Bilateral Scleral Thermal Injury: Complication After Skin Laser Resurfacing

In 1980, Beckmann and Fuller¹ were the first to use the carbon dioxide (CO₂) laser in blepharoplastic surgery. Reported advantages of CO₂ laser blepharoplasty include decreased postoperative edema, less pain, and a shorter convalescence in comparison with conventional surgery.² We are aware of only 1 report on the use of a combined CO₂/Nd:YAG laser: in 1996, Katalinich³ reported that 50 patients treated for cutaneous neurofibromas had shorter surgery times, less hemorrhages, and sufficient removal with the Nd:YAG laser vs with the CO₂ laser alone. To the best of our knowledge, complications of this treatment have not yet been described.

A 45-year-old man with Recklinghausen neurofibromatosis had undergone laser resurfacing because of multiple facial neurofibromas, especially in the periorbital region. He was treated in a plastic surgeon's office using, as far as we know, a combined CO₂/Nd:YAG laser (Combolaser; Madtec GmbH, Ulm, Germany) (power settings: CO₂ laser, 20-25 watts [W]; Nd:YAG laser, 7-8 W). The technique has been described by Katalinich³: the skin over the tumor is dissected, then the tumor is evaporated by a defocussed laser beam. The use of 2 laser types is supposed to remove the neurofibromas radically enough.³ Five days after treatment, the patient was referred to our hospital suffering from deteriorated vision in the left eye. Best-corrected visual acuity was 1.0 OD and 0.16 OS. In both eyes, left worse than right, slitlamp microscopy revealed broad-based defects of the lower eyelid margins (small arrows) with corresponding conjunctiva-covered scleral lesions (large arrows), resembling a thermal injury (Figure 1). The left eye showed slight intraocular inflammation. No injury of other anterior segment structures was observed in either eye. Intraocular pressure was 12 mm Hg OU. The swinging flashlight test showed no afferent pupillary defect. Funduscopy was normal in the right eye; in the left eye, it revealed discrete optic nerve head swelling, with peripapillary bleeding and angiographically proven peripapillary exudation, which explained the transient visual acuity loss. In kinetic perimetry, a relative defect to the right side was observed. Systemic and neurological inflammatory diseases were excluded by clinical and laboratory investigation and magnetic resonance imaging. Visual acuity recovered with high-dose systemic corticosteroids, beginning with 100 mg of fluocortolone daily and tapering off over 6 weeks. Seven months after the laser injury, visual acuity was 1.0 OU. Slitlamp microscopy revealed scarred scleral lesions in correspondance with scarred lower eyelid margin defects in both eyes. Macula and optic nerve head were normal in both eyes. A second fluorescence angiogram was refused by the patient.

In a safety study, plastic and metal corneal eye protectors were tested with CO₂ laser beams of different energy levels to assess flammability and heat production: only the metal protectors showed no damage.⁴ Therefore, metal scleral eye protectors are recommended for laser treatment in the periorbital region.² Although the plastic surgeon insists that he took adequate measures to protect the globe, some doubts remain about whether these recommendations were considered properly in the case of this patient. To find out which laser source had caused which type of damage, we used a Monte-Carlo calculation (S. William, PhD, A. Terenji, PhD, unpublished data, December 1998) to estimate the laser intensity (watts per square centimeter) in different tissues of the human eye when either a CO₂ or a Nd:YAG laser is employed (Table 1). This calculation shows that nearly all the energy of the CO₂ laser is absorbed in the sclera, whereas the energy of the Nd:YAG laser easily penetrates the sclera and is able to damage the posterior pole. We therefore conclude that the scleral lesions in our patient were most probably caused by a CO₂ laser, whereas the posterior pole damage in the left eye must have been caused by a Nd:YAG laser. Penetrations of the globe after CO₂ laser treatment have been reported anecdotally but have not been published so far (J. J. Woog, written communication, June 29, 1998).

In conclusion, severe ocular complications caused by CO₂ or Nd:Yag laser treatment can occur if eye protection is inappropriate. Therefore, safety considerations should be observed carefully.

Corresponding author: Helga Spelsberg, MD, Eye Hospital, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany (e-mail: spelsber@uni-duesseldorf.de).