Correlation of Average Retinal Nerve Fiber Layer Thickness Using OCT with the Perimetric Staging in Primary Open Angle Glaucoma

Abstract

Background: Primary open angle glaucoma (POAG) is the most common type of glaucoma which is considered chronic progressive optic neuropathy, accompanied by a characteristic cupping and atrophy of the optic disc, visual field loss, open angle and no obvious systemic or ocular cause. Subjects and Methods: In this study all cases were examined in the period extending from December, 2016 to august, 2017, including 46 eyes of 30 subjects, the eyes were classified according to disease severity into 22 cases with early glaucoma, 16 cases with moderate glaucoma and 8 cases with severe glaucoma according to Hodapp, Parrish, and Anderson classification. Objectives: Inclusion criteria included: All cases have primary open angle glaucoma, presence of at least one reliable visual field, controlled IOP within range 12-21 mm/Hg. Exclusion criteria included: Cases with closed angles or any angle abnormality on gonioscopy, any other retinal or choroidal insult, including other causes of optic atrophy, patients with affected visual field due to any cause rather than POAG, secondary glaucomas. Results: This study included 46 eyes of 30 subjects which were classified according to disease severity into: Early glaucoma: included 22 eyes. Moderate glaucoma: included 16 eyes. Severe glaucoma: included 8 eyes. Conclusion: There is significant direct correlation between average retinal nerve fibre layer thinning and visual field mean deviation.