Oe. Hanuch et al., POSTERIOR CAPSULE POLISHING WITH THE NEODYMIUM-YLF PICOSECOND LASER -MODEL EYE STUDY, Journal of cataract and refractive surgery, 23(10), 1997, pp. 1561-1571
Purpose: To determine the ability and threshold energy of the neodymiu
m:yttriumlithium-fluoride (Nd:YLF) picosecond laser to achieve micron-
level polishing of a latex posterior capsule facsimile (PCF) as an alt
ernative to laser capsulotomy to treat posterior capsule opacification
. Setting: University of Rochester Medical Center, Rochester, New York
, USA. Methods: A solid-state, mode-locked Nd:YLF picosecond laser was
used to polish a latex PCF in contact with a poly(methyl methacrylate
) intraocular lens (IOL) in an experimental model eye. Eight study gro
ups were treated at different energy levels ranging from 5 to 15 mu J.
All treatments were done at least three times in different latex caps
ules and lenses. An atomic force microscope was used to measure IOL da
mage and an interferometric surface analysis microscope to assess the
polishing effect on the PCF. The IOLs were further subjected to a scat
ter analysis to assess the optical significance of the damage produced
.Results: The latex PCF revealed a polishing effect with all energy se
ttings used. The IOLs were damaged with all energy settings but 5 mu J
. Energy settings higher than 5 mu J caused significantly more polishi
ng effect to the latex and damage to the lenses. At the 10 mu J energy
level, a single parameter with no depth produced a relative polishing
depth of 3.01 mu m +/- 0.10 (root mean square +/- SD). At this energy
, the damage to the IOLs was 188 +/- 20.52 nm, and it was associated w
ith typical craters over the surface at regular intervals that corresp
onded to each individual laser pulse. Conclusion: This model documente
d the feasibility of achieving micron-level precision in excising mate
rial with the picosecond laser and showed that posterior capsule polis
hing should be feasible and safe in human eyes.