Correlation of Macular Ganglion Cell Complex Thickness With Frequency-doubling Technology Perimetry in Open-angle Glaucoma With Hemifield Defects

Correlating Structural and Functional Damage in Glaucoma

Structural and functional tests are essential for detecting and monitoring glaucomatous damage. However, the correlations between structural and functional tests in glaucoma are complex and faulty, with the combination of both modalities being recommended for better assessment of glaucoma. The objective of this review is to explore investigations from the last 5 years in the field of structure-function correlation in glaucoma that contributed to increment in the understanding of this correlation and have the potential to improve the diagnosis and detection of glaucoma progression.

Usefulness of 10-2 Matrix Frequency Doubling Technology Perimetry for Detecting Central Visual Field Defects in Preperimetric Glaucoma Patients

It is generally acknowledged that structural loss can precede functional loss in some patients with early glaucoma. However, conventional standard automated perimetry (SAP) has limitations in the detection of functional loss, especially in the macular area. This study explores visual field loss in the macular areas of patients with preperimetric glaucoma exhibiting structural thinning in the area by examining the correlations between the ganglion cell-inner plexiform layer (GCIPL) and the results of matrix frequency-doubling technology (FDT) 10-2 tests. The structure-function relationships between the GCIPL thicknesses and the mean sensitivities (MSs) of the corresponding areas based on conventional SAP 24-2, FDT 10-2, and FDT 24-2 were examined in 62 patients. The highest correlation was found for FDT 10-2 (r = 0.544, P < 0.001) followed by FDT 24-2 (r = 0.433, P = 0.002) and SAP (r = 0.346, P = 0.007). The correlation coefficients between each GCIPL sector and the corresponding central MS according to FDT 24-2 and 10-2 were all statistically significant, and the correlations were significantly stronger for FDT 10-2 than 24-2 in the inferior and inferonasal sectors. In conclusion, preperimetric glaucoma patients with structural loss in the macula as indicated by GCIPL thinning also exhibited functional loss as revealed by FDT 10-2, and the functional loss was less evident with conventional SAP.

Detection of Functional Change in Preperimetric and Perimetric Glaucoma Using 10-2 Matrix Perimetry

PURPOSE

To evaluate an effective functional strategy for detecting glaucomatous damage of the macula in preperimetric to perimetric glaucoma.

DESIGN

Cross-sectional study.

METHODS

Preperimetric glaucoma patients (n = 102) and perimetric glaucoma patients (n = 88) with isolated paracentral scotoma or combined paracentral scotoma were enrolled in this study. Global and sectoral mean sensitivities (MS) were evaluated using 10-2 standard automated perimetry (SAP) with a stimulus of sizes III (0.43-degree diameter) and V (1.72 degrees), and 10-2 Matrix perimetry with a stimulus of 2 degrees. Ganglion cell-inner plexiform layer (GCIPL) was measured using spectral-domain optical coherence tomography.

RESULTS

The percentage of significantly depressed visual field (VF) points <5% and <1% in the pattern deviation plot was higher with frequency doubling technology (FDT) 10-2 than with SAP 10-2 III in patients with preperimetric glaucoma (both P < .001). Using FDT 10-2 tests, the global structure-function correlation was superior to SAP 10-2 (III or V) in both preperimetric and perimetric glaucoma. Topographic structure-function relationships for each VF test were more favorable with the FDT 10-2 test. The preperimetric glaucoma patients showing VF abnormalities on FDT 10-2 or SAP 10-2 (III) showed thinner average, minimum, superior, inferior, and inferotemporal GCIPL thicknesses than in those without VF abnormalities (all P < .05).

CONCLUSIONS

FDT 10-2 was found to detect functional damage of the macula early in preperimetric glaucoma, and to perform better than with SAP 10-2 (size III or V) from preperimetric to perimetric glaucoma in the structure-function relationship. FDT 10-2 can be considered a useful tool to detect glaucomatous damage of the macula early and appropriately.

Usefulness of frequency doubling technology perimetry 24-2 in glaucoma with parafoveal scotoma

The standard automated perimetry (SAP) 24-2 test cannot adequately test the paracentral region because test points are located sparsely in macular area where is crowded with retinal ganglion cells (RGCs), even though paracentral scotoma is clinically related to a risk of losing visual function. More sensitive visual field (VF) tests are needed to assess paracentral VF defects precisely. We investigated the structure-function relationship on the SAP 10-2 test and the frequency doubling technology (FDT) 24-2 test as well as the SAP 24-2 test in glaucoma with parafoveal scotoma (PFS). Glaucoma patients with PFS (134 patients) were included in this cross-sectional study. Sub-analysis was performed with isolated PFS (51 patients). Global and sectoral mean sensitivities (MS) were evaluated using SAP 24-2, 10-2, and FDT 24-2 program. MS was analyzed as dB or unlogged 1/lambert (SAP) or 1/Michelson contrast (FDT). Ganglion cell-inner plexiform layer (GCIPL) thickness was measured using spectral domain optical coherence tomography. Topographic relationships between the structure and the function were analyzed. In the total PFS group, good structure-function correlations were found in all zones with SAP 24-2, 10-2, and FDT 24-2 test. For glaucoma with isolated PFS, average GCIPL thickness was significantly correlated with central cluster MS (dB) using the SAP 10-2 test (r = 0.279, P = .047) and the FDT 24-2 test (r = 0.289, P = .039), but not the SAP 24-2 test (r = 0.264, P = .061). Topographically, the FDT 24-2 test showed significant correlations in all sectors between sectoral MS and corresponding GCIPL thickness. With regard to the SAP 10-2 test, there was significant topographical structure-function correlations for the superotemporal, inferotemporal, and inferonasal sectors. For SAP 24-2, only inferonasal GCIPL thickness was correlated with the corresponding VF sensitivity. Topographical structure-function on the macula was better with the SAP 10-2 test (superotemporal sector) and the FDT 24-2 test (superotemporal sector) than with the SAP 24-2 test in glaucoma with isolated PFS. In conclusion, FDT 24-2 and SAP 10-2 tests performed more favorably than the SAP 24-2 test in the structure-function relationship of glaucoma patients with isolated paracentral scotoma. FDT 24-2 tests can be another good option for detecting and monitoring RGC loss on the macular area while not missing VF defects outside the central 10°.