The purpose of this study is to explore the safety and efficacy of ranibizumab to treat
non-arteritic ischemic optic neuropathy based on clinical and anatomical findings.
Nonarteritic anterior ischemic optic neuropathy (NAION) is the most common acute optic
neuropathy in people older than 50 years. It is characterized by sudden partial loss of
vision in one eye and has an increased risk of vision loss in the fellow eye. Although
cause has not been determined, NAION is thought to occur following an idiopathic ischemic
event involving the short posterior ciliary arteries that supply blood to the most anterior
part of the optic nerve. A complete loss of vision is rare, but partial loss of visual
field or acuity can result from NAION in the affected eye(s).
Patients who have a 'disc at risk' or 'crowded disc' (small cup: disc ratio) are at
increased risk for developing NAION. Other risk factors for NAION include age > 50 years
and white race (estimated 95% of cases). Hypertension and diabetes also predispose to NAION
development. Other factors that have been associated with NAION include high cholesterol,
arteriosclerosis, stroke, cardiac and intraocular surgery, tobacco use, nocturnal
hypotension, blood loss, glaucoma, elevated homocysteine and sleep apnea. The association
between NAION and hypertension, high cholesterol and diabetes is stronger in individuals
younger than 50 years than in older persons.
Patients with NAION caused by ischemia leading to swelling of the optic nerve and rapidly
progressing visual loss have had limited results with therapy such as corticosteroids,
brimonidine, levodopa or surgery, such as optic nerve sheath decompression, in the past.
Currently, there is no standard of care for these patients.
Although the role of vascular endothelial growth factor (VEGF) in NAION has not been
established, ischemic conditions may lead to VEGF production which could be the cause of
edema and swelling. This possibility suggests that VEGF may be a target for therapeutic
intervention by ranibizumab. Ranibizumab has demonstrated an effect on edema and vascular
permeability. In animal studies it has shown a concentration- dependent effect of blunting
the vascular permeability induced by VEGF. Of the more than 5,000 subjects with age-related
macular degeneration in current and completed clinical trials, vascular permeability and
edema have decreased with the use of ranibizumab.
- provide written informed consent
- 21 years of age or older
- new onset, within 14 days, of ischemia and vision loss
- Best Corrected Visual Acuity (BCVA) 20/40 or worse
- pregnancy or lactation
- patients with proliferative diabetic retinopathy, diabetic macular edema, uveitis,
history of ocular trauma, severe glaucoma, age-related macular degeneration
- prior or concomitant treatment of oral steroids within 30 days, participation in any
studies of investigational drugs within 30 days, participation in a ranibizumab
clinical trial or prior treatment intravitreally or intravenously of Avastin or