Quantifying the effectiveness and uses of Progressive Power Lenses (PPL) in comparison to other methods of correction for presbyopia.

Quantifying the effectiveness and uses of Progressive Power Lenses (PPL) in comparison to other methods of correction for presbyopia. Order Description   *Is patient satisfaction higher with better quality PPL's than lower quality PPLS's? *Is there a higher success rate with people wearing PPL's over the age of 50, as opposed to people under the age of 50? *What are the barriers/challenges which lead to patient dissatisfaction with PPL's?