I don't have a lot for you except that perhaps you were having decreased circulation. THat could have caused a temporary reduction in the action of your photoreceptors, It could also have been a medicine side effect due especially to certain heart drugs and central nervous system meds. If you notice any loss or decrease of vision again please see an ophthalmologist in your area. Please discuss the situation with your own personal eye physician and you can mention my ideas if you wish.
MJK MD
For 1 week, I've been taking Lorazepam 1 mg tablet at bedtime for sleep. Could this be the reason for the green hue? I will not take it for a while and see what happens. Thank you for your advice.