What Causes A Bruise Under The Corner Of The Eye Post Cataract Surgery?

I woke up at 3 a.m. this morning and in my trip to the bathroom saw a bruise in the skin under the corner of my eye. I had a cataract removed at least two months ago from that eye....as well as the other cataract removed two - three weeks ago. All went well, and have had my post -op by the surgeon and says all is perfect. Have received a prescription for the eyes, but do not have the glasses yet.I sm on blood thinner, and at 81 years of age, skin is fragile. I wonder if I may have attempted to clean the eye lid and below the eye with too much effort although don t see it different than any other evening when I washed my face.