Abstract
Purpose:
Non-arteritic ischemic optic neuropathy (NAION) is the most common acute optic neuropathy in those older than 50. and young onset NAION has been reported in 4-23% of patients. The aim of our study is to investigate the age of onset of NAION and correlation with risk factors.
Methods:
We performed a retrospective review at a single institution of consecutive patients with the diagnosis of NAION (2009-2014) who had neuro-ophthalmic evaluation, automated static perimetry, and optical coherence tomography (OCT).
Results:
We studied 50 NAION eyes in 32 patients (24 male, 8 female; unilateral: 14 patients, bilateral: 18 patients). The average age of first events was 54.6±2.4 years (median 54 years; ≤50: 11 (33.7%) patients, >50: 20 (66.3%) patients; range 24-80 years). In fact, 50% of patients presented with their first event between ages 40-55. In all ages, AION led to significant visual field loss (mean deviation AION: -14.1±1.5 dB; control: -1.6±0.5 dB; P<0.001, Mann-Whitney) and significant thinning of thickness of the retinal nerve fiber layer (AION: 66.0±3.9 µm; control: 89.9±4.6 µm; P<0.001) and macular ganglion cell complex as measured by OCT (AION: 61.7±1.8 µm; control: 82.4±3.4 µm, P<0.001). In terms of AION risk factors, all age groups had small optic disc area (mean optic disc area 1.65± 0.30 mm2, N = 43 eyes), obstructive sleep apnea (≤50: 82%, average AHI 27.9±7.9; >50: 80%, average AHI 24.6±7.7), and vascular risk factors (hypertension, diabetes, hyperlipidemia). Treatment for obstructive sleep apnea did not prevent future events but was associated with delayed onset of new events (treated: 63.5±54.9 months, median 10 months; not treated: mean 21.6±16.4 months, median 5 months; P=0.2). The presence of optic disc drusen was associated with earlier onset of AION by 2 decades (N=2 patients, 3 affected eyes), but all affected eyes had final visual acuity of 20/20. Consistent with this finding, age may be an important factor in visual prognosis, since those ≤50 years old at first event had a trend of better final visual acuity, visual field mean deviation, and OCT retinal thickness measurements than those >50.
Conclusions:
Fifty percent of NAION patients had onset of first event at 40-55, so age greater than 40 should be considered the common presentation of NAION. Age may also be an important factor in NAION prognosis, since younger patients had better visual outcome.