When was the last time you changed a patient to a different contact lens material? What was the main reason for this change? Reasons might include:
To improve comfort by reducing modulus
To improve comfort by decreasing friction or increasing lubricity
To improve oxygen profile by increasing Dk/t
To improve address desiccation by changing to a silicone hydrogel material
Give details of the change and suggest how the lubricity of the newer lens material might differ from the previous one (even if this was not the main reason for change).