Patterns of Visual Field Loss in Patients with Open Angle Glaucoma

To determine the prevalence of various types of visual field defects in patients with open angle glaucoma at the time of diagnosis. This cross-sectional study was performed on patients who were referred to our glaucoma clinic. Open angle glaucoma was confirmed by intraocular pressure measurement, perimetry, fundoscopic examination and gonioscopy. The last perimetry of patients who had at least three reliable visual fields was selected for interpretation. Acceptable reliability indices were false negative and false positive error of less than 33% and fixation loss less than 20%. Patients with other ocular abnormalities were excluded. Based on mean deviation (MD), visual field defects were classified as mild (MD up to -6 db), moderate (MD between -6 to -12 db) and advanced (MD beyond -12 db). We evaluated 308 eyes of 189 patients with mean age of 53.2±12.0 (range 13-79) years. The average MD was -12.3±9.0 (range -0.4 to -34.4 decibel). This average value was -10.7±9.2 in women and -13.2±9.4 in men (P=0.02). Based on MD, 104 eyes (33.8%) had mild, 74 eyes (24.0%) had moderate and 130 eyes (42.2%) had advanced disease. Visual field defects included generalized depression in 23 eyes (7.5%), superior field defects in 102 eyes (33.1%), inferior field defects in 75 eyes (24.3%) and combined defects in 91 eyes (29.5%). There was paracentral scotoma in 7 (2.3%) and central island in 3 (1.0%) eyes however, 7 eyes (2.3%) had no visual field defect. Arcuate scotoma (35.6%) was the most common form of localized visual field defects. Glaucoma was diagnosed in advanced stages of the disease in a large number of patients. This fact notifies the necessity of screening methods.