Abstract
Amblyopia is a developmental disorder which results in poor spatial vision. Many have suggested that the contrast sensitivity function (CSF) characterizes these spatial vision deficits better than letter acuity, which is currently used for the screening, early intervention and treatment evaluation of amblyopia. However, the long testing-times or imprecision of traditional CSF measurements limit their clinical potential. We evaluated the qCSF method (Lesmes et al, 2008) in adults with amblyopia, to test its usefulness for measuring CSF in amblyopia with acceptable testing-time, accuracy and precision. For ten normal and eight amblyopic participants, two sets of CSFs were obtained with a 2AFC contrast detection task in two separate sessions of interleaved qCSF and conventional CSF procedures. We found that: 1) The assumptions used in the qCSF were valid for seven normal participants and all amblyopic participants. 2) For both groups and both methods, threshold estimates in two separate runs were well matched (all R0.94). 3) The qCSF method provided an accuracy of 2.3 dB and 3.7 dB in only 120 trials (∼ 5 mins) for normals and amblyopes, respectively. 4) Measures of the area under log CSF (AULCSF) and the cut-off spatial frequency (cSF) were lower in the amblyopic group; these differences were captured within 50 qCSF trials. 5) Using a logistic regression model with AULCSF and cSF as predictors, we detected amblyopia with an about 80% correct rate in 50 trials. We conclude that the qCSF method is rapid, accurate, and precise enough to measure CSFs in normal and amblyopic populations; it has great potential for clinical practice.