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Updated: Feb 12, 2026
Assessing Early Stage Open-Angle Glaucoma in Patients by Isolated-Check Visual Evoked Potential
Published on: May 25, 2020
Event-based analysis of visual field change can miss fast glaucoma progression detected by a combined structure and
Chunwei Zhang1,2, Andrew J Tatham1,3, Fábio B Daga1
1Visual Performance Laboratory, Duke Eye Center and Department of Ophthalmology, Duke University School of Medicine, 2310 Erwin Rd, Durham, NC, 27710, USA.
Purpose:
To investigate the relationship between progression assessed by the visual field guided progression analysis (GPA) and rates of structural and functional change in glaucoma eyes.
Methods:
This was a longitudinal observational study of 135 eyes of 97 patients with glaucoma followed for an average of 3.5 ± 0.9 years. All patients had standard automated perimetry (SAP) and retinal nerve fiber layer (RNFL) analysis with spectral domain optical coherence tomography (SDOCT), with an average of 6.8 ± 2.3 visits. A control group of healthy eyes followed longitudinally was used to estimate age-related change. Visual field progression was assessed using the Humphrey Field Analyzer GPA. Estimates of retinal ganglion cell counts from SAP and SDOCT were used to obtain a combined index of glaucomatous damage (RGC index) according to a previously described algorithm. Progression by SDOCT and the retinal ganglion cell (RGC) index were defined as statistically significant (P < 0.05) slopes of change that were also faster than age-related change estimated from healthy eyes.
Results:
From the 135 eyes, 15 (11%) progressed by GPA, 21 (16%) progressed by SDOCT, and 31 (23%) progressed by the RGC index. Twenty-one eyes showed progression by the RGC index that was missed by the GPA. These eyes had an average rate of change in estimated RGC counts of - 28,910 cells/year, ranging from two to nine times faster than expected age-related losses.
Conclusion:
Many glaucomatous eyes that are not found to be progressing by GPA may actually have fast rates of change as detected by a combined index of structure and function.
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