Cataract Removal in a Loggerhead Sea Turtle
IAAAM 1995
M. Andrew Stamper, DVM; Brent R. Whitaker, MS, DVM; Dr. Relley Corcoran, DVM
National Aquarium in Baltimore, Baltimore, MD

After initial stabilization, the Virginia Institute of Marine Science transferred a stranded 35.5 kg juvenile loggerhead sea turtle to the National Aquarium in Baltimore for removal of bilateral hypermature cataracts and further rehabilitation.

The animal was anesthetized with 25 mg/kg of ketamine/ace mixture (1 cc of acepromazine into l0 cc of ketamine) IV and was intubated with a 6.5 mm endotracheal tube. The turtle was force-ventilated every 15 seconds at 3.5% isoflurane. The heart rate was steady at approximately 30 b.p.m.

After 45 minutes ocular reflexes were still present, but these diminished after increasing the isoflurane to four percent.

Intraocular cocaine was administered as a mydriatic in one eye, but was determined to be unsuccessful. A 3.5 mm corneal incision was performed one millimeter from the limbus in the clear cornea and the anterior chamber was inflated with hyaluronic acid. After capsulorexhis was performed, the liquefied lenticular material was removed by irrigation and aspiration. The posterior capsule was found to have an axial opacity; a portion was removed by capsulorexhis. The cornea was sutured with 8-0 nylon in a cross-stitch pattern and glued closed with ophthalmic cyanoacrylate.

Anesthesia was discontinued 20 minutes prior to the termination of surgery and ambulation was noted following two hours of oxygen administration. As the turtle recovered it unsuccessfully attempted to scratch its eyes with its pectoral flippers.

Triple antibiotic with dexamethasone was placed in each eye three times a day. Along with this, 25 mg of oral prednisolone was administered once a day for 5 days, reducing to 10 mg of prednisolone once a day for 3 more days, then 5 mg of prednisolone for 3 days. The water was drained once a day to keep fecal material and food particulate to a minimum.

The cornea healed without difficulty; the lens capsules in each eye showed focal opacities which appeared to be permanent. The turtle was considered visual despite this.

The turtle's vision was assessed in several ways. First, the animal was observed to track a small dark 5 mm neutrally-balanced object floating through the water column. Second, to make sure the animal could forage, the turtle was placed in a 100,000 gallon pool with various obstacles. The animal proved it could navigate well and was able to forage for food when the food was placed in randomly selected areas.

Speaker Information
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M. Andrew Stamper, DVM


MAIN : Session VI : Cataract Removal
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