Abstract
Familial Exudative Vitreoretinopathy (FEVR) is a rare genetic condition and several genes have been identified.
Clinically, it can cause macular dragging and therefore pseudo-strabismus or exudative or tractional retinal
detachment leading to loss of vision in severe cases. Other symptoms including refractive error, cataract and
glaucoma have been documented. The main differential diagnosis remains retinopathy of prematurity. We
report two phenotypically identic twins that were seen in a lower level hospital and diagnosed with strabismus
presumed to be secondary to myopia. A multidisciplinary team including optometrist, paediatric and vitreoretinal
ophthalmologists re-examined the twins and found eccentric fixation and features of FEVR on fundoscopy
and angiography. There was a high chance that the twins would have been managed only with spectacles
missing the opportunity to be followed up for a more severe vitreoretinal proliferative disease. This case report
underlines the genetic basis of the disease with symmetrical and equally distributed myopia, macular dragging
and subsequent pseudo-strabismus and FEVR angiographic features. A multidisciplinary team-work was of
utmost importance. Beside refractive error correction, the twins also benefited from laser photocoagulation to
the avascular retinae to prevent further progress of the proliferative vitreoretinopathy. A good clinical history is
enough to rule out retinopathy of prematurity and focus on other causes of retinal fibrovascular membranes in
the pediatric population. The fluorescein angiography can be decisive in the clinical setting while genotyping is
essential for genetic counseling. Clinicians in low income countries may depend solely on a good clinical history
and examination but a high index of suspicion in presence of clinical features of FEVR is key.
References
Gilmour DF. Familial exudative vitreoretinopathy
and related retinopathies. Eye. 2015;29:1–14.
doi:10.1038/eye.2014.70.
Yonekawa Y, Thomas BJ, Drenser KA, et al. Familial
exudative vitreoretinopathy spectral-domain optical
coherence tomography of the vitreoretinal interface,
retina, and choroid. Ophthalmology. 2015;122:2270–
doi:10.1016/j.ophtha.2015.07.024.
Dawson DG. Persistent fetal vasculature. Arch
Ophthalmol. 2003;121:1340. doi:10.1001/
archopht.121.9.1340.
Ghorbanian S, Jaulim A, Chatziralli IP. Diagnosis
and treatment of coats’ disease: A review of the
literature. Ophthalmologica. 2012;227:175–182.
doi:10.1159/000336906.
Holmström G, Thorén K. Ocular manifestations
of incontinentia pigmenti. Acta Ophthalmol
Scand. 2000;78:348–353. doi:10.1034/j.1600-
2000.078003348.x.
Levasseur R. Treatment and management of
osteoporosis-pseudoglioma syndrome. Expert Rev
Endocrinol Metab. 2008;3:337+. doi:http://dx.doi.
org.ezproxy.is.ed.ac.uk/10.1586/17446651.3.3.337.
Sızmaz S, Yonekawa Y, Trese MT. Familial
exudative vitreoretinopathy. Turk Oftalmoloiji Derg.
;45:164–168. doi:10.4274/tjo.67699.
Ranchod TM, Ho LY, Drenser KA, et al. Clinical
presentation of familial exudative vitreoretinopathy.
Ophthalmology. 2011;118:2070–75. doi:10.1016/j.
ophtha.2011.06.020.
Nikopoulos K, Venselaar H, Collin RWJ, et al.
Overview of the mutation spectrum in familial
exudative vitreoretinopathy and Norrie disease
with identification of 21 novel variants in FZD4,
LRP5, and NDP. Hum Mutat. 2010;31:656–666.
doi:10.1002/humu.21250.
Nienke Boonstra F, Erik van Nouhuys C, Schuil J,
et al. Clinical and molecular evaluation of probands
and family members with familial exudative
vitreoretinopathy. Investig Ophthalmol Vis Sci.
;50:4379–85. doi:10.1167/iovs.08-3320.
Robitaille JM, Zheng B, Wallace K, et al. The
role of Frizzled-4 mutations in familial exudative
vitreoretinopathy and Coats disease. Br J Ophthalmol.
;95:574–579. doi:10.1136/bjo.2010.190116.
Seo SH, Kim MJ, Park SW, et al. Large deletions of
TSPAN12 cause familial exudative vitreoretinopathy
(FEVR). Investig Ophthalmol Vis Sci 2016;57:6902–
doi:10.1167/iovs.16-20585
Natung T, Venkatesh P, Thangkhiew L, et al.
Asymmetric presentations of familial exudative
vitreoretinopathy. Oman J Ophthalmol 2013;6:129.
doi:10.4103/0974-620x.116661.
Ziylan Ş, Öztürk V, Yabaş-Kızıloğlu Ö, et al.
Myopia, visual acuity and strabismus in the long term
following treatment of retinopathy of prematurity.
Turk J Pediatr. 2014;56:518–523.
Sardiwalla Z, Ebrahim H, Sukati VN. Familial
Exudative Vitreoretinopathy (FEVR). African Vis Eye
Heal 2016;71:95–99. doi:10.4102/aveh.v71i2.72.
Maden G. Unilateral familial exudative
vitreoretinopathy. Biomed J Sci Tech Res. 2018;8:6398–
doi:10.26717/bjstr.2018.08.001624.
Scheiman M, Gallaway M, Mckewicz L. Heterotopia
of the Macula (Ectopic Macula). Optom Vis
Sci. 1986;63:567–570. doi:10.1097/00006324-
-00011.
Sanfilippo PG, Hewitt AW, Hammond CJ,
et al. The heritability of ocular traits. Surv
Ophthalmol. 2010;55:561–583. doi:10.1016/j.
survophthal.2010.07.003.
Tedja MS, Haarman AEG, Meester-Smoor MA, et al.
IMI – Myopia genetics report. Investig Ophthalmol
Vis Sci. 2019;60:M89–105. doi:10.1167/iovs.18-