Ultraviolet Keratitis

Ovid: 5-Minute Sports Medicine Consult, The

Ultraviolet Keratitis
Carrie B. Zaslow
Tracy L. Zaslow
  • Also known as photokeratitis
  • Acute syndrome occur after exposure of the eyes to ultraviolet (UV) radiation.
  • Painful but usually self-limited
Exposure to various forms of UV radiation leads to corneal edema and sloughing, followed by secondary inflammation of the iris.
Risk Factors
  • UV exposure to unprotected eyes associated with various recreational and occupational activities
  • Sources of exposure:
    • Welder's arc burns
    • Snowblindness
    • High-voltage-line short circuits
    • Other solar exposure
    • Sunlamps
    • Damaged metal halide lamps
    • Aquaria disinfection lamps
    • Laboratory or germicidal UV lamps
No genetic association
General Prevention
The mode of prevention depends on the type of exposure.
  • Recreational sun exposure: Well-fitting sunglasses that meet the American National Standards Institute (ANSI) standards with protection against most UV-A and UV-B radiation
  • Occupational exposure to solar and artificial-solar UV sources: UV-blocking safety goggles in accordance with ANSI
  • Occupational exposure to metal halide or mercury vapor lamps: Adherence to the Food and Drug Administration (FDA) radiologic health program is recommended.
  • Cornea transmits light in visible spectrum.
  • Cornea absorbs light UV spectrum.
    • 10–20% of light in UV-A spectrum is absorbed.
    • Nearly 100% of UV-C light is absorbed.
  • Damage to the cornea in UV keratitis:
    • Results from absorption of light at the transition point between UV-B and UV-C (290 nm)
    • Occurs from absorption in the corneal epithelium, the most anterior part of the cornea, which is several layers thick
    • Causes surface epithelial cells to die and desquamate
    • Damaged cells contain epithelial nociceptor terminal axons that are destroyed, leading to corneal pain secondary to stimulation of the subepithelial nerve plexus.
Commonly Associated Conditions
Facial edema and erythema, resulting from the same UV exposure injury
  • Accurate history, including:
    • Type of exposure
    • Timing and duration of exposure
    • Use of protective eyewear
  • Visual acuity
  • Complete ocular exam, including:
    • Extraocular movements
    • Conjunctiva/sclera/corneas with fluorescein
    • Anterior chambers (checking for cell and flare)
    • Lenses
    • Eversion of the lids to check for foreign bodies
    • pH exam
  • Exposure without protective eyewear 6–12 hr prior to onset of symptoms
  • Symptoms (usually bilateral):
    • Intense pain
    • Photophobia
    • Foreign-body sensation
    • Mild to moderate decrease in visual acuity
    • Increased lacrimation
Physical Exam
  • Topical anesthetic generally is needed to obtain a good physical exam.
  • Penlight exam:
    • Tearing, injection, chemosis of the bulbar conjunctiva and corneal haziness
    • No discharge present in the tarsal conjunctiva; lack of discharge distinguishes photokeratitis from conjunctivitis.
    • Pupils are usually relatively miotic and react sluggishly.
  • Fluorescein exam: Confluent superficial punctuate staining between the lids
  • Slit-lamp exam:
    • Eversion of the eyelids should not reveal a foreign body.
    • Corneal edema and anterior chamber reaction (cell and flare) may be seen.
Diagnostic Tests & Interpretation
A thorough eye exam including fluorescein staining and slit-lamp exam generally is sufficient for diagnosis.
Orbit radiographs/US/CT scan/MRI for suspected intraocular foreign body
Diagnostic Procedures/Surgery
pH of tear lake: To distinguish from a chemical burn, check pH of tear lake in lower conjunctival fornix; pH should be normal in UV keratitis.
Differential Diagnosis
  • Foreign body of the cornea or eyelids
  • Intraocular foreign body
  • Corneal abrasion
  • Thermal burns
  • Toxic epithelial keratopathy (from exposure to chemicals or drugs)
  • Exposure keratopathy
  • Nocturnal lagophthalmos
  • Conjunctivitis
  • Stevens-Johnson syndrome
  • Infectious keratitis
  • Neurotrophic keratopathy
  • Contact lens–related problems
  • Trauma
  • Dry eye syndrome
  • Dacryocystitis
  • Canaliculitis
  • Scleritis


Ongoing Care
  • Corneal surface regenerates in 24–72 hr.
  • Surface regeneration leads to symptom resolution.
Follow-Up Recommendations
  • Reexamination in 24–48 hr
  • If symptoms improved: Patient can continue with topical antibiotics q.i.d.
  • If symptoms not improved and superficial punctate staining is still present: Continue treatment with cycloplegics, antibiotics, and possibly pressure patch.
  • If new symptoms develop or symptoms persist: Refer to an ophthalmologist.
Patient Monitoring
Long-term monitoring is generally unnecessary with the exception of counseling patients on using protective eyewear.
Patient Education
Depending on their daily activities, patients should be referred to the appropriate resource to learn about protective eyewear:
  • American National Standards Institute (www.ANSI.org)
  • FDA Radiological Health Program (www.FDA.gov)
Generally, acute, single episodes heal without long-term sequelae.
370.24 Photokeratitis

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