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ULY CLINIC

ULY CLINIC

11 Septemba 2025, 05:29:05

Halo vision

Halo vision
Halo vision
Halo vision

Halo vision refers to the perception of rainbow-like, colored rings around lights or bright objects. This occurs when incoming light is scattered, refracted, or diffracted by abnormal ocular media, particularly the cornea, lens, or tear film.


Pathophysiology

  • Corneal edema (acute angle-closure glaucoma, endothelial dystrophies): Increased intraocular pressure (IOP) or endothelial dysfunction forces aqueous fluid into the corneal stroma anterior to Bowman’s membrane, leading to epithelial and stromal edema. This disrupts light refraction, creating halo rings.

  • Lens opacities (cataract): Abnormal lens fibers scatter incoming light, producing halos, particularly noticeable with night driving.

  • Tear film abnormalities (dry eye, excessive tearing, contact lens issues): Uneven tear film causes diffraction of light and halo perception.

  • Pharmacologic/toxic causes (digoxin, digitalis, chloroquine): Retinal or optic nerve toxicity alters visual signal processing, leading to colored halos or altered color perception.


History taking

Ask:

  • Onset & duration: Acute (suggests glaucoma, drug toxicity) vs gradual (cataract).

  • Timing: Morning halos → acute angle-closure glaucoma (when IOP peaks).

  • Associated symptoms:

    • Pain, headache, nausea/vomiting → angle-closure glaucoma (emergency).

    • Painless gradual vision loss → cataract.

    • Systemic drug history (digoxin, chloroquine, steroids).

  • Past history: Glaucoma, cataracts, corneal disease, systemic medications.


Physical examination

  • General inspection: Conjunctival injection, tearing, photophobia.

  • Pupil examination: Fixed mid-dilated non-reactive pupil → acute angle-closure glaucoma.

  • Cornea: Cloudy cornea, microcystic edema → glaucoma; guttata → endothelial dystrophy.

  • Lens: Opacities or nuclear sclerosis → cataract.

  • Fundus: Optic disc cupping (open-angle glaucoma); digoxin toxicity may show retinal disturbances.


Causes of Halo vision

Cause

Distinguishing Features / Associated Findings

Cataract

Gradual, painless vision decline, glare at night, lens opacity; halos worsen in dim light.

Acute angle-closure glaucoma

Sudden severe eye pain, halos, headache, nausea/vomiting, cloudy cornea, fixed mid-dilated pupil; ocular emergency.

Chronic angle-closure glaucoma

Intermittent halos, gradual visual field loss, mild ocular ache.

Open-angle glaucoma

Late halos, insidious peripheral vision loss, optic disc cupping.

Corneal endothelial dystrophy (Fuchs’ dystrophy)

Morning halos, blurred vision improving through day, corneal guttata, epithelial edema.

Contact lens overwear / poor fit

Halos with irritation, excessive tearing, photophobia; symptoms improve on lens removal.

Dry eye / epiphora

Transient halos due to irregular tear film; often with burning or gritty sensation.

Drug toxicity (e.g., Digoxin, Chloroquine, Amiodarone)

Yellow/green halos, photophobia, visual field defects, altered color vision.

Snow blindness / UV keratitis

Acute halos after UV exposure, pain, photophobia, lacrimation.

Congenital cataract or glaucoma (pediatrics)

Halos reported by parents observing visual behavior; often associated with nystagmus or photophobia.

Special considerations

  • Pediatrics: Halo vision is uncommon but, when present, usually indicates congenital cataract or congenital glaucoma. Because young children cannot verbalize halos, suspicion arises from behavioral cues (light sensitivity, eye rubbing, nystagmus).

  • Geriatrics: Age >60 increases risk of primary open-angle glaucoma and senile cataracts—two leading causes of halos. Routine screening is essential.


Management overview

  • Emergency: Acute angle-closure glaucoma → immediate IOP-lowering treatment (IV acetazolamide, topical beta-blockers, osmotic agents) and urgent referral for laser iridotomy.

  • Cataracts: Elective surgical extraction when visual impairment affects activities of daily living.

  • Endothelial dystrophy: Hypertonic saline drops, corneal transplant in advanced disease.

  • Drug-induced halos: Discontinue or adjust causative medication (e.g., digoxin).

  • Supportive: Artificial tears, avoid bright light exposure, correct contact lens hygiene.


Patient counseling

  • Educate about the significance of sudden painful halos (possible glaucoma emergency).

  • Stress adherence to glaucoma medications and regular follow-ups.

  • Teach correct instillation of prescribed eyedrops.

  • Encourage timely cataract evaluation if daily activities are impaired.


References

  1. Biswas J., Krishnakumar S., Ahuja S. Manual of Ocular Pathology. Jaypee-Highlights Medical Publishers, 2010.

  2. Gerstenblith A. T., Rabinowitz M. P. The Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease. 6th ed. Lippincott Williams & Wilkins, 2012.

  3. Roy F. H. Ocular Differential Diagnosis. Jaypee-Highlights Medical Publishers, 2012.

  4. Kanski J. J., Bowling B. Clinical Ophthalmology: A Systematic Approach. 8th ed. Elsevier, 2016.

  5. American Academy of Ophthalmology. Basic and Clinical Science Course (BCSC): Glaucoma and Lens Disorders. AAO, 2021.

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