Erbium: YAG laser ablation of retinal tissue under perfluorodecaline: determination of laser-tissue interaction in pig eyes.
OBJECTIVE
To evaluate the effect of Er;YAG laser on pig retina using a perfluorodecaline/retina interphase with the goal of precisely determining the extent of retinal tissue ablation.


METHODS
Free running (tau = 250 microsec) Er:YAG laser pulses were transmitted through a zirconium fluoride (ZrF4) fiber guarded by quartz rod (d = 1000 microm). Laser pulses were applied to the retinal surface of enucleated pig eyes. Eyes were mounted in a specially designed rotating sample holder. The fiber probe was elevated 1.0 +/- 0.3 mm above the retinal surface with perfluorodecaline serving as transmitting medium. The laser energy was applied in a circular pattern with a radius of 3.0 mm. Radiant exposures were set to 1, 3, 5, and 10 J/cm2.


RESULTS
Tissue ablation linearly increased with radiant exposure from 3.2 +/- 3.7 microm at 1 J/cm2 up to 40.9 +/- 12.9 microm at 10 J/cm2. Thermal tissue changes extended 70 +/- 10 microm vertically into the retina and 25 +/- 5 microm horizontally. Distortion of outer photoreceptor segments was noticed when the retina was exposed to radiant exposures of 3 J/cm2 or higher.


CONCLUSIONS
The Er:YAG laser in combination with perfluorodecaline produced precise ablation of the pig retina, which suggests the feasibility of this technique for safe ablation of epiretinal membranes.
Wesendahl
T
T
Department of Ophthalmology, University of Freiburg, Germany.
Janknecht
P
P
Ott
B
B
Frenz
M
M
D000818:Animals; D019773:Epiretinal Membrane / Q000601:surgery; D005466:Fluorocarbons; D053685:Laser Therapy / Q000379:methods*; D013508:Ophthalmologic Surgical Procedures; D012160:Retina / Q000473:pathology / Q000601:surgery*; D013552:Swine; D014822:Vitreous Body
D005466:Fluorocarbons; C008805:perfluorodecalin