Unilateral congenital non-syndromic retinal vessel dilation and tortuosity



To present a case of atypical unilateral developmental retinal vascular anomaly.


A 10-year-old girl presented to her paediatrician after an absent red reflex was noted in a photograph. She had right anisometropic amblyopia and right iris heterochromia, but was otherwise healthy, with no visual complaints. Fundus examination revealed abnormal right retinal vasculature in keeping with an arteriovenous malformation (AVM). OCTA performed at age 16, showed large aberrant veins in the right eye, whereas OCTA B-Scans showed that the same eye had significantly higher retinal blood perfusion than the unaffected eye.

Conclusions and Importance

OCTA is a valuable, non-invasive emerging method of evaluating patients with AVMs, with this patient having a unique unilateral presentation of a developmental anomaly, without evidence of progression or other vessel malformation. OCTA allowed assessment of flow between the affected and non-affected eye, quantifying the greater blood perfusion in the affected eye due to the AVM.


A retinal arteriovenous malformation (AVM) refers to a congenital abnormality of the retinal vasculature with arteriovenous shunting and the capillary system being bypassed. This may result in significant reduction of visual acuity. Congenital retinal macrovessels (CRM) is a venous malformation of the retina that is associated with brain vessel abnormalities, which can present similarly to AVMs. However, usually diagnosis is based on a retinal vessel crossing the macula that passes both below and above the horizontal raphe and usually presents monocularly. The goal of this case report is to compare retinal blood perfusion between both eyes in a patient with AVM.

Case report

A 10-year-old female with a history of iris heterochromia and anisometropic amblyopia (diagnosed at age 6) presented to her paediatrician after she had an absent red reflex noted in a photograph. The patient had no notable family medical history and an otherwise unremarkable personal medical history, including no history of cyanotic disease. The patient was referred to our tertiary eye centre for evaluation (Moorfields Eye Hospital, London, UK). Fundoscopic examination revealed healthy optic discs. Tortuous and dilated retinal vessels in the right fundus, and to a far lesser extent on the left were noted, without exudation or hemorrhage present ( Fig. 1 A). The diagnosis of arteriovenous malformation was made, with no evidence of progression or visual consequence reported over seven years of annual evaluation ( Fig. 1 B). Visual acuity of the patient was 6/24 and 6/6 for the right and left eye respectively, having high hyperopia in the right eye and no refractive error in the left. Right eye vision had not improved significantly after attempted patching in early childhood. Visual acuity remained stable over time. The eyes were normally aligned, and extra-ocular movements were full. Visual fields to confrontation were normal. Intraocular pressure in both the right eye and left eye was 12 mmHg. Slit-lamp examinations of the anterior segments of both eyes were unremarkable.

Fig. 1

Multimodal Retinal Imaging of a case of unilateral vessel malformation.

(A) Ultra-widefield (200°) confocal scanning laser color fundus imaging (Optos plc, Dunfermline, UK) of the right eye with evident vessel tortuosity and dilation at 11 years of age. (B) Infrared image (IRR Spectralis, Heidelberg Engineering Ltd, Heidelberg, Germany) of both eyes at 11 years old, and after 6 years of follow-up, without evidence of change. (C) Swept-source OCT Angiography (SS-OCTA, PLEX Elite, Zeiss) of the superficial capillary plexus for both eyes (12mm square scan, centered to the fovea). Turbulence in the vasculature causes variances in the images, which is depicted as vessels. The right eye has an arteriovenous malformation and displays microvascular capillary irregularities (such as large aberrant veins). An increased vascular blood flow was observed in the large aberrant vessels. The patient’s vision in the left eye was normal and has no significant abnormalities. (D) Ten times magnification of the SS-OCTA images at (C), of the foveal avascular zone (FAZ). The aberrant vessels do not have an impact on the size or shape of the FAZ. (E) Horizontal optical coherence tomography angiography B-scans of the right and the left eye over the superior arcade (1,4), fovea (2,5) and inferior arcade (3,6). These numbered images correspond to the locations marked with orange dashes in (C) . The color-coded SS-OCT B-scans can clearly show blood flow in the superficial (red) and deep (green) capillary plexuses. The highly saturated clusters of red are veins. The right eye has significantly higher retinal blood perfusion than the unaffected eye. The percentage difference of blood flow between the left and right eye reached a maximum of 1102% in the superior arcade (1 and 4). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

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Jan 3, 2022 | Posted by in OPHTHALMOLOGY | Comments Off on Unilateral congenital non-syndromic retinal vessel dilation and tortuosity
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