Insights into the Immune System and Glaucoma

Glaucoma is a neurodegenerative disease of the optic nerve characterized by progressive loss of retinal ganglion cells (RGCs), which can lead to irreversible blindness. Numerous factors have been implicated in the disease, with high intraocular pressure (IOP), coupled with advanced age, being major risk factors. Other factors include ischemia, generation of reactive oxygen species, a genetic pre-disposition and neurotrophin deprivation in the retina or optic nerve (Figure 1).1 The pathogenesis of glaucoma is challenging to understand since it is a multifactorial neurodegenerative disease.2,3 It is even more confounding what causes normal tension glaucoma (NTG). Despite a normal IOP, patients still suffer optic nerve degeneration. The immune system is a probable player in both high tension glaucoma (HTG) and normal tension glaucoma (NTG). Findings from numerous studies support the notion that both the innate and adaptive immune responses are involved in the pathogenesis of glaucoma.1,3-18 Yet, the precise mechanisms of immune responses and the specific cell interactions contributing to the disease process are still not fully understood. Many questions remain about the role of the immune system in glaucoma (Figure 1).