[A comparative study of optic nerve damage between primary open angle glaucoma and normal tension glaucoma]

Area of Science:

• Ophthalmology
• Glaucoma Research
• Optic Nerve Imaging

Background:

• Glaucoma is a leading cause of irreversible blindness.
• Primary open-angle glaucoma (POAG) and normal tension glaucoma (NTG) are distinct subtypes.
• Understanding differences in optic nerve damage is crucial for diagnosis and treatment.

Purpose of the Study:

• To compare optic nerve head and retinal nerve fiber layer (RNFL) characteristics between POAG and NTG patients.
• To identify specific structural differences in optic nerve damage between these glaucoma types.

Main Methods:

• Heidelberg retina tomograph II, color stereo-optic disc photography, and Octopus automated perimetry were used.
• Optic disc parameters and RNFL were measured in 47 POAG eyes and 38 NTG eyes.
• Intraocular pressure (IOP) was >24 mmHg for POAG and <21 mmHg for NTG.

Main Results:

• NTG eyes had significantly smaller rim areas, rim/disc area ratios, and RNFL thickness, particularly in temporal sectors.
• Cup-to-disc (C/D) ratio and cup depth were significantly larger in NTG eyes.
• RNFL defects differed significantly: POAG showed more diffuse loss (53.19%), while NTG showed more local defects (55.26%).

Conclusions:

• Distinct structural and RNFL defect patterns exist between NTG and POAG.
• These differences suggest varying underlying mechanisms of optic nerve damage in the two glaucoma types.
• Further research into these mechanisms may improve targeted therapies for glaucoma subtypes.