Induced prismatic effect in spectacle prescriptions sampled in Saudi Arabia.

We determined the prevalence of prescription glasses-induced prismatic effect among a sample of 100 patients in the Kingdom of Saudi Arabia. All the glasses sampled had a certain degree and type of induced prismatic effect. A small percentage (5%) of the subjects complained about their glasses. Prism adaptation is thought to be the reason why the number of patients complaining about improperly fitted glasses does not reflect the frequency of the problem. Simple ways of eliminating these inaccuracies are suggested.