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Arch Ophthalmol. 1999;117:836-837.

Radial keratotomy (RK) incisions may gape in response to external trauma, allowing small or particulate foreign bodies to become embedded within.

Report of a Case.
A 41-year-old man had successful bilateral 8-incision RKs done elsewhere in 1992, resulting in 20/20 OU uncorrected visual acuity. As he was trimming a bush in September 1998, a branch (Figure 1) struck him in the right eye. There was immediate pain, blurriness, and tearing. He was seen immediately at a local hospital emergency department by an ophthalmologist and was referred to our cornea clinic for further treatment.

View larger version (84K): [in this window] [in a new window] Figure 1. Broken branch responsible for eye injury.

At presentation to our clinic, his uncorrected visual acuity was 20/70 OD and 20/20 OS. Manifest refraction in the right eye improved the visual acuity to 20/50 with a +0.75+1.00x135 correction. Dark brown particles of what appeared to be wood bark were wedged in the anterior corneal stroma in the nasal, inferonasal, and inferior RK incisions (Figure 2). The anterior lips of these incisions were splayed open by a combination of the foreign bodies, reactive inflammation, and secondary corneal edema. In addition, there was a partial-thickness, paracentral corneal laceration perpendicular to and crossing the 3 injured RK incisions. Findings from the Seidel test were negative. The rest of the anterior segment, including the crystalline lens, was normal. A dilated retinal examination revealed no intraocular foreign bodies or retinal pathologic condition.

View larger version (53K): [in this window] [in a new window] Figure 2. Wood foreign bodies lodged in three consecutive radial keratotomy incisions (direct slit-beam illumination).

Under retrobulbar anesthesia, the foreign bodies were easily swept out of the RK incisions with a Barraquer iris sweep and were sent for microbiological cultures. The 3 RK incisions, together with the anterior stromal laceration, were copiously irrigated with balanced-salt solution. A subconjunctival injection of cephalosporin was administered and a 1-week course of topical ofloxacin, 4 times daily, was begun.

The uncorrected visual acuity improved to 20/30 OD within 1 week. After 5 weeks, the RK incisions and the paracentral laceration appeared to be healing well, with only mild anterior stromal scarring and mild residual fluorescein pooling over the injured incisions. The uncorrected visual acuity remained 20/30 OD. The cycloplegic refraction was -0.25+0.25x30 OD, giving a corrected visual acuity of 20/25 OD. The cultures were negative for organisms.

Comment.
Many studies have previously shown delayed wound healing in RK wounds.^1-5 The failure of RK incisions to regain full preoperative tensile strength has been responsible for complications ranging from unstable or progressive refractive changes to traumatic rupture of the globe. Radial keratotomy incisions frequently open spontaneously during penetrating keratoplasty, even as late as 9 years after the original surgery.⁵ Full-thickness corneal perforation through a preexisting RK incision by a wooden foreign body has been previously reported in the military literature.⁶ In that case, the injured eye had undergone a 3-step, 24-incision RK 1 year previously. Our patient had considerably fewer incisions and was already 6 years from the time of RK surgery. Unsutured wounds typically have a plug of epithelial cells that may persist for years, thus weakening the structural integrity of the stroma. Even in the absence of epithelial plugs, well-healed stromal scars have less than 70% of native tensile strength.^1-4 Consequently, RK wounds appear to be susceptible to entry or entrapment of particulate foreign matter.

AUTHOR INFORMATION

Kaz Soong, MD
Ann Arbor, Mich

Reprints: H. Kaz Soong, MD, W. K. Kellogg Eye Center, 1000 Wall St, Ann Arbor, MI 48105.

REFERENCES
1. Girard LJ, Rodrigues J, Nino N, et al. Delayed wound healing after radial keratotomy. Am J Ophthalmol. 1985;99:485-486. PUBMED 2. Ingraham HJ, Guber D, Green WR. Radial keratotomy: clinico-pathologic case report. Arch Ophthalmol. 1985;103:683-688. ABSTRACT 3. Deg JK, Zavala EY, Binder PS. Delayed corneal wound healing following radial keratotomy. Ophthalmology. 1985;92:734-740. ISI | PUBMED 4. Luttrell JK, Jester JV, Smith RE. The effect of radial keratotomy on ocular integrity in an animal model. Arch Ophthalmol. 1982;100:319-320. ABSTRACT 5. McNeill JI. Corneal incision dehiscence during penetrating keratoplasty nine years after radial keratotomy. J Cataract Refract Surg. 1993;19:542-543. PUBMED 6. Nolan BT. Perforation by a foreign body through a preexisting radial keratotomy wound. Mil Med. 1991;156:39-42. PUBMED