Ophthalmology (, or ) is a branch of medicine and surgery (both methods are used) that deals with the diagnosis and treatment of eye disorders. An ophthalmologist is a specialist in Ophthalmology. Their credentials include a doctorate degree in medicine, followed by an additional four years of Ophthalmology residency training. They may or may not receive residency training in internal medicine, pediatrics, or general surgery before the ophthalmology residency. Additional training may be sought through a fellowship in a particular specialty of eye pathology. Ophthalmologists are allowed to use medications to treat eye diseases, implement laser therapy, and perform surgery when needed. Ophthalmologists may participate in academic research on the diagnosis and treatment for eye disorders.