As we know, the cornea is the outside front layer of transparent thin film in the eyes. They are often exposed to the air, unless you are asleep. So the contact germs get more opportunities to get foreign trauma. The corneal ulcer can be caused by the situation after eliminating the damage sand or dust which comes in during the daytime. In addition, the corneal ulcer may also be caused by coming bacteria, fungi, viruses and so on. All above ones may cause infection and then produce corneal ulcer. The too much allergy character may cause the corneal ulcer. And the lack of vitamin A, facial paralysis and cause bad eyelid closure caused by eyelid scar may also lead to the corneal ulcer. If your corneal ulcer is not serious, you may keep on using the eye drops to eliminating the bacterium which will be ok after a month. If it is serious, you could get the surgery which will be OK after half a month after the surgery.
It is hard to tell. And the time need to heal and recovery from corneal ulcer will vary depending on the causes of ulcer and its sizes, location and depth. Usually, Two or three weeks can improve your eyes if you treat the corneal ulcer appropriately. But it need more time to reduce the amount of potential scarring. And i think your eye doctor will know better about the time for healing corneal ulcer if you have such problems.