A critical view of presbyopic add determination.

From a previous study at the Optometric Center of Fullerton, it was found that 17.5% of the review clinic population returned due to improper presbyopic reading adds. The population sample for the present study consisted of patients between 40-60 years of age who returned to the clinic between September 1983 and May 1985 due to improper add power. The add power originally prescribed was compared to each of four commonly used methods of add power determination. Our results indicate that the age expected add powers account for the fewest errors while the binocular cross cylinder the most. Upper and lower limits for an acceptable range of add powers versus age were determined.