Challenges and difficulties in diagnosis of normal-tension glaucoma

Abstract

Aim The aim of this study is to clinically investigate the challenges and pitfalls of normal-tension glaucoma (NTG) diagnostic methods by ophthalmic clinical and investigative examinations. Setting This study was conducted at Al-Agouza Police Authority Hospital and Badr University Hospital. Methods A cross-sectional comparative study between the diagnosis of normal nonglaucoma patients and NTG. It included 40 normal nonglaucoma patients’ eyes as controls and 40 NTG patients’ eyes who met inclusion criteria. They were assessed by a complete ophthalmic exam., visual field (VF), and optical coherence tomography (OCT) variables between January 2022 and September 2022. Results The median age of the control group was 38 years old, while that of glaucomatous patients was 41 years old. The mean intraocular pressure (IOP) for the normal group was 15.53 mmHg (±1.935), while that for the glaucomatous group was 16.85 mmHg (±1.703). The intraocular pressure was considerably higher in the NTG group compared with the control (P = 0.0017). The mean deviation (MD) in dB of VF loss was considerably higher in the NTG group compared with the control (P = 0.0001). Also, the mean standard deviation (MSD) was considerably varied between the two groups (P < 0.0001). The average Retinal Nerve Fiber Layer (RNFL) in the NTG group, with a mean of 72.3 սm (±10.239) was significantly lower than in the control group with a mean of 102.025 սm (±7.454), P = 0.0001. Optic Disc Parameters: The Cup Area (mm2) was significantly wider in the NTG group with a mean of 1.62 (±0.476) than in the control with a mean of 1.297 (±0.44), P = 0.0024. Also, the Rim Area was significantly smaller in the NTG group with a mean of 0.614 (±0.342) than in the control with a mean of 1.135 (±0.319), P = 0.0024. The Cup/disc ratio was significantly larger in the NTG group than in the control group (P < 0.0001). The average Ganglion cell complex (GCC) was considerably thinner in the NTG patients in comparison to the controls (P = 0.0001). Conclusion The effects of NTG on VF and optic nerve seems to be more intensive. More focal notches and disc hemorrhage were noted in NTG. In the NTG group, the Cup Area was potentially wider, the rim area was significantly thinner, and the Cup/disc ratio was significantly larger.