Mooren Ulcer Following Epikeratoplasty for Keratoconus

Epikeratoplasty offers a reasonable therapeutic option for many young patients with keratoconus in Saudi Arabia who are contact lens intolerant because of unfavorable climatic conditions, often with concomitant vernal keratoconjunctivitis, who have a relatively clear visual axis, and for whom the higher risks of penetrating keratoplasty offset the benefits of a slightly better visual prognosis.¹ We report the first case, to our knowledge, of Mooren ulcer occurring following epikeratoplasty performed for keratoconus.

A 12-year-old Saudi girl was referred to the Anterior Segment Division of the King Khaled Eye Specialist Hospital in Riyadh for management of keratoconus. Her ocular history was remarkable for chronic vernal keratoconjuctivitis that was well controlled with topical mast cell inhibitors. Her best-corrected spectacle visual acuity was 20/160 OD with −6.00 −2.25 × 135, and 20/40 OS with −6.00 −4.00 × 25. Keratometry readings were 54.50/57.25 OD and 56.00/49.50 OS, with much more marked irregularity in the right eye. Findings from slitlamp examination showed apical corneal thinning and Vogt striae, more pronounced in the right than in the left eye. There was no visually noteworthy apical scarring in either eye. She was fitted with rigid gas permeable contact lenses and had a visual acuity of 20/25 OU, but proved to be contact lens intolerant.

She underwent epikeratoplasty on January 1, 1996, in the right eye with a 9-mm graft in an 8.5-mm bed with 16 interrupted sutures. Unfortunately, all sutures loosened prematurely, requiring complete suture removal between 2 and 4 months postoperatively. She returned on May 7, 1996, with a poorly adherent, edematous graft with peripheral melting and thinning of the graft with serrated edges. Following removal of the epikeratoplasty lenticule, the cornea reepithelialized, was clear and compact, and her uncorrected visual acuity was 20/80 OD.

On June 1, 1996, she returned with a complaint of moderately severe pain and poor vision in the left eye. On examination, the visual acuity was counting fingers at 6 ft OD and 20/25 OS. There were progressive peripheral thinning and vascularization involving the entire periphery of the right cornea, with marked centripetal extension in the superior cornea from the 10- to 2-o'clock position (Figure 1). The leading edge of centripetal extension was undermined with corneal stromal involvement 1 to 2 mm beyond the apparent clinical edge of involvement. There was an epithelial defect involving the entire cornea. Results from examination of the left eye were normal with the exception of the unchanged appearance of her pre-existing keratoconus. She was hospitalized and treated for 7 weeks with a bandage contact lens, topical corticosteroids, progestational steroids, tetracycline ointment, lubricants, systemic prednisone, and doxycycline. Findings from her systemic evaluation (which included erythrocyte sedimentation rate, rheumatoid factor, antinuclear antibodies, immunoglobulin levels, and electrophoresis) were normal with the exception of a markedly elevated IgE level (687 U; normal <100 U [to convert to the SI units of milligram per liter, IgE first needs to be reported as milligram per deciliter; then multiply this value by 10 to get the SI value]). There was no clinical evidence of systemic helminth infection, although specific serum and gastrointestinal evaluation was not performed. Therapy resulted in reduction in inflammation, vascular regression, cessation of centripetal spread of the ulcer, and preservation of the clarity of the central visual axis. Conjunctival resection was not performed because of her favorable response to therapy with the medications prescribed. Systemic immunosuppression was not used because of her age. She was discharged with an uncorrected visual acuity of 20/80 OD. At no time during her hospitalization was there any inflammation or other evidence of any involvement of the left eye.

Over the next several months, there was progressive scarring, thinning, and vascularization of the central cornea, with a reduction in her visual acuity to counting fingers at 1 ft. With continuous therapy for her vernal keratoconjunctivitis and vascularization with topical cromolyn and medroxyprogesterone, there was gradual clearing of the visual axis over the next 12 months, although the entire cornea remained thin. At the time of her last examination, visual acuity had improved to 20/125 OD uncorrected, and to 20/100 OD with pinhole. At no time during the follow-up period was there any inflammation or other evidence of any involvement of the left eye.

Mooren ulcer is a painful, relentless, chronic ulcerative keratitis that begins peripherally and progresses circumferentially and centrally.² It is by definition idiopathic, meaning that it occurs in the absence of any systemic disorder to which ulcerative keratitis may be attributed.² There have, however, been a number of systemic diseases associated with Mooren ulcer, including helminthiasis, syphilis, tuberculosis, and chronic hepatitis C.² In addition, there have been a number of reports of local corneal disorders associated with Mooren ulcer that include physical trauma, foreign bodies, chemical burns, and herpes simplex and herpes zoster infections,² as well as surgical procedures such as cataract extraction and penetrating keratoplasty.^2,3

With this case report, epikeratoplasty has been added to this list. While this patient is in the age range typical of the "malignant variety" of Mooren ulcer, her strictly unilateral course lends support to the observation that the epikeratoplasty was the initiating event. Although it is tempting to speculate that the concomitant presence of atopic keratoconjunctivitis, irritation from premature suture loosening, and/or antigenic reaction to the lenticule may have played a role in the pathogenesis of the Mooren ulcer, it must be emphasized that in more than 500 cases, epikeratoplasty has been performed for keratoconus on patients with similar ocular surface and allergic abnormalities without such a complication at the Anterior Segment Division at King Khaled Eye Specialist Hospital.

The authors do not have any proprietary interest in the epikeratoplasty lenticule or the manufacturer, nor do they have any financial interest or receive any payment as a consultant, reviewer, or evaluator for the manufacturer.

Reprints: Michael D. Wagoner, MD, Medical Library, King Khaled Eye Specialist Hospital, PO Box 7191, Riyadh 11462, Kingdom of Saudi Arabia.