الفهرس 
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Abstract
The mfERG is considered a useful test to detect regional retinal disorders that are not sufficiently extensive to significantly reduce the full-field ERG and more over early detection of some retinal diseases.
Basic equipments for mfERG include stimulation unit, electrodes and central processing unit. For the routine mfERG, the retina is stimulated with an array of hexagons that produce a single continuous ERG record which is then extracted and analyzed by the computer. Because the electrodes are placed on the cornea and offer no spatial resolution by themselves, the response generated is not truly a series of individual response elements but rather the result of mathematical calculation.
Conventional analysis of the trace arrays is the most accurate and reliable method of analysis of mfERG results. However other methods such as topographic (3-D) response density plot and group averages are valuable.
Regarding clinical applications of mfERG, it is useful in the assessment and follow up of various congenital and hereditary macular diseases and in retinitis pigmentosa.
Also, mfERG is useful in the assessment and follow up of various acquired macular diseases. In early age-related macular degeneration (ARMD) there is progressive loss in the cone-driven mfERG response despite stable visual acuity. The response deterioration extends beyond the visible drusen’s area. The mfERG implicit time is significantly increased in the early ARMD eyes but only within the central four rings of 12°. On the other hand rod-mediated mfERG can detect the effect of ARM on the rod system objectively before changes in the cone-mediated mfERG. Also, mfERG is valuable in the assessment and follow up of different therapies of AMD.
In retinal vascular diseases mfERG has an important role. In macular edema secondary to diabetes mellitus and retinal vein occlusion, mfERG is valuable in the assessment of macular function and follow up of different therapeutic measures. In retinal artery occlusion (RAO) second order mfERG can detect more subtle changes in the inner retina than can the first order mfERG.
Regarding toxic macular diseases, patients undergoing long-term hydroxychloroquine therapy are advised to have periodic testing with mfERG. In case of drug toxicity there is reduced amplitudes in response density blot and prolonged implicit times or prolonged implicit times without significantly attenuated amplitudes which take the characteristic perifoveal pattern hence the value of ring analysis by which the mfRG becomes a more sensitive and objective test. Also, in long-term exposure to mercury vapor mfERG reflects losses in cone-mediated responses.
mfERG parameters appear to be a more sensitive predictor for visual acuity in central serous chorioretinopathy (CSCR).
In macular hole and idiopathic epiretinal membrane (IEM) mf ERG is useful in evaluation of retinal function before and after surgery.