Chlorpromazine and several other phenothiazine neuroleptic drugs appear to induce cataract formation. However, the newer generation of antipsychotic agents has shown no evidence of an etiologic relationship with cataract occurrence. Research did reveal cataract occurrence in dogs who received quetiapine, which prompted concern despite there being no known causal link between quetiapine and lens opacities in humans. Nevertheless, quetiapine's manufacturer issued formal recommendations for ophthalmological follow-up examinations with the use of this drug. Infrequent occurrences of cataract development have been documented in people taking olanzapine but, again, without established causative association; a similar situation is seen with ziprasidone. Periodic ocular examinations of the lens are suggested for patients prescribed long-term treatment with phenothiazines or quetiapine.