An unusual presentation of nonarteritic ischemic optic neuropathy with subretinal fluid treated with intravitreal bevacizumab.

A 62-year-old hypertensive male presented with acute nonarteritic ischemic optic neuropathy (NAION) with contiguous macular edema and subretinal fluid in the right eye. Presenting vision was 20/1000. The patient was treated with intravitreal bevacizumab 1.25 mg/0.05 ml. At 1 month follow-up, the macular edema and the optic nerve head edema completely resolved with a good visual improvement up to 20/40. The visual improvement was maintained at the last follow-up 6 months postinjection. Intravitreal bevacizumab may be a good option for acute NAION especially in an unusual presentation with macular edema and subretinal fluid.

Nonarteritic ischemic optic neuropathy (NAION) is one of the most common ischemic optic neuropathies. It causes sudden painless monocular loss of vision typically in patients after their fourth and fifth decades. The etiology is described to be ischemia of the optic nerve due to ciliary circulation insufficiency.[1] In most cases, the natural course of optic disc edema is characterized by spontaneous resolution over 2–3 months culminating optic atrophy and variable levels of final vision loss.[2] Over the years, many therapies have been tried in NAION with varied and limited success including optic nerve sheath decompression, levo L-3,4-dihydroxyphenylalanine (DOPA), intravitreal steroids, and aspirin. Recently, a large prospective study demonstrated the benefit of systemic steroids.[3] As ischemia is the central pathology in NAION, recently intravitreal antivascular endothelial growth factor (VEGF) has shown possible promise. In this case report, we shall discuss a peculiar presentation of NAION with macular edema and subretinal fluid with a favorable response to a single injection of intravitreal bevacizumab.

Case Report

A 62-year-old controlled hypertensive male presented to us with complaints of blurred vision in the right eye oculus dextrus (OD) since 2 weeks. At a presentation to our clinic, the best-corrected visual acuity (BCVA) in OD was 20/1000 and in the left eye (OS) to be 20/200. Intraocular pressure was 14 mm Hg in both eyes. A relative afferent pupillary defect was noted in OD. Rest of the anterior segment examination was within normal limits in both the eyes. Fundus examination in OD revealed a clear vitreous cavity, pallid disc edema, and macular edema. Localized subretinal fluid on the nasal macula was noted on slit lamp biomicroscopy. OS showed disc pallor with the rest of the retina within normal limits. The patient gave a history of a similar complaint in OS 2 years back. Optical coherence tomography (OCT) and humphrey visual field perimetry were advised. OCT scan through the macula showed neurosensory detachment in OD along with macular edema. A line scan through the optic disc demonstrated severe disc edema [Fig. 1]. Perimetry showed an altitudinal visual filed loss characteristic of NAION. There was no history of any other complaints. Blood investigations done included platelet count, erythrocyte sedimentation rate, and C-reactive protein which were all within normal limits.

Figure 1

(a) Fundus photo showing nonarteritic ischemic optic neuropathy with macular edema (b) perimetry showing classical altitudinal defect (c) macular optical coherence tomography showing subretinal fluid with macular edema (d) optical coherence tomography through nerve head showing disc edema

The patient was diagnosed as a case of OD acute NAION with subretinal fluid at macula and OS optic atrophy status post-NAION. After discussing the pros and cons of the therapy and with a written informed consent, intravitreal bevacizumab (Avastin, Genentech, San Francisco) 1.25 mg/0.05 ml was injected in OD. At 1 month, the BCVA had improved to 20/40 in OD. OCT at 1 month visit showed completely resolved macular edema and disc edema [Fig. 2] 20/40 vision was maintained at the last visit 3 months postinjection.

Figure 2

(a) Fundus photo showing resolved disc edema and pallor (b) resolved subretinal fluid (c) resolved disc edema

Discussion

Pathogenesis of NAION can be explained by “compartment syndrome” and reperfusion injury as shown by Chen et al.[4] It can be hypothesized that there is local VEGF release which causes early vasogenic edema of the optic nerve head. Anti-VEGF can reduce this early vasogenic edema and decrease the severity of the compartment syndrome thus leading to a better final visual outcome. Bajin et al. in their study of four eyes showed visual improvement after injecting intravitreal ranibizumab for NAION.[5] Pece et al. and Arnold and Hepler in their study, on the other hand, showed no visual improvement in vision after intravitreal ranibizumab.[67] Rootman et al.[8] in a prospective trial found no difference between bevacizumab and natural history for change in visual field, visual acuity, or optic nerve OCT thickness. Saatci et al.[9] found a beneficial effect of intravitreal ranibizumab in their case series of 17 eyes.

Macular edema is an unusual presentation in NAION not described as a part of the natural history of NAION. Neither is it described in the fluorescein angiography features nor in cases with giant cell arteritis.[1910] It most likely represents spillover edema from the optic nerve head. Very few case reports suggest the presence of macular star associated with cases of NAION.[1112] It has been hypothesized that there may be a better visual outcome in these subset of patients postresolution of macular edema and that some sort of therapy toward resolution of macular edema may be warranted.

To the best of our knowledge, this is the first case of NAION with macular edema and subretinal fluid treated with intravitreal bevacizumab with good visual outcome. Further, large studies are warranted to elucidate a clear role of intravitreal anti-VEGF therapy in NAION though our case report shows a possible role in concurrent macular edema.

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Conflicts of interest

There are no conflicts of interest.