Causes and Evaluation of Halos Around Lights

Common Causes of Halos

Halos around lights are a classic symptom of angle-closure, particularly during an acute angle-closure crisis, often accompanied by blurred vision, eye pain, headache, eye redness, and potentially nausea and vomiting, requiring immediate medical attention to prevent permanent vision loss 1, 2
The American Academy of Ophthalmology suggests that pressure-induced corneal edema is experienced as blurred vision and halos around lights, and requires prompt ophthalmologic evaluation 2
Different types of cataracts can cause halos around lights, particularly when driving at night, with posterior subcapsular cataracts commonly causing glare and poor vision in bright light conditions 3
The American Academy of Ophthalmology recommends that patients with a history of refractive surgery, such as LASIK, be evaluated for possible irregular astigmatism or corneal ectasia, as smaller treatment-zone sizes may increase the likelihood of visually disturbing halo formation in low-light conditions 4, 5

The initial assessment of a patient with halos around lights should determine the urgency based on associated symptoms, with the presence of pain, redness, nausea, or sudden vision loss suggesting acute angle-closure requiring emergency evaluation, according to the American Academy of Ophthalmology 1, 2
Key history elements to obtain include duration and progression of symptoms, history of refractive surgery, and family history of glaucoma, as recommended by the American Academy of Ophthalmology 1, 2, 7
The physical examination should focus on visual acuity assessment, pupil examination, and slit-lamp examination to assess corneal edema, lens opacities, and anterior chamber depth, according to the American Academy of Ophthalmology 1, 2
Immediate medical therapy to lower IOP, including topical beta-blockers, alpha2-agonists, carbonic anhydrase inhibitors, and oral/IV hyperosmotic agents, is recommended for acute angle-closure, with definitive treatment with laser peripheral iridotomy once IOP is controlled, as suggested by the American Academy of Ophthalmology 2
Regular monitoring for progression and consideration of cataract surgery when visual function is significantly affected are recommended for cataracts, according to the American Academy of Ophthalmology 3