Trabecular meshwork alteration and intraocular pressure change following pulsed near-infrared laser trabeculoplasty in cats.
OBJECTIVE
To comparatively assess the safety and variation in intraocular pressure (IOP) of two pulsed near-infrared lasers (titanium:sapphire and alexandrite) for laser trabeculoplasty versus conventional blue-green argon laser trabeculoplasty in an animal model.


METHODS
The left eyes of 15 healthy cats received a 180 degree laser trabeculoplasty treatment: 5 with a titanium:sapphire laser, 5 with an alexandrite laser, and 5 with an argon laser. Preoperatively and postoperatively, all animals underwent tonometry, gonioscopy, and slit-lamp examination. The cats were observed up to 12 weeks. Scanning electron microscopy and histologic examination were performed to evaluate potential alterations in the trabecular meshwork structure.


RESULTS
IOP at 1 hour, 1 day, and 1 week following treatment was remarkably lower, irrespective of the laser source used. Following treatment with both near-infrared lasers, gonioscopy showed depigmentation underneath the area of the treated trabecular meshwork and histologic evaluation showed a decrease in pigment density. On scanning electron microscopy, damage to the trabecular meshwork structure could not be detected after treatment with near-infrared lasers.


CONCLUSIONS
Near-infrared laser trabeculoplasty was found to be effective to temporarily lower IOP in cats. The lasers selectively altered pigment-containing cells, avoiding structural damage of the trabecular meshwork anatomy.
Stoiber
Josef
J
Bascom Palmer Eye Institute, Ophthalmic Biophysics Center, University of Miami Miller School of Medicine, Miami, Florida 33136, USA.
Fernandez
Viviana
V
Lamar
Peggy D
PD
Decker
Susan J
SJ
Dubovy
Sander
S
Hitzl
Wolfgang
W
Salas
Nelson
N
Fantes
Francisco
F
Parel
Jean-Marie
JM
D000818:Animals; D002415:Cats; D004195:Disease Models, Animal; D005260:Female; D005500:Follow-Up Studies; D005901:Glaucoma / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D006068:Gonioscopy; D007429:Intraocular Pressure / Q000502:physiology*; D053685:Laser Therapy; D008855:Microscopy, Electron, Scanning; D011897:Random Allocation; D014129:Trabecular Meshwork / Q000601:surgery / Q000648:ultrastructure*; D014130:Trabeculectomy / Q000379:methods*; D016896:Treatment Outcome