|Year : 2016 | Volume
| Issue : 3 | Page : 146-148
Congenital retinal macrovessel with macular edema: An unusual presentation
Geetika Khurana, Poninder Kumar
Department of Ophthalmology, Army College of Medical Sciences, Base Hospital, New Delhi, India
|Date of Web Publication||7-Oct-2016|
Dr. Geetika Khurana
A 38, Sector 26, Noida, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Congenital retinal macrovessel (CRM) is a rare developmental condition in which a large vein, artery, or occasionally an artery and a vein together, cross the macular region. Most often, this aberrant vessel originates from a branch of the inferotemporal vein, with branches crossing the horizontal raphe. CRMs do not affect vision unless there are associated foveolar cysts, foveal ectopia, pigmentary changes at fovea, macular hemorrhage, exudates, serous macular detachment, or the macrovessel crosses the fovea. We present a case of a 13-year-old male patient with congenital macular artery crossing the fovea, associated with macular edema and decreased visual acuity. In this case report, we highlight the fundus fluorescein angiography findings and optical coherence tomography evaluation of the patient.
Keywords: Congenital retinal macrovessel, fundus fluorescein angiography, macular edema, optical coherence tomography
|How to cite this article:|
Khurana G, Kumar P. Congenital retinal macrovessel with macular edema: An unusual presentation. MAMC J Med Sci 2016;2:146-8
| Introduction|| |
Aberrant retinal vessels in the macular region were first described in 1869 by Mauthner. Congenital retinal macrovessels (CRMs) are usually discovered as an incidental finding. The aberrant vessel can be an artery or vein, the latter being more common.  The visual acuity remains unaffected in majority of the cases.  In this case report, we present a 13-year-old male patient with congenital macular artery, associated with macular edema and decreased visual acuity.
| Case Report|| |
A 13-year-old male patient presented to the outpatient department with a complaint of reduced visual acuity in right eye (OD). Unaided visual acuity and best-corrected visual acuity (BCVA) in OD were 6/24 and 6/18, respectively. BCVA in left eye (OS) was 6/6. Examination of the anterior segment was unremarkable in both eyes. There was no afferent pupillary defect or anisocoria. There was orthophoria with normal extraocular muscle movements. Applanation Goldmann tonometry disclosed intraocular pressure of 18 mmHg OD and 16 mmHg OS.
Fundus examination of the OD revealed an anomalous superior retinal vessel, which was traversing the horizontal raphe through the fovea toward equator after giving secondary branches, one near the optic disc margin and another over the papillomacular bundle [Figure 1]. There were tortuosity and saccular dilatations of small vessels near the superior and inferior temporal arcades. Macular edema was present. Fundus examination of the OS was normal [Figure 2].
|Figure 1: Fundus photograph of right eye showing aberrant retinal macrovessel|
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|Figure 2: Fundus photograph of left eye showing normal posterior segment|
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Fluorescein angiography revealed the filling of the macrovessel in the arterial phase [Figure 3]. The macrovessel had numerous branches spread over the macula, and the foveal avascular zone was involved [Figure 4]. Macular edema was confirmed.
|Figure 3: Fundus fluorescein angiography of right eye showing filling of aberrant macrovessel in arterial phase|
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|Figure 4: Early venous phase of fundus fluorescein angiography of right eye|
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Optical coherence tomography of the macular region of the OD showed loss of foveal contour, cystic spaces, and central macular thickness of 378 μ [Figure 5].
|Figure 5: Macular optical coherence tomography photograph of right eye showing cystoid macular edema|
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| Discussion|| |
CRM is a rare condition that can be an artery alone, a vein alone, or an artery and a vein traveling together. In general, the aberrant retinal macrovessel is of venous origin and is present as a unilateral finding. It may traverse the central macula and have large tributaries that extend beyond the horizontal raphe.
CRMs are usually identified and are seen during routine examination. Typically, visual acuity is unaffected but when the vessel crosses over the fovea or there are foveolar cysts or hemorrhage, visual impairment may be encountered. , Amblyopia can occur in children where vessel is crossing the fovea. In our patient, the fovea was involved and macular edema was present, correspondingly leading to reduced visual acuity.
Archer et al. proposed a classification system for congenital vessels that exhibited arteriovenous communications, in which there were three categories based on the severity of the vascular disorders. 
In Group 1, anomalous arteriovenous communications are localized to one sector of the retina, most commonly the macula. The site of arteriovenous communication is virtually impossible to be located without fluorescein angiography where these vessels show full perfusion with rare decompensation. In Group 2, the anomalous vessels are larger than that in Group 1. The arteriovenous malformations exhibit direct communication without interposition of capillary or arteriolar elements. Decompensation of this arteriovenous communication can occur, and photocoagulation may be needed. Group 3 contains the most severe forms with largest caliber vessels that can result in retinal complications that lead to severe vision impairment. The anastomosing channels are of large caliber, and they are intertwined and convoluted so that separation into arterial and venous components becomes almost impossible. Findings in our patient can be classified into Group 1.
Abnormal vessel development is the most popular theory to be the cause of congenital macrovessels. It was described in 1969 by Ashton.  During 15 th to 16 th prenatal week, mesodermal mesenchymal cells appear near the hyaloid artery on the disc. These cells later form the vascular system that replaces the embryonic blood supply of the hyaloid system. Mesenchymal cells invade the nerve fiber layer of the retina and eventually differentiate into endothelial cells and form cords that canalize to become capillaries. Initially, no arteries or veins are recognizable. After differentiation, arteries, veins, and capillaries are formed. Eventually, blood is diverted into these arterioles, venules, and capillaries. During the migration, formation of cords, and canalization process, it is possible that a vessel might enlarge to a greater extent than others and also assume an abnormal retinal position. The exact time and triggering mechanisms for this phenomenon are unknown.
CRMs can mimic certain vascular anomalies such as capillary hemangiomas, racemose angiomas, and retinal venous collaterals following venous occlusions and tumors such as malignant melanoma and retinoblastoma. 
These vascular anomalies usually tend to remain stable. However, the patients must be kept under follow-up to ensure early diagnosis and suitable management of complications, if any.
| Conclusion|| |
CRMs are a rare and incidental finding. Thorough clinical examination, fluorescein angiography, and OCT are useful in the diagnosis and management of such cases. Regular follow-up is an important aspect to appropriately manage cases developing complications associated with these aberrant vessels.
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Conflicts of interest
There are no conflicts of interest.
| References|| |
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Archer DB, Deutman A, Ernest JT, Krill AE. Arteriovenous communications of the retina. Am J Ophthalmol 1973;75:224-41.
Ashton N. The mode of development of the retinal vessels in man. The William MacKenzie Centenary Symposium on the Ocular Circulation in Health and Disease. St. Louis: CV Mosby Co.; 1969. p. 7-17.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]