Clinical experiences with the "Swedish interactive threshold algorithm" (SITA)

BACKGROUND: The "Swedish Interactive Threshold Algorithm" (SITA) is a new technique minimizing test time without reduction of data quality. In this retrospective study we compared visual fields assessed with the conventional full-threshold technique with those by SITA and analyzed qualitative and quantitative differences and the test time reduction of SITA. PATIENTS AND METHODS: 113 eyes with different glaucomatous field damage of 66 patients aged from 22 to 89 years were included. The patients underwent perimetry with each strategy within four months. Exclusion criteria were eyes with progressing glaucomatous damage and high rate of false-positive results or artifacts by corrective glasses. RESULTS: The qualitative differences of the analysis were small: full threshold demonstrated more relative scotomas in eyes with normal SITA readings, whereas scotomas assessed with SITA were often pronounced to absolute scotomas. Average time reduction by SITA was 40% and depended on the severity of glaucomatous stage. No reduction was found for advanced glaucoma, whereas normal fields using SITA were performed in half of the time of full threshold strategy. CONCLUSION: Differences of SITA to conventional full threshold testing may be related to fatigue effects of full threshold strategy due to longer test time. The reduction of test time enables more motivation for more frequent visual field examinations and thus a better detection of early glaucoma or progressing visual field damage.     

Sensitivity of Swedish interactive threshold algorithm compared with standard full threshold algorithm in Humphrey visual field testing

OBJECTIVE: To compare the sensitivity of Swedish interactive threshold algorithm (SITA) strategies with the standard full threshold algorithm in the Humphrey Field Analyzer. DESIGN: Observational case series. PARTICIPANTS: Forty-eight glaucoma patients who were experienced in automated perimetry. TESTING: Central field testing was performed with the 30-2 program using standard full threshold (SFT), SITA standard (SS), and SITA fast (SF) strategies. All three tests were carried out on each of four different days in a span of 4 weeks. MAIN OUTCOME MEASURES: Sensitivity, repeatability, time saved, and the extent of defect in the SITA strategies were compared with those of the SFT. RESULTS: The sensitivity of SS and SF were 95.12% and 92.68%, respectively. The time saved in SS and SF was 53.12+/-9.51% and 70.69+/-8.81%, respectively. The repeatability as assessed by intraclass correlation showed excellent repeatability for the SFT and SS strategies and excellent to poor repeatability with the SF strategy. With increasing mean deviation, the defects (significant at P<0.5%) in the pattern deviation plots tended to be more in the SITA strategies as compared with SFT. CONCLUSIONS: Swedish interactive threshold algorithm strategies have good sensitivity and are significantly faster as compared with the standard threshold algorithm. The repeatability of the SFT and SS strategies are excellent, whereas that of the SF strategy is variable.     

Comparison of Swedish interactive threshold algorithm and full threshold algorithm for glaucomatous visual field loss

PURPOSE: To compare the prevalence of visual field loss, the sensitivity distribution, and the size and depth of glaucomatous visual field defects using the standard full threshold (FT) and the Swedish interactive threshold algorithm (SITA) standard (SS) procedures in patients with early or suspected glaucoma. METHODS: Automated perimetry findings were retrospectively evaluated in 53 patients (105 eyes) with early or suspected glaucoma. RESULTS: The number of eyes judged to have glaucomatous visual field loss by SS (48 eyes) was significantly larger than what was found with FT (35 eyes), and 70 eyes were classified as pre-perimetric glaucoma. In these 70 eyes, there were many locations where the sensitivity was significantly higher with SS than with FT (intrasubject difference), and SS had less intersubject variability than FT at most locations. The cumulative decibel scores at the region of glaucomatous defects were larger with SS (206.2+/-103.3 dB) than with FT (162.1+/-87.5 dB) (p=0.02), which indicated that the depth of defects measured by SS was shallower than that by FT. The sizes of defects were significantly larger with SS (11.2+/-5.6) than with FT (9.7+/-5.1) (p<0.05). CONCLUSIONS: Glaucomatous defects were measured as being significantly shallower and larger with SS than with FT. In addition, the prevalence of visual field defect was higher with SS according to some of the criteria for glaucomatous visual field defects. These results might be related to the fact that SS strategy has a lower variability and to the Bayesian statistical properties of the SITA algorithm.     

Evaluation of two Humphrey perimetry programs: full threshold and SITA standard testing strategy for learning effect

PURPOSE: To compare learning effect of Swedish interactive threshold algorithm (SITA) standard strategy with full threshold testing. METHODS: Thirty-nine medical students with no experience in visual field testing had full threshold (FT) and SITA standard for either right or left eyes. They were chosen in such a way that 20 (Group I) had FT for right and SITA for left eyes and 19 (Group II) had SITA standard for right and FT for left eyes. It was designed to have both strategies on same person whereby eliminating inter-individual variability. Visual field testing was repeated in the same week of the first test on the same subject with the same strategy that was chosen for that eye. RESULTS: The authors found an improvement in mean deviation (MD) and pattern standard deviation (PSD) of first and second testings correspondingly for FT (MD from -3.04 to -2.55; PSD from -2.60 to -2.29) and SITA standard (MD from -2.86 to -2.20; PSD from 2.25 to 2.10) and changes were statistically significant (p<0.05). To analyze learning effect of visual field testings, we calculated percentage change in MD and PSD for full threshold and SITA standard strategy. The percentage changes in visual field parameters were significantly lower in SITA standard strategy testing for MD (p=0.02) and PSD (p=0.01). CONCLUSIONS: This study shows that a learning effect is present for both strategies and SITA standard may have a reduced learning effect compared to FT.     

Comparison of Humphrey MATRIX and Swedish interactive threshold algorithm standard strategy in detecting early glaucomatous visual field loss

Purpose:

The aim of this study was to compare the Humphrey MATRIX visual field (frequency doubling technology threshold) and Swedish interactive threshold algorithm (SITA) standard strategy white on white perimetry in detecting glaucomatous visual field loss.

Material and Methods:

Twenty-eight adult subjects, diagnosed to have glaucoma at a tertiary eye care hospital, who fulfilled the inclusion criteria, were included in this prospective study. All subjects underwent a complete ophthalmic examination. Subjects with glaucomatous optic disc changes underwent repeat perimetric examination on the same day with the Humphrey visual field analyzer (HFA II) and Humphrey MATRIX, the order of testing being random. Only reliable fields, where the HFA results corresponded to the disc changes were considered for analysis. A cumulative defect depth in each hemifield in both HFA and MATRIX reports was calculated.

Results:

Thirty-seven eyes of 24 subjects had reliable fields corresponding to optic disc changes. The mean age of the subjects was 56 ± 12 years. There were 12 males and 12 females. The test duration was significantly less on the MATRIX, mean difference in test duration was −81 ± 81.3 sec (p < 0.001). The mean deviation and the pattern standard deviation between the two instruments showed no significant difference (p = 0.55, p = 0.64 respectively) and a positive correlation coefficient of 0.63 and 0.72 respectively. Poor agreement was found with the glaucoma hemifield test.

Conclusion:

The Humphrey MATRIX takes less time in performing the test than SITA Standard and shows good correlation for mean deviation and pattern standard deviation. However, the glaucoma hemifield test showed poor agreement. The Humphrey MATRIX diagnoses were similar to established perimetric standards.     

Inter-subject variability and normal limits of the SITA Standard, SITA Fast, and the Humphrey Full Threshold computerized perimetry strategies, SITA STATPAC.

PURPOSE: To establish and evaluate inter-subject variability and normal threshold limits for the new SITA strategies and to compare them with those obtained with the traditional Humphrey Full Threshold algorithm. METHODS: Data from 330 eyes of 330 normal subjects were collected at 10 centres in order to establish limits of normality for the new SITA strategies and thus, to make it possible to subject SITA fields to computer-assisted visual field analysis. Two visual field tests were obtained with each of the SITA Standard, SITA Fast, and the Full Threshold algorithms. RESULTS: Inter-subject variance was 31% smaller with SITA Standard and 41% smaller with SITA Fast than with Full Threshold (p<0.0001). Age-dependent decrease of differential light sensitivity was also significantly smaller with both SITA algorithms than with Full Threshold (p<0.0001), 23% and 25% respectively. Mean sensitivity was somewhat higher with both SITA Standard (29.5 dB) and SITA Fast (29.9 dB) as compared to Full Threshold (28.3 dB) (p<0.0001). Normal limits were tightened between 9 to 29% at different significance levels with SITA. CONCLUSION: SITA test results from eyes with normal visual fields will on average be more even from centre to mid-periphery as compared with Full Threshold fields. They will also appear slightly lighter in grey-scale representations. Because of smaller inter-subject variance, shallower depressions are needed in SITA fields for statistical and clinical significance.     

Properties of perimetric threshold estimates from Full Threshold,SITA Standard,and SITA Fast strategies

PURPOSE: To investigate the distributions of threshold estimates with the Swedish Interactive Threshold Algorithms (SITA) Standard, SITA Fast, and the Full Threshold algorithm (Humphrey Field Analyzer; Zeiss-Humphrey Instruments, Dublin, CA) and to compare the pointwise test-retest variability of these strategies. METHODS: One eye of 49 patients (mean age, 61.6 years; range, 22-81) with glaucoma (Mean Deviation mean, -7.13 dB; range, +1.8 to -23.9 dB) was examined four times with each of the three strategies. The mean and median SITA Standard and SITA Fast threshold estimates were compared with a "best available" estimate of sensitivity (mean results of three Full Threshold tests). Pointwise 90% retest limits (5th and 95th percentiles of retest thresholds) were derived to assess the reproducibility of individual threshold estimates. RESULTS: The differences between the threshold estimates of the SITA and Full Threshold strategies were largest ( approximately 3 dB) for midrange sensitivities ( approximately 15 dB). The threshold distributions of SITA were considerably different from those of the Full Threshold strategy. The differences remained of similar magnitude when the analysis was repeated on a subset of 20 locations that are examined early during the course of a Full Threshold examination. With sensitivities above 25 dB, both SITA strategies exhibited lower test-retest variability than the Full Threshold strategy. Below 25 dB, the retest intervals of SITA Standard were slightly smaller than those of the Full Threshold strategy, whereas those of SITA Fast were larger. CONCLUSIONS: SITA Standard may be superior to the Full Threshold strategy for monitoring patients with visual field loss. The greater test-retest variability of SITA Fast in areas of low sensitivity is likely to offset the benefit of even shorter test durations with this strategy. The sensitivity differences between the SITA and Full Threshold strategies may relate to factors other than reduced fatigue. They are, however, small in comparison to the test-retest variability.     

Normal intersubject threshold variability and normal limits of the SITA SWAP and full threshold SWAP perimetric programs

PURPOSE: To compare intersubject variability and normal limits of threshold values between the new Swedish interactive test algorithm short wavelength automated perimetry (SITA SWAP) and the older Full Threshold SWAP programs (Carl Zeiss Meditec, Dublin, CA). METHODS: Normal reduction of differential light sensitivity with age, age-corrected thresholds, intersubject variability, and normal limits of sensitivity were calculated from SITA SWAP and Full Threshold SWAP fields obtained in 53 normal subjects between 20 and 72 years of age. RESULTS: Age influence on threshold sensitivity was the same with the two SWAP programs. On average, sensitivity decreased by 0.13 dB per year of age. Age-corrected normal threshold sensitivity was significantly higher (P<0.0001) for SITA SWAP than for Full Threshold SWAP. The means for a subject 45.4 years of age were 28.8 dB with SITA SWAP and 24.4 dB with Full Threshold SWAP. Intersubject variance was 22% smaller with SITA SWAP than with Full Threshold SWAP. Normal limits at the P<5% significance level were, on average, 14% narrower with SITA SWAP than with Full Threshold SWAP using Total Deviations from age-corrected normal thresholds and 11% narrower when applying Pattern Deviation, which is intended to adjust for general depression or elevation of the field. CONCLUSIONS: SITA SWAP test results from normal eyes showed higher sensitivities than results from the older Full Threshold SWAP. This represents an increase of the dynamic range, which implies that more patients can be tested with SWAP. The smaller intersubject variability with SITA SWAP means narrower normal limits and may be associated with more sensitive probability maps.     

SITA standard in optic neuropathies and hemianopias: a comparison with full threshold testing

PURPOSE: To compare visual sensitivity, fatigue effect, and probability plot data between Full Threshold (FT) Humphrey automated perimetry and Swedish Interactive Threshold Algorithm (SITA) standard strategies in patients with optic neuropathies and hemianopias. METHODS: Twenty-four patients with nonglaucomatous optic neuropathies and 18 patients with a relative homonymous or bitemporal hemianopia were tested with both conventional perimetry (Humphrey 24-2 program) and "back to back" SITA standard tests (SITA 1, SITA 2) to approximate the test time of the FT test conditions. Also, 28 normal subjects between the ages of 20 and 80 were tested with this protocol. The visual field quadrants with the most damage were used to evaluate any fatigue effect (i.e., possible lack of fatigue effect with SITA standard due to the shorter test time) and to compare probability plot data between FT, SITA 1, and SITA 2. Pointwise total and pattern deviation probability plot defects were weighted by degree of significance and summed. RESULTS: Test times for normal subjects were 45 seconds longer for FT than for the combined test time of SITA 1 + SITA 2. Patients' test times were 40 seconds longer for hemianopias and 90 seconds longer for optic neuropathies with FT than the combined times for two SITA tests. There were higher sensitivities found with SITA 1 compared with Full Threshold (1.06 dB, P< 0.001) and SITA 2 with Full Threshold (0.73 dB, P< 0.001) in the most damaged quadrant for the optic neuropathy patients; for the hemianopia patients the difference in values were between SITA 1 and Full Threshold (0.96 dB, P = 0.07) and between SITA 2 and Full Threshold (0.11 dB, P = 0.87). The second SITA standard test had lower sensitivity than the first SITA standard test by 0.82 dB in hemianopias and by 0.71 dB in optic neuropathy patients. Analysis of the total and pattern deviation probability plot data showed slightly more defects (number and magnitude) with SITA 1 compared to FT for both groups, but the differences were not statistically significant. CONCLUSIONS: Sensitivities were higher in patients with hemianopias or optic neuropathies using SITA standard compared with FT by approximately 1 dB. The probability plot comparison suggests SITA standard is at least as good as FT for detection of visual loss in individual examinations. However, efficacy of SITA standard for serial examinations has not yet been evaluated.     

Between-algorithm, between-individual differences in normal perimetric sensitivity: full threshold, FASTPAC, and SITA. Swedish Interactive Threshold algorithm

PURPOSE: To determine the between-algorithm differences in perimetric sensitivity for the Swedish Interactive Threshold algorithm (SITA) Standard, SITA Fast, FASTPAC, and Full Threshold algorithms; to determine the between-subject, between-algorithm differences in the magnitude of the normal variation in sensitivity. METHODS: The sample comprised 50 normal subjects (mean age, 52.9 +/- 18.5 years) experienced in automated perimetry. One randomly assigned eye was examined at three visits with Program 30-2 of the Humphrey Field Analyzer (HFA). The first visit was a familiarization session. A two-period crossover design with order randomization within visits was used over the second and third visits. SITA Standard, SITA Fast, and HFA 640 Full Threshold were administered during one visit. FASTPAC and HFA 750 Full Threshold were administered during the remaining visit. RESULTS: Group mean Mean Sensitivity was 0.8 dB higher for SITA Standard than for Full Threshold (P < 0.001) and 1.3 dB higher for SITA Fast than for Full Threshold (P < 0.001). A similar trend was found between SITA and FASTPAC. The group mean Mean Sensitivity for SITA Fast was 0.5 dB higher than for SITA Standard (P < 0.001). The pointwise between-algorithm difference in sensitivity was similar for all algorithms. The pointwise between-algorithm, between-subject variability was lower for SITA. The examination durations for SITA Fast and SITA Standard were half those for FASTPAC and Full Threshold; SITA Fast was 41% that of SITA Standard (P < 0.001). CONCLUSIONS: SITA produced marginally higher mean mean sensitivity compared with that of existing algorithms and markedly reduced examination duration. The reduced between-subject variability of SITA should result in narrower confidence limits for definition of normality.     

Assessment of false positives with the Humphrey Field Analyzer II perimeter with the SITA Algorithm

PURPOSE: To evaluate the effects of false-positive (FP) response errors on mean deviation (MD), pattern standard deviation (PSD), glaucoma hemifield test (GHT), and test duration in the Humphrey Field Analyzer's (HFA II) Swedish Interactive Threshold Algorithm (SITA; Carl Zeiss Meditec, Inc., Dublin, CA). METHODS: Five individuals with glaucoma (ages 52, 63, 69, 77, and 78 years) and five individuals with normal, healthy eyes (ages 25, 34, 43, 45, and 52 years), participated in the study. Each subject was experienced in automated perimetry and performed multiple, monocular baseline SITA-standard (SITA-S) 24-2 visual field tests. In addition, normal subjects completed SITA-S 24-2 field examinations in which known frequencies of FP error were introduced (0%, 5%, 10%, 20%, or 33% frequency). Likewise, the subjects with glaucoma completed visual field examinations with 0%, 20%, and 33% error introduced during the test. RESULTS: Reported FP errors were significantly lower than the introduced frequency of error. The SITA algorithm more accurately identified FP errors when the MD and PSD diverged from normal. Test duration increased as introduced error frequencies increased. The Statpac single-field analyses indicated that two thirds of the tests with introduced errors produced a "low-patient-reliability" determination. CONCLUSIONS: HFA II SITA-S underestimates patients' FP errors, particularly among normal patients. High FP error frequencies can have adverse effects on MD and PSD, leading clinicians and researchers to an inaccurate determination of the amount and severity of visual field loss.     

Sensitivity and specificity of frequency-doubling technology, tendency-oriented perimetry, and Humphrey Swedish interactive threshold algorithm-fast perimetry in a glaucoma practice

PURPOSE: To evaluate the sensitivity and specificity of the screening mode of the Humphrey-Welch Allyn frequency-doubling technology (FDT), Octopus tendency-oriented perimetry (TOP), and the Humphrey Swedish Interactive Threshold Algorithm (SITA)-fast (HSF) in patients with glaucoma. DESIGN: A comparative consecutive case series. METHODS: This was a prospective study which took place in the glaucoma unit of an academic department of ophthalmology. One eye of 70 consecutive glaucoma patients and 28 age-matched normal subjects was studied. Eyes were examined with the program C-20 of FDT, G1-TOP, and 24-2 HSF in one visit and in random order. The gold standard for glaucoma was presence of a typical glaucomatous optic disk appearance on stereoscopic examination, which was judged by a glaucoma expert. The sensitivity and specificity, positive and negative predictive value, and receiver operating characteristic (ROC) curves of two algorithms for the FDT screening test, two algorithms for TOP, and three algorithms for HSF, as defined before the start of this study, were evaluated. The time required for each test was also analyzed. RESULTS: Values for area under the ROC curve ranged from 82.5%-93.9%. The largest area (93.9%) under the ROC curve was obtained with the FDT criteria, defining abnormality as presence of at least one abnormal location. Mean test time was 1.08 +/- 0.28 minutes, 2.31 +/- 0.28 minutes, and 4.14 +/- 0.57 minutes for the FDT, TOP, and HSF, respectively. The difference in testing time was statistically significant (P <.0001). CONCLUSIONS: The C-20 FDT, G1-TOP, and 24-2 HSF appear to be useful tools to diagnose glaucoma. The test C-20 FDT and G1-TOP take approximately 1/4 and 1/2 of the time taken by 24 to 2 HSF.     

Evaluation of threshold estimation and learning effect of two perimetric strategies, SITA Fast and CLIP, in damaged visual fields

PURPOSE: The threshold estimation, learning effect, and between-algorithm differences of the Fast Swedish Interactive Thresholding Algorithm (SITA Fast), of the Humphrey Field Analyzer (HFA), and the Continuous Light Increment Perimetry (CLIP) strategy of the Oculus Twinfield perimeter were evaluated in damaged visual fields. METHODS: Twenty-one glaucomatous patients with damaged visual fields (MD worse than -8 dB) underwent Oculus Full Threshold (FT), Humphrey FT, SITA Fast, and CLIP 30-2 perimetric examinations. All the tests were repeated in a second session at least 3 days later. The point-wise differences in absolute sensitivity and of the total deviation plot values between FT and fast algorithms, between fast algorithms and the learning effect were evaluated (Wilcoxon test and Bland-Altman analysis). RESULTS: The average point-wise sensitivity difference between SITA Fast and HFA FT strategy (0.84 dB) was significantly lower than that found between CLIP and Oculus FT strategy (1.71 dB). Between-algorithm point-wise differences of the total deviation plot values of the fast strategies were not significantly different. Learning effect for SITA Fast (0.67 dB) was higher than that found for CLIP (0.39 dB). Test time for SITA (367+/-71 sec) and CLIP (453+/-98 sec) were about 55% and 35%, respectively, shorter (p<0.001) than those found with FT algorithms. The acceptance for fast algorithms and particularly for CLIP was significantly better. CONCLUSIONS: The two fast strategies, even though using very different algorithms, showed good threshold estimation compared to FT strategies with a consistent time saving in damaged visual fields.     

Sensitivity and specificity of the Swedish interactive threshold algorithm for glaucomatous visual field defects

PURPOSE: To determine the sensitivity and specificity of two new visual field algorithms in detecting glaucomatous visual field defects: (1) Swedish interactive threshold algorithm (SITA) standard and (2) SITA fast. DESIGN: Prospective observational case series. PARTICIPANTS: Ninety normal subjects and 82 glaucoma patients. TESTING: Central 30 degrees fields were performed with the Humphrey visual field analyzer 30-2 program (Humphrey Systems, Dublin, CA) using full threshold, SITA standard, and SITA fast algorithms on the same day for two or more sessions within a 1-month period. MAIN OUTCOME MEASURES: Sensitivity and specificity in detecting glaucomatous visual field defects with SITA standard and SITA fast using full threshold testing as the reference standard. RESULTS: The sensitivity of SITA standard and SITA fast in detecting glaucomatous defects overall was 98% and 95%, respectively. In the subset of mild glaucomatous field defects (26 patients), sensitivity of SITA standard was 92% versus 85% with SITA fast. Sensitivity was 100% for both algorithms in moderate to severe glaucomatous defects. Specificity for glaucoma defects using SITA standard and SITA fast was 96% for both algorithms. SITA standard reduced test-taking time from full threshold by 52% in normal subjects and 47% in glaucoma patients (P < 0.001). SITA fast reduced test-taking time by 72% in normal subjects and 65% in glaucoma patients (P < 0.001). Mean deviation values were 0.4 dB and 0.8 dB better in SITA standard and SITA fast fields, respectively, in normal subjects (P < 0.001), and 0.7 dB and 1.2 dB in SITA standard and SITA fast fields, respectively, in glaucoma patients (P < 0.001) compared with full threshold values. CONCLUSIONS: The new algorithms for measuring visual fields, SITA standard and SITA fast, have excellent sensitivity and specificity for glaucomatous visual field loss with considerable savings in time.     

Evaluation of the Humphrey FASTPAC threshold program in glaucoma.

The makers of the Humphrey perimeter have developed a rapid thresholding program, FASTPAC, to address the problems of fatigue and poor test performance associated with prolonged perimetry. The performance of FASTPAC was compared with the standard threshold program of the Humphrey visual field analyser (program 24-2) in 44 glaucoma patients. FASTPAC reduced the mean test time by 35% (from 12.6 to 8.2 minutes), owing to a reduction in the number of stimulus presentations. FASTPAC underestimated the mean deviation (MD) (Wilcoxon, p = 0.007) and corrected pattern standard deviation (CPSD) (Wilcoxon, p = 0.005). The sum of the differences between FASTPAC and the standard program was -1.19 (SD 2.37) dB for MD and 0.97 (2.14) dB for CPSD. The measured difference between the two methods was independent of the value of either MD or CPSD, indicating that the measurement error was just as likely to occur with either early or advanced visual field loss. No difference was noted in short term fluctuation or in the reliability indices of test performance. These results indicate that FASTPAC, while considerably faster, is not as accurate as the standard threshold program at measuring retinal sensitivity in glaucoma. This inaccuracy may be offset in practical terms by greater patient acceptability and by increasing the number of patients capable of performing reliable threshold perimetry because of the reduction in duration of the FASTPAC program.     

Relationship between Humphrey 30-2 SITA Standard Test, Matrix 30-2 threshold test, and Heidelberg retina tomograph in ocular hypertensive and glaucoma patients

PURPOSE: To evaluate the relationship between global indices of Humphrey standard automated perimetry (SAP, 30-2 SITA standard test), Humphrey Matrix frequency doubling technology (FDT, 30-2 threshold test), and Heidelberg Retina Tomograph (HRT II) parameters and measure the level of agreement among these 3 tests in classifying eyes as normal or abnormal. METHODS: The study included 1 eye of 29 ocular hypertensive and 56 glaucoma patients with a mean age of 60.9+/-10.5 years. All subjects had reliable visual fields and HRT measurements performed within a 2-week period. The eyes were classified as normal/abnormal according to visual field criteria and Moorfields regression analysis (MRA). Correlations between visual field indices (mean deviation and pattern standard deviation) and HRT parameters were analyzed using Spearman correlation coefficient (r) and the agreement between the tests in classifying eyes was defined with kappa value. RESULTS: FDT Matrix mean deviation and pattern standard deviation parameters were found to be highly correlated with those of SAP (r=0.66 and 0.69, respectively). Visual field indices showed statistically significant correlations with cup area, rim area, cup/disc (C/D) area, linear C/D, cup shape, mean retinal nerve fiber layer thickness and retinal nerve fiber layer area parameters (P<0.05). Fifty-eight patients (68.2%) had abnormal results at least with 1 of the tests and 21 subjects (24.7%) had abnormal results with all 3 tests. The kappa values were 0.6 for SAP and Matrix (P<0.001), 0.33 for SAP and MRA (P=0.002), and 0.31 for Matrix and MRA (P=0.004). CONCLUSIONS: FDT Matrix results are highly comparable with SAP in the assessment of glaucoma. Visual field global indices show statistically significant, but low-moderate correlations with most of the HRT parameters. The agreement among MRA and visual fields for abnormality is fair. Either HRT or visual fields may show the first evidence of glaucomatous damage; therefore, the combination of optic nerve head parameters and visual field results could improve glaucoma diagnosis and follow-up.     

Reproducibility of visual field end point criteria for standard automated perimetry, full-threshold, and Swedish interactive thresholding algorithm strategies: diagnostic innovations in glaucoma study

PURPOSE: To compare the interthreshold and intrathreshold strategy agreement of visual field end point criteria for standard automated perimetry (SAP) with the full-threshold (FT) algorithm and the Swedish interactive threshold algorithm (SITA). DESIGN: Prospective, longitudinal cohort study. METHODS: The interstrategy group included a randomly selected eye of 173 participants in the Diagnostic Innovations in Glaucoma Study who had undergone FT algorithm and SITA analysis within three months (sequence 1, FT + SITA). Intrastrategy agreement for the FT algorithm (sequence 2, FT + FT) was tested for 44 (25.4%) participants who had undergone FT analysis within one year of the FT used in the interstrategy pairing, and for 89 patients (51.4%) who had undergone SITA analysis within one year before (sequence 3, SITA + SITA). Four different end point criteria using Statpac II indices were tested. Interstrategy agreement was compared with intrastrategy agreement using kappa statistics. RESULTS: FT + SITA agreement (kappa) for pattern standard deviation (PSD) < 1% was 0.82; for PSD < 5%, the kappa value was 0.64; and for four or more pattern deviation plot points, the kappa value was 0.43. Agreement with glaucoma hemifield test (GHT) results was significantly higher (P < .01) for FT + FT (kappa = 0.94) than FT + SITA (kappa = 0.67), and approached significance (P = .07) when comparing FT + FT with SITA + SITA (kappa = 0.77). GHT results were more likely to be abnormal on the SITA analysis than on the FT analysis. No other significant differences were found. CONCLUSIONS: To minimize misinterpreting abnormal GHT results on SITA as evidence of change when switching strategies, both SITA and FT should be performed and compared within a short period. Other indices are comparable between the two strategies.