Which lens material simultaneously has the lowest Abbe value and high chromatic aberration risk?

Which lens material simultaneously has the lowest Abbe value and high chromatic aberration risk?

• A. Ophthalmic crown glass
• B. CR-39
• C. Polycarbonate
• D. Trivex

Answer: (C)

Chromatic dispersion in lens materials is quantified by the Abbe value: the lower the Abbe value, the more different wavelengths bend differently, leading to greater chromatic aberration. Among common ophthalmic materials, polycarbonate has the lowest Abbe value (around 30), so it exhibits the highest chromatic dispersion and thus the highest chromatic aberration risk. In contrast, crown glass and CR-39 have much higher Abbe values (roughly in the 50s to 60s), indicating much less chromatic aberration, while Trivex sits between polycarbonate and the others with an Abbe value around the 40s. Therefore, polycarbonate best fits the description of having the lowest Abbe value and the highest chromatic aberration risk.

Chromatic dispersion in lens materials is quantified by the Abbe value: the lower the Abbe value, the more different wavelengths bend differently, leading to greater chromatic aberration. Among common ophthalmic materials, polycarbonate has the lowest Abbe value (around 30), so it exhibits the highest chromatic dispersion and thus the highest chromatic aberration risk. In contrast, crown glass and CR-39 have much higher Abbe values (roughly in the 50s to 60s), indicating much less chromatic aberration, while Trivex sits between polycarbonate and the others with an Abbe value around the 40s. Therefore, polycarbonate best fits the description of having the lowest Abbe value and the highest chromatic aberration risk.