Humphrey Matrix perimetry in optic nerve and chiasmal disorders: comparison with Humphrey SITA standard 24-2.

PURPOSE: To compare the Humphrey Matrix 24-2 perimetry (Matrix; Carl Zeiss Meditec, Inc., Dublin, CA) with the standard automated perimetry Humphrey Visual Field Analyzer using SITA (Swedish Interactive Threshold Algorithm) program 24-2 (SAP; Carl Zeiss Meditec, Inc.) in neuro-ophthalmic disorders affecting the optic nerve and chiasm. METHODS: Matrix and SAP were performed on 93 patients with neuro-ophthalmic disorders affecting the optic nerve and optic chiasm. Three readers compared the total and pattern deviation probability plots and judged the similarity and the extent of the visual field defects. The sensitivity and specificity of both perimeters were calculated. RESULTS: Concordance was good in 61%, fair in 30%, and poor in 9% of the total deviation plots. For the pattern deviation, concordance was good in 52%, fair in 34%, and poor in 14%. The extent of field loss was equal in 50%, 23% more extensive with Matrix, and 27% more extensive with SAP for total deviation plots. For the pattern deviation, the extent was equal in 47%, 20% more extensive with Matrix and 33% more extensive with SAP. The sensitivity for detecting defects was 84% (SAP) and 77% (Matrix) for total deviation and 80% (SAP) and 79% (Matrix) for pattern deviation (no significant difference, P > 0.05). The specificity was 84% (SAP) and 86% (Matrix) for total deviation and 68% (SAP) and 74% (Matrix) for pattern deviation (no significant difference, P > 0.05). CONCLUSIONS: The new Humphrey Matrix 24-2 testing strategy provides a visual field testing method for optic nerve and chiasmal disorders that has fair to good concordance with the Humphrey SITA Standard 24-2 program. Both tests have similar sensitivity and specificity.

Sensitivity and specificity of the Humphrey Matrix to detect homonymous hemianopias.

PURPOSE: To compare the sensitivity and specificity of the Humphrey Matrix frequency-doubling perimeter (Carl Zeiss Meditec, Inc., Dublin, CA) to that of standard automated perimetry (SAP) in detecting homonymous hemianopic visual field defects. METHODS: Thirty-three patients with homonymous hemianopias and 50 normal subjects were tested with SAP with the Humphrey Visual Field Analyzer (SITA standard program 24-2) and Humphrey Matrix frequency-doubling perimetry, program 24-2 (Matrix) on the same day. Patients with hemianopias had lesions of the retrochiasmal visual system that were documented by magnetic resonance imaging or by computed tomography. To be classified as a hemianopic visual field defect, the abnormal test location had to be homonymous, respect the vertical meridian, and have no additional scattered abnormal points that obscured the hemianopic pattern. The sensitivity and specificity of SAP and Matrix in detecting hemianopic defects were calculated. The chi(2) test was used to test for differences between groups. RESULTS: The sensitivity for hemianopic defects by total deviation probability plots was 75% for SAP and 59% for Matrix (not statistically significant, P = 0.29). The sensitivity of hemianopic defects by pattern deviation probability plots was 88% for SAP and 69% for Matrix (not statistically significant, P = 0.13). The specificity of total deviation probability plots was 84% for SAP and 86% for Matrix. The specificity of the pattern deviation probability plots was 68% for SAP and 74% for Matrix. CONCLUSIONS: Although there was no statistically significant difference between the Matrix and SAP in the detection of hemianopias, the sensitivity of SAP was higher, probably because of the obscuration of defects by scattered abnormal test locations with the Matrix.

The effect of attention on conventional automated perimetry and luminance size threshold perimetry.

PURPOSE: To investigate the effects of divided attention on conventional automated perimetry (CAP) and luminance size threshold perimetry (LSTP). METHODS: Ten healthy subjects, ages 27 to 65, with two perimetry types (CAP and LSTP) were tested in random order. At a later session, these tests were given with a mental workload to simulate the effect of anxiety or distraction on subjects performing visual field testing, also in random order. The mental workload, the Paced Auditory Serial Addition Test (PASAT), was first administered to each subject, and the score was recorded. During the visual field testing, the PASAT was again administered continuously. Each subject was instructed to attend primarily to the PASAT while taking each visual field test. RESULTS: CAP was affected by the addition of the PASAT, with a worsening of sensitivity from an average of 30.0 +/- 0.67 to 24.2 +/- 7.4 dB with a range of -0.04 to -23.2 dB (P = 0.04). LSTP showed a generalized reduction in threshold 1.71 +/- 0.22 to 2.35 +/- 0.72 dB with a range of 0.12 to -2.17 dB (P = 0.25). The percentage of correct responses on the PASAT was not significantly different between CAP (76.9%) and LSTP (74.8%). False-positive and -negative catch trial responses were increased during CAP with PASAT testing (P = 0.009). A substantial increase of fixation losses occurred during CAP with PASAT (3.7-16.2, P = 0.002). LSTP with PASAT showed increases in localization error (P < 0.001) and reaction time (P = 0.004). CONCLUSIONS: Divided attention significantly affects performance on conventional automated perimetry with its fixed size stimuli and when the stimuli are scaled (LSTP). The deficits may simulate nerve-fiber-bundle-like defects.

Sensitivity and specificity of frequency doubling perimetry in neuro-ophthalmic disorders: a comparison with conventional automated perimetry.

PURPOSE: Frequency-doubling technology (FDT) perimetry was developed as a screening test for glaucoma. Patients with damage to the neuro-ophthalmic sensory visual pathways have different patterns of visual loss than patients with glaucoma. The current study was designed to determine the sensitivity and specificity of FDT as a screening test, compared with conventional automated perimetry (CAP) in neuro-ophthalmic disorders and to test the extent to which it may isolate the M(y) cells. METHODS: FDT and CAP were performed in 97 patients with sensory neuro-ophthalmic disorders and 42 subjects from the general population. The total and pattern-deviation probability plots for test loci common to the two perimetric tests were compared. The gold standard was an unequivocal clinical diagnosis. RESULTS: The sensitivity of FDT was 81.3%, with a specificity of 76.2%. The difference in sensitivity and specificity of CAP, 87.5% and 81.0%, respectively, was not statistically significant (by chi(2) test). In subjects with optic neuropathies, the similarity of the defect shown on FDT and CAP was judged good or fair in 62 of 72 cases. The extent of the defect as seen with FDT and CAP was equal in 41 of 72 cases, more extensive with FDT in 12, and more extensive with CAP in 19. In the patients with hemianopia, scattered abnormal test locations with FDT testing masked the hemianopic nature of the defect in 15 of 25 patients. Also, test locations along the vertical midline in densely hemianopic areas were seen with FDT testing in some patients with hemianopia, probably due to light scatter across the vertical midline and into the uninvolved hemianopic field. CONCLUSIONS: FDT has sensitivity and specificity similar to that of CAP for detecting visual field defects in patients with optic neuropathies. However, defects in patients with hemianopias may be missed because of the presence of scattered abnormal test locations and failure to detect test locations along the vertical meridian. The defects demonstrated by both tests in patients with optic neuropathies are similar in number, extent, and shape of the defects. This suggests FDT may not be isolating the magnocellular (M) cells with nonlinear responses to stimulus contrast (M(y) cells) in patients with visual loss.

The effective dynamic ranges of standard automated perimetry sizes III and V and motion and matrix perimetry.

OBJECTIVES: To establish the associations between threshold estimates of 4 perimetric tests and to define and compare the tests' effective dynamic ranges. METHODS: We examined 152 patients with glaucoma and 80 controls using standard automated perimetry (SAP) with stimulus size III, SAP with size V, and motion and matrix perimetry. We explored the intertest associations using principal-components analysis. We defined the effective dynamic range bottom using the frequency of 0-dB trials on retest. We defined the upper effective dynamic range as a value above which fewer than 0.5% of the values fall in the controls. We also calculated the number of discriminable steps from normal to the floor value of the perimeter. RESULTS: The association between SAP III and V was approximately linear up to a sensitivity of about 20 dB on both tests and with motion and matrix perimetry up to about 25 dB from 0 dB. While the upper bounds were similar among the tests, size V SAP had a lower floor and more discriminable steps. CONCLUSIONS: The effective dynamic range of SAP III is substantially less than its physically tested limits. Size V stimuli have a greater effective dynamic range than size III by about 1 log unit and have about twice as many discriminable steps.

Repeatability of automated perimetry: a comparison between standard automated perimetry with stimulus size III and V, matrix, and motion perimetry.

PURPOSE: Standard automated perimetry (SAP) shows a marked increase in variability in damaged areas of the visual field. This study was conducted to test the hypothesis that larger stimuli are associated with more uniform variability, by investigating the retest variability of four perimetry tests: standard automated perimetry size III (SAP III), with the SITA standard strategy; SAP size V (SAP V), with the full-threshold strategy; Matrix (FDT II), and Motion perimetry. METHODS: One eye each of 120 patients with glaucoma was examined on the same day with these four perimetric tests and retested 1 to 8 weeks later. The decibel scales were adjusted to make the test's scales numerically similar. Retest variability was examined by establishing the distributions of retest threshold estimates, for each threshold level observed at the first test. The 5th and 95th percentiles of the retest distribution were used as point-wise limits of retest variability. Regression analyses were performed to quantify the relationship between visual field sensitivity and variability. RESULTS: With SAP III, the retest variability increased substantially with reducing sensitivity. Corresponding increases with SAP V, Matrix, and Motion perimetry were considerably smaller or absent. With SAP III, sensitivity explained 22% of the retest variability (r(2)), whereas corresponding data for SAP V, Matrix, and Motion perimetry were 12%, 2%, and 2%, respectively. CONCLUSIONS: Variability of Matrix and Motion perimetry does not increase as substantially as that of SAP III in damaged areas of the visual field. Increased sampling with the larger stimuli of these techniques is the likely explanation for this finding. These properties may make these stimuli excellent candidates for early detection of visual field progression.

A comparison of catch trial methods used in standard automated perimetry in glaucoma patients.

PURPOSE: To compare the false-positive (FP) response rates between 2 methods used by the Humphrey Field Analyzer in glaucoma patients. METHODS: One eye of one hundred and twenty glaucoma patients was tested twice within 2 months with 24-2 SITA Standard and 24-2 full threshold (FT) perimetric test procedures. FP rates were obtained with the response time window (RTW) method used by SITA and the blank presentation (BP) method of the size V FT procedure. False-negative (FN) catch trial rates were also examined. A repeated measure, 2 x 2 analysis of variance was used to examine error rates, and FP rates for visits 1 and 2 were regressed to investigate its relationship. RESULTS: For FP rates on the first 2 visits, glaucoma patients had no significant differences comparing RTW (SITA) with BP (FT) (1.99% vs. 1.88%) and higher mean FN rates (4.11% vs. 1.69%, P=0.001); the FP rates at visit 2 were similar (1.69% vs. 2.08%) and FN rates were lower for both methods at visit 2. However, when comparing patients with FP responses that occurred with both RTW and BP methods, RTW rates were lower (3.58% vs. 7.72%, P=0.007). CONCLUSIONS: The RTW method seems to underestimate FP response rates.

Total deviation probability plots for stimulus size v perimetry: a comparison with size III stimuli.

OBJECTIVE: To compare empirical probability plots in patients with glaucoma for size V and III perimetry testing. METHODS: We computed empirical probability plot percentile limits after testing 60 age-matched controls tested with both size III (Swedish interactive thresholding algorithm) and size V (full threshold) perimetry twice. Probability plots of 120 patients with glaucoma tested in the same way were computed. We compared the number of abnormal test locations in the 2 stimulus sizes; we then compared these results with those from size III StatPac software (Zeiss Humphrey Systems, Dublin, California) using 2-way repeated-measures analysis of variance. RESULTS: We found a similar number of abnormal test locations (P < or = .05) for the size III and size V testing conditions identified by the probability plots (no significant difference); there were significantly fewer abnormal locations using StatPac (size III) than from our size III database. When results were stratified by mean deviation, the mild visual loss group again did not show any significant differences between sizes III and V. CONCLUSIONS: Size V full-threshold testing gives a similar number of abnormal test locations in patients with glaucoma compared with the size III Swedish interactive thresholding algorithm standard test. Size V testing, with its greater dynamic range and lower variability, may be a viable alternative to size III testing in patients with glaucoma.