Complex sentence: The most extensive epidemiological survey on this congenital malformation has been carried out by Dharmasena et al and using English National Hospital Episode Statistics, they calculated the annual incidence of anophthalmia, microphthalmia and congenital malformations of orbit/lacrimal apparatus from 1999 to 2011.
Split into simpler sentences: The most extensive epidemiological survey on this congenital malformation has been carried out by Dharmasena et al. Using English National Hospital Episode Statistics, they calculated the annual incidence of anophthalmia, microphthalmia and congenital malformations of orbit/lacrimal apparatus from 1999 to 2011.