What does CT stand for in GP lens terminology?

What does CT stand for in GP lens terminology?

• A. Center Thickness
• B. Corner Thickness
• C. Central Thickness
• D. Core Thickness

Answer: (C)

CT in GP lens terminology refers to the central thickness—the thickness at the optical center of the lens. This central thickness is a key parameter because it directly affects how much oxygen can pass through the lens to the cornea (oxygen transmissibility expressed as Dk/t). A thicker center reduces oxygen reaching the cornea, which matters for corneal health and lens comfort, while a thinner center preserves more oxygen but can influence the lens’s rigidity and how it maintains its optical shape. The term central thickness is the standard way to describe this measurement in GP lens design and fitting, whereas other phrases describe thickness in different areas (like the edges or other zones) and aren’t used for this abbreviation.

CT in GP lens terminology refers to the central thickness—the thickness at the optical center of the lens. This central thickness is a key parameter because it directly affects how much oxygen can pass through the lens to the cornea (oxygen transmissibility expressed as Dk/t). A thicker center reduces oxygen reaching the cornea, which matters for corneal health and lens comfort, while a thinner center preserves more oxygen but can influence the lens’s rigidity and how it maintains its optical shape. The term central thickness is the standard way to describe this measurement in GP lens design and fitting, whereas other phrases describe thickness in different areas (like the edges or other zones) and aren’t used for this abbreviation.