scanning photorefractive keratectomy (SPRK) system were evaluated by optical profilometry. A prototype frequency- quintupled Nd:YAG laser (Laser Harmonic, LaserSight, Orlando, FL) was used (wavelength: 213 nm, pulse duration: 15 ns, repetition rate: 10 Hz). The laser energy was delivered through two computer-controlled galvanometer scanners that were controlled with our own hardware and software. The system was programmed to create on a block of PMMA the ablations corresponding to the correction of 6 diopters of myopia with 60%, 70%, and 80% spot overlap. The energy was 1.25 mJ. After ablation, the topography of the samples was measured with an optical profilometer (UBM Messtechnik, Ettlingen, Germany). The ablation depth was 10 to 15 micrometer larger than expected. The surfaces created with 50% to 70% overlap exhibited large saw-tooth like variations, with a maximum peak to peak variation of approximately 20 micrometer. With 80% overlap, the rms roughness was 1.3 micrometer and the central flattening was 7 diopters. This study shows that scanning PRK can produce smooth and accurate ablations.
AB - The smoothness and accuracy of PMMA ablations with a prototype scanning photorefractive keratectomy (SPRK) system were evaluated by optical profilometry. A prototype frequency- quintupled Nd:YAG laser (Laser Harmonic, LaserSight, Orlando, FL) was used (wavelength: 213 nm, pulse duration: 15 ns, repetition rate: 10 Hz). The laser energy was delivered through two computer-controlled galvanometer scanners that were controlled with our own hardware and software. The system was programmed to create on a block of PMMA the ablations corresponding to the correction of 6 diopters of myopia with 60%, 70%, and 80% spot overlap. The energy was 1.25 mJ. After ablation, the topography of the samples was measured with an optical profilometer (UBM Messtechnik, Ettlingen, Germany). The ablation depth was 10 to 15 micrometer larger than expected. The surfaces created with 50% to 70% overlap exhibited large saw-tooth like variations, with a maximum peak to peak variation of approximately 20 micrometer. With 80% overlap, the rms roughness was 1.3 micrometer and the central flattening was 7 diopters. This study shows that scanning PRK can produce smooth and accurate ablations.
UR - http://www.scopus.com/inward/record.url?scp=0029752189&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0029752189&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:0029752189
SN - 0819420476
SN - 9780819420473
T3 - Proceedings of SPIE - The International Society for Optical Engineering
SP - 57
EP - 60
BT - Proceedings of SPIE - The International Society for Optical Engineering
A2 - Parel, Jean-Marie
A2 - Joos, Karen M.
A2 - Rol, Pascal O.
T2 - Ophthalmic Technologies VI
Y2 - 27 January 1996 through 28 January 1996
ER -