A GP lens with a higher refractive index allows for which of the following physical characteristics?

A GP lens with a higher refractive index allows for which of the following physical characteristics?

• A. thinner and lighter lens, allowing for better centration and comfort
• B. thicker and heavier lens
• C. lower oxygen permeability
• D. more color options

Answer: (A)

Higher refractive index in a gas-permeable lens means you can achieve the same corrective power with less material. That lets the lens be thinner and lighter while still bending light to the same degree. A thinner, lighter lens brings less mass on the eye, which helps it sit more stably and centrally on the cornea, reducing edge lift and improving comfort and centration. Oxygen permeability depends on the material’s inherent Dk (oxygen permeability) and the lens thickness. A higher index doesn’t inherently lower oxygen delivery; in fact, because the lens can be thinner for the same power, oxygen passage to the cornea can be maintained or even improved in practice. The other ideas don’t fit because a higher index isn’t tied to a thicker or heavier lens, nor does it dictate color options.

Higher refractive index in a gas-permeable lens means you can achieve the same corrective power with less material. That lets the lens be thinner and lighter while still bending light to the same degree. A thinner, lighter lens brings less mass on the eye, which helps it sit more stably and centrally on the cornea, reducing edge lift and improving comfort and centration.

Oxygen permeability depends on the material’s inherent Dk (oxygen permeability) and the lens thickness. A higher index doesn’t inherently lower oxygen delivery; in fact, because the lens can be thinner for the same power, oxygen passage to the cornea can be maintained or even improved in practice.

The other ideas don’t fit because a higher index isn’t tied to a thicker or heavier lens, nor does it dictate color options.