Alcaine

Ocular trauma is a leading cause of visual impairment in the United States. Approximately 2.4 million eye injuries occur each year, of which about 95 percent are limited to the anterior segment.[1,2] These injuries can be successfully treated with prompt, appropriate intervention and ophthalmologic referral as necessary.[3] Corneal abrasion is one of the most frequent eye injuries treated by primary care physicians.[4]

The cornea is composed of five layers (Figure 1) with a normal central thickness of only 0.50 mm to 0.65 mm. It is vulnerable to injury despite the protection afforded by the eyelids, eyebrows, lashes and tears and neurologic reflexes such as blinking and Bell's phenomenon (upturning of the eyes on lid closure). The exquisite sensitivity of the cornea and its importance in vision usually motivate patients to seek medical care without delay. Whereas injuries to the epithelial layer heal without scarring, defects extending through Bowman's layer result m scar formation.

Corneal abrasion is a loss of epithelial tissue caused by trauma. It is a common acute ocular injury with typical presenting symptoms (Table 1). When the history is not clear-cut or the duration of symptoms seems more chronic or recurrent, consideration of nontraumatic factors (especially infection) is appropriate. Ophthalmologic consultation may be warranted in patients with an atypical history.

Recurrent corneal erosion can be frustrating for both the patient and the physician. Symptoms may seem out of proportion to observable pathology. Less severe corneal defects may have already healed by the time of examination, leaving the patient and physician doubting each other's veracity. Unhealed recurrent erosions win show frank epithelial defects and win stain vigorously with fluorescein (Figure 3). Alternatively, these erosions may appear as irregular, "heaped-up" epithelium, and may look like blistered skin.

Herpes simplex virus (HSV) keratitis is usually a self-limiting, potentially recurrent epithelial disease that can present with many of the symptoms of corneal abrasion. Features that distinguish herpetic keratitis from corneal abrasion may include a history of a vesicular facial skin eruption, symptoms of upper respiratory tract infection, decreased corneal sensation and a characteristic branching or dendritic pattern (Figure 4) on fluorescein staining.[8] Steroid-containing drugs should never be used in patients with suspected HSV-related epithelial defects since these agents may exacerbate the infection. Patients with suspected HSV keratitis should be referred to an ophthalmologist.

Ulcerative keratitis signifies a break in the corneal epithelium associated with underlying suppuration of the corneal stroma. A corneal ulcer should be suspected if there is a focal white opacity (infiltrate) with an overlying epithelial defect. The defect will stain with fluorescein application. Corneal ulcers in persons who wear contact lenses are especially prone to bacterial infection, most often with Pseudomonas species.[9] Patients with corneal ulcers should be referred to an ophthalmologist for further evaluation and treatment.

Ultraviolet light is absorbed by the superficial cornea and can lead to epithelial damage. Light from a welding torch, bright sunlight on snow or use of a sunlamp without protective eyewear can cause ultraviolet keratitis. This injury typically appears as bilateral diffuse punctuate or confluent fluorescein staining in an interpalpebral distribution. Symptoms are similar to those listed in Table I and are usually worse six to 12 hours after the exposure. Treatment of ultraviolet keratitis is similar to that of corneal abrasion. Generally, the more severely affected eye is patched and the patient is instructed to apply ointment in the contralateral eye on arriving home.[10]

Chemical burns can also cause corneal defects. Exposure to a caustic substantial necessitates immediate treatment, even before visual acuity is assessed. Alkaline solutions cause more extensive injury than acidic solutions because they penetrate much more rapidly. Initial treatment for both types of exposures is copious irrigation, preferably with saline or Ringer's lactate solution.[10] Although mild chemical keratitis can be treated by the family physician, consultation with an ophthalmologist is frequently required.

Management

Many options are available for the treatment of corneal abrasions, although the vast majority will heal with simple measures, including use of cycloplegics, topical antibiotics and patching.[6] Objectives of therapy include pain relief, prevention of secondary infection and promotion of corneal reepithelialization.[7] A short-acting cycloplegic such as 2 percent cydopentolate (Cyclogyl) or 2 percent homatropine (Isopto Homatropine) will relieve pain from a low-grade iridocyclitis that can result from a corneal abrasion (Table 5). A topical anesthetic, such as 0.5 percent proparacaine (Alcaine, Ophthetic, Ophthaine), may be used to facilitate examination but should never be prescribed for continued use. Topical anesthetics retard healing, aggravate the keratitis and can become a virtual addiction for pain relief.[11] Oral analgesics should be considered, with dosages titrated to the degree of pain. Topical steroids should not be used since they retard corneal epithelial and stromal wound healing and increase the risk of infection.[12]

[TABULAR DATA 5 OMITTED]

Secondary infection is prevented by instillation of a topical ophthalmic antibiotic ointment or solution (such as bacitracin or erythromycin [Ilotycin] ointment before patching or sulfacetamide [AK-Sulf, Bleph-10, Cetamide, etc.) drops every six hours if the eye is not patched). Pseudomonas,keratitis is commonly associated with the wearing of contact lenses. Therefore, an antipseudomonal antibiotic (e.g., ciprofloxacin [Ciloxan], tobramycin [AKTob, Tobrex], gentamicin [Garamycin, Genoptic, Gentacidin, etc.1) is especially important in patients who wear contact lenses.[9,13] The clinical need for an antibiotic in the management of traumatic epithelial defects in patients who do not wear contact lenses has been disputed by some investigators.[14,15] Because of the relatively low cost and the lack of clinically harmful effects of antibiotics, however, they are considered standard in the treatment of corneal abrasion.

Corneal abrasions in patients who do not wear contact lenses are usually treated with ointment and a pressure patch (Figure 5). The patch is removed at follow-up approximately 24 hours later. The need for eye patching for corneal epithelial defects has been disputed.[16,17] Small (less than 5 [mm.sup.2]), noncentral abrasions can be treated without patching. No controlled study has conclusively proved that pressure patching, collagen shields or bandage contact lenses enhance epithelialization in a clinically significant manner.[18] The primary indication for patching has been for pain relief and to prevent eyelid movement from aggravating the denuded corneal surface. Patching, however, can be fraught with risks. It increases corneal temperature and decreases oxygenation and tear exchange, thereby facilitating microbial replication.[7] Therefore, herpetic infections or suspected ulcers and abrasions in patients who wear contact lenses should never be treated with patching.[9] Many patients, especially children, find patches intolerable and remove them after leaving the doctor's office. A loose pressure patch is useless.

Topical nonsteroidal anti-inflammatory drugs (NSAIDs) (Table 6) are being used as an alternative to patching for treating pain associated with corneal epithelial defects.[12,19,20] NSAIDSs can be especially useful for topical analgesia when patching is contraindicated. Significant pain relief, but some delay of early reepithelialization, has been, reported with use of NSAIDs.[12]

[Figures 1 to 7 ILLUSTRATION OMITTED]

RELATED ARTICLE: What to Do About a Corneal Abrasion

What is a corneal abrasion?

A corneal abrasion is a cut or scratch on your cornea. The cornea is the clear, protective window at the front of your eye. It lies directly over the colored part of your eye (the iris).

What can cause a corneal abrasion?

Many things can cause a corneal abrasion, such as sand, dust, dirt, wood or metal shavings that get in your eye. The cornea can also be scratched by a fingernail, a tree branch or a contact lens. Rubbing your eyes very hard is another way that an abrasion can occur. Sometimes, if a corneal abrasion hasn't healed properly, it can come back weeks or months after the original injury. In some people, the outer layers of the cornea are weak. These people may get a corneal abrasion for no apparent reason.

How do I know if I have a corneal abrasion?

The cornea is very sensitive, and a corneal abrasion is usually quite painful. You may feel like you have sand or grit in your eye. You may notice tears or blurred vision, or your eye may. look red. You may also notice that light hurts your eye. Some people get a headache when they have a corneal abrasion.

What do I do if I get something in my eye?

If you think something has gotten into your eye, first try to wash out the eye by splashing clean water into it. Your workplace may have an eye rinse station for this purpose. Sometimes, blinking or pulling the upper eyelid over the lower eyelid may remove a particle from under the eyelid. Avoid rubbing your eye. If you or someone else notices something on the white part of your eye, use a soft tissue or cotton swab to gently lift it out of the eye. Don't try to remove something that is directly over the cornea--this might cause more serious damage. If you can't remove the particle or if there doesn't seem to be anything in your eye, call your doctor.

What will my doctor do for a corneal abrasion?

Your doctor will examine your eye for any damage or particles that may be trapped under your eyelid. A yellow-orange dye may be placed on your eye to help your doctor see the abrasion. Your doctor will probably treat the abrasion with eye drops or ointment. You may need to wear a patch on your eye overnight. Most small abrasions heal within 24 hours, but you may need to return to your doctor for another exam the next day.

What if I wear contact lenses?

If you wear contact lenses, you need to be especially careful with a corneal abrasion because you have a higher risk of infection. If you have of the symptoms described in this handout, call your doctor.

This information provides a general overview on corneal abrasions and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.

REFERENCES

[1.] Dannenberg AL, Parver LM, Bredmer RK, Khoo L. Penetration eye injuries in the workplace. The National Eye Trauma System Registry. Arch Ophthalmol 1992;110:843-8. [2.] Schein OD, Hibberd PL, Shingleton BJ, Kunzweiler T, Frambach DA, Seddon JM, et al. The spectrum and burden of ocular injury. Ophthalmology 1988; 95:300-5. [3.] Shingleton BJ. Eye injuries. N Engl J Med 1991; 325:408-13. [4.] Shields T, Sloane PQ A comparison of eye problems in primary care ophthalmology practices. Fam Med 1991;23:544-6. [5.] Benson WH, Snyder IS, Granus V, Odom JV, Macsai MS. Tetanus prophylaxis following ocular injuries. J Emerg Med 1993;11:677-83. [6.] Hykin PG, Foss AE, Pavesio C, Dart JK. The natural history and management of recurrent corneal erosion: a prospective randomised trial. Eye 1994; 8(Pt 1):35-40. [7.] Parrish CM, Chandler JW. Corneal trauma. In: Kaufman HE, McDonald MB, Barron BA, Waltman SR, eds. The cornea. New York: Churchill Livingstone, 1988:599-646. [8.] Kodama T, Hayasaka S, Setogawa T. Immunofluorescent stairing and corneal sensitivity in patients suspected of having herpes simplex keratitis. Am J Ophthalmol 1992;113:187-9. [9.] Schein OD. Contact lens abrasions and the nonophthalmologist. Am J Emerg Med 1993;11:606-8. [10.] Cullom RD Jr, Chang B. The Wills eye manual. 2d ed. Philadelphia: 1994:19-23,62-3. [11.] Epstein DL, Paton D. Keratitis from misuse of corneal anesthetics. N Engl J Med 1968;279.-396-9. [12.] Hersh PS, Rice BA, Baer JC, Wells PA, Lynch SE, McGuigan LJ, et al. Topical nonsteroidal agents and corneal wound healing. Arch Ophthalmol 1990; 108:577-83. [13.] Kenyon KR, Wagoner MD. Conjunctival and corneal injuries. In: Shingleton BJ, Hersh PS, Kenyon KR, eds. Eye trauma. St. Louis: Mosby Year Book, 1991:63-78. [14.] Deutsch TA, Feller DB. Abrasions of the globe. In: Deutsch TA, Feller DB, eds. Paton and Goldberg's Management of ocular injuries. 2d ed. Philadelphia: Saunders, 1985:123-31. [15.] Kruger RA, Higgins J, Rashford S, Fitzgerald B, Land R. Emergency eye injuries. Aust Fam Physician 1990;19:934-8. [16.] Hulbert MF. Efficacy of eyepad in corneal healing after corneal foreign body removal. Lancet 1991; 337:643. [17.] Kirkpatrick JN, Hoh HB, Cook SD. No eye pad for corneal abrasion. Eye 1993;7(Pt 3):468-71. [18.] Schwab IR, Epstein RJ, Harris DJ, Pflugfelder SC, Wilhelmus KR, eds. Anterior segment traumacorneal abrasions. In: Extemal disease and cornea. San Francisco: American Academy of Ophthalmology, 1994:294-6. [19.] Solomon LD, ed. Proceedings of the Ophthalmic NSAID roundtable: at the American Academy of Ophthalmolbgy's 96th annual meeting; 2d ed. Montreal: Medicopea, 1994:28. [20.] Salz JJ, Reader AL 3d, Schwartz LJ, Van Le K. Treatment of corneal abrasions with soft contact lenses and topical diclofenac. J Refract Corneal Surg 1994;10:640-6. [21.] 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; 27:295-8. [22.] Pastor JC, Calonge M. Epidermal growth factor and corneal wound healing. A multicenter study. Cornea 1992;11:3114. [23.] Rubinfeld RS, Laibson PR, Cohen EJ, Arentsen JJ, Eagle RC Jr. Anterior stromal puncture for recurrent erosion: further experience and new instrumentation. Ophthalmic Surg 1990;21:318-26. [24.] Geggel HS. Successful treatment of recurrent corneal erosion with ND:YAG anterior stromal puncture. Am J Ophthalmol 1990;110:404-7. [25.] Wood TO, Griffith ME. Surgery for corneal epithelial basement membrane dystrophy. Ophthalmic Surg 1988;19:20-4. [26.] Dausch D, Landesz. M, Klein R, Schroder E. Phototherapeutic keratectomy in recurrent corneal epithelial erosion. Refract Corneal Surg 1993,9:419-24.

The Authors

PETER G. TOROK, M.D. currently is a family physician at Evans Army Community Hospital, Ft. Carson, Colo. Dr. Torok earned a medical degree from the R. Edward Hubert School of Medicine, Uniformed Services University of the Health Sciences in Bethesda, Md. He completed a residency in faniily practice at Martin Army Community Hospital at Fort Benning, Ga., and a residency in ophthalmology at Madigan Army Medical Center, Tacoma, Wash.

THOMAS H. NUDER, M.D. is chief of the ophthalmology service and director of the ophthalmology residency at Madigan Army Medical Center. Dr. Mader earn medical degree from the University of Arizona College of Medicine, Tucson, and completed a residency in ophthalmology at Fitzsimmons Army Medical Center in Hannover. Dr. Mader also completed a fellowship in corneal and extemal disease fellowship at Emory University School of Medicine in Atlanta.

Address correspondence to Peter G. Torok, M.D., Family Practice Clinic, Evans Army Community Hospital, Ft. Carson, CO 80913.

COPYRIGHT 1996 American Academy of Family Physicians
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