Eales' disease - current concepts in diagnosis and management

Eales' disease was first described by Henry Eales [1], a British ophthalmologist, in 1880 and 1882 who thought that it is a noninflammatory condition. The definition and etiology of Eales' disease are not adequately established [2]. In recent years, clinical and basic research have provided significant clues to the understanding of the clinical features and etiology of Eales' disease. Since the review article we published on Eales' disease in 2002, there has been tremendous advancement regarding the understanding of Eales' disease. This review aims to examine the current concepts of understanding of the etiopathogenesis and management of Eales' disease through clinical, biochemical, immunological, and molecular biological studies.Recently, Saxena and Kumar [3] have given a new staging system. The new system, according to the authors, is useful in classifying and assessing the severity of the disease (Table 1).Of the several etiologies proposed, the most favored are tuberculosis and hypersensitivity to tuberculoprotein. In a retrospective study, 70% of epiretinal membrane (ERM) samples were positive for one or more Mycobacterium species tested by polymerase chain reaction (PCR). Further, we reported the presence of the MPB64 gene of Mycobacterium tuberculosis in a significant number of ERMs of well-documented Eales' patients as compared with controls of well-documented non-Eales' patients [4]. PCR was found to be specific and sensitive enough to detect 2.5 pg of M. tuberculosis complex DNA. In another study, 11 out of 23 ERMs removed from the eyes of patients with Eales' disease showed M. tuberculosis genome by nested PCR technique [5]. However, culture of vitreous specimen did not show growth of M. tuberculosis in any of the vitreous aspirates. It appears that Eales' disease patients may not carry viable organisms, but may probably harbor nonviable organisms or DNA of M. tuberculosis in a significant number of cases. In a recent study, Singh et al. demonstrated MTB