Soft Contact Lenses – Materials, Manufacturing, and Screening Practice Test

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Which Dk/t value is the highest among the listed extended wear recommendations?

125 x 10^-9

87 x 10^-9

24 x 10^-9

125 x 10^-9

Dk/t measures how much oxygen can reach the cornea through a contact lens; higher values mean more oxygen is getting through. For extended wear, supplying enough oxygen is crucial to keep the cornea healthy during overnight or long-duration wear, so the option with the highest Dk/t offers the best oxygen supply. Among the options, 125 x 10^-9 is the largest value (and it appears in two options), so it represents the highest oxygen transmissibility. The other values, 87 x 10^-9 and 24 x 10^-9, provide less oxygen and are less suitable for extended wear.