Macular Telangiectasia - Pathophysiology

Pathophysiology

IJRT is probably best defined as an acquired capillary ectasia (i.e., a focal expansion or outpouching) and dilation in the parafoveal region, leading to vascular incompetence. The telangiectatic vessels develop micro-aneurysms, which subsequently leak fluid, blood, and occasionally, lipid. Some have described IJRT as a variant of Coats' disease, although this is a more accurate depiction of the Type 1 form than the Type 2 form.

While the precise etiology is unknown, it has been speculated that chronic venous congestion caused by obstruction of the retinal veins as they cross retinal arteries at the horizontal raphe may be a contributory factor.

In recent years, optical coherence tomography has been helpful in identifying more detailed fundus morphology associated with IJRT. One such finding is that there is often progressive fovealatrophy through the late stages of this disease.

It is thought that this collective loss of retinal cells may induce intraretinal neovascularization and, ultimately, subretinal or choroidal neo-vascularization (CNV). However, it should be noted that not all patients will develop CNV, as IJRT often spontaneously arrests.