Original sentence: Filipino ophthalmologists can receive further in subspecialties of ophthalmology such as neuro-ophthalmology, etc... by completing a fellowship program which varies in length depending on each program's requirement
Edited sentence: Attainment of board certification in ophthalmology from the Philippine Board of Ophthalmology is optional and not mandatory to practice ophthalmology.Graduates of ophthalmology residency programs can receive further in subspecialties of ophthalmology such as neuro-ophthalmology, etc... by completing a fellowship program which varies in length depending on each program's requirement