Warning Signs That Your Red Eye Could Be Serious

close up of a bloodshot eye

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Most of the time, a case of red eye is short-lived and disappears on its own. Sometimes, however, red eyes can be caused by a more serious condition. The following danger symptoms in a red eye should be evaluated by a medical professional.

Blurry Vision

Blurry vision is often associated with serious ocular disease. If your eye is red and your vision is blurry, something significant is going on. You need an evaluation to determine what is causing both symptoms.

When your doctor checks your vision during a routine eye exam, it is a simple, quick way to determine the health of the eye. If a patient can read the 20/20 line on the eye chart with ease, that tells the doctor that light is being focused on the retina fairly accurately and the retina is processing the information correctly. If your vision is acutely decreased with redness, this may indicate an issue in the transmission of light to the back of the retina due to a non-refractive issue. If your vision is blurry without associated redness, then it may be that you need vision correction or an update of your corrective prescription.

Severe Pain

Conjunctivitis may produce mild irritation or scratchiness, but not extreme pain. Severe pain is a symptom of keratitis, a corneal ulcer, iridocyclitis, or acute open-angle glaucoma.

Severe pain should always be evaluated as soon as possible as damage can occur in a short period of time. For example, a corneal ulcer caused by a bacteria called Pseudomonas can advance to a blinding eye infection within 48 hours if not treated.


Photophobia, or extreme sensitivity to light, is usually a symptom of iritis. Iritis is an inflammatory disorder of the eye in which the ciliary muscle becomes inflamed and begins to spasm, causing the eye to feel sensitive to light. Light sensitivity is also a general symptom that occurs when the cornea is irritated. A corneal abrasion or corneal ulcer can bring on debilitating light sensitivity.

Colored Halos

Colored halos are a symptom of corneal edema and acute open-angle glaucoma. Usually, halos seen around lights are caused by a disruption in the optical system of the eye. The cornea, the clear dome light structure on the front part of the eye, becomes thicker, due to the swelling, or edema. As it thickens, it also becomes cloudy. When this occurs, light scatters and we see halos.

If you think you may have one of the warning symptoms with red-eye, it is important to see a medical professional.

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Article Sources
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  1. Uveitis. National Institutes of Health. National Eye Institute. July 11, 2019

  2. Upadhyay MP, Srinivasan M, Whitcher JP. Diagnosing and managing microbial keratitis. Community Eye Health. 2015;28(89):3–6.PMID: 26435583

  3. Digre KB, Brennan KC. Shedding light on photophobiaJ Neuroophthalmol. 2012;32(1):68–81. doi:10.1097/WNO.0b013e3182474548

Additional Reading
  • R. Douglasss Cullom, Jr., Benjamin Chang, The Wills Eye Manual Office and Emergency Diagnosis and Treatment of Eye Disease, 2nd edition. Rev. ed. of: Wills Eye Hospital Office and Emergency Room Diagnosis and Treatment of Eye Disease, 1990. ISBN 0-397-51380-1. Chapter Differential Diagnosis of Ocular Symptoms, Pages 1-6 and Differential Diagnosis of Ocular Signs; Pages 7-17.