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Biomedical subjects

M V Drake

Publications and source records attributed to M V Drake.

4 recordsLinked to original sources

Filtering seton implant for glaucoma: initial animal trial.

A newly developed silicone filtering seton device was implanted in each of five eyes of four rhesus monkeys after they had undergone extensive argon-laser trabeculoplasty to raise their intraocular pressure (IOP). One animal (one implant eye) was killed at 6 weeks. The other three animals (four implant eyes) were observed for 17 to 24 months following implantation surgery. Mild to moderate postoperative inflammation subsided during the first postoperative week. The eyes remained quiet throughout the remainder of follow up. The postoperative IOPs varied between 18% and 70% of the IOPs at the time of implant surgery. In the three monkeys that had unilateral surgery, the IOP at the final follow-up measurement was equal to or lower than the IOP in the unoperated fellow eye. In the monkey that had bilateral surgery, both of the final IOPs were lower than the preoperative ones.

Animals

Subconjunctival THC:YAG laser thermal sclerostomy.

A THC:YAG laser (thulium, holmium, chromium-doped YAG crystal) was used to create thermal sclerostomies in 21 glaucomatous eyes of 19 patients. The laser is a long-pulsed (300 microsec), compact, self-contained, solid state laser operating in the near infrared (2.1 mu). A 1-mm conjunctival stab incision was made 12 mm away from the sclerostomy site to allow entry of a specially designed 22-gauge (712 mu) optic probe that delivers energy at a right angle to the long axis of the fiber. Probe insertion produced minimal disturbance of the conjunctiva. Pulse energies of 80 mJ to 120 mJ were used with a repetition rate of 5 pulses/second. Total energy levels to produce full-thickness sclerostomies ranged from 1.4 to 4.8 J. Subconjunctival 5-fluorouracil injections were administered in 15 eyes. At 3 months the mean intraocular pressure of successful cases (16) was 14 mmHg (range, 9 to 22 mmHg). Of successful cases, the mean intraocular pressure at 6 months was 13 mmHg (range, 2 to 22 mmHg). Five cases failed within the initial 3 months, and 3 additional cases failed by 6 months. The authors conclude that this full-thickness sclerostomy technique may simplify filtering surgery without anterior chamber instrumentation and with minimal conjunctival trauma.

Adult

A new contact neodymium:YAG laser for cyclophotocoagulation.

A newly developed compact (40 kg), self-contained contact Neodymium:YAG laser produces high-peak, high-energy (800 mJ/pulse), short (1.0 millisecond) pulses with 1 to 3 pulses/exposure. Energy is delivered via a 320-microns cleaved quartz fiber optic probe. Cyclophotocoagulation was performed in five eyes of three medium-sized Dutch-pigmented rabbits. The eyes received exposures of 1 to 3 pulses/exposure. Energy delivered ranged from 100 to 800 mJ/pulse. Histopathology revealed ciliary body disruption and hemorrhage with no damage to overlying sclera. When used for transscleral cyclodiathermy in the rabbit, the laser created significant ciliary body disruption with minimal scleral injury.

Animals