Quick status update 😃: still been sick with eye pressure pain but have noticed no added eyestrain using the MBP. Been using it a lot with both Windows 8.1 and Mac OS X Yosemite and on both AMD and Intel GPU (Windows seems to be forced into using the AMD GPU) and it all feels the same.
Need to find a good resolution and DPI for Windows however, as Windows does it differently from OS X.
UPDATE: September 10th - 00:50 PDT: Still feel fine, turning down screen brightness as the night goes it to not have sleep issues, going to go to bed in a minute.