Change in the location of the equator and recessed muscles in young rabbit eyes

Purpose: To study the changes in the location of the equator and the new insertion of extraocular muscle after recession surgery in a rabbit model. Method: An experimental study was performed in ten eyes of five rabbits. Eyes were divided into two groups according to the amount of recession. In right eyes, 5 mm superior recti (SR) muscle recession, approximately 2 mm posterior to the equator, was performed (5 mm recession group), while in the left eyes, 3 mm recession was performed to the location of the equator (3 mm recession group). We measured the distance of the equator from the limbus, as well as the distance between the superior rectus insertion and the equator. The preoperative measurements were compared with the results 2 months after the surgery. The change in location of the superior rectus and the equator was compared between the two eyes. Result: The recessed SR muscle did not show any significant change in location in both groups (p = 0.18 and 0.16 respectively). However, the location of the equator of rabbit eye showed movement of about 1 mm posterior to the initial location with the growth of the eyeballs (p = 0.04 and 0.03, respectively). Conclusion: The location of the equator moved posteriorly at 2 months postoperatively in young rabbit model while the insertion of the recessed SR did not show any significant movement.