Welcome to Vision Source Castle Hills. If you have delayed getting an eye exam but know you need one, you are not alone. Many eye disorders are asymptomatic or progress so gradually that they can remain undetected for years. A majority of San Antonio residents have not had an eye exam in years. As a full lab, full optical, Dr. owned and operated eye care center, your San Antonio Optometrist, Dr. Raul Trevino, and the team at Vision Source are have been serving San Antonio residents for over a decade and are committed to providing you with superior vision care.