Morphological features and important parameters of large optic discs for diagnosing glaucoma

Area of Science:

• Ophthalmology
• Medical Imaging

Background:

• Large optic discs present diagnostic challenges in glaucoma detection.
• Accurate assessment of optic disc parameters is crucial for timely glaucoma diagnosis and management.

Purpose of the Study:

• To compare optic disc parameters between glaucomatous and non-glaucomatous eyes with large optic discs.
• To develop and evaluate a new formula for glaucoma diagnosis using Heidelberg Retina Tomograph II (HRT II) parameters.

Main Methods:

• Studied 225 eyes with large optic discs (>2.82 mm2): 91 with glaucoma and 134 without.
• Utilized Humphrey Field Analyzer for glaucoma diagnosis and HRT II for optic disc parameter assessment.
• Developed a new diagnostic formula based on logistic regression analysis of HRT II parameters and compared it with Moorfields Regression Analysis (MRA).

Main Results:

• Glaucomatous eyes exhibited significantly larger cup area, cup volume, and cup-to-disc ratios, but smaller rim area and retinal nerve fiber layer (RNFL) thickness compared to non-glaucomatous eyes.
• Cup-to-disc area ratio, height variation contour (HVC), and RNFL cross-sectional area were key for early glaucoma detection.
• Cup-to-disc area ratio and cup volume were important for advanced glaucoma diagnosis in eyes with large discs.

Conclusions:

• Cup-to-disc area ratio, HVC, RNFL cross-sectional area, and cup volume are critical for diagnosing glaucoma in large optic discs.
• The diagnostic importance of optic disc parameters varies with glaucoma stage in patients with large discs.
• The newly developed formula demonstrated superior sensitivity and specificity compared to MRA for glaucoma diagnosis.