Features
Familial exudative vitreoretinopathy (FEVR) is an inherited vitreoretinal disease characterized by abnormal retinal vascular development. FEVR is a lifelong disease that often shows progression with periods of quiescence and exacerbation and has been linked to the Wnt pathway. Wnt signaling is an evolutionarily conserved signal transduction pathway that controls the fate of cells during animal development and functions in the process of maintenance, repair, and self-renewal of adult tissues. Genetic associations of FEVR have been identified, roughly 50% of which can be linked to four causative genes (FZD4, LRP5, TSPAN12, and NDP) pertaining to the Wnt-signaling pathway. The expressivity and inheritance patterns (autosomal dominant, autosomal recessive, and X-linked recessive) are variable. Genetic testing is useful in guiding prognostication, family planning, and potential future therapeutic intervention.
101.1.1 Common Symptoms
Usually asymptomatic, possible decreased visual acuity, strabismus (typically esotropia) and strabismic amblyopia, latent nystagmus (as a consequence of binocularity disruption), and/or leukocoria.
101.1.2 Exam Findings
Bilateral (85%) but asymmetric exam findings which correspond to clinical staging (▶ Table 101.1). Peripheral avascular retina is the most prominent feature. Clinical features may include progressive retinal vascular dropout, vessel dragging, exudation, hemorrhage, and neovascularization. Also possible are retinal arterial tortuosity and dragging, supernumerary retinal vessels emerging from the optic nerve head, and aberrant circumferential retinal vessels with loops and/or shunts. Radial and/or circumferential retinal folds appearing as knife-like folds extending anteriorly from the optic nerve are typical (▶ Fig. 101.1). Preretinal vitreous organization; subretinal exudation; and serous, tractional, and/or combined retinal detachment are possible.
FEVR stage | Clinical features |
Subclinical | Mild straightening of vessels Mild peripheral nonperfusion |
Stage 1 | Avascular peripheral retina without extraretinal vessels |
Stage 2 | Avascular peripheral retina with extraretinal vessels 2a. No exudate 2b. Exudate |
Stage 3 | Partial retinal detachment—fovea spared 2a. No exudate 2b. Exudate |
Stage 4 | Partial retinal detachment—fovea spared 2a. No exudate 2b. Exudate |
Stage 5 | Total retinal detachment 2a. No exudate 2b. Exudate |
Fig. 101.1 Fundus photograph demonstrating knife-like dry fold in familial exudative vitreoretinopathy.
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