Eales disease (ED) is an idiopathic, inflammatory retinal venous occlusive disease characterized by 3 stages: vasculitis, occlusion and retinal neovascularization, leading to recurrent vitreous hemorrhages and vision loss.
ED is most commonly observed on the Indian subcontinent where the reported incidence is 1/200-1/250 ophthalmic patients. Males are predominantly affected.
The age of onset of ED is 20-30 years (earlier in Asians). ED is characterized by 3 sequential vascular responses that determine the course of the disease: inflammation (peripheral retinal perivasculitis); occlusion (peripheral retinal capillary non-perfusion); and neovascularisation of the retina or disk, which often leads to vitreous hemorrhage. The first 2 stages are generally asymptomatic while vitreous hemorrhage (often sudden and unilateral) is characterized by small specks, floaters, ''cobwebs'' and a decrease in visual acuity (often remission). The second eye is affected in 50-90% of cases after a gap of 3-10 years. Recurrences are common. Recurrent bleeds result in tractional retinal detachments, retinal tears, and epimacular membranes. Others may show a mild reduction of vision associated with retinal vasculitis (without vitreous hemorrhage). In addition, headache, variation in peripheral circulation, dyspepsia, chronic constipation, and epistaxis have also been associated with ED. ED rarely results in blindness, even in patients who suffer vitreous hemorrhages.
The etiology of ED remains elusive; some studies suggest that T cell infiltration and certain peptide growth factors, such as vascular endothelial growth factor (VEGF), have a key role in the process of neovascularization. ED has also been associated with several diseases, in particular tuberculosis. However, their role in the pathogenesis of ED is yet to be ascertained.
Diagnosis is based on fundus fluorescein angiography (FFA) findings that may show early changes such as periphlebitis, vascular sheathing or peripheral nonperfusion and neovascularization. Ultrasonography is needed to rule out associated retinal detachment and ocular coherence tomography (OCT) offers high-resolution imaging of the retina. OCT can demonstrate regions of neovascularization, hemorrhage, and macular edema. Nongranulomatous anterior uveitis may be observed.
Differential diagnosis includes retinopathy of prematurity (ROP) sequelae, familial exudative vitreoretinopathy, sarcoidosis, Behçet disease, sickle cell anemia (see these terms), Terson syndrome, posttraumatic vitreous hemorrhage, juvenile diabetes and primary branch retinal vein occlusion.
Management and treatment
Management is symptomatic and depends on the stage of the disease. It includes periodic assessment (in the regressed stage of periphlebitis or fresh vitreous hemorrhage), steroids (periocular injections or systemic) and antitubercular drugs (in the active perivasculitis stage). Laser photocoagulation is used in case of neovascularisation of retina or gross capillary nonperfusion. Vitreous surgery is indicated in non-resolving vitreous hemorrhage (usually > 3 months). Intravitreal anti-VEGF therapy is currently being tested as a definitive therapy for ED.
Isolated episodes of vitreous hemorrhage usually settle down without visual deficit. However, some patients may lose vision significantly due to recurrent episodes of vitreous hemorrhage, macular changes, and tractional or combined retinal detachment involving the macula. Blindness due to ED is rare.