Electroretinography, Ocular Ultrasonography, and Phacoemulsification of Bilateral Cataracts in Two Juvenile Loggerhead Sea Turtles (Caretta caretta) of the Mediterranean Region

SIMPLE SUMMARY: The present study describes the medical approach to a severe ocular disease impairing the vision of two young sea turtles rescued in the Tyrrhenian Sea. Proper diagnosis and treatment of ocular diseases in these animals is necessary because their sight is extremely important for their survival. Clinical examination of the eyes showed a bilateral lens opacity (cataract). The two turtles underwent an instrumental examination for accurate diagnosis. Ultrasonography was performed to study the anatomical features. Electroretinography was necessary to obtain functional data on the eyes’ ability to translate the light signal perceived by the retina into a nerve signal to be transmitted to the brain. Only after verifying that there were no other eye impairments besides the cataracts, we decided to proceed to remove them surgically. The surgery was performed by phacoemulsification under a microscope. After surgery, both turtles were treated with antibiotics and anti-inflammatory drugs, both parenterally and topically. After 10 months of follow up, the two turtles are able to feed normally and to interact with obstacles. Clinically, all four eyes appear to be healthy. ABSTRACT: Bilateral cataracts were diagnosed in two rescued juvenile, immature loggerhead sea turtles (Caretta caretta), weighing 1.65 and 1.7 kg. Both animals showed vision impairment and difficulty in feeding without assistance. In fact, they did not notice the presence of the food in the tank unless it was brought close to touching the mouth. Ocular ultrasonography and electroretinography showed no lesions of the vitreal body and retinal layer, therefore, both animals were candidates for bilateral cataract surgery. Topical administration of tropicamide + phenylephrine alternating with rocuronium resulted in only minimal mydriasis. Administration of intracameral rocuronium did not improve mydriasis. Phacoemulsification using a one-handed technique was performed bilaterally with a phacoemulsification device (Sovereign, AMO (Abbott Medical Optics(®)). After surgery, the systemic anti-inflammatory drug (dexamethasone 0.2 mg/kg, IM daily for one week) and antibiotics (enrofloxacin 10 mg/kg IM q 72 h, for 4 weeks; ceftazidime 20 mg/kg IM q 72 h for 3 weeks) were administered. Topical ofloxacin, flurbiprofen and tobramycin/dexamethasone were instilled TID for 4 weeks. Both turtles regained vision in both eyes. Results at a 10-month follow-up were satisfactory. This is the first report of cataracts in turtles rescued in the Mediterranean Sea and the first description of surgical treatment of cataracts in loggerhead turtles so young.