Atropine cycloplegia: how many instillations does one need?

Atropine is accepted generally as the most efficient cycloplegic agent. Although it is considered a relatively safe drug, toxic local and systemic side effects do occur. The recommended regimen for atropine cycloplegia has been 7 to 10 applications within 3 to 4 days. We compared the cycloplegic effect of four instillations of atropine drops to the effect of eight instillations. The results showed that the cycloplegia obtained after eight instillations was not greater than after four instillations.