AIM:To assess quantitative changes of the macula in diabetic eyes after cataract surgery using optical coherence tomography(OCT)and to estimate the incidence of development or worsening of macular edema(ME)in diabetic eyes with or without pre-existing ME.·METHODS:In this prospective,observational study,92eyes of 60 diabetic patients who underwent cataract surgery were evaluated before surgery and 1,3mo after surgery using OCT.Macular thickness was measured with OCT at nine macular subfields defined by the 9zones early treatment of diabetic retinopathy study(ETDRS),as well as total macular volume obtained by OCT at 1,3mo after surgery were compared with baseline features obtained before surgery.In addition,the incidence of development or worsening of ME was analyzed in diabetic eyes with or without pre-existing ME.·RESULTS:The central subfield mean thickness increased 21.0μm and 25.5μm at 1,3mo follow-up,respectively(P<0.01).The average thickness of inner ring and outer ring increased 14.2μm and 9.5μm at 1mo,18.2μm and 12.9μm at 3mo.Central-involved ME developed in 12 eyes at 3mo,including 4 eyes with preexisting central-involved and 8 eyes with pre-existing non-central involved ME.Pre-existing diabetic macular edema(DME)was significantly associated with centralinvolved ME development(P<0.001).·CONCLUSION:A statistically significant increase could be detected in the central subfield as well as perifoveal and parafoveal sectors though the increase was mild.And eyes with pre-operative DME prior to cataract surgery are at higher risk for developing central-involved ME. AIM: To assess quantitative changes of the macula in diabetic eyes after cataract surgery using optical coherence tomography (OCT) and to estimate the incidence of development or worsening of macular edema (ME) in diabetic eyes with or without pre-existing ME. : In this prospective, observational study, 92eyes of 60 diabetic patients who underwent cataract surgery were evaluated before surgery and 1,3mo after surgery using OCT. Mthickness was was measured with OCT at nine macular subfields defined by the 9zones early treatment of diabetic retinopathy study (ETDRS), as well as total macular volume obtained by OCT at 1,3mo after surgery were compared with baseline features obtained before surgery. In addition, the incidence of development or worsening of ME was analyzed in diabetic eyes with or without pre-existing ME. RESULTS: The central subfield mean thickness increased by 21.0 μm and 25.5 μm at 1,3 mo follow-up, respectively (P <0.01). The average thickness of inner ring and outer ring increas ed 14.2μm and 9.5μm at 1mo, 18.2μm and 12.9μm at 3mo.Central-involved ME developed in 12 eyes at 3mo, including 4 eyes with preexisting central-involved and 8 eyes with pre-existing non-central involved ME.Pre -existing diabetic macular edema (DME) was significantly associated with centralinvolved ME development (P <0.001). CONCLUSION: A quite significant increase could be detected in the central subfield as well as perifoveal and parafoveal sectors though the increase was mild. And eyes with pre-operative DME prior to cataract surgery are at higher risk for developing central-involved ME.