Systemic C-Reactive Protein Levels in Normal-Tension Glaucoma and Primary Open-Angle Glaucoma

Glaucoma is the second leading cause of visual loss worldwide [1][2].It is becoming an increasing cause of blindness as the world's population ages, and perhaps presents an even greater public health challenge than the first-placed cataract, since the disease is irreversible.A recent estimate suggests that roughly 80 million people will be diagnosed with glaucoma by 2010, with 4.5 million of those suffering bilateral blindness [3].Glaucoma is a general term for a group of ocular diseases characterized by progressive thinning of the neuroretinal rim of the optic nerve head and loss of the retinal nerve fiber layer, together with a particular pattern of visual field loss.Primary open-angle glaucoma (POAG) is the most common type of glaucoma, with a prevalence rate ranged from 0.5 to 8.8% in different population based prevalence studies [4][5][6][7][8][9][10][11][12].The exact cause of glaucoma is still elusive yet after years of extensive research.Traditionally, elevated intraocular pressure (IOP) has been identified as a primary risk factor in this illness and IOP lowering remains the principle and the only available treatment.However, factors quite independent of IOP may be responsible for glaucoma [13].Approximately one third to one half of patients with POAG consistently have IOPs within the normal range of less than 22 mmHg [14-17], identified as having normal tension glaucoma (NTG) [18].Besides, some glaucoma patients continue to present disease progression despite effective lowering of IOP.The Early Manifest Glaucoma Trial (EMGT) showed that glaucoma progression rate in the treatment group was 45% as compared with 62% in the nontreated control group [19].In the Collaborative Initial Glaucoma Treatment Study (CIGTS), substantial visual field loss occurred in 10.7% of medically treated and 13.5% of surgical treated participants during 5 years of follow up [20].It is clear that glaucoma is a multifactorial disease and cannot be prevented or cured by IOP reducing therapy alone.Risk factors other than IOP elevation may be responsible for glaucoma progression.Several large scale trails have found aging, systemic blood pressure, nocturnal hypotension, ocular perfusion pressure, migraine, disk hemorrhage, and diabetes to be related to open-angle glaucoma (OAG).Vascular dysregulation and blood flow disturbances have been reported www.intechopen.com