First Refracting Surface

In the second century AD Galen formulated a model of the eye that remained “correct” for hundreds of years. The cornea was thought to be the first refracting surface of the eye. It took Ophthalmologists nearly 2000 years to fully appreciate that the first refracting surface is not the cornea but the tear film. Much attention of late has been directed to disturbances of the tear film including dry eye and Meibomian gland disease (aka blepharitis) among others and how it can affect our vision and especially our choices as it relates to cataract surgery.