A basis for customising perimetric locations within the macula in glaucoma

Area of Science:

• Ophthalmology
• Medical Imaging
• Neuroscience

Background:

• The macula is crucial for diagnosing glaucoma, but standard perimetry grids may not adequately sample this region.
• Retinal nerve fiber layer (RNFL) bundle damage is a key indicator in glaucoma.
• Customizing perimetry based on RNFL imaging can potentially improve diagnostic accuracy.

Purpose of the Study:

• To investigate the efficacy of customizing perimetric locations within the macula.
• To guide this customization using en face images of RNFL bundles.
• To compare perimetric data with RNFL damage patterns in glaucoma patients and controls.

Main Methods:

• Used SD-OCT en face montages of RNFL in 10 glaucoma patients and 30 controls.
• Employed a customized blob stimulus for perimetric testing at 10-2 grid locations.
• Defined perimetric defects using total deviation (TD) and pattern deviation (PD) values (-0.5 log unit or deeper).
• Analyzed correspondence between perimetric defects and damaged RNFL bundles, accounting for ganglion cell displacement.

Main Results:

• Perimetric defects in glaucoma patients largely corresponded with damaged RNFL bundles observed on en face images.
• Found 132 abnormal perimetric locations in patients and 6 in controls.
• Proportions of abnormal locations outside damaged RNFL bundles were 0.08 (unadjusted) and 0.07 (adjusted), not statistically significant.

Conclusions:

• Customizing perimetric locations guided by en face RNFL imaging is effective for macular assessment in glaucoma.
• The 10-2 grid perimetry demonstrated patterns similar to damaged RNFL bundles.
• This approach enhances the ability to detect and characterize glaucomatous damage in the macula.