Many are asymptomatic, but patients may report decreased vision depending on the stage.

(See Figure 8.3.1.)

Figure 8.3.1: Familial exudative vitreoretinopathy with a falciform fold.

Critical

Vascular dragging and peripheral retinal nonperfusion, most prominently temporally, although can extend 360 degrees. Bilateral but often asymmetric. Peripheral retinal vessels have a fimbriated border. Present at birth.

Other

Peripheral neovascularization and/or fibrovascular proliferation at the border of vascular and avascular retina; temporal dragging of macula through contraction of fibrovascular tissue; radial retinal folds; vitreous hemorrhage; epiretinal membranes; tractional, exudative, and/or rhegmatogenous retinal detachment; peripheral intraretinal and subretinal lipid exudation. May  present with strabismus or leukocoria in childhood. Cataract, band keratopathy, neovascular glaucoma, or phthisis possible.

• ROP: Appears similar to FEVR, but there is lack of family history, and there should be a history of prematurity. See 8.2, Retinopathy of Prematurity.

• See 8.1, Leukocoria, for additional diagnoses in the differential including retinoblastoma, Coats disease, PFV, incontinentia pigmenti, Norrie disease, X-linked retinoschisis, toxocariasis, and peripheral retinal nonperfusion. Positive family history and bilaterality can help distinguish from others.

Due to defects in the Wnt signaling pathway. Often autosomal dominant, but can be autosomal recessive or X-linked. Usually no history of prematurity or oxygen therapy (differentiates it from ROP).

1. History: Positive family history? History of prematurity or oxygen therapy?

2. Complete ocular examination, including dilated retinal examination looking for supernumerary vessels, vascular dragging, macular dragging, neovascularization, and tractional retinal detachment. Fluorescein angiography of both eyes (under general anesthesia if necessary) has become vital for evaluation of diagnosis of anomalous vasculature, retinal nonperfusion, and neovascularization in peripheral retina, which can lead to tractional retinal detachment and result in decreased visual outcomes.

3. All family members suspected of carrying the gene should also have dilated retinal examinations and fluorescein angiography. This may be essential to preventing family members from experiencing permanent vision loss, as this disease is typically asymptomatic.

4. Genetic testing: Commonly affected genes include FZD4, LRP5, TSPAN12, and NDP. LRP5 mutation has been associated with early-onset osteoporosis. Many others are included now in genetic panels.

Laser of peripheral avascular retina is performed if there is neovascularization and/or exudation. Scleral buckling or vitrectomy can be considered for retinal detachments. Anti-VEGF treatment may be effective in cases with neovascularization, though further long-term studies are needed. Treat amblyopia as needed. Genetic testing and examination of family members recommended.

FEVR is a lifelong disease. All patients should be followed throughout life to monitor for progression.