Photokeratitis or ultraviolet keratitis is a form of radiation injury to the eye. It is caused by exposure to (UV) Ultraviolet rays, either from the sun or from artificial sources such as tanning lamps and welder’s arc.
Ultraviolet radiation is the most common cause of radiation eye injury and it greatly involves the cornea as it absorbs most of the UV rays. Photokeratitis is like sunburn of the cornea and conjunctiva. It can be left unnoticed until damage has been done and symptoms start to present.
Snow blindness is a form of photokeratitis caused by UV rays reflected off from snow and ice. Snow blindness may also be caused by severe cold and extremely dry air. People living in Polar Regions and mountainous areas with high altitude, where air is thinner and intensity of UV rays increases, are at high risk of developing this condition. Activities such as skiing and mountain climbing are commonly associated with this condition.
Symptoms Of Snow Blindness
Twitching of eyelids
Blurring of vision
Discomfort from bright lights
Diagnosis of Snow Blindness
Snow blindness is diagnosed through relevant history assessment and examination of the eye with the use of fluorescein dye to detect UV damage on the cornea. Examination of surrounding tissues may reveal swelling and redness of lids and conjunctiva.
A full eye exam, including the assessment of visual acuity, is usually done to assess extent of injury.
Prevention of Snow Blindness
Use snow goggles – Snow goggles are designed to protect the eyes from the harmful UV rays and dry, freezing wind.
Use sunglasses that have UV protection – make sure that your sunglasses blocks both UVA and UVB radiation. Always wear your sunglasses outside even on a cloudy day as UV rays can pass through clouds even if the light appears dim.
Some contact lenses are manufactured with a built-in anti-UV system. They may protect the wearer’s cornea but not the lids and conjunctiva. The use of sunglasses or goggles is still recommended.
Always protect your eyes from UV radiation as prolonged exposure results to a cumulative effect that can cause a variety of eye conditions. Epidermoid carcinoma of the bulbar conjunctiva has also been associated with UV exposure.
Treatment of Snow Blindness
Treatment of snow blindness is mainly symptomatic as the condition resolves on its own. Once the source of injury is removed, healing takes place and the condition resolves in 2 to 3 days.
Stay away from the sun. The longer you are exposed to the UV rays, the more damage your eyes incur. Stay in a dark room if possible.
Do not rub your eyes to avoid further injury.
Remove contact lenses and do not resume use until symptoms improve.
Apply a wet washcloth or any form of cool compresses over your closed eyes to soothe them.
Oral pain relievers may be taken for severe discomfort.
Apply lubricating drops on the eye if available.
Seek medical advice. Your doctor may prescribe Nonsteroidal anti-inflammatory drug (NSAID) eye drops to relieve pain and inflammation. Topical anesthesia may be used on examination but is not prescribed for continued treatment as it impairs corneal healing and may eventually lead to ulceration.