Macular inner plexiform and retinal nerve fiber layer thickness in glaucoma

Area of Science:

• Ophthalmology
• Glaucoma Research
• Optical Coherence Tomography (OCT) Imaging

Background:

• Glaucoma diagnosis relies on detecting retinal nerve fiber layer damage.
• Macular ganglion cell-inner plexiform layer (mGCIPL) thickness is a potential biomarker for glaucoma.
• Differentiating between normal-tension glaucoma (NTG) and primary open-angle glaucoma (POAG) is crucial for treatment.

Purpose of the Study:

• To compare macular ganglion cell-inner plexiform layer (mGCIPL) thickness measurements between NTG and POAG using Cirrus high-definition optical coherence tomography (OCT).
• To evaluate the diagnostic performance of mGCIPL thickness against peripapillary retinal nerve fiber layer (pRNFL) thickness in glaucoma detection.

Main Methods:

• Enrolled 100 normal controls, 80 NTG patients, and 80 POAG patients.
• Measured mGCIPL and pRNFL thickness using Cirrus HD-OCT.
• Calculated areas under the receiver operating characteristic curves (AROCs) and Pearson correlation coefficients with visual field mean deviation (MD).

Main Results:

• All mGCIPL parameters differed significantly between controls and glaucoma patients.
• POAG showed greater reductions in superior mGCIPL and pRNFL thickness with higher AROCs compared to NTG.
• Both mGCIPL and pRNFL parameters correlated with MD, with specific parameters showing stronger associations in NTG versus POAG.

Conclusions:

• mGCIPL thickness demonstrates diagnostic capability comparable to pRNFL thickness in both NTG and POAG.
• mGCIPL loss in NTG is predominantly inferior, whereas POAG exhibits more diffuse mGCIPL thinning.