it's important to take it slow when there are temperature fluctuations, I've done my usual running* around this weekend and I noticed my vision doubling before. Perhaps I ran too much? Maybe its only the heat. Regardless of the cause it serves as a good reminder to slow down, I turned the ac down and I'm in for the day as it seems. For anyone with Multiple Sclerosis the sun and warm temps can be a real burden at times, it's always best to err or on the side of caution especially to prevent a relapse.
(*of course I didn't run, I use a cane for pete's sake)