Is a reading addition necessary for clinical contrast sensitivity measurements?

Purpose: Clinical tests of contrast sensitivity are performed at near with letters large enough to be above the acuity threshold of presbyopes with normal vision. Is a reading addition necessary to obtain accurate thresholds? Method: Contrast sensitivity was assessed using Pelli-Robson and Mars charts. Participants were presbyopes with normal or corrected-to-normal distance and near acuity. Contrast sensitivity was assessed with participants wearing distance refractive correction, and also wearing an appropriate addition for the working distance (+0.75DS for the Pelli-Robson at 1m; +2.00DS for the Mars at 50cm). Results: The difference between contrast sensitivity measurements made with and without the reading addition was not signifi cant for either chart (repeated measures t-test, p>0.05 for Pelli-Robson and Mars). Conclusion: Contrast sensitivity can be assessed in presbyopic visual normals with patients wearing either distance or near correction without affecting thresholds.