ANSI standards specify that for Refractive Power above 6.50D, what is the acceptable tolerance?

According to ANSI standards, for refractive power measurements above 6.50D, the acceptable tolerance is indeed ±2%. This tolerance is important because it ensures that the optical performance of lenses remains consistent and reliable for patients who require such refractive corrections.

When considering lenses with higher refractive power, there's a greater risk of optical distortion or aberrations that can arise from manufacturing processes. Therefore, maintaining a ±2% tolerance is critical for ensuring that the lenses perform as intended and meet the necessary standards for quality and accuracy. This standard helps optical professionals provide patients with lenses that will effectively improve their vision without introducing significant errors that could hinder visual performance.

In contrast, other tolerance levels such as ±0.10%, ±0.13%, or ±3% do not align with the established guidelines for this specific range of refractive power. They may be more applicable to different measurements or lower refractive powers, but they do not guarantee the same level of precision needed in lenses above 6.50D.