Would an optometrist be able to tell if there was something seriously wrong with the eyes caused by brain during their exams?or wuld it go unnoticed?

Would expect so: Some serious issues might include papilledema, a sign of increased brain pressure, double vision, optic atrophy, visual field cuts, and most eye exams would pick this up. The optometrist would likely then refer to ophthalmologist or neurologist.

Often Detectable: The likelihood of identifying or diagnosing such a condition would be greatest if a dilated eye exam were undertaken, a visual field test was performed, and if there were initial concerns in the history provided to raise the suspicion for any such process.