Purpose

To test the hypothesis that structural and functional measures predict contrast sensitivity (CS) outcomes in glaucomatous eyes.

Design

Cross-sectional prospective study.

Methods

One hundred five eyes of 65 patients who underwent macular spectral-domain optical coherence tomography imaging, 24-2 standard achromatic visual fields (VF), and CS measurement on the same day were enrolled. Association of CS at 4 spatial frequencies (3, 6, 12, and 18 cycles per degree, cpd) with structural and functional outcomes was explored with correlation and regression analyses.

Results

The median (IQR) 24-2 visual field mean deviation was -7.6 (-11.1 to -3.0). Significant correlations were found between CS at 6 cpd and ganglion cell/inner plexiform layer thickness at inferotemporal and inferonasal macular sectors (ρ = 0.222, P = .023 and ρ = 0.209, P = .032, respectively). CS at 6 cpd demonstrated higher correlations with full macular thickness measurements, the strongest of which was with the central macular thickness in the superior 6 × 3-degree region (ρ = 0.311, P = .001). Contrast sensitivity at 6 cpd also had the strongest correlation with mean deviation of the 4 central VF points (ρ = -0.420; P < .001). There was a significant correlation between logMAR visual acuity and contrast sensitivity at 6, 12, and 18 cpd (ρ = -0.306, ρ = -0.348 and ρ = -0.241, P < .013, respectively).

Conclusions

Structural and functional measures showed a fair relationship with contrast sensitivity. This association was most prominent between full-thickness macular measures or central VF parameters and CS at 6 cpd. Contrast sensitivity was not a reliable surrogate for glaucoma severity in this cross-sectional study.

Purpose

To evaluate the performance of ganglion cell layer/inner plexiform layer (GCL/IPL) measurements with spectral-domain optical coherence tomography (Cirrus HD-OCT) for detection of early glaucoma and to compare results to retinal nerve fiber layer (RNFL) measurements.

Design

Cross-sectional prospective diagnostic study.

Methods

We enrolled 99 subjects, including 59 eyes with glaucoma (47 subjects) (mean deviation >-6.0 dB) and 91 normal eyes (52 subjects). Patients underwent biometry and peripapillary and macular OCT imaging. Performance of the GCL/IPL and RNFL algorithms was evaluated with area under receiver operating characteristic curves (AUC), likelihood ratios, and sensitivities/specificities adjusting for covariates. Combination of best parameters was explored.

Results

Average (SD) mean deviation in the glaucoma group was -2.5 (1.9) dB. On multivariate analyses, age (P < 0.001) and axial length (P = 0.03) predicted GC/IPL measurements in normal subjects. No significant correlation was found between average or regional GC/IPL thickness and respective outer retina (OR) thickness measurements (P > 0.05). Average RNFL thickness performed better than average GCL/IPL measurements for detection of glaucoma (AUC = 0.964 vs 0.937; P = 0.04). The best regional measures from each algorithm (inferior quadrant RNFL vs minimum GCL/IPL) had comparable performances (P = 0.78). Entering the GC/IPL to OR ratio into prediction models did not enhance the performance of the GCL/IPL measures. Combining the best parameters from each algorithm improved detection of glaucoma (P = 0.04).

Conclusions

Regional GCL/IPL measures derived from Cirrus HD-OCT performed as well as regional RNFL outcomes for detection of early glaucoma. Using the GC/IPL to OR ratio did not enhance the performance of GCL/IPL parameters. Combining the best measures from the 2 algorithms improved detection of glaucoma.

Purpose

To determine factors affecting the disc-fovea angle (DFA), and to test the hypotheses that adjusting for DFA improves limits of retinal nerve fiber layer (RNFL) variability in normal subjects or enhances performance of RNFL measures for glaucoma detection.

Methods

Disc-fovea angle was measured on scanning laser ophthalmoscope fundus images from 170 eyes (110 normal and glaucoma subjects). The DFA measurements were repeated in 24 eyes. The relationship between DFA and various anatomic variables was explored. Main outcome measures were changes in 95% RNFL prediction limits or glaucoma discrimination after adjusting for DFA. We also explored the angle between temporal raphe and horizontal meridian in 19 eyes with nasal field defects limited to one hemifield.

Results

Average mean deviation and DFA were -0.1 (±1.2) dB and -6.6° (±3.4°) and -4.1 (±3.3) dB and -7.9° (±3.9°) in the control and glaucoma groups, respectively (P < 0.001 and = 0.029). The average difference between DFA repeat measurements was 2.0° (±1.8°). Predictors for DFA were female sex (P = 0.004), smaller disc area (P = 0.006), and glaucoma diagnosis (P = 0.019). The absolute change in sectoral RNFL thickness was 6.1 (±3.9) and 4.6 (±3.1) μm in control and glaucoma subjects, respectively. Retinal nerve fiber layer prediction limits improved in 5, 9, and 10 o'clock sectors (P < 0.02). Discrimination ability for the best-performing RNFL sector did not improve (P = 0.936). The average angle between temporal raphe and horizontal meridian was 0.8° (±0.8°).

Conclusions

Disc-fovea angle measurements demonstrated fair intersession repeatability. While adjusting for DFA improved RNFL prediction limits in some sectors, it did not enhance glaucoma detection.