Cilioretinal artery occlusion

Description

The cilioretinal artery is so-called because it arises from the posterior ciliary circulation and perfuses the retina. It is a congenital anomaly, being present in only 20-30% of people. The cilioretinal artery is seen ophthalmoscopically as a single vessel emerging from the edge of the optic disc, most commonly toward the macula.

Both the central retinal artery and the cilioretinal artery share the same main vascular supply, so that vascular disturbances affecting the internal carotid artery or ophthalmic artery will have a similar affect on both the major retinal artery as well as the cilioretinal artery. However once in the orbit, the ophthalmic artery branches into the central retinal artery, the posterior ciliary arteries and the muscular branches. For this reason, an occlusion of the cilioretinal artery can occur without the central retinal artery being affected.

Cilioretinal artery occlusion may result from embolism or vascular hypertension and there are associations with vasculitis (e.g. giant cell arteritis, see Arteritic Ischemic Optic Neuropathy, AION) and central retinal vein occlusion (CRVO).

Symptoms

Moderate blurring of vision, usually unilateral, may be reported.

Signs

Occlusion of the cilioretinal artery is usually unilaterat. The acute presentation is seen as an attenuated cilioretinal artery with localized areas of superficial retinal whitening, often between the optic nerve head and macula. There may be an associated CRVO or AION. After the occlusion, the retinal pallor fades and the circulation may be restored over several weeks. The retina in arterial occlusions is free of hemorrhages, unlike the fundus appearance in vein occlusions or nonproliferative diabetic retinopathy.

Prevalence

Rare (approximately 1/10,000) to very rare (less than 1/100,000)

Significance

Retinal vascular occlusions have systemic implications; require prompt systemic workup.

Differential diagnosis

Branch retinal artery occlusion; commotio retinae.

See also

Central retinal artery occlusion, Arteritic Ischemic Optic Neuropathy (AION), Vascular occlusions – classification, Diabetic retinopathy

Management

Urgent Cilioretinal artery occlusion is not an ophthalmic emergency, as there is no proven treatment. However a prompt systemic workup is indicated, similar to a branch retinal artery occlusion.

Blood tests Urgent erythrocyte sedimentation rate and C-reactive protein are measured in patients aged over 60 years, when a diagnosis of giant cell arteritis cannot be excluded. Coagulation studies, full blood examination and screening tests for vasculitis are usually performed. In the longer term, cardiovascular risk assessment includes measurement of fasting blood sugar and lipid profile.

Oral medication A review of the patient’s oral medication for any systemic conditions may be indicated.

Review w Initial review is often conducted after an interval of several weeks. In arterial occlusions, neovascular sequelae are uncommon, unlike venous occlusions, perhaps as a result of the complete ischemia in the affected retinal segment.

Prognosis The visual prognosis is usually good if the macula has been spared, but a visual field defect may remain. Most patients with isolated cilioretinal artery occlusion regain visual acuity of 20/40 (6/12) or better, and the prognosis is only slightly worse if combined with a CRVO. However, if the condition is combined with AION the visual prognosis Is poor.