What is the ruling on taking the insurance amount and using it to buy sunglasses that are more expensive than the compensation, or using it for something other than eyeglasses?

If the intent of the question is to defraud the insurance company, then this is impermissible in the legitimate cooperative Takaful insurance, and it is obligatory to adhere to the conditions, based on the words of Allah Almighty: "O you who have believed, fulfill [all] contracts," and the words of the Prophet, peace and blessings be upon him: "Muslims are bound by their conditions." As for commercial insurance, which is forbidden, it is not permissible to voluntarily subscribe to it. One who has subscribed to it is not allowed to take more than what he has paid, but he is permitted to use deceptive means to recover what he has paid. If an employee is entitled to treatment and his employer refers him to insurance, he has the right to fully claim his entitlement, and the sin falls upon the employer.