Description

• Corneal abrasions: result from cutting, scratching, or abrading the thin, protective, clear coat of the exposed anterior portion of the ocular epithelium. These injuries cause pain, tearing, photophobia, foreign body sensation, and a gritty feeling (1).
• Corneal ulceration: break in the epithelial layer of the cornea leading to exposure of the underlying corneal stroma, which results in a corneal ulcer. Superficial ulcers, limited to loss of the corneal epithelium, are the most common form of ulceration (2).
• Corneal abrasion and ulceration can both lead to impaired vision from scarring.

Epidemiology

Incidence
Eye-related diagnoses make up 8% of total ER visits and are commonly caused by direct/minor trauma. Of those eye-related visits caused by injury, 64% are corneal abrasions (3). Abrasions are the third leading cause of red eye, following conjunctivitis and subconjunctival hemorrhage (4).

Etiology and Pathophysiology

• Most often caused by mechanical trauma but may also result from foreign bodies: sand and dust, contact lenses wear, or chemical and flash burns
• Corneal ulceration seen with contact lenses use, HIV, trauma, ocular surface disease. Edema plays a major role in epithelial defect. Edema can lead to trauma, ischemia, and increased intraocular pressure. Excessive fluid disrupts the normal architecture of the epithelial layer (1).
• Causes of ulcerations include:
  • Gram-positive organisms ~29–53% (Staphylococcus aureus and coagulase-negative Streptococcus are common.)
  • Gram-negative organisms ~47–50% (Pseudomonas most common, followed by Serratia marcescens, Proteus mirabilis, and gram-negative enteric bacilli)
  • Herpes simplex with bacterial superinfection
  • Varicella virus
  • Autoimmune disorder: Sjögren, rheumatoid arthritis, inflammatory bowel disease
• Increased risk of corneal ulceration in HIV, diabetes mellitus (DM), and immunocompromise
• Eyelid abnormalities (chronic blepharitis, entropion)
• Nutritional deficiencies (vitamin A and protein undernutrition)
• Dry eyes/bullous keratopathy/mucous membrane pemphigoid

Risk Factors

• History of trauma (direct blunt trauma, chemical burn, radiation exposure, etc.)
• Contact lenses wear
• Male gender
• Age: 20 to 34 years old
• Job (construction, manufacturing); lack of eye protection

General Prevention

• Protective eyewear during work (auto mechanics, metal workers, miners, etc.) and during sports
• With the increasing use of face masks during the COVID-19 pandemic, a case has even been reported of corneal abrasion from removal of face mask with the edge of the mask causing a corneal abrasion (5).

Commonly Associated Conditions

• Vitamin A deficiency is associated with corneal ulcers.
• Neuropathy of cranial nerve (CN) V
• DM, thyroid dysfunction, immunocompromised states, connective tissue disease
• Critically ill patients who lack blinking reflex or inability to close their eyes and those on intermittent positive pressure from ventilation (6)