Ripcoin

Two Math wizards at MIT take a course on crypto currency and form a study group. During their numerous hours in the library discussing monetary theory, they begin to fall in love. On weekends, they visit Cambridge pubs to participate in quiz night, specifically when the subject matter is topology. They become so intimate with each other, that they share their prescriptions; one is taking Adderall, the other is ingesting Wellbutrin, and after a week of co-imbibing they both suffer seizures (a side effect of mixing the medications) while erasing a chalk board. They are rushed to the ED where they are counseled to stop sharing meds. Unfortunately, both are now suffering diplopia., possibly from injuring their heads during their seizures. Karoline suffers diplopia at all times except when she focuses her eyes to her right. Saif experiences diplopia at all times except when he looks towards his left. Wasting no time, they immediately start a crypto exchange that takes off and both become multi billionaires in weeks. But something is amiss with their balance sheets – their profit margins are exuberantly above their verified assets. The Security and Exchange Commission charges them with fraud and Karolina pleads guilty. She agrees to testify for the prosecution. Saif, instead, claims the elevated reports of his net worth were simply a result of his diplopia; he was mistakenly seeing double the value of his assets. Which damaged nerve could account for Saif’s diplopia leading to his naïve (criminal?) interpretation of his assets?

What is the reason for the diplopia?