Medication-Induced Gaze Abnormalities

Introduction to Medication-Induced Gaze Abnormalities

• Ethambutol can cause retrobulbar neuritis, leading to decreased visual acuity or red-green color discrimination, with a dose-related risk and higher risk in patients with renal insufficiency, as noted by the American Thoracic Society and the American College of Chest Physicians 1
• Hydroxychloroquine has a risk of QT prolongation when combined with other medications, according to the National Comprehensive Cancer Network 2

Medication-Specific Risks

• Ethambutol can lead to permanent vision loss if not detected early, with a minimal risk at 15 mg/kg daily and higher risk at >30 mg/kg daily, and requires dose adjustment in patients with renal insufficiency to minimize toxicity, as recommended by the American College of Chest Physicians and the National Kidney Foundation 1

Monitoring and Management

• Regular monitoring, including monthly questioning about visual disturbances and testing of visual acuity and color discrimination, is recommended for patients on doses >15-20 mg/kg, treatment duration >2 months, or with renal insufficiency, and discontinuation of ethambutol is advised if any signs of visual toxicity occur, as stated by the American Academy of Ophthalmology, the American Thoracic Society, and the American College of Physicians 1
• Patients should be educated to report any vision changes immediately, as recommended by the American College of Physicians 1

Patient Risk Factors

• Patients with specific conditions, such as narrow anterior chamber angles, renal insufficiency, high myopia, and elderly patients, are at increased risk of medication-induced gaze abnormalities, as noted by the American Academy of Ophthalmology, the National Kidney Foundation, and the American Geriatrics Society 1
• Patients with glaucoma, especially angle-closure glaucoma, are at risk of acute ocular hypertension crises, and those with a history of glaucoma, family history of primary open-angle glaucoma, diabetes mellitus, high myopia, or age over 40 years are at increased risk of developing medication-induced glaucoma, as reported by 3

Prevention of Medication-Induced Gaze Abnormalities

• Baseline assessment before starting high-risk medications and regular monitoring during treatment are crucial to prevent delayed recognition of early symptoms and continuing medication despite visual symptoms, as warned by the American Medical Association and the American College of Physicians
• Immediate ophthalmology referral, discontinuation of the offending medication, and administration of IOP-lowering medications are recommended if a medication triggers acute angle closure, as advised by the American Academy of Ophthalmology
• The use of corticosteroids can lead to increased intraocular pressure and cause secondary glaucoma, and patients requiring corticosteroid treatment should be regularly monitored by an ophthalmologist, as recommended by the American Academy of Ophthalmology 3