A soft lens with an 8.6 base curve from one manufacturer may not fit the same as another 8.6 BC lens from a different manufacturer. Which statement is true?

A soft lens with an 8.6 base curve from one manufacturer may not fit the same as another 8.6 BC lens from a different manufacturer. Which statement is true?

• A. They will fit identically
• B. They may not fit the same due to manufacturing variations
• C. They always require different lens powers
• D. They are interchangeable without fitting checks

Answer: (B)

Base curve is just one part of how a soft lens fits. Even if two lenses share the same base curve number, they can feel and behave differently because manufacturers vary edge design, overall diameter, center thickness, and material properties. Small manufacturing tolerances can also shift the actual curve or diameter slightly from the labeled value, leading to different lidocentric fit and movement on blink. So two lenses with the same numerical base curve may not fit identically, and you’d still need fitting checks when switching brands. The other statements imply guarantees about identical fit, required different powers, or no fitting checks, which don’t hold true given these design and production differences.

Base curve is just one part of how a soft lens fits. Even if two lenses share the same base curve number, they can feel and behave differently because manufacturers vary edge design, overall diameter, center thickness, and material properties. Small manufacturing tolerances can also shift the actual curve or diameter slightly from the labeled value, leading to different lidocentric fit and movement on blink. So two lenses with the same numerical base curve may not fit identically, and you’d still need fitting checks when switching brands. The other statements imply guarantees about identical fit, required different powers, or no fitting checks, which don’t hold true given these design and production differences.