Glaucoma Diagnostic Testing: The Influence of Optic Disc Size.

Area of Science:

• Ophthalmology
• Medical Imaging
• Glaucoma Research

Background:

• Assessing optic discs in glaucoma patients presents challenges with anatomically large or small discs.
• Existing imaging techniques may struggle with atypical optic disc sizes.

Purpose of the Study:

• To compare the Bruch's membrane opening (BMO) method using spectral domain optical coherence tomography (SD-OCT) with the Heidelberg retina tomograph (HRT) for glaucoma detection.
• To evaluate these methods across different optic disc sizes (macro and micro).

Main Methods:

• Analyzed 216 glaucoma patients' optic discs using BMO analysis in SD-OCT.
• Compared BMO measurements with HRT-derived optic disc sizes for macro (Ma) and micro (Mi) optic discs.
• Investigated the correlation between BMO area, HRT optic disc size, and visual field defect severity (MD [dB]).

Main Results:

• A modest correlation (r=0.53) was found between BMO and HRT optic disc size measurements for both micro and macro discs.
• No significant correlation was observed between BMO area and optic disc size measured by HRT.
• Micro-optic discs with a BMO area < 1.5 mm² showed a significant tendency towards deeper visual field defects (MD < -5 dB).

Conclusions:

• The BMO parameter in SD-OCT provides a reliable assessment of glaucoma across a wide range of optic disc sizes.
• BMO area and HRT optic disc size measurements are not correlated.
• Small BMO areas in micro-optic discs indicate a higher risk for severe visual field loss in glaucoma patients.