Blurred Vision, Hidden Danger: Drug-Induced Glaucoma Following Olanzapine Therapy
Year: 2025
Type: article
Abstract: Dear Editor, Olanzapine, a second-generation antipsychotic, is commonly prescribed for schizophrenia and bipolar disorder due to its lower risk of extrapyramidal symptoms and superior efficacy. However, it is associated with metabolic side effects such as weight gain, diabetes, and dyslipidaemia.[1] Less commonly, olanzapine can cause ophthalmic complications, including acute angle-closure glaucoma (AACG), a rare but serious condition leading to a rapid increase in intra-ocular pressure (IOP). If untreated, AACG can cause optic nerve damage and irreversible vision loss.[2] Olanzapine’s anticholinergic effects can induce pupillary dilation and forward movement of the lens-iris diaphragm, narrowing the anterior chamber angle and precipitating AACG. The risk is heightened in individuals with predisposing anatomical factors such as shallow anterior chambers and in those taking other anticholinergic medications like trihexyphenidyl.[3] This case highlights the importance of recognising AACG as a potential adverse effect of olanzapine. A 34-year-old female with schizophrenia presented to the ophthalmology emergency department with acute-onset headache, bilateral eye pain, blurred vision, and nausea for 2 days. She had no prior history of ocular disease, systemic illnesses, or a family history of glaucoma. She had been stable on risperidone 4 mg daily but was recently switched to olanzapine 10 mg daily, which was increased to 15 mg over 2 weeks due to worsening psychotic symptoms. Additionally, she was taking trihexyphenidyl 2 mg daily for extrapyramidal symptoms, sertraline 50 mg for depression, clonazepam 0.5 mg for insomnia, and levothyroxine 50 mcg for hypothyroidism. About 10 days after increasing the olanzapine dose, she developed worsening ocular symptoms. Examination revealed reduced visual acuity (6/18 in the right eye, 6/24 in the left eye), conjunctival congestion, corneal oedema, and a shallow anterior chamber in both eyes. IOP was markedly elevated (42 mmHg in the right eye and 45 mmHg in the left eye). Gonioscopy confirmed narrow and occludable angles bilaterally. Laboratory tests were within normal limits. Anterior segment optical coherence tomography showed anterior chamber narrowing and ciliary body rotation. She was treated with topical timolol 0.5%, brimonidine 0.2%, and dorzolamide 2% eye drops twice daily, along with systemic acetazolamide 250 mg four times daily. Intravenous mannitol (20%, 300 mL) was administered to reduce IOP. Olanzapine and trihexyphenidyl were discontinued, and she was switched to aripiprazole 10 mg daily. Within 24 h, her symptoms improved, and IOP decreased to 18 mmHg. Laser peripheral iridotomy was performed bilaterally to prevent recurrence, and she remained stable on follow-up. AACG is a rare but critical side effect of olanzapine, likely due to its anticholinergic activity, which induces pupillary dilation and worsens angle closure. The concurrent use of trihexyphenidyl likely exacerbated this risk. While AACG is typically seen in older individuals with predisposing anatomical factors; it can occur in younger patients due to drug-induced mechanisms.[4] Clinicians should be cautious when prescribing olanzapine, particularly in patients on multiple anticholinergic drugs. Early recognition and intervention are crucial in preventing permanent vision loss. Patients at risk should undergo baseline ophthalmic screening, and those on olanzapine should be educated on recognising early glaucoma symptoms. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Author: Shatavisa Mukherjee
Institution: School of Tropical Medicine
Language: English
Topic: Drug-Induced Ocular Toxicity
Subfield: Ophthalmology
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W4411784386