Pig Cadaver Eyes Research Articles

Anterior Lens Capsulotomy Using the Holmium YAG Laser in Pig Cadaver Eyes

Anterior lens capsulotomy was performed on pig cadaver eyes using the evaporation and coagulation functions of the holmium YAG laser. Laser energy ranging from 50 to 80 mJ was delivered to the lens-capsule surface by a 26-gauge fiber-optic quartz needle probe. In eight of 10 eyes, a tear-free, 4.0-millimeter-diameter circular capsulotomy was achieved, through which endocapsular phacoemulsification and aspiration were performed and a posterior chamber intraocular lens with a 6.5-millimeter-diameter optic was placed inside the lens capsule. Throughout the procedure, capsular integrity was maintained in all eight eyes, with no tearing at the capsular margin.

Lamellar excimer laser keratoplasty: reproducible photoablation of corneal tissue. A laboratory study.

We examined the depth of ablation of the recipient bed with different counts of oscillations of excimer laser beam, to determine the correlation between planned and real depth. The ablation rate per oscillation was tested preoperatively by blackened photographic paper of defined thickness and thus was calculated to be 5 microns. Forty pig eyes were used for the first study. Each eight eyes were ablated in the planned depth 100 microns, 200 microns, 300 microns, 400 microns and 500 microns. The corneal thickness was measured with an ultrasonic pachymeter before and after the procedure. The depth measured after the photoablation was 99.4 +/- 36.4 microns for 100 microns planned depth, 186.7 +/- 55.3 microns for 200 microns, 298.4 +/- 68.5 microns for 300 microns, 373.9 +/- 65.7 microns for 400 microns and 480.1 +/- 59.3 microns for 500 microns. Comparing the depth measured after the photoablation to planned depth, there was a significant correlation (correlation coefficient: R = 0.93; p < 0.0001). Five other corneas trephinated from pig cadaver eyes were ablated from the endothelial side to the desired thickness (100 to 500 microns) of lamellar graft. In a second step a donor mask was placed onto the cornea and a laser light spot was led until perforating on all sides. The lamellar keratoplasty was completed by suturing the corneal graft into the bed. Macroscopic and microscopic examination of sutured eyes after fixation showed a good fit of wound margins and stromal interface. These results indicate that excimer laser is useful for reproducible corneal photoablation in lamellar keratoplasty.

Further development of experimental techniques for refilling the lens of animal eyes with a balloon

Various techniques for experimental refilling of the lens of animal eyes are possible. We describe two new methods: Balloon insertion after endocapsular phacoemulsification and after phacoemulsification with circular capsulorhexis. The feasibility of these techniques was tested in both rabbit eyes and pig cadaver eyes. With organosilicone gel as the balloon filling material, postoperative refractive changes of up to 4 diopters of residual hyperopia were achieved; accommodation changes were up to −1 diopter. The technique of refilling the lens with a balloon to avoid leakage of filling material warrants further study.

Excimer Laser Keratoplasty Part 1: Basic Concepts

ABSTRACT A commercially available ophthalmic excimer laser was used with a new "open mask system" to perform noncontact and nonthermal excimer laser keratoplasty in 20 human and 40 pig cadaver eyes. Circular penetrating corneal trephinations and corneal grafts were performed with the excimer laser set at 193 nm. Light microscopy and scanning and transmission electron microscopy of the human and pig eyes demonstrated the high quality of excimer laser trephination (smooth wound margins that were approximately parallel to the optical axis of the eye), and the superior wound configuration and geometry.