Thyroid Eye Disease with Compressive Optic Neuropathy

Abstract

A 57-year-old male had hyperthyroidism for 3 years. He first suffered diplopia with right eye fullness 9 months ago. He received methylprednisolone pulse therapy for 3 days at a local hospital under the impression of thyroid eye disease with right optic nerve compression. The vision in his right eye improved after treatment. Six months later, he began to suffer from left eye fullness and blurred vision OS. Left visual acuity dropped to 6/60 then. He received methylprednisolone pulse therapy for 3 days, and his vision improved to 6/20 OS. He was then discharged with oral prednisolone tapered completely within 2 weeks. He came to our clinic 2 months later due to persistent diplopia and blurred vision in the left eye. Ophthalmologic examination showed visual acuity of 6/7.5 OD and 6/30 OS. He could identify 15 plates in the right eye and 10 plates in the left eye using the Ishihara test. Intraocular pressures were normal. Bilateral eyelids were mildly swollen. A prism cover test showed that there were 4 prism diopters of esotropia on primary gaze, which increased to 8 prism diopters on left gaze. Mild cortical opacity was found in both lenses. Fundoscopic examination showed disc swelling in the left eye. In addition, horizontal retino-choroidal foldings were identified in the left macula (Fig. 28.1). OCT demonstrated an increased peripapillary retinal nerve fiber layer (RNFL) thickness of 283 μm in the left eye, with decreased ganglion cell-inner plexiform layer (GC-IPL) thickness over macular region (Fig. 28.2). Fluorescein angiography revealed dye staining on the left disc and retino-choroidal foldings over the macula (Fig. 28.3). A visual field examination showed a constricted visual field in the left eye (Fig. 28.4). An orbital CT scan revealed enlargement of the bilateral superior rectus, medial rectus, and inferior rectus, with left optic nerve compression (Fig. 28.5). One week later, his vision decreased to 6/60 in the left eye, and color sense worsened to nine plates. MR imaging showed similar findings of extraocular muscle enlargement, with compression of the left optic nerve (Fig. 28.6). Surgical decompression and pulse therapy were explained to the patient, and the patient elected steroid pulse therapy first. He received methylprednisolone pulse therapy, and his visual acuity improved to 6/15 OS on the third day of steroid treatment. His vision improved to 6/6.7 OD and 6/8.6 OS 1 month later, and his left peripapillary RNFL thickness decreased to 138 μm.