Hi Pedro and welcome to Frog Forum!

The injury looks quite serious. Is the toad behaving normally and eating properly? If it is, then there is a chance the eye injury is not affecting basic life skills. I suggest making an eye drop solution with the powder of one tetracycline capsule (aquarium type). Take a small pinch of powder and mix thoroughly with 1/4 cup (about 60 ml) of distilled water. Apply one drop in infected eye for 8 days. Make a new batch of solution and sterilize eye drop after each application. This should help control any bacterial infection.

Good luck and hope the frog's eye gets better.