1.to evaluate the potential role of the optic nerve diameter ( OND determined by ultrasonography and and visual nerve function by visual evoked potential as a biomarker of early axonal loss and disability in patients with relapsing remitting multiple sclerosis (RRMS).

Multiple sclerosis (MS) is one of the leading disabling neurological diseases in young Adults. Characteristically reliable biomarkers for every independent MS pathogenic factor are extremely important.

1 Increasing evidence has demonstrated that neuronal and axonal damage within the central nervous system (CNS) contributes substantially to the development of permanent disability in patients with MS

• 2 Thus, reliable, economic and easily assessable complementary surrogate biomarkers for axonal Degeneration and consequently disability remain to be identified
• 3 The optic nerve can serve as a useful clinical tool for studying these characteristics and can be used to Measure and monitor the pathological process of the disease. The optic nerve is most commonly assessed by ophthalmoscopy and magnetic resonance imaging (MRI), But measurement of the optic nerve diameter (OND) by a simple ultrasound examination and measurement of optic nerve function by visual evoked potential might permit a rough estimation of the extent of brain parenchymal involvement and the consequent global cerebral atrophy and disability In relapsing-remitting MS (RRMS) patients.

The analysis of the diameter of the optic nerve showed that it is possible To detect its atrophy in the affected eyes (with optic neuritis ) and, to a lesser extent, in un affected eye Also the visual evoked potential study has the ability to quantify the unsuspected clinically silent lesions, hence, allows confirming the vague deterioration of visual functions.

1. inclusion criteria

   1. both sex
   2. Age group from 15 to 50 yrs
   3. Patient with RRMS without history of optic neuritis

2. Exclusion criteria :

   1. History of previous optic neuritis
   2. Medical illness of eye(e.g. diabetes and hypertension)
   3. MS patient on fingolimod for 6 months or more
   4. Relapsing or use of steroid in the past 3 months
   5. Proved alternative diagnosis (neuromyelitis optica )
   6. local eye disease or surgery

both sex and RRMS with out previous optic neuritis