Binazal Hemianopsi Prezentasyonlu Optik Disk Druzeni

1. 1Çanakkale Onsekiz Mart University Medical Faculty, Department Of Ophthalmology, Çanakkale, Turkey
2. 2Çanakkale Onsekiz Mart University Medical Faculty, Department Of Radiology, Çanakkale, Turkey

Sorumlu Yazar: Visual field defects may arise due to ocular or neurologic pathologies. Different neurological difficulties cause characteristic forms of visual disturbances, including hemianopia and quadrantanopsias. Isolated loss of the nasal fields of vision is uncommon. Binasal hemianopsia, unlike types of visual field loss such as bitemporal heteronymous hemianopia, unilateral homonymous hemianopia, is not common and cannot be explained by a single visual tract lesion. It develops from bilateral involvement of the uncrossed fibers at the chiasma such as bilateral internal carotid artery atherosclerosis or aneurysm, olfactory groove meningioma, empty sella syndrome, chronic raised intracranial pressure, and neurosyphilis affecting both optic nerves.3,4 Binasal hemianopia commonly occurs due to retinal or optic nerve head pathologies. In an overview reported by Salinas-Garcia and Smith, it is stated that 75% of the binasal hemianopia cases originated from ocular pathologies.5 Optic nerve pathologies presenting with binasal hemianopia were glaucoma (most common), ischemic optic neuropathy, congenital optic nerve pits, and optic nerve drusen in those patients. Most large series report that 75% of patients with disc drusen have visual field defects.6 The described ODD-associated field defects were nerve fiber bundle defects, arcuate defects, enlargement of the blind spot, and concentric narrowing. These defects were reported to affect the inferonasal quadrant most frequently. Dramatic visual field loss in ODD is most often due to vascular complications, but it can also be caused by ODD alone when proposed pathogenetic mechanisms are considered.7 These mechanisms may be described as: 1) impaired axonal transport in an eye with a small scleral canal leading to gradual attrition of optic nerve fibers, 2) direct compression of prelaminar nerve fibers by drusen, 3) ischemia within the optic nerve head. Although no effective treatment of ODD has been established, a prophylactic topical antiglaucomatous treatment was given to our patient as it had been suggested in the presence of visual field loss in the previous reports.8 A careful ocular examination must be done for all patients with binasal hemianopia. Although disc drusen are commonly diagnosed with ophthalmoscopy alone, their appearance may change throughout the patient’s lifespan from buried to superficial in location; thus it might be confirmed by ancillary tests. The correct diagnosis is critical as they can mimic a number of serious pathologies presented with binasal hemianopia. In conclusion, the ophthalmologists should consider ODD in the differential diagnosis of advanced visual field loss and binasal hemianopia. Address for Correspondence/Yazisma Adresi: Hasan Ali Tufan MD, Çanakkale Onsekiz Mart University, Department of Ophthalmology, Çanakkale, Turkey Phone: +90 286 263 59 56 E-mail: ha_tufan@hotmail.com Received/Gelis Tarihi: 09.09.2012 Accepted/Kabul Tarihi: 04.01.2013