Evaluation of the effect of intravitreal ranibizumab on choroidal thickness in eyes treated for diabetic macular edema

Purpose: To evaluate the effect of intravitreal Ranibizumab on central choroidal thickness (CCT) in eyes treated for diabetic macular edema (DME). Materials and Methods: This prospective non-randomized interventional cohort study included 20 eyes of 20 diabetic patients, recruited between March 2013 and March 2014. Eyes with DME (thickness from 290 to 600 μm) underwent intravitreal injection of Ranibizumab (three consecutive injections, 1 month apart). Prior to injection, all patients had a complete ophthalmic examination, including manifest refraction, slit-lamp bio-microscopy, intraocular pressure measurement, and a detailed fundus examination. Prior to injection and 1 month from the third injection, the central macular thickness and CCT were assessed again by SD-OCT. After each injection, patients were followed to diagnose and treat any complications from injections. Results: Twenty eyes of 20 diabetic retinopathy (DR) patients, 9 females and 11 males with a mean age of 49.7 ± 4.1 years, were included. The pre-injection mean CCT was 234.35 ± 38.36 μm. In the NPDR group, it was 238.2 ± 41.36 μm; and in the PDR group, it was 228.5 ± 35.26 μm. This was not significantly different (P = 0.851). After injections, the mean CCT in all patients, in the NPRD group and in the PDR group showed a decrease to 215.5 ± 39.08, 224.9 ± 40.72 and 201.31 ± 34.02 μm, respectively (P = 0.362). There was a statistically significant difference between the pre-injection and the post-injection CCT (P < 0.001). The improvement in the CCT after treatment was not significantly correlated with the pre-injection CCT or the pre-injection CMT (P = 0.346, P = 0.096 respectively). No significant correlation was found between post-injection CCT and CMT in all patients (P = 0.436) or in the different groups separately (P = 0.191, P = 0.817, respectively). No injection-related complication was observed in either group. Conclusion: Intravitreal injection of Ranibizumab was effective in significantly decreasing the CCT as well as the CMT after three consecutive injections, 1 month apart regardless of the level of DR. Whether the number of injections can influence the amount of this reduction or not should be evaluated in future studies. No correlation was found between the reduction in CMT and that of the CCT after intravitreal injection with 0.5 mg of Ranibizumab.