Is the vision loss related to a corneal ulcer temporary?

Usually: The ulcer is a spot of bacterial growth on the cornea. They generally respond well to treatment is detected in time. However if the ulcer is in the center of the cornea (the visual axis) there may be effects on the vision from the residual scar.

Not always: If the ulceration is in the center of the cornea ANS results in scarring, there may be apermanent reduction in best corected visual acuity.