What Causes Redness In Eyes After Cataract Surgery?

My 92 year old mom had cataract surgery about a month ago...only on her right eye. She has glaucoma and macular degeneration. She is now off all the steroids post surgery, and had still been using Alphagan (2x/day) and Lumigan (1x at night). A few days ago, she put the Lumigan in herself, and thinks she she may have used too much. Right afterwards, the right (surgical) eye was stinging, and blurry. Since, she has discontinued the Lumigan until she will see the surgeon again (appointment is the day after tomorrow). Could the Lumigan have been causing the blurriness? It is still blurry, but a lot of the redness has dissipated in that right eye. Her vision with that eye seemed to be slightly improving before the night she put the drops in herself. YYYY@YYYY