I know that corneal abrasions on the corneas can be bad, but can you predict which ones will go bad?
It depends. Depends on the cause of the corneal abrasion. If it is due to an accidental superficial scratch from a finger nail or piece of paper, these usually heal quickly and leave no long term visual effects. If it is due to an infectious etiology such as a bacterial corneal ulcer or viral herpes, the corneal defect is likely deeper and associated with other corneal findings. These require topical therapy.