Comparative Study Of Vitrectomy With Or Without Internal Limiting Membrane Peeling On Diabetic Macular Edema In Severe Proliferative Diabetic Retinopathy

ObjectiveTo evaluate the clinical effect of minimally invasive vitrectomy(MIV)with or without internal limiting membrane(ILM)peeling on macular edema(ME)in severe proliferative diabetic retinopathy(PDR),investigate the advantages of internal limiting membrane peeling and analyze the factors which might predict the visual outcome.MethodsA total of 69 eyes in 69 patients with severe PDR combined with ME who underwent MIV in Tianjin Ophthalmological Hospital from June 2015 to December 2016 were included.The patients were examined with best corrected visual acuity(BCVA),intraocular pressure(IOP),optical coherence tomography(OCT),fluorescein angiography(FFA),B-scan ultrasound,slit lamp biomicroscopy,binocular indirect ophthalmoscope.All patients were divided into two groups: 36 eyes received MIV(ILM peeling group),another 33 eyes received MIV combined with ILM peeling(non-ILM peeling group).All patients underwent panretinal photocoagulation(PRP)and silicone oil tamponade was performed after operation,and 3 months after the surgery,the patients with good retinal reattachment were treated with silicone oil removal.All patients were followed up in 6-12 months after operations,the average follow-up time was(10.47 + 2.17)months,BCVA,central retinal thickness(CRT),total macular volume(TMV),the grade of ME,IOP and complications at 1,3,6 and 12 months were examined.Analyze the changes of these indicators and the related factors affecting visual acuity.Result1.The BCVA of two groups were significantly improved at 3,6 months and the end of follow-up postoperatively(P<0.05).At 6 months and the end of follow-up,the logMAR BCVA of ILM group were better than non-ILM group,the differences were statistically significant(P < 0.05),there were no significant difference between the two groups at other observation points(P > 0.05).At the last follow-up,the VA of ILM group was improved in 23 eyes(69.7%)were better than that of the non-ILM group 17 eyes(44.44%)(P < 0.05).2.The CRT of two groups were significantly decrease compared with preoperative at every observation points during the follow up(P<0.05).The CRT of ILM group were thinner than non-ILM group at 3,6 mouths and the last visit(P < 0.05).3.The TMV of two groups were significantly decrease at 3,6 months and the end of follow-up postoperatively(P<0.05).There were no significant differences between the two groups at any time during the follow up(P > 0.05).4.At the last follow-up,the moderate and severe edema ratio of two groups were significantly lower than preoperative(P < 0.05);the moderate and severe edema in 8 eyes(24.24%)in ILM group were significantly lower than that of non-ILM group 18 eyes(50%)(P<0.05).5.The postoperative complications of non-ILM group mainly included epimacular membrane(3 eyes),recurrence of ME(2 eyes),temporary intraocular hypertension(5 eyes),vitreous hemorrhage(1 eye)and traction retinal detachment(1 eye).In ILM group,temporary intraocular hypertension(3 eyes),vitreous hemorrhage(2 eyes).The incidence of postoperative complications showed no significant difference between the two groups(P > 0.05).6.The postoperative logMAR BCVA was significantly positively correlated with the duration of diabetes,the grade of DME and preoperative CRT(P<0.05),and there was no significant correlation with other indexes.The results showed that the longer the duration of diabetes,the more severe ME,the thicker the preoperative CRT,the worse the VA.Conclusion1.MIV is conductive to remove the vitreous hemorrhage,epiretinal membrane and reduce ME,combined with ILM peeling can accelerate the absorption of ME,MIV combined with ILM peeling is an efficient treatment for DME combined with vitreous hemorrhage and epiretinal membrane.2.MIV combined with or without ILM peeling both can improve the VA of severe PDR with DME,but MIV combined with ILM peeling appears to have more advantages than pure MIV,it is an efficient treatment of severe PDR with DME.3.MIV combined with ILM peeling appears to significantly reduce the CRT and TMV compared with the simple MIV,which is helpful for the further improvement of anatomical structure and function of macular.4.The removal of the ILM causes the migration and proliferation of the pigment cells and the fibrous cells loses the stent,which can ceffectively inhibit the formation of the epimacular membrane and reduce the incidence of recurrence of ME.5.Diabetes duration,the grade of DME,CRT were significantly correlated with the visual outcome.The longer the duration of diabetes,the more severe ME,the thicker the preoperative CRT,the worse the VA.The full evaluation of the patient's condition,reasonable selection of cases and proper operation time can make the better curative effect.