Choroidal Microvasculature Dropout in Glaucoma

Glaucoma is a group of diseases characterized by distinctive visual field defect and optic nerve atrophy usually associated with elevated intraocular pressure (IOP). It is one of the most serious visual disorders and the leading cause of irreversible blindness worldwide. As a multifactorial disease, the pathogenesis of glaucoma is complicated and has been far from fully understood, where vascular factors are recognized to play an important role in its development and progression of glaucoma. Empirical researches have shown that parapapillary choroidal microvasculature dropout (CMvD) is closely associated with the impairment of optic nerve head (ONH) perfusion, probably accelerating the progression of glaucoma. Accordingly, it is necessary to explore the details regarding the relationship between CMvD and glaucoma progress, hoping to enhance the understanding of pathogenesis of glaucoma. In this review, we aimed to establish comprehensive understanding of the relationship between CMvD and glaucoma with generally going through relevant up-to-date literatures. Among the events that are closely associated with CMvD, we summarized the ones specifically involved in the term of glaucomatous pathological process, including thickness of retinal nerve fiber layer (RNFL) thickness, lamina cribrosa (LC) morphology, cricumpapillary vessel density (cpVD) and visual function such as visual field (VF) defect as well as the prognosis of glaucoma. Although researchers have made great advances, there are still many issues need to be addressed particularly concerning the pathogenic role of CMvD in glaucoma development and its clinical implications with respect to glaucoma prognosis.