welcome to the forum melko. i don't know about MRI for sure, but if they're doing brain and spine looking for lesions, then lesions will still show up in a couple weeks.
i can offer assistance re nutritional approaches. for example i would ask them to test your zinc level since you are dealing with ON. make sure the seurm level is up around 18-19 umol/L (very top of the normal range). serum zinc is reduced in TTON (tobacco toxic ON) so regardless of whether you smoke, a look at zinc status could be useful.
Zinc in the eyehttp://www.surveyophthalmol.com/article/0039-6257(82
Zinc has long been recognized as an essential constituent of various tissues. Many clinical conditions and dietary factors reduce the absorption or the biological availability of zinc, and lead to zinc deficiency which produces structural and functional alterations in many organ systems. The highest concentration of this trace element in the human body is measured in the eye, particularly in the pigment-containing components. The deficiency of zinc has a dramatic effect on ocular development especially when it occurs during early prenatal period. Zinc is required for the structure and activity of many ocular metalloenzymes. Although the exact mechanism of its molecular and cellular functions are largely unknown the essentiality of this element in the components of the eye, including the retina, choroid, cornea and lens, is well established; it is also well known that zinc deficiency causes functional impairments in various parts of the eye. Zinc related toxicities have been shown in human and animal eyes.