Clinical features of glaucoma, such as pre-treatment intraocular pressure (IOP), influence whether structural progression of disease is detected earlier with macular ganglion cell-inner plexiform layer (mGCIPL) or peripapillary retinal nerve fiber layer (pRNFL) imaging, according to a new study. Researchers recently found IOP, baseline pRNFL thickness, baseline mGCIPL thickness and systemic hypertension were associated with location of first progression.

Researchers in Australia evaluated 271 eyes from 207 individuals with statistically significant evidence of glaucomatous progression on optical coherence tomography, using software to compare earliest evidence of longitudinal progression on mGCIPL GPA and pRNFL GPA.

Eyes demonstrating earliest progression on mGCIPL had significantly lower maximum-recorded pre-treatment IOP (mean difference: 3.90mm Hg). The time interval between progression on pRNFL and progression on mGCIPL increased by 12.4 months for every 5mm Hg increase in IOP. While eyes that demonstrated earliest longitudinal progression on mGCIPL had significantly lower baseline average pRNFL thickness than eyes progressing on pRNFL first, eyes progressing first on mGCIPL parameters were 3.03 times more likely to develop a new paracentral field defect than cases found on pRNFL parameters.

The researchers concluded that mGCIPL imaging is useful alongside pRNFL analysis for detecting glaucoma progression, particularly in patients with normal IOP.