الفهرس 
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Abstract
Summary and Conclusion
Idiopathic intracranial hypertension (IIH) is defined as an elevation of intracranial pressure (ICP) in the absence of a brain lesion or any other secondary etiology, the visual pathway is particularly sensitive to elevated intracranial pressure and due to chronic course of the disease and to prevent delayed visual loss, monitoring of vision in IIH patients is crucial.
In addition to papilledema and optic nerve atrophy that represent the main complication of IIH and can be seen in 25% of patients, a number of retinal changes may contribute to the visual deficit, including choroidal compression across the macula, choroidal neovascularization and axoplasmic stasis in the retinal ganglion cells (RGCs) which lead to retinal ganglion cells dysfunction and contribute to visual dysfunction.
Our study aimed specifically to clarify the effect of chronic increased ICP on the retina and optic nerve through studying the findings of mfERG and VEPs in chronic IIH patients.
Visual evoked potentials (VEPs) are sensitive and non-invasive method for evaluation of the visual function that has been long used for studying suspected cases of optic nerve disease.
Multifocal electroretinogram (mfERG) is an electrophysiological test that allows the function of multiple discrete areas of the retina to be tested simultaneously.
Thirty female patients with chronic IIH were enrolled in our study with thirty age and sex matched controls.
All subjects underwent full neurological and ophthalmological examinations. They were subjected to electrophysiological tests including VEP and mfERG.
In our study, about 20 (66.6%) of chronic IIH patients had abnormal VEP responses while only 10 (33.3%) patients had normal VEP responses. There was a significant delay in P100 latencies on check size 1degree and 15minute in IIH patients when compared to controls. While, the P100 amplitudes were within normal range.
There was a statistically significant positive correlation between VEP latency and both pressure of the CSF and the degree of papilledema in IIH patients.
Regarding the mfERG, our study revealed that chronic IIH patients had a significant reduction in amplitudes of mfERG- P1 wave in the five retinal rings and the four retinal quadrants together with delayed peak times of mfERG- P1 wave only in retinal rings 1 and 2 when compared to the control group.
A statistically non-significant correlation existed between mfERG and either CSF pressure or the degree of the papilledema in IIH group.
In conclusion, chronic increased ICP have a significant effect on VEP and mfERG. A significant increased ICP in IIH patients was associated with delayed P100 latency in VEPs with positive correlation between P100 latency and both increased ICP and the degree of the papilledema.
Moreover there was a significant reduction in amplitude of P1 in the five retinal rings and the four retinal quadrants with delayed peak time of P1 in the ring 1and 2 in IIH patients when compared to controls. However , a non-significant correlation existed between mfERG and either the pressure of CSF or the degree of the papilledema. These findings may reflect diffuse dysfunction of the macular cones and bipolar cell layers, with more affection of the central part of macula (fovea and parafovea) than the peripheral part and this could not thoroughly be evaluated by VEPs alone. Also, this can be attributed to the retinal manifestations associated with IIH that include chorioretinal folds, macular exudate, choroidal neovascular membrane and macular edema.