If the eye is injured by a nail in the black eye, do not press on the eye, you can gently cover it with a handkerchief or tissue as appropriate, and go to a nearby hospital immediately.
If it is a common corneal epithelial injury, you need to use a topical ointment to apply under the guidance of a doctor, or treat it with antibiotic medication to avoid the eye from being infected by bacteria. Improper treatment will result in vision loss and scarring of the cornea in the pupil area.
In the case of corneal perforation, the iris and lens may be injured causing cloudy crystals or vitreous hemorrhage, which in severe cases can cause eye infections and may require surgical treatment.
It is recommended to go to the hospital immediately after getting a black eye from a nail in the eye and get treatment with the help of a doctor.