Case of acute zonal occult outer retinopathy with altitudinal hemianopsia.

LETTERS Case of acute zonal occult outer retinopathy with altitudinal hemianopsia Since the clinical entity of acute zonal occult outer retinopathy (AZOOR) was initially proposed, 1 it has been noted that the visual loss may be misattributed to lesions in the optic nerve or central nervous system. Even with a likely visual field defect for those diseases—an afferent pupillary defect and reduced subjective central flicker fusion threshold—clinicians should be always aware of the possibility of AZOOR. A 32 year old woman noticed a large scotoma in her right eye. She was examined by an ophthalmologist who found her corrected visual acuity to be 0.4 in the right eye and 1.0 in the left eye. She also had an afferent pupillary defect in the right eye. Goldmann perimetry showed a superior altitudinal hemianopic defect in the right eye (fig 1). Subjective central flicker fusion threshold was reduced in the right eye (18 Hz) and normal in the left eye (35 Hz). Ophthalmoscopic examination, fluorescein angiography, blood screening, and computed tomography were normal. Suspecting ischae-mic optic neuropathy (ION), a 5 day course of intravenous succinic hydrocortisone, 100 mg/ day, was used but this treatment was not effective. The patient was then referred to us for further examination. Full field rod and cone electroretinograms (ERGs) were reduced in her right eye (about 50% of those in the left eye). Multifocal ERGs (mfERGs) recorded with the VERIS Science 4.0 system USA) revealed reduced responses in areas corresponding to the visual field defect (fig 2). These findings led us to presume the diagnosis to be AZOOR. 1 While we have followed her for approximately a year, no retinal finding has been observed and the visual defect has not changed. Comment Although altitudinal hemianopsia is found in many optic nerve disorders—for example, as meningioma, optic neuritis, ION, sinuses or intracranial artery disorders, and congenital abnormalities of the optic nerve head, 2 this type of field defect had been rarely reported in AZOOR. 3 The visual field abnormality in AZOOR varies from case to case, 1 but central or paracentral scotoma is most common. When the clinical entity of AZOOR was initially proposed, 1 the visual loss was attributed to retrobulbar neuritis, a pituitary adenoma, or other intracranial lesions during the early stages of this disease. Normal fundus and fluorescein angiographic findings with dense scotoma led ophthalmologists to suspect optic nerve or intracranial diseases. In addition, the …