Recurring corneal abrasion arises from the detachment of the epithelial layer, the outermost layer of the cornea, from its underlying basement membrane. This disruption leads to intense pain since the loss of epithelial cells exposes the nerve endings within the cornea. Typically, there is a prior history of corneal injury such as finger, paper, or towel contact, but it can also be a manifestation of chronic corneal diseases that lead to recurrent abrasions.
Symptoms include sharp and severe eye pain, foreign body sensation, light sensitivity, blurred vision, and tearing, especially during eye-opening. Signs encompass a corneal defect or irregularity in the epithelial cell layer, and sometimes streaks resembling fingerprints or minor ridges in the epithelial layer can be observed. A fluorescein stain (yellow dye) can be applied to the corneal epithelium, and under blue light, the location and size of the abrasion can be identified.
The immediate goal of treatment for corneal abrasion is to alleviate severe eye pain and promote the formation of a new, stable epithelial layer to prevent re-erosion. Most patients respond well to conservative treatment, but in some cases, surgical intervention may be required based on the severity and condition. For a first-time occurrence of corneal abrasion, a simple approach involves bandaging with antibiotic ointment or placing a contact lens on the eye for a few days. To reduce the likelihood of recurrent abrasions in the future, continued application of ointment every night for several weeks is advisable, even if symptoms improve. In cases of recurrent abrasions, a sustained regimen of artificial tears, nightly ointment, 5% saline solution rinses, and therapeutic contact lenses might be needed for an extended period. The use of nightly ointment, similar to using a contact lens, aims to shield the corneal epithelium from eyelid movement during eye closure.
Conservative treatment often includes the use of steroid eye drops and a course of doxycycline over several months. The underlying theory of this treatment is to counter the inflammatory agents in patients with recurring erosions. These inflammatory agents disrupt the connection between epithelial cells and their basement membrane. It's important to remember that steroid eye drops can elevate intraocular pressure and may lead to issues such as cataracts and lens opacities. Therefore, close monitoring by an ophthalmologist is essential. Doxycycline, from the tetracycline antibiotic family, possesses both anti-inflammatory and anti-infective properties. In practice, we primarily use its anti-inflammatory effects. To mitigate abdominal pain side effects, a daily dosage of just 50 mg is often prescribed (half a tablet).
Surgical interventions include epithelial debridement (with or without laser assistance) and keratectomy using a needle. In cases where conservative measures fail, surgical intervention might involve removing the surface epithelial tissue to facilitate proper healing of the corneal ulceration. This can be done mechanically using a burr or with alcohol. Another method involves the use of an Excimer laser (PTK), which gently and precisely ablates deeper layers of corneal tissue without damaging the surrounding tissue. Laser usage can affect corneal refractive power, meaning it can alter the number of corrective lenses needed. Therefore, laser treatment is preferable when the abrasion site is very specific. Needle keratotomy is effective in cases where the recurrent erosion area is small and not centered on the cornea, as the needle punctures create gentle scarring that might affect visual quality.