Postoperative Management of
Excimer Laser PRK

BY JAMES V. AQUAVELLA, M.D.
SEPT. 1996

What is the usual postsurgical response of a 'normal' patient after PRK? Clearly, this varies depending upon the amount of myopia corrected and the specifics of the procedure. Most post-PRK patients have a hydrophilic bandage lens applied and are placed on a regimen of prophylactic antibiotics, a nonsteroidal anti-inflammatory (NSAID) drug and systemic pain medication.

THE FIRST 24-48 HOURS

Most patients report moderate but tolerable discomfort during the first day. There may be 1 to 2+ swelling of the upper lid in those individuals with more discomfort, particularly if the bandage lens does not fit properly. Slit lamp examination should reveal trace to 1+ injection of the conjunctiva, and there may be mild photophobia and epiphora. If the patient is comfortable and you can assess the corneal surface through the bandage lens, there is no need to remove the lens. There should be no stromal infiltration and no sign of an anterior chamber inflammatory response. In general, the bandage lens, antibiotic and NSAID should be continued. If the patient is comfortable, you may discontinue the NSAID. Never continue the NSAID for longer than 72 hours.

THE THIRD DAY POSTOP

By the third day, the cornea should be almost totally re-epithelialized, and you may remove the bandage lens, taper the topical antibiotics and initiate topical steroids. In all cases, discontinue the NSAID.

Uncorrected visual acuity will vary from about 20/80 to 20/200 due to irregular healing of the corneal epithelium. Superficial punctate corneal staining or small areas of epithelial defect or pseudodendritic patterns are common. There should be no infiltration of the corneal stroma and no inflammatory response in the anterior chamber. Patients should be comfortable at this point.

POSTOPERATIVE DAY 7

By day 7, patients should be symptom-free and comfortable. Uncorrected visual acuity may vary from 20/40 to 20/100, depending upon the integrity of the healing corneal epithelium. Evaluate both the epithelium and the stroma carefully for signs of infection or corneal infiltration. A preliminary refraction is also useful. Expect an initial hyperopic response varying from 0.5 to 1.5 diopters. Continue topical steroids and if the surface appears dry, prescribe ocular lubricants.

POSTOPERATIVE DAY 30

Uncorrected visual acuity should be improving and will vary from 20/20 to 20/60. A refraction of less than one diopter of hyperopia is desired. There should be no superficial stromal haze. The epithelium should be intact without signs of corneal infiltration or anterior segment inflammatory response. You may titrate topical steroids to modulate the refractive response. If the refraction varies from plano to residual myopia, consider increasing the frequency and potency of the topical steroids, particularly if there is stromal haze. If the refraction is hyperopic, reduce or discontinue topical steroids. Monitor and record intraocular pressure, although there is rarely any indication for intervention even with modest IOP elevation.

THREE MONTHS POSTOP

At three months, we expect an uncorrected visual acuity of 20/20 to 20/40. Most patients will still be using the topical steroid four times daily and artificial tear lubricants as needed. A trace to 1+ stromal haze is not unusual, and given a stable refractive status, is not an indication for increasing the steroids. Manage residual myopia by increasing the potency and frequency of instillation of topical steroids. In instances of a hyperopic refraction, reduce or eliminate steroids.

SIX MONTHS POSTOP

From three to six months, there should be essentially no change in the refractive status while the quality of the acuity improves. Many surgeons recommend tapering topical steroids. After six months, there should be no refractive change.

While these are standard responses, we must be prepared for unintended postoperative occurrences such as: ocular surface drying and delayed re-epithelialization; undercorrection or overcorrection; increased inflammatory response and stromal haze; regression; and reduction in best corrected visual acuity (corneal haze, central island, irregular astigmatism). I will discuss these topics in subsequent columns. CLS

Dr. Aquavella is chairman of the Genesee Valley Eye Institute and director of the corneal research lab at the University of Rochester.