Protruded retinal layers within the optic nerve head neuroretinal rim

Area of Science:

• Ophthalmology
• Medical Imaging
• Retinal Anatomy

Background:

• Optical coherence tomography (OCT) is crucial for assessing neuroretinal rim (NRR) in glaucoma diagnosis.
• Accurate NRR measurements are vital for detecting glaucomatous optic neuropathy.
• The composition of NRR measurements, particularly the inclusion of other retinal layers, is not fully understood.

Purpose of the Study:

• To quantify the frequency of protruded retinal layers (PRL) within neuroretinal rim (NRR) measurements using OCT.
• To investigate variations in PRL presence across different racial groups and retinal sectors.

Main Methods:

• A radial scan pattern (24 B-scans centered on Bruch's membrane opening [BMO]) was employed.
• Ninety healthy subjects (White, Black, Japanese) were analyzed.
• The presence and proportion of PRL within minimum rim width (MRW) at 48 measurement points were assessed.

Main Results:

• Protruded retinal layers (PRL) were present in 11.6% of all measurement points.
• Nearly 77% of subjects exhibited PRL in at least one measurement point.
• PRL occurred more frequently in White subjects and the temporal sector, with thickness varying significantly.

Conclusions:

• Protruded retinal layers (PRL) are a common component of OCT-based neuroretinal rim (NRR) measurements in healthy individuals.
• Racial variations and a higher prevalence in the temporal sector highlight the need to consider PRL in NRR analysis.
• Understanding PRL presence is essential for accurate glaucoma assessment using OCT.