Comparison of the New Method of " Freiburg" with Static Contrast Sensitivity of " MetroVision" System

To compare Freiburg new method with static contrast sensitivity of “MetroVision” system. Fourty emmetropic volunteers aged 18-35 (mean, 21.7±0.4) years and corrected visual acuity of 20/20 or better participated in this study. The participants had no systemic disease, ocular or neurological problems, and received no systemic medication. An informed consent was obtained from all participants. Contrast sensitivity was measured at spatial frequencies of 1, 5 and 15 cycles per degree (cpd) using Freiburg and MetroVision. The agreement between the two methods was evaluated using Bland Altman agreement, relevant maps and correlation methods. Mean contrast sensitivity measured with Freiberg and the MetroVision methods were 22.2±1.3 and 19.4±1.9 dB at frequency of 1 cpd, 22.7±0.7 and 20.7±2.4 dB at frequency of 5 cpd, and 20.5±2.5 and 13.3±3.5 dB at frequency of 15 cpd, respectively. The correlation coefficients of the differences between these two methods with average measurements by the two methods were r= -0.35 (P= 0.001), r= -0.86 (P= 0.000) and r= -0.34 (P=0.002) at frequencies of 1, 5 and 15 cpd, respectively. Freiburg method overestimates contrast sensitivity as compared to MetroVision technique. This overestimation is more remarkable at higher spatial frequencies and lower contrast sensitivities.