Non arteritic anterior ischemic optic neuropathy; does Anticoagulation help?

BACKGROUND: Non Arteritic Anterior Ischemic Optic Neuropathy (NAION) is the most common acute optic neuropathy in patients over 50 years of age. This study was conducted to determine the beneficial effects of anticoagulation with Heparin and Warfarin in patients with NAION presenting within 4 weeks of onset of symptoms.
METHODS: A prospective, interventional, pilot study was conducted in Eye- A unit of Khyber Teaching Hospital from July 2010 onwards on patients with NAION presenting within 4 weeks of onset of symptoms. Patients underwent complete ophthalmological examination including Snellen's visual acuity (latter converted to Log MAR), pupil examination, fundus examination and automated Humphrey visual field analysis. Hematologic tests, Thrombophilia screening, Echocardiography and carotid Doppler ultrasound were carried on patients. All patients were anticoagulated with Heparin and Warfarin after obtaining informed written consent. Patients were examined at 1 Month, 3 months and 6 months' time period. Primary parameter measured was improvement in visual acuity.
RESULTS: Total number of patients in our study was 24. Regarding visual outcome total number of patients having significant improvement of visual acuity in our study was 16 (66.6%), while 4 (16.7%) patients had marginal improvement of visual acuity. Three (12.5%) patients maintained stable visual acuity of 6/6 throughout the study period in presence of thrombophilic disorders. One patient (4.1%) suffered a decline in visual acuity compared to VA at baseline presentation.
CONCLUSIONS: Anticoagulation using heparin and warfarin does benefit patients with NAION presenting within 4 weeks of onset of symptoms. In our study a higher proportion of patients experienced significant improvement of visual acuity following anticoagulation as compared to the highest reported spontaneous improvement in such patients.