Betta Fish: Bettas eyes look weird. Popeye?

Hi, this is Topaz, I’ve had her for around a year and a half and she’s always been pretty healthy but tonight when I went to check on her, I noticed her eyes look weird. Not sure if this is popeye? The rim around her eyes is a similar color to her body and it looks like a bit of a precipitate in the lower portion of one of there eyes. The tank is well established, 5 gallon, heated with filter. I did a 20% water change and put a fresh filter in about a week ago. What’s the best treatment for this?