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Join IAPBCorneal visual impairment encompasses a wide variety of infectious, degenerative, and inflammatory eye diseases that cause scarring of the cornea, the clear window positioned at the front of the eye.
Corneal Opacity accounts for 3.46% of global blindness and 1.65% of global blindness and visual impairment (IAPB Vision Atlas). As a leading cause of blindness in children (Solomon, 2005) and within developing nations, Corneal blindness affects all age groups. As approximately 80% of cases are avoidable (i.e. preventable or treatable), it is essential that ophthalmology maximises a patients’ opportunities for successful visual recovery (Gain et al, 2015). Unfortunately, CB remains an under reported cause of vision impairment (Robaei & Watson, 2014), – with a scarcity of data to increase equitable access to services.
Corneal opacity may be caused by a wide variety of disorders, including congenital, nutritional, traumatic, infectious, degenerative, and hereditary conditions.
Repeated Trachoma infection causes corneal scarring and is a significant cause of CB in low-income settings where trachoma is endemic.
The main causes of CB in children are xerophthalmia caused by Vitamin A deficiency, ophthalmia neonatorum (affecting an est. 1.6% – 12% of all newborns, Matejcek & Goldman, 2013; Teoh & Raynolds, 2003; Wagner RS, Aquino, 20008), and ocular infections such herpes simplex keratitis. In teenagers, keratoconus and chronic allergic conjunctivitis can cause corneal blindness.
Ocular trauma and suppurative keratitis are common causes of corneal opacity and may be under-reported.
Although both onchocerciasis, and leprosy are public health successes these diseases still cause corneal visual impairment (est. prevalence in 2003 of 200 000–300 000 – being 0.5–1% cause of blindness. Courtright & Lewallen, 2003).
Corneal infections, inflammatory disease, and trauma, can be treated or prevented in order to minimise scarring and prevent blindness. However, other conditions, such as keratoconus, or hereditary corneal dystrophies, cannot be prevented, and require long term treatment, such as corneal transplants.
Corneal opacity can result from poor-quality cataract surgery. As more cataract operations are performed, there may be an increase in the number of eyes with corneal opacity caused by cataract surgery.
There are other conditions, such as pterygium that can also impact vision.
In significant cases, treatment may only be relieved by a surgical procedure – corneal transplantation.
Prevention and treatment plans will depend on specific cause, and the severity and the stage of presentation. Many patients may also require surgical intervention. Prevention and treatment remain dependent on access to services, resources and trained personnel.
Information consolidated by: Global Alliance of Eye Bank Associations, International Council of Ophthalmology, World Council of Optometry, and eye tissue providers: Eversight International, Lions NSW Eye Bank-AU, LV Prasad Eye Institute Eye Bank -India, Keralink International, and SightLife. With thanks to David Yorston.
Corneal visual impairment box: by Shabana Shahzad for #StrongerTogether photo competition.
Resources box: Akbar back to work after corneal graft by Shabana Shahzad
