The cornea is very well supplied with pain receptors, as anyone who has ever stuck a finger in their eye knows. Therefore any disruption of the membrane over the cornea (the corneal epithelium) causes exposure of these nerve endings and severe pain.
Arc eye is an extremely painful condition caused by arc welding without an appropriate visor. Multiple small burns to the cornea caused by the intense light from the welding torch cause the pain. The pain settles when the cornea has healed, usually within 24 hours.
Foreign bodies on the cornea are also extremely uncomfortable. Angle grinding without protective eyewear is a common cause in workmen. The foreign body is removed with a sterile hypodermic needle after the eye has been anaesthetised with eye drops.
Corneal ulcers cause a painful, red eye, and the vision is mildly to severely affected. Herpes viruses cause a recurring, typical, branching type of ulcer which is difficult to notice in the early phase. Permanent loss of best vision can occur as a result of scarring. Bacterial and fungal ulcers are even more sight threatening and must be referred to an ophthalmologist as soon as possible. Amoebic ulcers are subtle but very painful ulcers usually occurring in soft contact lens wearers. Sterile peripheral corneal ulcers may be associated with underlying disorders such as rheumatoid arthritis.
South African Optometric Association
Tel: 011 805 4517
South African National Council for the Blind
Tel: 012 452 3811
Retina South Africa
Tel: 011 622 4904
Ophthalmological Society of South Africa