TNOA Journal of Ophthalmic Science and Research

CASE REPORT
Year
: 2022  |  Volume : 60  |  Issue : 3  |  Page : 264--265

A case of embolic non-arteritic anterior ischaemic optic neuropathy in a young patient


R Kokila Priya1, Arthi Mohankumar2, Priya Sivakumar1,  
1 Department of Neurophthalmology, Aravind Eye Hospital, Pondicherry, India
2 Department of Retina and Vitreous, Rajan Eye Care Hospital, Chennai, Tamil Nadu, India

Correspondence Address:
Arthi Mohankumar
Vidyodaya Second Street, T. Nagar, Chennai - 600017, Tamil Nadu
India

Abstract

We report a rare case of unilateral non-arteritic anterior ischaemic optic neuropathy (NAAION) of embolic origin in a 47-year-old male caused by hypertriglyceridaemia and significant atherosclerotic stenosis of bilateral carotid arteries. The fundus fluorescein angiogram showed features supportive of an embolic aetiology. After left carotid endarterectomy and lipid-lowering therapy, there was complete resolution of disc oedema. Embolic anterior ischaemic optic neuropathy (AION) contributes to less than 10% of total AION cases and is often underevaluated. This case report emphasises the importance of thorough systemic evaluation by the ophthalmologist in patients with AION and the role of fundus fluorescein angiography (FFA) in establishing the aetiology in AION cases.



How to cite this article:
Priya R K, Mohankumar A, Sivakumar P. A case of embolic non-arteritic anterior ischaemic optic neuropathy in a young patient.TNOA J Ophthalmic Sci Res 2022;60:264-265


How to cite this URL:
Priya R K, Mohankumar A, Sivakumar P. A case of embolic non-arteritic anterior ischaemic optic neuropathy in a young patient. TNOA J Ophthalmic Sci Res [serial online] 2022 [cited 2023 Jan 27 ];60:264-265
Available from: https://www.tnoajosr.com/text.asp?2022/60/3/264/357116


Full Text



 Case Report



A 47-year-old male presented with complaints of sudden onset defective vision in his left eye (OS). He gave a history of two episodes of transient blurring of vision lasting for around 2 min in the same eye in the last 2 months. He is a known diabetic for the past 3 years with good glycaemic control. On examination, his BP was 120/70. Ocular examination (OS) showed the best-corrected visual acuity (BCVA) of 6/36. OS had grade 1 relative afferent pupillary defect with diffuse oedema of optic nerve head with adjacent splinter haemorrhages and mild non-proliferative diabetic retinopathy (NPDR) [Figure 1]a. Right eye (OD) had a BCVA of 6/6 with mild NPDR. Intraocular pressures and colour vision of both eyes (OU) were normal. Static perimetry done with Humphrey field analyser 24-2 protocol showed a superior altitudinal defect in OS. Based on these clinical features, a diagnosis of non-arteritic anterior ischaemic optic neuropathy (NAAION) (OS) was made and the patient was evaluated. Haematological reports revealed abnormalities in serum lipid profile - triglycerides of 1312 mg/dl and total cholesterol of 365 mg/dl. Other parameters were normal. Carotid Doppler imaging showed significant stenosis of bilateral common carotid arteries (50% in left and 30% right) with evidence of atherosclerotic plaque. Fundus Fluorescein Angiography (FFA) of OS revealed hypoperfusion of disc with choroidal filling defect in early stages [Figure 2]a with leakage of dis in late stages [Figure 2]b. The patient was referred to a vascular surgeon who performed a left carotid endarterectomy and started lipid-lowering therapy. One month later, complete resolution of disc oedema was noted [Figure 1]b, but reduced visual acuity and visual field defect persisted.{Figure 1}{Figure 2}

 Discussion



Anterior ischaemic optic neuropathy (AION) describes a state of hypoxic injury of the optic disc resulting from occlusion of posterior ciliary arteries (PCA).[1] 10–23% of these patients are less than 50 years of age.[2] Previous studies have shown that NAAION in younger individuals is more likely to be bilateral (42.6%) and strongly associated with systemic risk factors.[3] The role of carotid atherosclerosis in NAION has been reported by Hayreh and Zimmerman in their study, which included 191 patients of NAION. The authors found that in patients with NAAION, 52% had plaques in the ipsilateral carotid arteries.[4] These atherosclerotic plaques may give rise to small emboli which may be lodged in the smaller calibre vessels of the eye including short PCA.[5] These arteries, unlike the retinal arteries, cannot be directly observed with an ophthalmoscope.[5] For this reason, if AION were to occur from arterial emboli, to actually see the culpable embolus on ocular fundus examination would be impossible. This explains why little direct evidence is available to implicate emboli from the carotid artery as a cause of AION. Embolic AION contributes to less than 10% of total AION cases and is often underevaluated. Fluorescein angiography is diagnostic in these patients which shows filling defects in the deep vessels of the optic disc and adjacent choroid, depending on the distribution pattern of the occluded short posterior ciliary artery (SPCA).[1] Similarly in our case, a choroidal filling defect was noted in the FFA [Figure 2]a. Cholesterol emboli do not occlude the vessel completely and permanently which may be the reason for the complete resolution of disc oedema in our case.[6]

Based on the history suggestive of transient ischaemic attacks, presence of carotid atherosclerotic plaques and resolution of disc oedema with characteristic FFA findings, we made a diagnosis of embolic NAAION in our patient. Hence, NAAION may be the initial manifestation of severe hypertriglyceridaemia in young patients, indicating a predilection for several other systemic diseases of embolic aetiology serving as a warning of possible dreaded complications of stroke and cardiovascular events.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Hayreh SS. Ischaemic optic neuropathy. Indian J Ophthalmol 2000;48:171-94.
2Preechawat P, Bruce BB, Newman NJ, Biousse V. Anterior ischemic optic neuropathy in patients younger than 50 years. Am J Ophthalmol 2007;144:953-60.
3Arnold AC, Costa RM, Dumitrascu OM. The spectrum of optic disc ischemia in patients younger than 50 years (an Amercian Ophthalmological Society thesis). Trans Am Ophthalmol Soc 2013;111:93-118.
4Hayreh SS, Zimmerman MB. Ocular arterial occlusive disorders and carotid artery disease. Ophthalmol Retina 2017;1:12-8.
5Horton JC. Embolic cilioretinal artery occlusion with atherosclerosis of the ipsilateral carotid artery. Retina 1995;15:441-4.
6Hayreh SS. Pathogenesis of classical non-arteritic anterior ischemic optic neuropathy. In Ischemic Optic Neuropathies. Berlin, Heidelberg: Springer; 2011. p. 265-316.