Analysis of Retinal Nerve Fiber Layer Thickness in Glaucoma Suspects and Glaucoma by Spectral Domain Optical Coherence Tomography and its Correlation with Visual Field Parameters

Abstract

Purpose: The purpose of the study was to quantitatively assess the retinal nerve fiber layer (RNFL) using spectral-domain optical coherence tomography (SD-OCT) and compare with standard automated perimetry in eyes with primary open-angle glaucoma patients and glaucoma suspects. Materials and Methods: RNFL thickness measurement by SD-OCT and visual fields (VFs) parameters assessment was done in 160 eyes of 80 patients who were divided into three categories as 80 glaucomatous eyes, 40 glaucoma suspects, and 40 age- and gender-matched normal controls. RNFL thickness values were analyzed and compared with perimetric results. One-way analysis of variance was used for the mean comparison analysis between the groups. The relationship between VF parameters and the average RNFL thickness was analyzed with the help of receiver operating characteristic curves. Results: The mean average RNFL thickness in normal controls, glaucoma suspects, and glaucoma patients was 101.58 ± 5.24, 92.35 ± 5.56, and 79.00 ± 7.97 μ, respectively (P < 0.001). There was a direct significant correlationship between average RNFL thickness and VF parameters of mean deviation and pattern standard deviation in glaucoma suspects and glaucoma patients. There was a significant association between average RNFL thickness and VF defects associated with glaucoma in glaucoma patients’ group. Conclusion: Patients with glaucoma had significantly lower RNFL quadrant measurements when compared with glaucoma suspects and normal controls. Analysis of RNFL is an excellent means for the early diagnosis of glaucoma and also aids in monitoring the progression of disease.

Keywords

• glaucoma suspects
• primary open-angle glaucoma
• retinal nerve fiber layer thickness
• spectral-domain optical coherence tomography
• visual field parameters