What is the primary benefit of using rigid gas-permeable lenses over soft lenses?

What is the primary benefit of using rigid gas-permeable lenses over soft lenses?

• A. Better comfort over long periods
• B. Higher oxygen permeability
• C. Lower cost
• D. Better durability

Answer: (B)

Oxygen delivery to the cornea is the essential factor here. The cornea has no blood vessels, so it relies on oxygen from the air through the tear film. Rigid gas-permeable lenses are made from materials with higher oxygen permeability (and their thin, rigid design allows oxygen to diffuse through more easily) compared with many traditional soft lenses. This means more oxygen reaches the cornea, reducing hypoxia and related problems, which is the main advantage of RGP lenses. Comfort, cost, and durability can vary and are influenced by many factors, but they do not outweigh the primary benefit of improved oxygen transmission to the cornea.

Oxygen delivery to the cornea is the essential factor here. The cornea has no blood vessels, so it relies on oxygen from the air through the tear film. Rigid gas-permeable lenses are made from materials with higher oxygen permeability (and their thin, rigid design allows oxygen to diffuse through more easily) compared with many traditional soft lenses. This means more oxygen reaches the cornea, reducing hypoxia and related problems, which is the main advantage of RGP lenses.

Comfort, cost, and durability can vary and are influenced by many factors, but they do not outweigh the primary benefit of improved oxygen transmission to the cornea.