The Arden contrast sensitivity was investigated in normal persons, cataract eyes, and glaucoma patients with only plates 6 and 7 of the Arden grating set. The mean score of 90 normal eyes on plate 6 was 9.50 +/- 2.29 and on plate 7 it was 9.44 +/- 2.32. The mean scores of patients with early cataract were 14.51 +/- 2.99 on plate 6 and 13.74 +/- 3.26 on plate 7. Several patients with cataract missed the grating on plate 7. Mydriasis and miosis did not affect contrast sensitivity in normal eyes. Mydriasis significantly improved contrast sensitivity in patients with early cataract. In patients with glaucoma enlargement of the pupil from a miotic state to near normal size significantly improved contrast sensitivity. It is predicted that if plate 6 and 7 are used in mass screening for glaucoma in the elderly, there will be a false negative rate of 83% for plate 6 and 52% for plate 7. A false positive rate of 17% is predicted.