History
A 35-year-old black male presented with a chief complaint of blurred vision at distance that had persisted for six months. He explained that his spectacles were old and that he wanted a new pair with an updated prescription. He had no significant ocular or systemic history, and reported no allergies.

Diagnostic Data
His best-corrected visual acuity measured 20/25 O.U. at distance and 20/20 O.U. at near. External examination was normal, with no evidence of afferent pupillary defect. Refraction yielded a small improvement in both eyes, revealing the presence of spherical myopia. 

The anterior segments of both eyes appeared healthy. Intraocular pressure measured 19mm Hg O.U. We detected an unusual finding in his right eye during the dilated fundus examination.

Your Diagnosis
How would you approach this case? Does this patient require any additional tests?

What is your diagnosis? How would you manage this patient? What’s the likely prognosis?

Discussion

Fundus photograph of our 35-year-old patient who complained of blurred vision. Do you notice anything particularly odd?

Additional tests/procedures included photodocumentation of the anomaly.

The diagnosis in this case is dual inferior cilioretinal arteries O.D. Cilioretinal arteries commonly supply a small area of the retina, usually in or around the vicinity of the macula.¹ They can serve a valuable purpose in preserving vision in cases where the normal retinal circulation has become occluded.^1-4 Instances have been described in the literature in which the total retinal circulation has been facilitated solely by an existing cilioretinal artery.¹

Cilioretinal arteries arise from the short posterior ciliary artery circulation or directly from choroidal circulation.² Some statistical analysis has supported the hypothesis that genetic factors influence their development.^3,4 For example, it has been proposed that the presence of one or more cilioretinal arteries in the eyes of otherwise healthy individuals is influenced by hereditary considerations, and may be part of a larger subset of genetically provoked optic disc anomalies.^3-5

In one study, cilioretinal arteries were found to accompany optic disc pits in 16 of 25 patients (64%).5 Moreover, 14 of the 16 patients (86%) were found to have two cilioretinal arteries.⁵ The authors concluded that the cilioretinal arteries were directly related to the optic disc pit and emerged either from the bottom or the margin of the pit in 86% of cases.⁵ This study lent some credibility to the postulation that cilioretinal vasculature may belong to the same spectrum of congenital anomalies as optic disc pits, disc colobomas, megalopapillae and morning glory syndrome.⁵

One research team suggested that the presence of a cilioretinal artery may play a role in optic disc compromise.² More specifically, they hypothesized that cilioretinal vessels siphon vascular flow from the peripapillary circulation, which likely accounts for worsening glaucomatous damage and/or contributes to the process of normal-tension glaucoma.² Nevertheless, this theory remains controversial.

Sohan Singh Hayreh, M.D., Ph.D., and associates have proposed that central retinal vein occlusion may be associated with cilioretinal artery occlusive processes.⁶ According to this research, the pathogenesis is due to a transient hemodynamic blockage of the cilioretinal artery.⁶ This blockage is precipitated by a sudden, sharp rise in intraluminal pressure in the retinal capillary bed secondary to venous occlusion above the level of that observed in the cilioretinal artery.⁶

Despite this research, there is no frank treatment recommended for patients with this vascular phenomenon (e.g., aspirin or anticoagulant therapy). In fact––in most cases––these vessels are heralded as a “vascular advantage” over a conventional anatomic structure, because they offer another perfusion source if the primary route fails. Therefore, our patient required no further treatment at this time.

1. Hegde V, Deokule S, Matthews T. A case of a cilioretinal artery supplying the entire retina. Clin Anat. 2006 Oct;19(7):645-7.
2. Mikelberg FS, Drance SM, Schulzer M, et al. Possible significance of cilioretinal arteries in low-tension glaucoma. Can J Ophthalmol. 1990 Oct;25(6):298-300.
3. Taarnhøj NC, Munch IC, Kyvik KO, et al. Heritability of cilioretinal arteries: a twin study. Invest Ophthalmol Vis Sci. 2005 Oct;46(10):3850-4.
4. Honkanen RA, Jampol LM, Fingert JH, et al. Familial cavitary optic disk anomalies: clinical features of a large family with examples of progressive optic nerve head cupping. Am J Ophthalmol. 2007 May;143(5):788-94.
5. Theodossiadis GP, Kollia AK, Theodossiadis PG. Cilioretinal arteries in conjunction with a pit of the optic disc. Ophthalmologica. 1992;204(3):115-21.
6. Hayreh SS, Fraterrigo L, Jonas J. Central retinal vein occlusion associated with cilioretinal artery occlusion. Retina. 2008 Apr;28(4):581-94.