A patient presents in your psychiatry OPD with complaints of diminished vision. Ophthalmological examination revealed corneal and lenticular opacities. He had been prescribed some antipsychotic drug during his last visit. Which of the following it can be?
First, I need to recall which antipsychotics have ocular side effects. I remember that some antipsychotics, particularly the older ones, can cause cataracts. Pimozide comes to mind because I've heard it can cause cataracts. Also, maybe thioridazine, but I'm not sure. Let me think again. Thioridazine is more associated with retinal toxicity, like retinal pigmentation, not cataracts.
Another possibility is clozapine, but I think clozapine's main issues are agranulocytosis and seizures. Risperidone might cause weight gain or extrapyramidal symptoms, but not sure about the eyes. Olanzapine is similar. Then there's chlorpromazine, which might have other side effects like photosensitivity, but not cataracts.
Wait, the key here is the corneal and lenticular opacities. Pimozide is known for causing cataracts. I think the mechanism is related to its anticholinergic effects, which can lead to lens opacification. Also, pimozide is a butyrophenone, used for schizophrenia, and its toxicity includes corneal deposits. So the correct answer would be pimozide.
Looking at the options, if one of them is pimozide, that's the right answer. The other options would be antipsychotics without this side effect. For example, if option C is pimozide, then that's correct. The distractors might include thioridazine, chlorpromazine, or others. Let me make sure. Thioridazine can cause retinal toxicity, not cataracts. Chlorpromazine can cause retinal toxicity too. So the wrong answers would be other antipsychotics not linked to cataracts.
Therefore, the correct answer is pimozide. The explanation would involve its anticholinergic effects leading to lens opacities. The other options are incorrect because they have different side effect profiles. The clinical pearl here is to remember that pimozide is associated with cataracts, while thioridazine with retinal issues.
**Core Concept**
The question assesses knowledge of antipsychotic medications associated with ocular toxicity, specifically corneal and lenticular opacities. This side effect is linked to anticholinergic activity and lens epithelial damage in certain drugs.
**Why the Correct Answer is Right**
Pimozide, a butyrophenone antipsychotic, is notorious for causing corneal and lenticular opacities. Its anticholinergic effects disrupt lens epithelial cell function, leading to cataract formation. Additionally, pimozide can deposit in corneal endothelium and lens, exacerbating opacities. These effects are dose-dependent and often reversible upon discontinuation.
**Why Each Wrong Option is Incorrect**
**Option A:** Thioridazine (a