Contrast chart aids diagnosis

This test can help in the early detection of disorders such as diabetic retinopathy and glaucoma. The chart consists of letters of the same size but of reducing contrast. Letters are arranged in groups of three of the same contrast, with two groups on a line. The contrast is decreased from one group to the next and also in the middle of each line. A patient's contrast sensitivity is recorded by the ability to read the contrast of the faintest group. Two charts each with a different sequence of letters, are supplied in each set along with a scoring pad. The chart was developed by Dr Denis Pelli of Syracuse University, New York and Dr John Robson of the University of Cambridge, UK. Contact Clement Clarke International on 01279 414969.