Ble participants underwent a comprehensive ophthalmic examination. Visual acuity of each eye was measured using the log of the minimum angle of resolution (LogMAR) Early Treatment Diabetic Retinopathy Study (ETDRS) chart at a distance of 4 m, with illumination 300 lux. In participants who were wearing glasses in their daily lives, visual acuity was measured with their spectacles. Both types of visual acuity mentioned above are known as the presenting visual acuity [36]. In addition, pinhole-corrected visual acuity was measured in participants with a presenting visual acuity worse than 0.7 in either eye. Anterior segment examinations with a slit-lamp 374913-63-0 biomicroscope, refractive media and fundus examinations with a direct ophthalmoscope were conducted by the ophthalmologists. If participants’ pinhole-correction visual acuity worse than 0.7 and the vision loss could not be attributed to corneal disease, the examinations were performed after pupil dilatation with 0.5 tropicamide and 0.5 phenylephrine (Mydrin-P; Santen Pharmaceuticals; Japan) except in case of a shallow anterior chamber. A digital 45u non-mydriatic retinal camera (CR-DGi Non-mydriatic Retinal Camera; Canon Inc., Tokyo, Japan) was used to obtain color retinal photographs of ETDRS standard field 1 [37] (centered on the optic disc) and field 2 (centered on the macula) for each eye.Prevalence and Risk Factors of iERM in ShanghaiThe retinal photographs were assessed respectively by two ophthalmologists with retinal subspecialty training for the presence of ERM and its grading. The prevalence-adjusted bias-adjusted kappa statistic was 0.82 for the presence of ERM, and the kappa statistic was 0.70 for its grading. In case of doubt, the lead ophthalmic doctor reassessed the retinal photographs to make the final diagnosis and grading. In our study, ERM was subdivided as idiopathic or secondary. iERM was defined as ERM 1531364 occurring in eyes without a secondary cause, such as DR (at least a history of Tunicamycin cost diabetes associated with retinal microaneurysms), retinal vascular disease, retinal detachment, or history of cataract surgery. Moreover, iERM was graded using the method described by Klein et al. [7], which divides iERM into two types, cellophane macular reflex (CMR) and premacular fibrosis (PMF). CMR was defined as a patch or irregular, increased reflection from the inner retinal surface. PMF, a more severe type, was defined as a grayish and opaque appearance of the inner retinal surface combined with superficial retinal folds or traction lines. Participants with both CMR and PMF were allocated to the PMF group. Thus, iERM was detected in 34 participants (1.02 ), who were all later confirmed by OCT. Part II: Case-control study. In November 2011, the 34 participants with iERM as the case group and 34 healthy participants randomly selected (using a computer-generated random number table) as the control group from the participants without ERM were further examined in the Beixinjing community health service center. Cases and controls were well matched in age, sex, body mass index (BMI), and the iERM-associated risk factors (diabetes and higher level of education) obtained from Part I. After explaining the purpose of this study, we obtained the written informed consent from all participants. Two ophthalmologists, two optometrists and one retinal specialist performed the following examinations. Blood samples were collected for testing plasma glucose, serum total cholesterol, creatinine, and trig.Ble participants underwent a comprehensive ophthalmic examination. Visual acuity of each eye was measured using the log of the minimum angle of resolution (LogMAR) Early Treatment Diabetic Retinopathy Study (ETDRS) chart at a distance of 4 m, with illumination 300 lux. In participants who were wearing glasses in their daily lives, visual acuity was measured with their spectacles. Both types of visual acuity mentioned above are known as the presenting visual acuity [36]. In addition, pinhole-corrected visual acuity was measured in participants with a presenting visual acuity worse than 0.7 in either eye. Anterior segment examinations with a slit-lamp biomicroscope, refractive media and fundus examinations with a direct ophthalmoscope were conducted by the ophthalmologists. If participants’ pinhole-correction visual acuity worse than 0.7 and the vision loss could not be attributed to corneal disease, the examinations were performed after pupil dilatation with 0.5 tropicamide and 0.5 phenylephrine (Mydrin-P; Santen Pharmaceuticals; Japan) except in case of a shallow anterior chamber. A digital 45u non-mydriatic retinal camera (CR-DGi Non-mydriatic Retinal Camera; Canon Inc., Tokyo, Japan) was used to obtain color retinal photographs of ETDRS standard field 1 [37] (centered on the optic disc) and field 2 (centered on the macula) for each eye.Prevalence and Risk Factors of iERM in ShanghaiThe retinal photographs were assessed respectively by two ophthalmologists with retinal subspecialty training for the presence of ERM and its grading. The prevalence-adjusted bias-adjusted kappa statistic was 0.82 for the presence of ERM, and the kappa statistic was 0.70 for its grading. In case of doubt, the lead ophthalmic doctor reassessed the retinal photographs to make the final diagnosis and grading. In our study, ERM was subdivided as idiopathic or secondary. iERM was defined as ERM 1531364 occurring in eyes without a secondary cause, such as DR (at least a history of diabetes associated with retinal microaneurysms), retinal vascular disease, retinal detachment, or history of cataract surgery. Moreover, iERM was graded using the method described by Klein et al. [7], which divides iERM into two types, cellophane macular reflex (CMR) and premacular fibrosis (PMF). CMR was defined as a patch or irregular, increased reflection from the inner retinal surface. PMF, a more severe type, was defined as a grayish and opaque appearance of the inner retinal surface combined with superficial retinal folds or traction lines. Participants with both CMR and PMF were allocated to the PMF group. Thus, iERM was detected in 34 participants (1.02 ), who were all later confirmed by OCT. Part II: Case-control study. In November 2011, the 34 participants with iERM as the case group and 34 healthy participants randomly selected (using a computer-generated random number table) as the control group from the participants without ERM were further examined in the Beixinjing community health service center. Cases and controls were well matched in age, sex, body mass index (BMI), and the iERM-associated risk factors (diabetes and higher level of education) obtained from Part I. After explaining the purpose of this study, we obtained the written informed consent from all participants. Two ophthalmologists, two optometrists and one retinal specialist performed the following examinations. Blood samples were collected for testing plasma glucose, serum total cholesterol, creatinine, and trig.