To compare Freiburg new method with Metro Vision static contrast sensitivity technique.

40 emetropic normal volunteers aged 18 – 35, mean 21.7 ± 0.4 and corrected visual acuity of 20/20, participated in this study. In Freiburg, contrast thresholds were determined at spatial frequencies (SF) of 1, 5 and 15 cycles per degree (cpd) based on contrast sensitivity (CS) was calculated in terms of decibel (dB). In Metro Vision, CS curve prepared at desired frequencies, and then CS in terms of dB was obtained by extrapolation. The findings of two methods were compared with Bland - Altman agreement and correlation methods.

Average values of CS in Freiburg and Metro Vision are respectively, 22.21 ± 1.31 and 19.43 ± 1.90 dB at 1 cpd, 22.76 ± 0.72 and 20.72 ± 2.41 at 5 and 20.53 ± 2.45 and 13.26 ± 3.49 at 15. Correlation between “two tests differences” and "two tests findings mean" at SFs of 1, 5 and 15 cpd are (r = -0.35, P = 0.001), (r = -0.86, P = 0.000 ) and (r = -0.34, P = 0.002) respectively.

Freiburg is greater than Metro Vision contrast estimate. This over estimation is more visible in high SF and low CS.