Chronic Subdural Hematoma: An Unusual Sequela of Laser Photocoagulation of the Retina at the Slitlamp

A 61-year-old healthy patient was seen for a second opinion regarding whether additional laser treatment was needed to treat a retinal break in his left eye. He had been seen elsewhere for monitoring of retinoschisis, where a superiorly located horseshoe tear, unassociated with the schisis cavity, and a smaller break were found in his left eye. Laser treatment was recommended. At that time, a contact lens was placed on the left eye under topical anesthesia, and approximately 100 moderate-intensity argon laser lesions were applied at the slitlamp, some of which were uncomfortable. Treatment required him to remain motionless, and after about 10 minutes, he told his laser surgeon that he felt light-headed. The surgeon stopped treatment but the patient lost consciousness, fell off his stool, and struck his head against the floor. The physician immediately went to summon assistance. On return with ancillary medical personnel, the patient was found on the linoleum floor, semiconscious.

He was examined in the emergency department, where x-rays and a computed tomographic scan of his head were obtained. As all findings were negative except for an ecchymosis on his scalp, the patient was released with the diagnosis of a vasovagal event and returned home. During the ensuing weeks, his wife noted some short-term memory loss, and he complained of a fullness in the head. On his return from a business trip, he was reunited with a physician friend of his who had not seen him for some time. She noted a change in her friend's affect. Both she and another physician questioned the patient and were concerned that he might have experienced a subdural hematoma from the fall. A repeated computed tomographic scan was ordered, and a marked shift (30 mm) of the falx cerebri was found, confirming the diagnosis (Figure 1).

The patient then underwent a craniotomy, 8 weeks after the photocoagulation session. A second craniotomy was necessary 1 month later because he developed paresis of his left hand, secondary to a reaccumulation of the hematoma. His paresis eventually resolved.

Four months after the accident, the patient was seen at our center. The retinal break had been incompletely treated, and additional photocoagulation was necessary. This time, an indirect laser delivery system was suggested to allow him to lie in a more comfortable, supine position during treatment and to avoid the necessity of placing a contact lens on his eye. He returned 2 months and then 8 months later and has remained stable and free from neurologic and visual symptoms.

Laser photocoagulation is customarily a safe outpatient procedure associated with few complications.¹ However, laser surgery to an eye is never trivial. Proper facilities, equipment, and extensive training are necessary to safely perform it and to manage potential complications. While treatment with excessive powers can cause chorioretinal hemorrhage and subsequent choroidal neovascularization, the development of subdural hematoma precipitated by discomfort occurring during laser treatment is distinctly unusual.

Many laser surgeons are currently exploring the use of several newer laser strategies for the treatment of macular degeneration, such as photodynamic therapy² and transpupillary thermal therapy.³ Such treatment, along with the application of many lesions during conventional panretinal photocoagulation, requires that the patient remain motionless, often for extended periods of time. In this case, the production of strong chorioretinal lesions for retinopexy necessitated the use of moderately intense laser spots. These conditions and perhaps pressure on the eye from the contact lens ultimately precipitated a vasovagal response in this case, which in turn resulted in severe consequences.

The head-mounted binocular indirect ophthalmoscope laser delivery system is preferred by many surgeons for panretinal photocoagulation and for the treatment of retinal breaks in the outpatient setting. With this delivery system, patients can be treated while lying down in a relaxed, supine position, which minimizes their discomfort and eliminates their chance of falling backward during photocoagulation.⁴ Such an option should be considered for the initial treatment of a patient with a peripheral lesion, and especially in a patient for whom discomfort and instability of positioning have been apparent during previous slitlamp laser delivery.

Regardless of the technique used, this case underscores the fact that very serious and unexpected sequelae can develop secondary to laser treatment of the human eye. All laser surgeons should have the appropriate medical training to deal with such issues.

The authors do not have any proprietary interest relevant to this study.

Corresponding author: Thomas R. Friberg, MD, MS, Department of Ophthalmology, 203 Lothrop St, Suite 824, Pittsburgh, PA 15213 (e-mail: friberg@pitt.edu).