We have reported two rare cases of GCA-induced A-AION combined with CLAO, which were confirmed by TAB, in Chinese patients who experienced a sudden decline in monocular visual acuity. To our knowledge, there are no prior reports of GCA-induced A-AION combined with CLAO in Chinese patients. Timely administration of corticosteroids improved the visual function in both patients and prevented a further decline in visual acuity of the affected eyes, damage of the contralateral eyes, or life-threatening events.
GCA, which is quite rare in Asian individuals, is an autoimmune inflammation that affects large and medium-sized blood vessels and is usually accompanied by systemic symptoms such as headache, scalp tenderness, chewing discomfort, anorexia, fever, and weight loss [4]. GCA may cause sudden loss of visual acuity, with blindness in severe cases. A-AION is the most common cause of permanent vision loss caused by GCA [5]. Vision loss in patients with A-AION is usually disastrous. Most patients have a visual acuity below 20/200, and up to 21% of patients are unable to perceive light. Other causes of blindness in patients with GCA include central retinal artery occlusion (14.8%), CLAO, posterior ischemic optic neuropathy, and ophthalmic artery occlusion [6]. Both of the patients described in our report had GCA, which led to A-AION combined with CLAO. Chalky white swelling of the optic disc and a focal region of gray edema between the macular and optic disc are highly suggestive of tissue ischemia.
Fundus fluorescein angiography (FFA) can be used to diagnose AION and CLAO, which is characterized by a choroidal filling delay [7]. However, as an invasive examination, FFA has some potential risks, including the possibility of allergic reactions to intravenous fluorescein sodium [8]. Unlike FFA, OCTA visualizes the microcirculation by detecting the motion contrast of flowing blood, allowing the ophthalmologist to observe the retinal and choroidal blood supplies in vivo. Furthermore, because OCTA does not require the administration of drugs, it is a safe and noninvasive procedure [9]. OCTA can also track the evolution of the capillary microcirculation in eyes with A-AION. In the acute stage, shallow expansion occurs around capillaries, which is followed by a decrease in the density of capillaries around the optic disc. Loss of perfusion of the paraoptic capillaries results in the loss of the visual field [10]. OCTA has also revealed decreases in the capillary density of the retina and choroid at the side of blood supply in eyes affected with CLAO [11], consistent with the findings in our cases.
Currently, the diagnosis of GCA is based on the American Society of Rheumatology (ACR) criteria published in 1990 [12]: (1) age > 50 years at onset; (2) recent headache; (3) temporal artery disease with tenderness or tenderness of the temporal artery and weak pulsation, except when caused by carotid atherosclerosis; (4) accelerated ESR (> 50 mm/h); and (5) abnormal arterial biopsy findings, such as vasculitis, inflammatory infiltration dominated by monocytes or granulomatous inflammation, often multinucleated giant cells. Although the diagnostic criteria were revised in 2016, with the addition of CRP, fibrinogen, and other parameters, it is still recommended that patients satisfy at least three of the original five criteria for diagnosis [13]. In this report, case 1 satisfied diagnostic criteria (1) and (3), and case 2 satisfied diagnostic criteria (1) and (4). Patients with suspected GCA still require confirmation of diagnosis by TAB.
TAB shows high specificity and is considered the gold standard method for the diagnosis of GCA. Because A-AION usually leads to irreversible visual loss, timely administration of corticosteroid could prevent further visual impairment and reduce the risk of disease recurrence. In order to confirm the diagnosis of GCA and avoid delaying treatment, TAB should be performed as soon as possible, and corticosteroid administration should not be delayed [6].
Limitation of the report is the lack of fluorescence angiography and ICGA results. because the patients were allergic to the contrast medium, thay could not be performed.
In conclusion, GCA can lead to A-AION combined with CLAO. OCTA is a noninvasive and convenient procedure that can reveal decreased density of capillaries around the optic disc and non-perfusion of the deep retina between the macula and the optic disc through the detected of retinal microcirculation in patient with GCA-induced A-AION combined with CLAO. Clinically, TAB and corticosteroid administration should be performed as soon as possible in patients with GCA-induced A-AION combined with CLAO. Corticosteroids can prevent further visual impairment, reduce the risk of disease recurrence and life-threatening accidents.