Optimal laser power to rupture Bruch's membrane and the retinal vein in the pig.
OBJECTIVE
For laser-induced chorioretinal venous anastomosis to become a viable treatment option for perfused central retinal vein occlusion, laser parameters must be refined to more reliably create venous anastomoses while minimizing complications. The aim of this study was to determine the lowest argon laser power at which Bruch's membrane and the retinal vein are ruptured in 100% of attempts in the porcine eye.


METHODS
Testing was performed on 6 eyes of 3 Yorkshire Cross pigs, using an argon green laser. The spot size was 50 microm and the duration was 0.2 seconds for all applications. Twelve laser powers were tested, from 0.5 to 6 W, increasing by increments of 0.5 W. Light microscopy was used to determine the frequency of rupture of Bruch's membrane and the retinal vein for each power.


RESULTS
The rupture rate of Bruch's membrane was 0% at 0.5 W, 5% at 1.0 W, 20% at 1.5 W, 70% at 2.0 W, and 100% for all powers from 2.5 to 6.0 W. The rupture rate of the retinal vein was 0% at 0.5 W, 5% at 1.0 W, 30% at 1.5 W, 60% at 2.0 W, 80% at 2.5 W, and 100% for all powers from 3.0 to 6.0 W.


CONCLUSIONS
Argon green laser powers of at least 2.5 and 3.0 W were necessary to rupture Bruch's membrane and the retinal vein, respectively, with a 100% success rate in the porcine eye. Because patients with central retinal vein occlusion have secondary retinal edema and may have lenticular opacity, higher laser powers may be required to achieve a 100% rupture rate of these structures.
Haupert
Christopher L
CL
Duke University Eye Center, Durham, North Carolina 27710-3802, USA.
Grossniklaus
Hans E
HE
Sharara
Nariman
N
Davidson
Michael G
MG
Syed
Arjumand
A
Fekrat
Sharon
S
D000714:Anastomosis, Surgical; D000818:Animals; D016570:Bruch Membrane / Q000473:pathology / Q000601:surgery*; D053685:Laser Therapy / Q000379:methods*; D012169:Retinal Vein / Q000473:pathology / Q000601:surgery*; D012170:Retinal Vein Occlusion / Q000601:surgery; D012421:Rupture; D013552:Swine