Ab-interno neodymium:YAG versus erbium:YAG laser sclerostomies in a rabbit model.
This study was undertaken to determine whether thermally-induced tissue necrosis was a factor in ab-interno contact-laser sclerostomy failure. A rabbit model was used to compare the continuous-wave Neodymium (Nd):YAG with the pulsed Erbium (Er):YAG laser with respect to such failure. Laser energy was focused into a fused-silica fiber optic (400 microns) for the Nd:YAG laser (12 W; 3 to 5 seconds), and into a single-crystal, uncladded sapphire fiber optic (250 microns) for the Er:YAG laser (7 to 8 mJ; 250 microseconds; 6 to 8 pulses). The Nd:YAG and Er:YAG lasers required from 21 to 35 J and from 42 to 64 mJ, respectively, to create the sclerostomies. Filtering blebs and intraocular pressure reduction lasted longer (log-rank test; P less than .03) and surgical complications were fewer in the Er:YAG group than in the Nd:YAG group. By creating sclerostomies with minimal thermal damage, the Er:YAG laser may offer significant clinical advantages over lasers producing larger thermal effects.
Hill
R A
RA
Department of Ophthalmology, University of California, Irvine 92717.
Ozler
S A
SA
Baerveldt
G
G
Viscardi
J J
JJ
Keates
R H
RH
Lee
M
M
Harrington
J A
JA
Berns
M W
MW
D000818:Animals; D003228:Conjunctiva / Q000473:pathology; D004195:Disease Models, Animal; D007429:Intraocular Pressure; D053685:Laser Therapy / Q000009:adverse effects*; D009336:Necrosis / Q000209:etiology / Q000473:pathology; D011183:Postoperative Complications; D011379:Prognosis; D011817:Rabbits; D012599:Sclerostomy / Q000379:methods*; D014130:Trabeculectomy