الفهرس 
Anatomy of the RetinaOnly 14 pages are availabe for public view
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Abstract
Diabetic retinopathy (DR) is one of the leading reasons of blindness throughout the world, and diabetic macular edema (DME) is a major complication of DR which leads to visual acuity loss, so early diagnosis and adequate treatment is a must to overcome this disaster. Our study is a prospective observational study aiming to evaluate electrophysiological responses of central retina following intravitreal injection of Ranibizumab in cases of central-involved diabetic macular edema in correlation with optical coherence tomography (OCT). The study involved 24 eyes of 20 patients suffering from diabetic macular edema. All the study participants underwent full ophthalmological assessment with measuring central foveal thickness (CFT) using Heidelberg Optical Coherence Tomography (OCT spectralis). Multifocal electroretinography (mfERG) was performed using RetiMax device in accordance with the ISCEV guidelines. Patients were examined at baseline (pre-injection) and one month after three intravitreal injections of Ranibizumab at monthly intervals (postinjection). The mfERG parameters our study focused on included, relative retinal density of response, P1 wave amplitude and implicit time in the 2 central rings R1 and R2. The results showed that intravitreal injection of Ranibizumab is accompanied by improvement in BCVA, reduction in central foveal thickness as seen in OCT and improvement in mfERG parameters in the form of increased relative retinal density of response, increased P1 wave amplitude and decreased P1 wave implicit time in both central rings (R1 and R2). There was statistically significant positive correlation between BCVA and OCT CFT. Also statistically significant positive correlation was found between OCT CFT and multiple mfERG parameters including relative retinal density of response in R2, P1 wave amplitude in R2 and the average P1 wave implicit time for both R1 and R2. On the other hand our study also noticed statistically significant positive correlation between BCVA and relative retinal density of response in R1. Multivariate regression analysis showed that the most significant variable correlating with OCT CFT is P1 wave amplitude in R2 and the most significant variable correlating with BCVA is relative retinal density of response in R1. So according to our study multifocal ERG can be used as an effective method in the follow up of patients with central-involved diabetic macular edema after intravitreal injection of Ranibizumab. It can also be used to detect the patient’s response to injection. It is obvious that mfERG has a potential role in demonstrating functional retinal impairment in patients with diabetic macular edema. In addition, it is suggested that OCT and mfERG could be used together to complement each other in the diagnosis and follow up of patients with DME to gain the benefit of both tests by combining both structural and functional retinal changes. Also our study showed that intravitreal Ranibizumab is not only able to reduce macular edema, but also can aid in the recovery of inner retinal cell function. Thus effectiveness of Ranibizumab in diabetic macular edema (DME) is demonstrated structurally and functionally as it improved the electrophysiological profile in eyes with DME by improving the macular function.