Erbium: YAG laser ablation on human trabecular meshwork by contract delivery endoprobes.
OBJECTIVE
Photoablation of the trabecular meshwork by the infrared laser is an experimental mode of glaucoma surgery.


METHODS
The authors studied different quartz fiber tips in erbium:YAG laser trabecular ablation. End-firing endoprobes (200 and 320 microns in core diameter) and a side-firing slope tip (200 microns in core diameter) were used. Ablation zones and collateral tissue damage in the trabecular meshwork of human donor eyes were analyzed using light and scanning electron microscopy.


RESULTS
The 320-micron end-firing endoprobe most effectively photoablated trabecular tissue by creating large circular craters. The side-firing endoprobe yielded smaller elliptic apertures in the trabecular meshwork. Collateral tissue damage was similar for all endoprobes using pulse energies of 4 and 6 mJ. Transmission impairment was obvious for all quartz fiber tips following frequent use.


CONCLUSIONS
Larger end-firing contact fiberoptic probes provide larger ablation areas in the trabecular meshwork without augmentation of collateral tissue damage.
Dietlein
T S
TS
Department of Ophthalmology, University Eye Hospital Cologne, Germany.
Jacobi
P C
PC
Krieglstein
G K
GK
D004871:Erbium; D005902:Glaucoma, Open-Angle / Q000601:surgery*; D006801:Humans; D066298:In Vitro Techniques; D017075:Laser Coagulation / Q000295:instrumentation*; D008855:Microscopy, Electron, Scanning; D014129:Trabecular Meshwork / Q000601:surgery* / Q000648:ultrastructure
D004871:Erbium