Adult rabbit eye and orbital volumes after periodic intrabulbar injections of silicone.

The intent of this experiment was to determine whether periodic injections of silicone into the adult rabbit eye would alter the volume of the eye and/or orbit. This procedure in growing rabbits had resulted in increased volumes of both the eye and orbit. Nineteen 13-month-old (adult) rabbits were used. In 12 animals silicone was injected into one eye but not the opposite one. No silicone was injected into the eyes of 7 untreated rabbits. In a 9-week period the total amount of ten silicone injections into each treated eye ranged from 5.7 to 7.6 ml. 1 week after the last injection each eye was enucleated, an impression made immediately, and a permanent model subsequently developed. From this the volume was determined. A t test was performed on the mean differences of the eye and orbital volumes of the injected and noninjected sides for each group. No significant differences was found. It was concluded within the limitations of this experiment that there was no evidence that periodic intrabulbar injection of silicone into the adult rabbit eye altered its volume. Thus, this procedure also did not alter orbital volume. In contrast, in the growing rabbit both eye and orbital volume had increased significantly after intrabulbar injection of silicone.