Clustered Trend-Type Analysis to Detect Progression of Visual Field Defects in Patients with Open-Angle Glaucoma

Glaucoma remains one of the leading causes of acquired blindness worldwide (Thylefors & Negrel, 1994; Quigley & Broman, 2006). Open-angle glaucoma (OAG) including primary open-angle glaucoma (POAG), and normal-tension glaucoma (NTG), is the most common type of glaucoma and is just a representative chronic disease such as hyptertension and diabetes mellitus (Schwartz & Quigley, 2008; Quigley, 2011). Because the ultimate goal of glaucoma treatment is to maintain long-term visual function, glaucomatous patients require essentially lifelong follow-up. Thus, we need an approach to glaucoma management that considers patients’ present visual functions as well as their future prognosis. The pathogenesis of glaucomatous optic neuropathy as well as the details of its long-term progression have not beeen clered yet. Many clinical trials have confirmed the importance of intraocular pressure (IOP) in the development and progression of OAG (Kass et al., 2002; Gordon et al, 2002; Heijl et al. 2002; 2003; Leske et al, 1999; 2003; Collaborative normaltension glaucoma study group, 1998; 2001; Anderson et al, 2003; The AGIS Investigators, 1994; 2000; Katz, 1999; Musch et al, 2009; Parrish et al, 2009; Chauhan et al, 2008). These studies have shown that lowering IOP reduces the risk of developing OAG and slows its progression. The aim of current glaucoma treatment approaches is to maintain patients’ visual function for as long as possible by reducing IOP. In addition to visual function, of course, we monitor patients’ IOP, optic discs, and retinal changes. Since preservation of visual fields is the final outcome in glaucoma management, ongoing evaluation of patients’ visual fields must be the most important activity in clinical practice. Recently, the morphological evaluation of optic disc cupping, retinal nerve fiber layer defects, and the retinal ganglion cell complex by imaging systems such as optical coherence tomography (OCT) has become popular (Wollstein et al, 2005; Tan O et al, 2009). After all these systems provide only the ability to reliably and safely detect or predict glaucoma progression beside monitering visual field and visual acuity (Hood & Kordon, 2007; Harwerth et al, 2010; Parrish et al, 2009). Standard automated perimetry (SAP) is used to examine and evaluate visual fields, but the technique is difficult to perform and have still has many problems. Furthermore, there is