| This problem can often be diagnosed by history as the patient will report being poked or scratched in the eye. Pound for pound, the cornea is the most richly innervated tissue in the body and the patient will report exquisite pain. A drop of topical anesthetic (0.5% Proparacaine HCL) may be necessary to allow examination of the eye and record visual acuity. Visual acuity will be normal if the abrasion is eccentric to the visual axis, but will be proportionately decreased if it is centred on the cornea. | |
| 1. | Detection of a corneal abrasion may be facilitated by the use of a fluorescein strip (see SLIDE 1) ... |
| 2. | ...where the missing epithelium takes up a greenish appearance as seen on SLIDE 2. |
| 3. | Use of cobalt blue filter (see SLIDE 3) facilitates detection of an abrasion but... |
| 4. | as seen on SLIDE 4 they are usually readily apparent with an ordinary penlight. In cases of more severe trauma, corneal abrasions may be accompanied by other intraocular injuries and prompt referral may be indicated if there is doubt. |
| 5. | The presence of a staining corneal defect in the absence of trauma may signal herpetic keratitis, with its typical dendritic staining pattern (see SLIDE 5). |
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TREATMENT OF CORNEAL ABRASIONS consists of topical antibiotic ointment, cycloplegics, and a tight pressure patch. Two drops of 2% or 5% homatropine instilled three minutes apart usually provide adequate cycloplegia, putting the ciliary body at rest and relieving ciliary spasm which can cause intense pain. Topical antibiotics such as Polysporin or a sulpha are indicated to prevent secondary infection of the abrasion, although this is an extremely rare complication. A tight pressure patch using two eye pads for deeply recessed orbits immobilizes the lid and promotes healing. Corneal epithelial defects heal by mitosis and migration of adjacent cells, and small to medium sized abrasions will heal in 24 to 36 hours. Follow up is indicated in 24 hours and the eye is re-patched if a staining epithelial defect is still present. If the defect is closed, two days of antibiotic drop therapy, such as Polytrim or 10% Sulpha drops four times per day is indicated. Topical anesthetic drops SHOULD NEVER be given to a patient as this significantly impairs corneal surface healing and although the patient is comfortable instilling drops every half an hour, the likelihood of a secondary corneal infection is extremely high. | |