1995 Volume 14 Issue 1-2 Pages 1-2_15-1-2_22
Effects of argon laser coagulation (Coherent Ultima 2000) were compared on the tapetal and non-tapetal zones of the ocular fundus in dogs by observing photographs of the ocular fundus and the fluorescein angiograms. The left eyes of five healthy adult mixed-breed dogs, weighing 11 to 14 Kg, and two 2-month-old native Japanese Shiba dog weighing 4 Kg each were used. The dogs were restrained under general anesthesia with xylasine and hydrochloride ketamine for the laser coagulation. The conditions were as follows, spot size: 100 μm; powere level: 100 mW; and exposure duration: 0.2 seconds.
Bleeding on the tapetal and non-tapetal zones was observed by ocular fundus angiography immediately after coagulation. The lesions were seen as dark spots on the tapetal zone and remained at least 4 weeks after coagulation. On the non-tapetal zone the lesions were bright spots immediately after coagulation and became unclear 4 weeks later. The light reflection on the peripheral tapetal zone had changed more than that of the non-tapetal zone. There was no difference between adult and young animals in the influence of the coagulation on the fundus.
Therefore, in dogs and other animals which have a tapetum lucidum in the choroid, the effects of laser coagulation seemed to be different between tapetal and non-tapetal zones.
