IF it is bright and sunny and especially if she has had cataract surgery and if she did not wear a hat or sunglasses it may be Pink vision due to ultraviolet affects on the retina. It is very unlikely that there is any damage from being outside in the future wear some eye protection.
JCH MD
Hi Fluffy~Seems like a form of photo-sensitivity to me, I would call the ophthalmologist and ask him/her what it could be and schedule a full eye exam appointment.