Photokeratitis

Question 1

Aetiology

Answer 1

Photokeratitis is a condition caused by unprotected exposure to UV radiation, where there is damage to corneal epithelial cells and a delayed onset of symptoms.

The corneal epithelium absorb the UV light causing damage to the superficial epithelial cells and exposure of the corneal nerves

Usually the symptoms can take 6-12 hrs to develop after exposure. However the latency varies inversely with the exposure dose and can be as short as 1 hr.

Typically caused by UVB (290-320nm) or UV (100-290nm). Sources include: welding arcs, sun (reflection from snow, water), tanning beds, high intensity therapeutic UV lamps, germicidal UV lamps,

Question 2

Predisposing factors

Answer 2

Lack of eye protection
Occupation exposure
Greater UV at high altitudes

Question 3

Symptoms

Answer 3

Mild cases - irritation and FB sensation
Severe cases - pain, photophobia, redness, watering, blepharospasm, blurring of vision

Question 4

Signs

Answer 4

Diffuse punctate staining of cornea and conjunctiva - can coalesce - check with NaFl.
Conjunctival hyperaemia
Lid oedema and hyperaemia
Epiphora
Transient reduced vision
Associated skin and eyelid erythema (facial burns)

Symptoms are typically bilateral

Question 5

Non-pharmacological management

Answer 5

Reassure - damage is transitory, symptoms gets better in 24-48hrs, however photophobia and blurred vision may persist for longer

Cold compresses, sunglasses for photophobia
Rest eyes, take it easy
Monitor closely - corneal surface should improve by the next day
Eye protection for the future
Avoid exposure to source.

Question 6

Pharmacological management

Answer 6

Topical anaesthetic to aid examination - not for pain relief.

Unpreserved drops during the day. Unmedicated ointment before bed.

Oral pain killers for pain relief e.g. ibuprofen

Cycloplegic to reduce pain from ciliary spasm

Topical prophylactic antibiotic to reduce the risk of infection if widespread damage.

Question 7

Refer?

Answer 7

Not required.