Why do I see better with my contact lenses?

I had a great question today from a nearsighted patient who wears contact lenses full time.  She reported - like many contact lens wearers do - that her vision seems better with her contact lenses vs. her glasses…. why is this so?        There are a few reasons for this… [1] because a contact lenses sits directly on the eye, the optical centre (best vision and prescription) always sits in the correct spot.  You are not looking out of a less perfect part of the lens [2] related but not exactly the same… there is overall far less distortion and aberration with a contact lens correction [3] in her case… she had a difference in the Right vs. Left prescription and contact lenses do a great job balancing this difference.  Of interest and for another blog post… Shaw spectacles lenses do a great job of this balance in spectacle lenses.  www.shawlens.com   [4]  In a higher degree of nearsightedness, the corrected image size is smaller with glasses than contact lenses.  i.e. when you look at someone's eyes through a high myopic (nearsighted correction) they appear smaller… this minification happens to the world of the person wearing the glasses but not contacts
 
dr.j