An oculist is a medical professional who specializes in the diagnosis and treatment of eye diseases and disorders. Oculists are also known as ophthalmologists, which is a 15-letter word that can be used to solve a crossword puzzle. Ophthalmologists are trained to diagnose, treat, and manage all eye diseases, including glaucoma, cataracts, macular degeneration, and other vision problems. They also perform eye surgery and prescribe corrective lenses.