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Unilateral vascular abnormality: A case of peripheral retinal arteriolar
tortuosity associated with a prepapillary vascular loop

Purpose: To report a case of unilateral prepapillary vascular loop along with peripheral third order retinal
arteriolar tortuosity in the same eye, and to discuss potential diagnostic considerations.
Observations: Color fundus pictures and wide-angle fluorescein angiography (FA) demonstrated a pre-papillary
vascular loop and a region of retinal arteriolar tortuosity in third order arterioles superotemporally in the left
eye. The examination and ancillary testing on the right eye were normal.
Conclusion and Importance: The vascular abnormality in this case does not fit a pattern present in other disease
states both hereditary or acquired. The patient’s immediate family do not demonstrate a similar abnormality and
the patient remains visually asymptomatic upon one-year follow-up.

  1. Introduction
    Retinal vascular abnormalities have been reported in a number of
    conditions both hereditary and congenital with varying degrees of visual
    impairment and differing systemic associations. Prepapillary retinal
    vascular loops are usually unilateral and congenital. They are far more
    commonly associated with an artery than a vein, typically arising from a
    hemiretinal artery root overlying the optic disc. They carry a small risk
    of occlusion but are generally benign in nature.1 Furthermore, retinal
    vascular tortuosity can also be a sign of a systemic disease state. The use
    of high-quality fluorescein angiography imaging can help to appreciate
    minute details in retinal vasculature in order to guide further
  2. Case report
    A 16-year old visually asymptomatic female with no significant past
    medical or surgical history was referred to our retina group practice for
    the evaluation of a retinal vascular abnormality in the left eye detected
    on a routine eye exam. The patient did not have a history of perinatal or
    postnatal medical problems and was born at term.
    Visual acuity was 20/20 in each eye, and intraocular pressures were
    19 mmHg and 18 mmHg for OD and OS, respectively. Anterior segment
    examination was unremarkable OU. Posterior segment exam was

normal OD, but in the OS, a prepapillary vascular loop (Fig. 1) and focal

superotemporal arteriolar tortuosity was discovered. Wide angle fluo-
rescein angiography showed multifocal third order arteriolar tortuosity

in the superotemporal periphery OS, with hairpin turns and corkscrew
characteristics (Fig. 2, A-B, curved arrows). There was delayed AV
transit within the tortuous superotemporal arterioles. The prepapillary
vascular loop was in a different distribution, associated with the inferior
hemiretinal branch artery. The distal portions of the inferotemporal
retinal vein crossed well over the horizontal meridian (straight arrow).

This is likely of less significance, and similar crossing of the super-
otemporal arcade artery was noted OD (Fig. 3). There was otherwise

normal microcirculation without vascular leakage or occlusion.
Examination and imaging of the patient’s two male siblings as well as

both parents were without notable retinal findings. The patient under-
went magnetic resonance imaging of the head and neck with and

without contrast, which was unremarkable.

  1. Discussion
    The patient’s clinical appearance did not fit neatly into established
    criteria for a number of hereditary and non-hereditary syndromes. As
    the patient’s siblings and parents did not have a similar abnormality or
    other notable conditions, a hereditary disorder seems less likely.
    Prepapillary vascular loops are usually unilateral and congenital. As
  • Corresponding author. NJRetina, 10 Plum Street #600, New Brunswick, NJ, 08901, USA.
    E-mail address: mwheatley@njretina.com (H.M. Wheatley).

Contents lists available at ScienceDirect

American Journal of Ophthalmology Case Reports

journal homepage: www.ajocasereports.com/

Received 18 May 2020; Received in revised form 14 July 2020; Accepted 9 August 2020

American Journal of Ophthalmology Case Reports 20 (2020) 100869

in our case, they are far more commonly associated with an artery than a
vein, typically arising from a hemiretinal artery root overlying the optic
disc. They carry a small risk of occlusion but are generally benign in
nature. They may be a component of persistent hyperplastic primary
vitreous.1 Additionally there is a report of prepapillary vascular loops in
a case of Williams-Beuren syndrome,2 however the affected patient
presented with bilateral visual decline, CME and mild foveal dysplasia
which were not present in our patient.
Familial retinal arteriolar tortuosity is characterized by tortuosity of
second or third order retinal arteries with inheritance typically being
autosomal dominant. Furthermore, familial retinal arteriolar tortuosity
is generally seen bilaterally with involvement of the posterior pole and
not solely in the periphery or in a segmental pattern.3 Mutations in the

COL4A1 gene, encoding type IV collagen within the basement mem-
brane, have been reported in this condition.4

Retinal tortuosity has also been reported in Wyburn-Mason Syn-
drome.5 This is a rare nonhereditary disorder characterized by multiple

arteriovenous malformations predominantly affecting the face and
brain. Visual symptoms at presentation range from normal vision to
absence of light perception with headaches, decline in vision, proptosis
and other neurological symptoms which were not present in our patient.
In particular, the multifocal pattern and lack of venous involvement
make Wyburn-Mason syndrome unlikely.
Retinal arterial tortuosity has been previously described in a case of
Moyamoya syndrome.6 In this case, the tortuosity was diffuse and
bilateral, and also appears to have been associated with some venous

involvement. Because of the potential serious cerebrovascular abnor-
malities associated with these conditions, our patient underwent CNS

imaging, which was negative.

Other causes of retinal vascular tortuosity include neurofibroma-
tosis, congenital retinal venous tortuosity, Fabry disease, and branch

retinal vein occlusion, all of which are associated with venous involve-
ment. Neurofibromatosis is a neurogenetic disorder classically display-
ing caf ́e-au-lait macules, bony abnormalities and neurofibromas. While

a correlation has been shown between the presence of retinal micro-
vascular abnormalities with age and the presence of neurofibromas,7 our

patient does not display the characteristic findings of neurofibromatosis.
Subsequent to the patient’s presentation, her father was diagnosed with

glioblastoma multiforme, which may also be associated with neurofi-
bromatosis, but in his case there is also no other systemic manifestation.

In summary, we present a case of unilateral multifocal retinal arterial
abnormalities in a 16 year old female. The pattern does not resemble
previously described syndromes, and there is no apparent systemic
disease association. All immediate relatives are visually asymptomatic
with no tortuosity on imaging. Follow up at one year revealed no
Patient consent
Consent to publish the case report was not obtained. This report does

not contain any personal information that could lead to the identifica-
tion of the patient.

No funding or grant support was received.
All authors attest that they meet the current ICMJE criteria for
Declaration of competing interest
JP serves as a consultant for Alcon. The following authors have no
conflicting interests to disclose (PP, MM, HW).

Fig. 1. Prepapillary vascular loop in inferior hemiretinal branch artery OS.

P.S. Patel et al.

American Journal of Ophthalmology Case Reports 20 (2020) 100869

Fig. 2. A–B. Fluorescein angiography OS demonstrated arteriolar tortuosity superotemporally with delayed A-V transit (curved arrows). There is crossing of the
distal inferotemporal arcade vein over the horizontal meridian (straight arrow).
P.S. Patel et al.

American Journal of Ophthalmology Case Reports 20 (2020) 100869


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    Written by

Parth S. Patel, Mansoor Mughal, Harold M. Wheatley, Jonathan L. Prenner