As far as I'm aware, the classic Sx of a pineal gland tumor is when the patient is unable to look up and the superior sclerae are visible. These Sx are due to bilateral superior collicular impingment (Parinaud syndrome) because of the growing pinealoma.
If the patient gets diplopia while walking up the stairs, that could signify unilateral oculomotor nerve lesion secondary to diabetic neuropathy.
If the patient cannot look down (I've seen this in a practice question as "diplopia when walking down the stairs at home"), that usually signifies a trochlear nerve lesion, typically secondary to diabetic neuropathy. Another example is not being able to read a page while scanning from top to bottom (i.e. anything that has to do with downward-directed convergence).
