Halo vision
Halo vision refers to seeing rainbowlike, colored rings around lights or bright objects. This effect can be explained by this physical principle: As light passes through water (in the eye, through tears or the cells of various anteretinal media), it breaks up into spectral colors.
Halo vision usually develops suddenly; its duration depends on the causative disorder. It may occur with disorders associated with excessive tearing and corneal epithelial edema. Among these causes, the most common and significant is acute angle-closure glaucoma, which can lead to blindness. With this disorder, increased intraocular pressure (IOP) forces fluid into corneal tissues anterior to Bowman’s membrane, causing edema. Halo vision is also an early symptom of cataracts, resulting from dispersion of light by abnormal opacities on the lens.
Nonpathologic causes of excessive tearing associated with halo vision include poorly fitted or overworn contact lenses, emotional extremes, and exposure to intense light such as in snow blindness.
History and physical examination
First, ask the patient how long he has been seeing halos around lights and when he usually sees them. The patient with glaucoma usually sees halos in the morning, when IOP is most elevated. Ask the patient if light bothers his eyes. Does he have eye pain? If so, have him describe it. Remember that halos associated with excruciating eye pain or a severe headache may point to acute angle-closure glaucoma, an ocular emergency. Note a history of glaucoma or cataracts.
Next, examine the patient’s eyes, noting conjunctival injection, excessive tearing, and lens changes. Examine pupil size, shape, and response to light. Then test visual acuity by performing an ophthalmoscopic examination.
Medical causes
Cataract
Halo vision may be an early symptom of painless, progressive cataract formation
The glare of headlights may blind the patient, making nighttime driving impossible. Other features include blurred vision, impaired visual acuity, and lens opacity, all of which develop gradually.
Corneal endothelial dystrophy
Typically, halo vision is a late symptom
Impaired visual acuity may also occur.
Glaucoma
Halo vision characterizes all types of glaucoma
Acute angle-closure glaucoma — an ophthalmic emergency — also causes blurred vision, followed by a severe headache or excruciating pain in and around the affected eye. Examination reveals a moderately dilated fixed pupil that doesn’t respond to light, conjunctival injection, a cloudy cornea, impaired visual acuity and, possibly, nausea and vomiting.
Chronic angle-closure glaucoma is usually asymptomatic until pain and blindness occur in advanced disease. Sometimes, halos and blurred vision develop slowly.
With chronic open-angle glaucoma, halo vision is a late symptom that’s accompanied by a mild eye ache, peripheral vision loss, and impaired visual acuity.
Special considerations
To help minimize halo vision, remind the patient not to look directly at bright lights.
Pediatric pointers
Halo vision in a child usually results from congenital cataracts or glaucoma
In a young child, limited verbal ability may make halo vision difficult to assess.
Geriatric pointers
Primary glaucoma, the most common cause of halo vision, is most common in patients older than age 60.
Book Source Details
- Book Title: Handbook of Signs & Symptoms (Third Edition)
- Author(s): Springhouse
- Year of Publication: 2006
- Copyright Details: Handbook of Signs & Symptoms (Third Edition), Copyright © 2006 Lippincott Williams & Wilkins.
Other Book Chapters Related to Hallucinations
Read excerpts from these other book chapters related to Hallucinations:
Medical Books Excerpts
- DELIRIUM
- "Algorithmic Diagnosis of Symptoms and Signs" (2003)
- [ read ]
- Delirium
- "In A Page: Pediatric Signs and Symptoms" (2007)
- [ read ]
- DELIRIUM
- "Differential Diagnosis in Primary Care" (2007)
- [ read ]
- Halo vision
- "Professional Guide to Signs & Symptoms (Fifth Edition)" (2006)
- [ read ]
- Delirium
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
- [ read ]
- Halo vision
- "Signs & Symptoms: A 2-in-1 Reference for Nurses" (2007)
- [ read ]
- DELIRIUM
- "Differential Diagnosis in Primary Care" (2007)
- [ read ]
Copyright Details: Handbook of Signs & Symptoms (Third Edition), Copyright © 2008 Williams & Wilkins.
More About Causes of Hallucinations
» Next page: Psychotic behavior (Handbook of Signs & Symptoms (Third Edition))
Rate This Website
What do you think about the features of this website?
Take our user survey and have your say:
Website User Survey
Medical Tools & Articles:
Next articles:
Tools & Services:
Medical Articles:
Forums & Message Boards
- Ask or answer a question at the Boards:
