I do not know what has happened to you, but I can describe my own experience. But first of all, you should be clear that with any sudden eye problem, you MUST GO TO HOSPITAL accident & emergency, or specialist eye casualty department as soon as possible, i.e. TODAY. This is because some eye problems can get very serious extremely quickly & they need to rule such urgent problems out or treat them urgently. I will describe my experience, but please remember, it may not be the same problem you have, and you must see an eye specialist. Don’t be afraid. It might not be something bad, but you must check. I had Optic Neuritis (inflammation of the Optic nerve). Because the myelin sheath which protects the nerve is damaged, the messages can't get through properly, hence vision is impaired. Visual acuity (sharpness/ clarity of vision), colour saturation (how strong/ deep colours appear) and visual field may be affected. This is temporary. Most people recover well. I feel I regained my vision each time, but not fully. What you describe has happened to me 4 times, always in only one eye (mine have been affected alternately), coming on over a period of hours or 2 days and then recovering by itself over a period of 2 weeks to 4 months. For me, it is accompanied by impairment of colour vision. Colours appear bleached out. e.g. bright red looks like baby pink. Sometimes the colour saturation is severely affected, sometimes very slightly. 90% of people with optic neuritis feel pain, but not everybody & not always. Pain can be in the eye at the back, or a feel bit deeper behind the eyeball. It can be pain on moving the eyes. You may find that your vision gets worse if you get warm (e.g. through exercise or a warm bath or hot sauna). The first time, I had no pain. Other times I have had pain in the head for up to 25 days. I experienced it as being more myopic (short sighted) than I normally am. This can not be corrected by wearing glasses / contact lenses, nor by increasing the strength of your prescription. It does not work that way. You wear your spectacles if that is what you normally do, but you will not be able to see so well. Optic neuritis makes me feel unsettled, disoriented, annoyed, less confident, less capable, angry even. Basically, you just have to put up with it. There is nothing the doctors nor you can do. Sorry. IF it is optic neuritis, you have not caused it yourself through unhealthy living. It happens by itself & doctors are not clear why. It is not preventable. I was offered steroids. These do not cure the problem, but merely speed up the recovery slightly. (I declined these strong drugs, due to the nasty side effects weighed up against the minimal benefits. Eye specialist agreed with my judgement, and a second one said she wouldn’t eat them either!). Optic neuritis is often but not always linked to Multiple Sclerosis (MS). Most people get diagnosed with this younger than you, so that is potentially a good sign for you, especially if you have not experienced any other problems of the nervous system. To be diagnosed with MS, one has to have had at least 2 attacks, which could be the nerves anywhere in the body (not just eyes). A diagnosis is then confirmed by an MRI scan of the brain. This is not painful at all. You just lie down & go into the scanner. Not scary. A neurologist (nerve doctor) interprets the scan. This could be many months later, as the eye consultant would have identified on first meeting with you that it is not urgent. “Not urgent” in this case means “not a hurry” and “because there is nothing the eye consultant can do to help in any case” and “the neurologist will probably not be giving you any treatment, or at least not unless/ until you experience more problems”. Multiple Sclerosis varies considerably in severity, so don’t be afraid. It can be mild. Like many people with MS, optic neuritis was the first sign for me. Having a brain scan can have negative implications for life insurance / travel insurance e.t.c. Good luck! Remember, you may have something entirely different to me. You must go to Casualty to find out. Go to the separate Eye Casualty department if your hospital has one. You do not need an appointment. They may not be open on a Sunday, but at least the normal A&E department may be able to rule out any urgent problems which may need to be dealt with immediately. Optic neuritis does not have this acute time pressure, but you do not know what is wrong with you yet. Best wishes. I will pray for you.