Epithelial debridement, corneal

Topical ocular appUcation of cocaine can result in serious corneal epithelial damage therefore clinical uses of this drug are limited. Although it is no longer used for such routine ophthalmic procedures as tonometry, the drug is useful in the diagnosis of Horner s syndrome (see Chapter 22). However, when administering hydroxyamphetamine, 48 hours must elapse before the subsequent test because cocaine inhibits the uptake of hydroxyamphetamine into the presynaptic vesticles. In addition, due to its ability to loosen the corneal epithelium, it can be helpful in the debridement of herpetic corneal ulcers. 

Topical anesthesia not only provides adequate surface anesthesia before debridement, it also has the beneficial effect of loosening the corneal epithelium. If both tetracaine and proparacaine are on hand, tetracaine is the preferred agent due to its greater effect on the corneal epithelium. Debridement may be accomplished with either a moistened cotton-tipped applicator or an Algerbrush. Both techniques effectively remove loose and damaged epithelial tissue. Debridement should be followed by irrigation and management of the corneal defect as an abrasion (see Chapter 26). 

If there is an anterior chamber reaction or if debridement has been performed, a cycloplegic agent such as 5% homatropine or 0.25% scopolamine should be used two to three times a day. Topical steroids should be tapered or discontinued in any patient using them, because they are contraindicated in the presence of active HSV corneal epithelial disease. Antibiotics have no benefit in the treatment of herpes simplex epithelial disease but can be used prophylactically if the epithelial defect is greater than 6 mm in size. 

Figure 26-15 Loosened epithelial cells may be debrided using a cotton-tipped applicator. (Reprinted with permission from Casser L, Fingeret M, Woodcome HT. Corneal debridement. In Atlas of primary eyecare procedures, ed. 2. Norwalk, CT Appleton Lange, 1997 180-183.)...

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