The latest technique for cataract extraction is phacoemulsification with foldable intraocular lens implantation. There are various methods available for IOL power calculation but your fathers doctor is the best person to decide which formula is best for his eyes.
Nakhuna (also known as pterygium) is a mass / growth of conjunctiva usually seen on the inner side of the eye growing onto the cornea. It can be either removed at the time of cataract surgery or as a separate procedure. However pterygium is known to recur. The best technique is pterygium excision with conjunctival auto-grafting, which minimizes the chances of recurrence.