Aetiology

Photokeratitis is a condition that occurs following unprotected exposure to ultraviolet radiation. It is characterised by damage to corneal epithelial cells and delayed onset of symptoms.

It results from exposure to UVB (290 to 320nm) or UVC (100 to 290nm). Sources include: welding arcs, sun (including reflection from snow or water), tanning lamps, therapeutic high intensity UV (for skin conditions or seasonal affective disorder), germicidal UV lamps, other sources of UVB or UVC.

Absorption of ultraviolet radiation by corneal epithelium causing damage to superficial cells and exposure of corneal nerves.

Predisposing factors

Lack of suitable eye protection
Greater UV exposure at high altitudes
Occupational exposure

Symptoms of photokeratitis

Delay of 6-12 hours between exposure and onset of symptoms is usual; however, latency varies inversely with exposure dose and can be as short as 1 hour

Mild cases:

• irritation and foreign body sensation

Severe cases:

• pain
• redness
• photophobia
• blepharospasm
• lacrimation
• blurring of vision

Signs of photokeratitis

Typically bilateral (if unilateral, suspect corneal or subtarsal foreign body)
Lid oedema and hyperaemia
Conjunctival hyperaemia
Epiphora
Punctate staining of corneal epithelium with fluorescein (may be coalescent)
Transitory reduction in visual acuity
Associated facial or eyelid erythema (‘skin burns’)

Differential diagnosis

Careful history usually reveals diagnosis
Acute viral keratoconjunctivitis
Contact or toxic keratitis
Contact lens overwear
Dry eye
Foreign body

Management by optometrist

Practitioners should recognise their limitations and where necessary seek further advice or refer the patient elsewhere

GRADE* Level of evidence and strength of recommendation always relates to the statement(s) immediately above

Advise against continuing exposure

Reassure patient that

• damage is transitory
• symptoms typically resolve within 24 to 48 hours (mild photophobia and blurring may persist for a week or longer)

Cold compresses, sunglasses for symptomatic relief
Advise rest with eyes closed
Close monitoring (corneal epithelium should have largely healed by the following day)
Advise patient to return/seek further help if symptoms persist
Advise patient on future eye protection
(GRADE*: Level of evidence=low, Strength of recommendation=strong)

Local anaesthetic (benoxinate or proxymetacaine) should only be used if required to aid examination, and not for pain relief
Drops: tear supplements (preferably unpreserved) for symptomatic relief
Ointment: unmedicated (to ease discomfort through lubrication)
Oral analgesic for pain relief (e.g. ibuprofen, paracetamol)
(GRADE*: Level of evidence=low, Strength of recommendation=strong)

Antibiotic (e.g. gutt. chloramphenicol) as prophylaxis against infection, if risk high (e.g. large epithelial defect)
Cycloplegic (short acting: e.g. gutt. cyclopentolate 1%) to relieve pain of ciliary spasm
(GRADE*: Level of evidence=low, Strength of recommendation=weak)
 

Management category

B3: management to resolution by Optometrist

Possible management by ophthalmologist

Not normally required

Evidence base

*GRADE: Grading of Recommendations Assessment, Development and Evaluation (www.gradeworkinggroup.org)

Sources of evidence

Bergmanson JP. Corneal damage in photokeratitis--why is it so painful? Optom Vis Sci. 1990;67(6):407-13

Cullen AP. Photokeratitis and other phototoxic effects on the cornea and conjunctiva. Int J Toxicol. 2002;21:455-64

DynaMed Plus. Photokeratitis (updated 2018).

Protective eyewear: A reference guide for ABDO members. 2014.

Remé CE, Rol P, Grothmann K, Kaase H, Terman M.Bright light therapy in focus: lamp emission spectra and ocular safety. Technol Health Care. 1996;4(4):403-13

Wang Y, Lou J, Ji Y, Wang Z. Increased photokeratitis during the coronavirus disease 2019 pandemic: Clinical and epidemiological features and preventive measures. Medicine (Baltimore). 2021;18;100(24):e26343

Photokeratitis (Ultraviolet [UV] burn, Arc eye, Snow Blindness)
Version 14
Date of search 02.10.23
Date of revision 27.11.23
Date of publication 23.01.24
Date for review 01.10.25
© College of Optometrists