Ranibizumab For Diabetic Macular Edema In Previously Vitrectomized Eyes

Objective:There is little information about the efficacy of intravitreal vascular endothelial growth factor(VEGF)inhibition in vitrectomized eyes with diabetic macular edema(DME).This study aimed to evaluate the efficacy of ranibizumab on DME in previously vitrectomized eyes.Methods:We collected all identifiable previously vitrectomized patients with DME who received intravitreal injections with ranibizumab from December 2014 to July 2016 in the Subsidiary First Hospital.Recorded and organized baseline characteristics of patients including age,gender,type and duration of diabetes,timing and operating reasons of the vitrectomies,history of cataract surgery and laser photocoagulation.The following was assessed in all eyes:best-corrected visual acuity(BCVA),intraocular pressure(IOP),central macular thickness(CMT)detected by optical coherence tomography(OCT).All patients received a series of three monthly intravitreal injections of 0.5 mg ranibizumab.The changes of postoperative BCVA,IOP and CMT were recorded during follow-up period.Statistical analysis was performed using SPSS 19.0.Visual acuity was transformed to logMAR values before analysis.Differences in BCVA,IOP and CMT before and after injections were tested with Student's paired t-test.Probability less than 0.05 was considered to be statistically significant.Result:We identified 33 previously vitrectomized eyes in 28 patients treated with a series of three monthly ranibizumab injections for DME.Baseline mean IOP was(17.45±2.77)mmHg.After injections,the mean IOP was(17.70±2.80)mmHg,there existed no statistically significant(P = 0.45).Mean BCVA was(0.58±0.27)logMAR(95%CI 0.22-1.30)before injections.After 3 injections,mean BCVA remained stable at 0.55±0.28 logMAR(95%CI 0.10-1.30)with a mean improvement of 0.03(P = 0.52).In 12 eyes(36%),vision was unchanged(gain or loss of 0-0.1 logMAR).In nine eyes(27%),vision decreased 0.1 logMAR or more,and 3 eyes(9%)of which lossed of 0.3 logMAR or more.In 12 eyes(36%),visual acuity improved 0.1 logMAR or more,and 3 eyes(9%)gained of 0.3 logMAR or more.CMT on OCT scan was(371.39±76.58)um(95%CI 290-450 um)before injections.After injections,the mean CMT decreased to(320.09±77.34)um(95%CI 234-410 um).The mean reduction in CMT was 14%(P ?0.01).Sixteen eyes(48.5%)became devoid of edema on the last OCT scan.Among the 17 eyes that had macular edema at the final OCT,six eyes(35%)had slight parafoveal or epiretinal fibrosis.Among the 16 eyes having no sign of edema,only two eyes(13%)had parafoveal or epiretinal fibrosis.Despite the significant reduction in CMT.the visual acuity remained unchanged.Conclusion:Intravitreal ranibizumab can be effective in previously vitrectomized eyes with diabetic macular edema.The CMT reduction was significant,despite the visual acuity remained unchanged.