Validation Of A New Test For Measuring The Contrast Sensitivity Function (Optopad-Csf) At Near

To develop and validate a new iPad-based contrast sensitivity (CS) test for measuring the contrast sensitivity function (CSF) at near (Optopad-CSF)

Optometric Clinic. Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain

Optopad-CSF test design and experimental setup was developed by our research group. The device was designed to measure spatial contrast sensitivity function with stimuli modulated along the cardinal directions of the DKL space defined from the device’s achromatic stimulus with mean luminance 60cd/m2. A total of 200 eyes of 100 healthy subjects (age, 17-63 years) were evaluated in a comparative study between Optopad-CSF (near vision) and CSV-1000E test (distance vision). A comparison was also made with a sample of 16 patients with bilateral cataract. The agreement between tests was assessed with the index of contrast sensitivity (ICS) and the area under the curve (AUC).

CS for all the spatial frequencies in both eyes showed a negative significant correlation with age, and distance and near corrected visual acuities (r≤-0.512, p≤0.013). Significantly lower CS with Optopad-CSF was found in the over 40 year-old subgroup for all the spatial frequencies evaluated compared to the below-40 subgroup (p≤0.008). Mean AUC of the Optopad-CSF test (5.84) was twice that of the CSV-1000E test (2.76). Mean ICS of Optopad-CSF (-0.019) and CSV-1000E (-0.075) showed similar values and close to 0 (p=0.3). A range of normality for the values obtained with the Optopad-CSF test was calculated as the range containing between percentiles 5% and 95%. Mean CS values in cataract patients were out of the normal range (p<0.001).

Optopad-CSF is a valid portable system for measuring CS at near for 5 spatial frequencies, allowing the detection of age-related changes of CSF with age and CSF loss in cataract, with no ceiling effect.