Normal versus high tension glaucoma: a comparison of functional and structural defects

Area of Science:

• Ophthalmology
• Neuroscience
• Medical Imaging

Background:

• Glaucoma is a leading cause of irreversible blindness.
• Distinguishing between normal tension glaucoma (NTG) and high tension glaucoma (HTG) is crucial for management.
• Visual field testing and optic disc analysis are key diagnostic tools.

Purpose of the Study:

• To compare visual field defects using multifocal visual evoked potential (mfVEP) and Humphrey visual field (HVF) tests.
• To correlate visual field findings with topographic optic disc measurements.
• To differentiate between NTG and HTG based on visual field and optic disc characteristics.

Main Methods:

• Studied 32 NTG and 32 HTG patients with reliable HVFs and glaucomatous optic discs.
• Acquired mfVEP and HVF probability plots, analyzing central and outer subfields.
• Utilized Heidelberg Retina Tomograph III for optic disc imaging and calculated 11 stereometric parameters.

Main Results:

• No significant differences in mean deviation or pattern standard deviation between NTG and HTG.
• NTG eyes exhibited a higher percentage of abnormal points and clusters in central mfVEP and HVF subfields.
• Heidelberg Retina Tomograph III parameters showed no significant differences between NTG and HTG groups.

Conclusions:

• Visual field testing indicates more localized and central defects in NTG compared to HTG.
• Optic disc topography did not differentiate between NTG and HTG in this cohort.
• mfVEP and HVF may offer complementary insights into glaucoma-related visual field loss.