So, what does corneal topography have to do with fitting contact lenses? Your eye doctor wants your contact lenses to fit your eyes as well as possible, and knowing the exact shape of your cornea is extremely important. Contact lenses that are too tight may constrict normal tear flow, creating an unhealthy environment for normal cell function. On the other hand, fitting a lens that is too loose may allow for excess movement of the lens on your eye, causing discomfort and possibly damage to the epithelial cells.
Wearing contact lenses requires a great deal of responsibility, by you and by your doctor. You must be diligent in following proper cleaning routines and wearing schedules. Your doctor must closely monitor small changes in your eyes in order to avoid potentially serious contact related complications.
Elliott, David B. Clinical Procedures in Primary Eye Care, Pp 115-116. Elsevier Limited, 2003.