Macular changes in retinal vasculitis.

Eales disease is the term used to describe primary retinal vasculitis of idiopathic origin. Association with Mycobacterium tuberculosis has been purported in these cases.[1] Irrespective of the probable etiology, it is predominantly a disease of peripheral retina and involves peripheral retinal vessels. The major sight-threatening complication in Eales disease is a recurrent vitreous hemorrhage.[2]

Involvement of macula in these eyes is mainly due to the complications of peripheral vasculitis. The authors of this study have attempted to elucidate the secondary macular complications in Eales disease and have used slit-lamp biomicroscopy coupled with spectral domain optical coherence tomography (SDOCT).[3] A total of 46 (58.2%) of their eyes had macular complications which is higher than previous reports.[45] Authors have attributed higher rate of macular complications in their series to use of SDOCT. Incorporation of SDOCT in all cases of Eales’ disease in their clinic, irrespective of presence or absence of suggestive macular findings on slit-lamp biomicroscopy which would warrant an SDOCT scan is intriguing but does bring value to the report. However, this is important to note that over 41.8% (33 out of 79) eyes in this cohort did not have any macular pathology clinically but underwent SDOCT imaging.

Macular edema, which is a complication of myriad of retinal vascular and inflammatory disorders was the most common macular complication noted in this study. Looking for macular edema in cases of retinal vasculitis is vital and is often not sought after because of continued focus of clinician on the peripheral retina; seeking changes such as retinal neovascularization and fibrovascular proliferation which would increase the risk of vitreous hemorrhage. Authors have noted neurosensory retinal detachment at macula in significant (11.4%) eyes with retinal vasculitis and consider it as a marker of worse visual acuity. It would have been interesting if authors had further performed analysis of the status of foveal bulge, external limiting membrane and ellipsoid zone, and correlated them with visual acuity. Authors also note that eyes with active vasculitis had a higher risk of having macular involvement than eye which had healed vasculitis. A study which would include only those eyes which had active retinal vasculitis will further add value to this published literature.

Inflammation of the retinal vessels in Eales disease is the harbinger of chain of clinical events which range from vascular nonperfusion to neovascularization, vitreous hemorrhage, and tractional retinal detachment. With the advent of SDOCT and enhanced depth imaging, it is becoming increasingly possible to image beyond retina and the study hitherto unknown choroid morphology. Choroid, being the most vascular layer of the eye, has been studied in other uveitic eye diseases.[6] It is only imperative that vasculitis being an inflammatory disease would ultimately attract research into choroidal changes in these eyes. It will be interesting to note how choroid behaves with recurring phases of disease activity and resolution in eyes with retinal vasculitis.

Macular changes in retinal vasculitis can also be further studied using newer imaging modalities such as blue and near-infrared autofluorescence and reflectance imaging. Macular findings in retinal vasculitis can range from macular edema with hard exudates to choroidal neovascularization and premacular hemorrhage.[5] Like any other retinal disease affecting macula, these newer imaging techniques may further enrich our understanding about macular changes in retinal vasculitis; a disease which still has debated etiology and carries profound systemic connotations.