The Case of the Cloudy Cornea
The diagnosis in this case is corneal abrasion with significant subepithelial infiltration (sterile corneal ulceration secondary to subepithelial inflammatory infiltration following mechanical abrasion).
Corneal abrasion is one of the common clinical entities that presents to the optometric practice. Patients usually present with some or all of the following: acute pain, photophobia, pain upon extraocular muscle movement, lacrimation, blepharospasm, foreign body sensation, blurry vision, and a history of contact lens wear or being struck in the eye.1-5 Biomicroscopy of the injured area often reveals diffuse corneal edema and epithelial disruption. In severe cases, when edema is excessive, folds in Descemets membrane may be visible. Cobalt blue light inspection, with the instillation of sodium fluorescein dye, will illuminate the damaged segment. The newly created wound appears as a bright green area compared with the rest of the cornea because the dye accumulates in the divot, adding density.3,5 Always rule out penetration using Seidels test.
Below the tears, the cornea has five distinct layers. From outer to inner, they are:
The corneal epithelium, which is actually composed of three tissues: the stratified surface epithelium, the wing cell layer (containing the corneal nerves), and the mitotically active basement membrane.
Bowmans membrane (a whirling structure designed to prevent penetrating injuries).
The organized 250 lamellar sheets of stroma.
Descemets membrane.
The endothelium.
There are two categories of corneal abrasion: superficial (not involving Bowmans membrane), and deep (penetrating Bowmans membrane but not rupturing Descemets membrane). Abrasions may result from foreign bodies, contact lenses, chemicals, fingernails, hairbrushes, tree branches, dust and the like.
The cornea has remarkable healing properties. The epithelium adjacent to any insult expands to fill in the defect, usually within 24-48 hours.5 Lesions that are purely epithelial often heal quickly and completely without scarring. Lesions that extend below Bowmans membrane possess an increased risk for leaving a permanent remnant.5
Treatment for corneal abrasion begins with history. The time, place and activity surrounding the injury should be recorded for both medical and legal purposes. In this case, the patient woke up in discomfort. More than likely she sustained the injury when an incompletely closed eyelid allowed her cornea to rub against the pillow before waking.
Record visual acuity (VA) before instilling drops or performing any procedures. If the blepharospasm is sufficiently intense to preclude an acuity measurement, administer 1 drop of topical anesthetic. Measure VA immediately thereafter.
The eye examination should proceed in a logical fashion from external adenexa to funduscopic examination. Evert the eyelids and scrutinize the fornices to rule out the presence of foreign material. Instill fluorescein dye (without anesthetic) to identify the corneal defects. Use the Seidel test (painting of the wound with dye observing for aqueous leakage) to uncover full thickness injuries. Document the abrasion for size, shape, location and depth. Observe and note the anterior chamber reaction (iritis=cell/flare) as well. Perform a dilated examination to rule out posterior effects from the trauma.
Initiate medical treatment by using adequate cycloplegia (determined on a case by case basis; atropine 1% for the worst and tropicamide 1% for the mildest) and topical antibiotics such as Polytrim (polymyxin B and trimethoprim, Allergan), gentamicin or Tobrex (tobramycin, Alcon). Fluoroquinolones such as Vigamox (moxifloxacin, Alcon), Zymar (gatifloxacin, Allergan), Quixin (levofloxacin, Santen), Ocuflox (ofloxacin, Allergan), and Ciloxan (ciprofloxacin, Alcon) may be used as well.
Bed rest, inactivity and over-the-counter analgesics can be used to quiet acute pain.
In cases where pain is severe, prescribe topical nonsteroidal anti-inflammatory medications qid such as Voltaren (diclofenac sodium, Novartis), Acular (ketorolac tromethamine, Allergan) or Ocufen (flurbiprofen, Allergan), or insert a thin, low-water-content bandage contact lens.1-6 Pressure patching is no longer considered standard-of-care, though it remains a useful modality to subjugate pain when bandage lenses are contraindicated or patients require a reminder to rest.1,2,4 -6 Reevaluate patients every 24 hours until the abrasion is reepithelialized.1-5
To promote healing, prevent recurrent erosion and reduce corneal edema, a hypertonic solution or ointment may be prescribed along with the other medications or after reepithelialization has occurred.5 In cases where excess epithelium impairs regrowth, use a cotton-tipped applicator saturated with anesthetic to debride loose tissue.5
When significant iritis is present or if subepitheial infiltration occurs during the reparative process, steroids such as Lotemax (lotoprednol etabonate 0.5%, Bausch & Lomb) and Alrex (lotoprednol etabonate 0.2%, Bausch & Lomb), FML (fluorometholone 0.1%, Allergan), FML Forte (fluorometholone 0.25%, Allergan), Flarex (fluorometholone acetate, Alcon), Vexol (rimexolone, Alcon) Pred Mild (prednisolone acetate 0.12%, Allergan) or Pred Forte (prednisolone acetate 1%, Allergan) may be required. Worsening subepithelial infiltration may be a sign of infection or impending ulceration. Lesions such as these should be considered vision threatening, and warrant immediate treatment with fluoroquinolone antibiotic drops and consideration for culture.3
1. Donnenfeld ED, Selkin BA, Perry HD, et al. Controlled evaluation of a bandage contact lens and a topical nonsteroidal anti-inflammatory drug in treating traumatic corneal abrasions. Ophthalmology 1995 Jun;102(6):979-84.
2. Kirkpatrick JN, Hoh HB, Cook SD. No eye pad for corneal abrasion. Eye 1993;7 (Pt 3):468-71.
3. Cullom RD, Chang B. Trauma: Corneal Abrasion. In: Cullom RD, Chang B. The Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease. Philadelphia: J.B. Lippincott Co. 1994;22-23.
4. Wedge CI, Rootman DS. Collagen shields: efficacy, safety and comfort in the treatment of human traumatic corneal abrasion and effect on vision in healthy eyes. Can J Ophthalmol 1992 Oct;27(6):295-8.
5. Hall JR. Mechanical Corneal Injuries. In: Nyman JS. Problems in Optometry: Ocular Emergencies. Philadelphia: J.B. Lippincott Co. 1990; 1(1):32-44.
6. Silbert JA. A review of therapeutic agents and contact lens wear. J Am Optom Assoc 1996 Mar;67(3):165-72.
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