الفهرس 
Retinal Anatomy and PhysiologyOnly 14 pages are availabe for public view
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Abstract
Type II diabetes is a worldwide growing burden. One of its major issues affecting the middle-aged population and causing visual impairment is diabetic retinopathy.
Traditionally diabetic retinopathy was always thought to have been only a microvascular disease. However, in recent years more studies have shed the light on the fact that a neurodegenerative element is part of the pathology and these studies also suggest that it may start even earlier than the clinically evident retinopathy.
Thus, we conducted this cross-sectional study using mfERG (RETI-port/scan 21) as a non-invasive tool to assess the functional status of the diabetic macula, and we compared these results to the visual acuity and OCT (retinascan RS-3000 advance; NIDEK, Gamagori, Japan) measurements which detects anatomical changes of these diabetic patients in order to see if there is a significant correlation between them.
This study was conducted between March 2016 to June 2017 when we included 30 diabetic patients (type II diabetes) who were attending the ophthalmological outpatient’s clinics of Ain Shams University and another 10 healthy subjects as a control group.
Those 30 patients were subdivided into 3 groups according to their stage of the disease, where we included 10 diabetics without diabetic retinopathy, 10 with early diabetic retinopathy and 10 with proliferative diabetic retinopathy.
We found that the retinal response density was significantly decreased in all diabetic patients compared to the controls and that it gradually decreases with the progression of diabetes.
The amplitude of mfERG was found to be significantly decreasing and the implicit time significantly increasing with the progression of diabetes, except that the significant differences between the non-proliferative and proliferative groups was only in ring 1.
Moreover, the central foveal thickness on OCT was found in the early diabetic retinopathy group and the no retinopathy group to be less than the control group, while the proliferative diabetic retinopathy group showed increased thickness.
And when correlating the parameters, we noticed that, in the diabetic patients without diabetic retinopathy, central foveal thickness showed negative correlation with RRD1, R1 P1 amplitude, DM duration and HBA1c and positive correlation with R1 latency. Their mean inner macula ring thickness showed negative correlation with DM duration and RBS. While their mean outer macula ring thickness showed no significant correlation between any of the measured parameters.
On the other hand, in diabetic patients with NPDR the central foveal thickness showed significant negative correlation with RRD1, R1 P1 amplitude, and positive correlation with R1 latency. Their mean inner macula ring thickness showed negative correlation with RBS and their mean outer macula ring thickness showed no significant correlation with the different parameters.
And lastly in Diabetic patients with PDR, central foveal thickness showed significant positive correlation with R1 latency. The mean inner macula ring thickness showed no significant correlation with the different parameters. And the mean outer macula ring thickness showed significant negative correlation with RRD3.
So as a conclusion, Multifocal electroretinogram (mfERG) has been shown to be capable of detecting the neural changes that occur in retina of diabetic patients before any vascular changes are visible.
And could differentiate between diabetics and controls, also can differentiate between diabetics without retinopathy and patient with retinopathy. The combination of MF-ERG and OCT may provide objective criteria for the evaluation and assessment of severity of diabetic retinopathy.