PURPOSE. To determine the incidence and causes of vision loss to assist in the objective determination of the preferred frequency of routine screening for those with normal vision. METHODS. A prospective, population-based study of people aged 40 or more years. Standardized examination protocols were used that included presenting and best corrected visual acuity, visual field testing, and comprehensive eye examination with dilation. RESULTS. There were 2529 people with a full data set, including 1590 with a normal baseline examination. The 5-year incidence of vision loss (<6/12 presenting acuity in the worse eye) was 2.39%. Overall, 24 (63%) of 38 of those with vision loss had noticed a change in their vision, and 18 (75%) of these 24 had attended an eye examination. This left only 14 (0.88%) people who had had normal baseline examination results and had asymptomatic vision loss develop over this 5-year period. CONCLUSIONS. Frequent routine eye examinations of those with normal examination results will have a low yield and may not be cost effective. Health promotion messages should target those who notice a change in vision and those at higher risk such as those with diabetes or a family history of eye disease.