Corneal epithelium is constantly being renewed as part of the cornea’s normal processes however it is fragile and can be susceptible to injury. A corneal abrasion is where there is a loss of the outer layer of the cornea – the epithelium – exposing the underlying nerve endings.
• Pain/discomfort (can be extreme) made worse by blinking
• Foreign body sensation.
• Reduced VA (if central)
• Photophobia (can be extreme)
• Red eye
Signs of corneal abrasions may not be obvious without the use of diagnostics stains such a fluorescein. Here we see a large area of staining indicating epithelial loss- note there is little associated limbal hyperaemia in this patient.
• Trauma to eye
• Foreign body
• Spontaneous- usually associated with chronic dry eye, recurrent epithelial erosion following previous trauma or some corneal dystrophies such as epithelial basement membrane dystrophy
This can depend on whether a whole patch of epithelium has been lost or a flap of epithelium remains.
In the event of loss of a small area then the practitioner may recommend lubricating ointments such as lacrilube or xailin night – these must be used on a very frequent basis to allow the epithelium to regenerate and bond to the underlying layer. Newly formed epithelium has a weak bond to the underlying layers and can easily be removed by a patient rubbing their eyes or even blinking when their eyes are dry. The addition of a dry eye drops (a more viscous drop is suggested) would be helpful and again should be used on a frequent basis).
Chloramphenicol ointment can be prescribed by the patient’s GP to act as both a lubricant and protection from chance infections and again could be combined with viscous dry eye drops.
In the case of a flap of epithelium remaining it may be necessary to refer the patient following local protocols to secondary care where the flap can be removed with a hypodermic needle or debridement and then this will allow the new epithelium to form in a normal fashion. Treatment can then follow the protocols above.
It is important to explain to the patient that although the cornea can heal extremely quickly – a minor scratch may heal with 2-3 days – it is important to continue with lubrication for anything up to three months in order to prevent recurrent epithelial erosions.
This is where the damaged epithelial cells do not adhere to the layers below and the patient can go through a lengthy and painful cycle of the epithelium eroding off the front of the cornea before it has time to adhere to the basement layers below.
The key is constant lubrication. Advise the patient to return if problems do not resolve and consider referral if required. Patients should be advised that the use of lubrication may be required for up to three months to avoid repeat erosions.
• Secondary infection
• Foreign body still in situ
• Deep wound
• Recurrent erosions
• Patients with diabetes (healing processes can be retarded)
Red Flags: When one or more of these red flags is raised, a conversation with another registrant in practice should take place following which appropriate referral or management should be actioned and noted. If there are no other registrants in practice then contact should be made with colleagues elsewhere or contact should be made for advice to the local Hospital Eye Service.