There is a myriad of changes that can be produced in the eye by toxic drugs <br />ranging from mild/no symptoms to severe loss of vision from <br />endophthalmitis. <br />This article describes in brief some of the ocular effects of commonly <br />abused drugs <br />Cannabinoids <br />Cannabis intake leads to conjunctival Injection dilated pupils reduced <br />accommodation amplitude and impaired oculomotor function in chronic <br />users. <br />Cocaine <br />Cocaine causes dilated pupils because of inhibition of reuptake of <br />norepinephrine. In high concentrations, it may cause cycloplegia, and in <br />chronic user’s exophthalmos. <br />Cocaine users can also present with complications like superficial punctate <br />keratitis, epithelial defects and ulcers because of contamination through <br />eye rubbing or retrograde passage of the substance through the <br />nasolacrimal duct by sniffing, as well as direct toxic effects from <br />substance smoke. <br />Conjunctival lesions and chronic red eye have been reported with the <br />transconjunctival use of crystallized heroin. <br />Hallucinogens <br />This group includes lysergic acid diethylamide (LSD), psilocybin, <br />phencyclidine and mescaline. These drugs can cause hallucinations , <br />sleeplessness, slurred speech, hyperarousal of the central nervous system <br />CNS loss of coordination and pupil dilation. Phencyclidine does not cause <br />changes in pupil size but often causes horizontal and vertical nystagmus in <br />intoxicated states. <br />A case of phencyclidine-induced oculogyric crisis with involuntary <br />conjugate upwards deviation of eyeballs was reported, the rest of the ocular <br />and systemic examinations were normal. <br />Conclusion <br />The use of illicit drugs is a public health concern. Identification of <br />ophthalmic side effects of these drugs is crucial for timely diagnosis and <br />management of these cases. Not only is it essential for the general <br />physician to use the ophthalmic signs for early diagnosis but also for the <br />ophthalmologist to timely refer and treat the patient. Early recognition can <br />go a long way in visual rehabilitation of these patients .<br />