[Endocapsular cataract surgery using the excimer laser at 308 nm]. / Endokapsuläre Kataraktoperation mit dem Excimerlaser bei 308 nm.

We present our experience with in vitro endocapsular cataract surgery ("phakoablation") using the excimer laser at a wavelength of 308 nm. The ablation threshold for human lens nuclei (0.5 J/cm2) was found to be significantly lower compared to that for the capsule (1.5 J/cm2). A total energy of 215 J (mean value) is required for endocapsular ablation of human lens nuclei. For cataract surgery the laser pulses are coupled to a quartz fiber that is integrated into an irrigation/aspiration handpiece. Using the prototype we developed, endocapsular cataract surgery on autopsy eyes with opaque lenses could be performed within about 30 min without major damage to the capsule. Initial measurements of retinal UV exposure indicate that retinal damage might be expected only if the posterior lens capsule is ruptured. Thus endocapsular cataract surgery with the excimer laser seems to be feasible.

[In vitro studies of refractive corneal surgery using the excimer laser with quartz fiber]. / In vitro Untersuchungen zur refraktiven Hornhautchirurgie mit dem Excimer-Laser über Glasfaser.

With the application of different approved drugs, UV absorption of the cornea at 308 nm could be increased by more than three orders of magnitude, which provided effective shielding of intraocular structures against 308 nm excimer laser radiation. The width of the thermal damage zones at the edges of 308 nm excimer laser excisions was reduced to a few micrometers by our treatment. The ablation threshold was reduced by this treatment and the ablation rates were increased by a factor of three to five. In principle, these results offer the possibility of performing refractive corneal surgery with excimer lasers at 308 nm via quartz fibers.