MAR 11, 2011
By Michael Vaphiades, DO
Neuro-Ophthalmology/Orbit
The authors report the case of a patient who developed bilateral ocular ischemic syndrome (OIS) 14 years after radiation therapy for nasopharyngeal squamous cell carcinoma. While they emphasize that radiation therapy of the head and neck has a relatively high likelihood of causing vascular stenosis, they believe this to be the first reported case of OIS following radiotherapy for nasopharyngeal carcinoma. Digital subtraction angiography indicated occlusion of common carotid arteries and stenosis of both vertebral arteries. Following stenting of the vertebral arteries, visual function improved and ophthalmoscopic abnormalities of OIS regressed in the right eye. The authors conclude that stenting of the vertebral and carotid systems may offer a successful form of therapy in selected cases.
The patient, a 39-year-old Chinese man, was admitted to the hospital complaining of blurred vision, transient blindness in both eyes and dizziness. Fourteen years earlier, he had been diagnosed as having stage T1N1M0 squamous nasopharyngeal carcinoma (NPC). He had received external radiation therapy to the nasopharynx with a total dose of 72 Gy in 36 fractions over 74 days and a supplemental dose of 59.42 Gy to the neck in 33 additional fractions. He had remained clinically stable since then.
An examination found that he had BCVA of 20/40 in the right eye and 20/400 in the left eye. Visual field testing showed nasal field loss in each eye. Ophthalmoscopy and fluorescein angiography revealed narrowed retinal arterioles, retinal vascular changes including microaneurysms and delayed arm-to-retina circulation time on the right.
The patient underwent endovascular stenting of the vertebral arteries first on the left side and then on the right side three months later. After the stenting, he was treated with antiplatelet therapy.
His blurred vision and transient visual loss resolved after one month, and dizziness disappeared after three months. Reassessment digital subtraction angiography revealed filling of both vertebral arteries at the site of previous stenosis. Six months after stenting, the retinal vascular abnormalities had improved, visual acuity in the right eye was 20/30 and the visual field had improved. However, the left eye developed a vitreous hemorrhage and a cataract four months after stenting.
The authors recommend that patients undergo regular diagnostic follow-up studies of the carotid and vertebral systems following radiotherapy for NPC until treatment guidelines are developed based on long-term observational studies.