What is meant by the Almighty’s saying, "Allah does not like the public mention of evil except by one who has been wronged," and is it permissible for the wronged to supplicate against the oppressor for the loss of his sight or for a calamity to befall his children?

The verse means that Allah does not like anyone to be supplicated against, except for one who has been wronged. Indeed, he who has been wronged is permitted to supplicate against his oppressor, though patience is better for him. It is permissible for the oppressed to take retribution from his oppressor in like measure, or to supplicate to Allah to assist him and restore his right. It is not permissible to transgress in supplication, such as supplicating against an oppressor for the loss of his sight or his children, unless the injustice is commensurate with the supplication.