الفهرس 
Anatomy of the MaculaOnly 14 pages are availabe for public view
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Abstract
Diabetic macular edema is a well-documented, sight threatening complication of diabetes mellitus. DME is the most common cause of visual impairment in patients with diabetes.
The pathogenesis of DME could be studied on the basis of changes in the blood-retinal barrier with the loss of pericytes, release of vasoactive factors like VEGF and abnormalities in virtreo-retinal interface.
Macular edema is defined as retinal thickening from accumulation of fluid within one disc diameter of the macula, which is often accompanied by retinal hard exudates.
This macular edema is best detected by contact lens slit lamp biomicroscopy. The term clinically significant macular edema is reserved for those which fulfill the criteria of ETDRS on clinical examination regardless the visual acuity and leakage on fluorescein. The role of fluorescein angiography and optical coherence tomography is to help diagnosis and guide for treatment modalities.
Laser treatment is clearly the first-line of treatment of DR and DME in order to reduce progression & the risk of doubling the visual angle by 50%.
Unfortunately, even with well-timed and adequate laser treatment, some patients will not have an improvement in vision and can even continue to lose vision.
Recent research in pharmacotherapy for diabetic retinopathy and macular edema offers new hope for these difficult situations like steroids and antiVEGF.
Bevacizumab (Avastin, Genentech, Inc., San Francisco, CA) is a recombinant humanized monoclonal IgG antibody that inhibits all isoforms of human VEGF which is currently approved for the treatment of metastatic colorectal cancer. Recent studies in ophthalmology show the beneficial effect of avastin on antagonizing VEGF and thus reducing macular edema.
According to our results, we found that laser photocoagulation produced statistically insignificant change in the visual acuity in spite of significant reduction of macular thickness. However the laser was characterized by its stability on visual acuity.
On the other hand, avastin in addition to laser had a significant improvement on visual acuity and central macular thickness. This improvement is more evident in those cases with severe macular edema as regarding leakage on fluorescein and central macular thickness.