The "Topography" of Glaucomatous Defect Using OCT and Visual Field Examination

Area of Science:

• Ophthalmology
• Neuroscience
• Medical Imaging

Background:

• Glaucoma is a leading cause of irreversible blindness.
• Retinal nerve fiber layer (RNFL) thinning is a key indicator of glaucomatous damage.
• Understanding the topographical distribution of RNFL defects is crucial for early diagnosis and management.

Purpose of the Study:

• To correlate superior and inferior RNFL thickness with visual field (VF) defect patterns in glaucoma patients.
• To compare RNFL thickness topography between healthy individuals and those with glaucoma.
• To investigate the utility of RNFL asymmetry in diagnosing glaucoma.

Main Methods:

• Retrospective analysis of 120 glaucomatous eyes and 94 healthy eyes.
• Utilized optical coherence tomography (OCT) for RNFL and optic nerve head (ONH) analysis.
• Assessed RNFL thickness in superior-nasal (SN), superior-temporal (ST), inferior-nasal (IN), and inferior-temporal (IT) sectors.
• Classified VF defects based on horizontal meridian distribution using computerized 30°VF testing.

Main Results:

• Glaucomatous eyes showed predominantly superior (65%) or inferior (32%) VF defects.
• Exclusive superior VF defects correlated with thicker ST RNFL, while exclusive inferior defects correlated with thicker IT RNFL.
• The inferior temporal (IT) RNFL sector was most compromised in glaucomatous eyes.
• Superior VF defects were associated with more significant mean deviation (MD) alterations.

Conclusions:

• Glaucomatous damage affects superior and inferior RNFL nearly simultaneously but asymmetrically.
• RNFL asymmetry, particularly in the IT sector, can support glaucoma diagnosis.
• OCT and VF testing provide complementary information for understanding glaucomatous progression.