He prescribed me the wrong contact prescription for 2 years and I didn't know this until I went to a much better optometrist near my college. I felt that there was something wrong with my vision during those 2 years but just disregarded it because I thought David Tsai knew best since he's an optometrist, but no he does not know best. I go back to him after I graduated because his office is so convenient, and I regretted my decision instantly. His skills have not improved in the 4 years that I've been away, still prescribes contacts that make me feel like I will forever have impaired vision. David Tsai is one of the worst "professionals" I have ever encountered.