Aim: To investigate if postoperative treatment with dexamethasone eye drops has the capacity to affect longitudinal growth in newborn rabbits.
Methods: Thirty-four male and female rabbits had clear lens extraction performed in one eye at 3 wk of age and were then treated either intensively (group 1) or less intensively (group 2) with de-escalating doses of dexamethasone eye drops for 8 wk (average doses 0.27 and 0.10 mg/kg body weight/day, respectively). The control group (group 3) received vehicle eye drops only. Body weight and crown-rump length were recorded every week. After 8 wk of treatment, all rabbits were killed and the left femur was measured.
Results: Rabbits treated with dexamethasone eye drops gained weight slower (711+/-42 and 989+/-153 g weight increase for groups 1 and 2, respectively) than control animals (group 3; 1224+/-87 g weight increase; p<0.001 vs group 1, p<0.01 vs group 2). Longitudinal growth, determined as increase in crown-rump and femur lengths, was impaired by dexamethasone eye drops in a dose-dependent way. Crown-rump length increased by 8.25+/-0.86, 10.90+/-1.19 and 15.35+/-1.31 cm in groups 1, 2 and 3, respectively (p<0.001 for all comparisons). At endpoint, i.e. after 8 wk of treatment, the average femur length was 6.36+/-0.21, 7.39+/-0.27 and 8.37+/-0.28 cm in groups 1, 2 and 3, respectively (p<0.001 for all comparisons).
Conclusion: Dexamethasone, administered topically as eye drops, has systemic effects and impairs longitudinal growth in young rabbits. Therefore, we propose that growth should be closely monitored in all children intensively treated with glucocorticoid eye drops.