Soft Contact Lenses – Materials, Manufacturing, And Screening Practice Test

Oxygen transmissibility can vary within the lens due to which factors?

Diameter and thickness Refractive index and color Center thickness and edge thickness Power and location on the lens

Correct Answer:

Power and location on the lens

Explanation:

Oxygen transmissibility, expressed as Dk/t, depends on the local thickness of the lens. The material’s permeability (Dk) is fixed for a given lens, so any variation in transmissibility across the lens comes from how thick or thin the lens is in different zones. In a typical lens, thickness varies from the center to the edge, so the center thickness and edge thickness are the key factors that determine how much oxygen can reach the cornea in different regions. Thinner areas have higher Dk/t and allow more oxygen through, while thicker areas have lower Dk/t. Other properties like diameter, refractive index, or color don’t by themselves change Dk/t within the lens, though the design can influence where thickness changes occur.

Access more questions from this quiz

Continue to Soft Contact Lenses – Materials, Manufacturing, and Screening Practice Test for more practice questions and the full quiz experience.

Access More Questions