Frequency doubling technology and high-pass resolution perimetry in glaucoma and ocular hypertension

PURPOSE: To study the correlation between frequency doubling technology perimetry (FDT) and high-pass resolution perimetry (HRP) in eyes with primary open-angle glaucoma, suspect glaucoma, ocular hypertension, and in normal eyes. PATIENTS AND METHODS: Ninety-four patients (162 eyes) were studied. Visual fields were assessed by HRP, FDT screening C-20-5 and FDT threshold C-20 programs. In eyes with a discrepancy between the test results, a comprehensive clinical examination was performed, including optic disc photography and Heidelberg retinal tomography (HRT). RESULTS: There was a strong correlation between HRP global deviation and the FDT mean deviation (for FDT threshold C-20 test), and between HRP score and FDT score (for FDT screening C-20-5 ). The correlation coefficients were r = -0.83 and r = 0.77, respectively. In all, 75 eyes (46.3%) had normal HRP and FDT screening results, while 67 eyes (41.4%) showed abnormal results in both tests. In 12 eyes (7.4%) HRP was within normal limits while FDT screening was abnormal. Seven of these eyes were judged to have glaucoma; three of them had converted from ocular hypertension to glaucoma. In eight eyes (4.9%) HRP was abnormal while FDT screening was normal. Three of these were judged to have glaucoma. Thus, the sensitivity and specificity of the FDT screening test for the detection of glaucoma were 91.7% and 87.8%, respectively. CONCLUSION: There was a strong correlation between FDT threshold C-20, FDT screening C-20-5 and HRP test results. Frequency doubling technology perimetry C-20-5 represents a good screening test for the detection of optic nerve damage in open-angle glaucoma.     

Detection of glaucomatous visual field defect by nonconventional perimetry

PURPOSE: To report the correlations among Humphrey Field Analyzer 750 (HFA), high-pass resolution perimetry (HRP), and frequency-doubling technology (FDT) perimetry in glaucoma patients and ocular hypertensive patients. DESIGN: Cross-sectional study. METHODS: Eighty-two eyes of 82 consecutive patients with primary open-angle glaucoma (POAG) or ocular hypertension were included in this study. One eye of each patient was randomly selected for data analysis. Visual fields were assessed by HFA, HRP, and FDT perimetry. HRP global deviation (HRP-GD), HRP local deviation (HRP-LD), FDT-mean deviation (FDT-MD), and FDT-pattern standard deviation (FDT-PSD) were considered for the analysis. Clinical agreement between HRP and FDT was evaluated. All data were analyzed by Pearson r coefficient when the distribution of the data was normal and by Spearman coefficient correlation when the distribution of the data was not normal. A P <.05 was considered statistically significant. RESULTS: Fifty-two eyes (52 patients) were classified as glaucoma and 30 eyes (30 patients) as ocular hypertension. In the entire group, a significant (P >.001) correlation was found between the HFA indices and those of either HRP or FDT. A significant (P <.001) correlation was found between HRP-GD and FDT-MD as well as between HRP-LD and FDT-PSD. In 14% of the glaucomatous patients and in 33% of the subjects with ocular hypertension, FDT and HRP showed different clinical features. CONCLUSIONS: Our data suggest that FDT and HRP are useful for detection of early glaucomatous visual field damage.     

New perimetric techniques: a comparison between rarebit and frequency doubling technology perimetry in normal subjects and glaucoma patients

PURPOSE: To compare rarebit microdot perimetry (RB) with frequency doubling technology (FDT) perimetry in normal subjects and a group of patients with ocular hypertension or glaucoma, with age-matched controls. MATERIALS AND METHODS:: Eighty-one subjects (age 17-88 years) were examined. Twenty-seven of these were patients, aged 50 to 88 years, with ocular hypertension or suspected/manifest glaucoma in at least one eye. All subjects were examined with the RB and FDT perimetry, using the standard procedures, recommended by the respective manufacturer. RESULTS: All patients were able to perform the RB perimetry, but three patients could not perceive the strongest FDT stimulus. The concordance in RB and FDT classifications as normal/outside normal limits was 96% (Cohen's kappa = 0.90). A curvilinear (quadratic) relationship (Rsq = 0.75) was found between RB hit rate and FDT MD. All patients, who could perform both examinations, preferred the RB perimetry. CONCLUSION: In the current study, the information from the RB and FDT perimetry was almost completely equivalent. However, RB perimetry was preferred by the patients and seemed to have a larger dynamic range than FDT. The RB hit rate is apparently a straightforward and efficient measure of visual field function.     

Variability components of standard automated perimetry and frequency-doubling technology perimetry

PURPOSE. To evaluate and compare intra- and intertest variability components for both standard automated perimetry (SAP) and frequency-doubling technology (FDT) perimetry in a small group of normal individuals and patients with glaucoma. METHODS. The method of constant stimuli (MOCS) was used to examine matched test locations with both SAP and FDT perimetry stimuli in a group of eight normal individuals and seven patients with glaucoma. Subjects were tested weekly at three predetermined visual field loci for 5 consecutive weeks. Frequency-of-seeing (FOS) curves were generated and used to quantify threshold sensitivity (50% seen on FOS, in decibels), intratest variability (FOS interquartile range, in decibels), and intertest variability (interquartile range of weekly repeated threshold determinations, in decibels). RESULTS. In patients with glaucoma, SAP intra- and intertest variabilities were found to increase with sensitivity reductions, as previously reported. FDT perimetry revealed that both intra- and intertest variability components did not appreciably change with reductions in sensitivity. With the measurement scales used in this investigation, both intra- and intertest variability components were significantly greater for SAP than for FDT perimetry (P < 0.001 and P = 0.003, respectively). Intratest variability exceeded intertest variability for both SAP (P = 0.001) and FDT perimetry (P < 0.001). CONCLUSIONS. For both SAP and FDT perimetry, variability occurring within a single test session contributed more to total variability than between-session variability. When the measurement scales available on commercial instrumentation were used, FDT perimetry exhibited significantly less variability than SAP, especially within regions of visual field sensitivity loss. FDT perimetry therefore shows promise as an effective test for detecting progressive glaucomatous visual field loss, although prospective longitudinal validation is still required to determine sensitivity to change.     

Standard achromatic perimetry, short wavelength automated perimetry, and frequency doubling technology for detection of glaucoma damage

OBJECTIVE: Reevaluation of the relationship between short wavelength automated perimetry (SWAP), standard achromatic perimetry (SAP), and frequency doubling technology (FDT) in glaucoma and ocular hypertensive patients and in glaucoma suspects. DESIGN: Prospective comparative observational study. PARTICIPANTS: Four age-matched groups were evaluated (42 patients with early to moderate glaucoma, 34 ocular hypertensives, 22 glaucoma suspects, and 25 normal controls) using SAP, SWAP, and FDT. INTERVENTION: All participants underwent full clinical ophthalmologic evaluation followed by SWAP, SAP, and FDT perimetry within a period of not more than 3 months. Mean defect (MD), pattern standard deviation (PSD), visual field (VF) indices, and the percentage of depressed visual field points with P value <5% and <1% in the pattern deviation plot were evaluated. MAIN OUTCOME MEASURES: For each of the four study groups, the MD, PSD, and the percentage of abnormal points significantly depressed <5% and <1% were compared for the three VF testing modalities. RESULTS: In the glaucoma group, the mean percentage of the total number of abnormal points in SWAP was significantly less than abnormal points in SAP and FDT, both for 5% (P values were 0.0001 and 0.0001, respectively) and 1% (P values were 0.0001 and 0.0001, respectively). The same applied to the ocular hypertensives group. However, in the suspects group, no significant difference was detected. In normal controls, the abnormal points in SWAP were significantly lower than those in SAP for 5% (P value was 0.01) and 1% (P value was 0.05). FDT detected significantly larger defects (percentage of points <5%) than SAP in ocular hypertensives and suspects (P values were 0.01 and 0.004, respectively). CONCLUSIONS: SWAP in its existing condition is markedly less efficient than either SAP or FDT in detecting VF defects, especially in glaucoma patients and ocular hypertensives (defects detected with SWAP are less than both SAP and FDT). Defects detected with FDT are equivalent to SAP and sometimes larger, especially in ocular hypertensives and glaucoma suspects; this makes it a useful tool for picking up early glaucomatous defects in populations at risk.     

Combined use of frequency doubling perimetry and polarimetric measurements of retinal nerve fiber layer in glaucoma detection

PURPOSE: The aim of this study was to evaluate the diagnostic usefulness of the combined use of frequency-doubling technology (FDT) perimetry and polarimetry of the retinal nerve fiber layer. DESIGN: Cross-sectional study. METHODS: Seventy ocular hypertensive patients (normal optic disk and standard perimetry, elevated intraocular pressure [>21 mm Hg]), 59 patients with "preperimetric" open-angle glaucoma (glaucomatous optic disk atrophy, elevated intraocular pressure [>21 mm Hg], no visual field defect in standard perimetry), 105 patients with "perimetric" open-angle glaucoma (glaucomatous optic disk atrophy and clearly marked visual field defect), and 73 control subjects had FDT screening (protocol: C-20-5) and polarimetric measurements (GDx). Criteria for exclusion: optic disks larger than 4 mm(2), media opacities, patients younger than 33 years or older than 66 years. None of the subjects had earlier FDT perimetry. One eye of each patient and control subject entered the statistical evaluation. Database and statistical software were used for case-wise recalculation of all missed localized probability levels to create a FDT screening score. RESULTS: At a predefined specificity of 94.5% in control eyes, discrimination between "perimetric" glaucoma and normal subjects is superior using the FDT perimetry (sensitivity = 84.8%) in comparison to polarimetry (sensitivity = 63.8%), whereas sensitivity is similar with both methods in "preperimetric" patients (GDx, FDT: 25.4%). In several cases, patients classified as glaucomatous by the GDx are not the same patients as identified by the FDT perimetry. Therefore, a two-dimensional discrimination analysis can increase correct positive classification. Using a linear combination of the present FDT screening score and polarimetry ("the number"), 92.4% of "perimetric" glaucoma eyes and 44.1% of "preperimetric" glaucoma eyes have been classified as glaucomatous. CONCLUSION: Joint usage of polarimetry and FDT perimetry indicate that a combination of different techniques which can uncover different glaucoma properties, might be helpful in early glaucoma detection.     

Glaucoma detection with frequency doubling perimetry and short-wavelength perimetry

PURPOSE: The aim of this analysis was to evaluate the diagnostic usefulness of frequency doubling technology (FDT) perimetry and short-wavelength perimetry (SWAP). Moreover, to study a combination of both methods using the machine-learning technique double-bagging, which was recently established in glaucoma research. METHODS: Forty-three patients with "preperimetric" open-angle glaucoma (glaucomatous optic disc atrophy and no visual field defect in standard perimetry), 26 patients with "perimetric" open angle glaucoma (glaucomatous optic disc atrophy and visual field defect in standard perimetry), and 40 control subjects had FDT screening (protocol: C-20-5) and SWAP (Octopus 101, G2). Criteria for exclusion were color vision abnormalities, media opacities, and an age below 31 years or above 63 years. Data of 1 eye of each patient and control subject entered the statistical evaluation. A point wise evaluation of the diagnostic power of SWAP values was performed to derive spatial patterns of visual field loss. A double-bagging machine-learning algorithm was used to train classification rules on the basis of a combination of FDT scores and nerve fiber related visual field losses in SWAP. The diagnostic power of the classifiers was compared regarding their misclassification error rates and area under the receiver-operating characteristic curve. RESULTS: The combination of FDT perimetry and SWAP yielded better diagnostic results compared with FDT or SWAP separately. The overall estimated misclassification error rate of the combined classifier was 24% compared with 28% for both SWAP and FDT perimetry. Regarding the estimated performance of classifier at high specificities (>80%) in control eyes as measured by the partial area under the receiver-operating characteristic curve, the combination of both instruments is also superior to the individual instruments. CONCLUSIONS: A combination of SWAP and FDT perimetry, each targeting different neuronal pathways, may improve early glaucoma detection.     

Relationship of SITA and full-threshold standard perimetry to frequency-doubling technology perimetry in glaucoma

PURPOSE: To compare full-threshold (FT) and SITA algorithms for standard automated perimetry (SAP) with frequency-doubling technology perimetry (FDT) in glaucoma, to help clinicians to relate results in patients who have had two or more of these tests during follow-up. METHODS: This study was a retrospective analysis of data from a longitudinal prospective study at the University of California, San Diego. One hundred four eyes of 104 patients with glaucomatous optic neuropathy detected by optic disc stereophotographs were included. All patients had standard perimetry (SITA and FT) and FDT within 3 months of each other. Global indices, abnormality and severity using two threshold algorithms of standard perimetry were compared with FDT. RESULTS: More eyes had normal visual fields by SAP-FT (57 eyes) than by either SAP-SITA (42 eyes) or FDT (45 eyes), although SAP-FT agreed more closely with FDT (kappa = 0.54 +/- 0.08) on the presence of a visual field defect than did SAP-SITA (kappa = 0.34 +/- 0.08). Correlations of FDT to standard perimetry global indices were similar regardless of the threshold strategy used for standard perimetry, yielding r2= 0.38-0.57 for SAP-FT with FDT, 0.36-0.54 for SAP-SITA with FDT. CONCLUSIONS: Despite many similarities of SAP-SITA and SAP-FT, switching the standard of comparison from SAP-FT to SAP-SITA changes the relationship to FDT with regard to visual field abnormality, but not correlations of global indices. FDT detected abnormal fields in more eyes than SAP-FT. SAP-FT tended to detect a subset of eyes found abnormal by FDT. Visual field defects may be detected more often by FDT and SAP-SITA in eyes with early visual field loss, but these two tests may not agree on which eyes show field loss in patients who undergo both tests at follow-up.     

青光眼中倍频视野检查与Octopus视野检查的相关性

目的 评价青光眼中倍频视野计（Frequency Doubling Technique FDT）与传统自动视野计Octopus检查结果的相关性。方法 35例正常对照，27例可疑青光眼患者，37例原发性开角型青光眼和50例正常眼压性青光眼患者进行FDT和Octopus检查。记录FDT视野检查的平均缺损（MeanDefect，MD）、图形标准偏差（Pattem Standard Deviation，PSI）），Octopus视野检查中的平均缺损、丢失方差（Loss Variance，LV）。应用线性回归分析计算回归方程及相关系数。结果 原发性开角型青光眼中，FDT-MD与Octopus-MD，FDT-PSD与Octopus-LV均显著相关（r=0．828，r=0．758，P均＜0．001）。正常眼压性青光眼中，FDT-MD与Octopus-MD，PDT-PSI）与Octopus-LV均显著相关（r=0．827，r=0．783，P均＜0．001）。结论 FDT检查的各指标无论在POAG还是NTG中均与传统自动视野计Octopus有很好的相关性。     

Frequency doubling technology perimetry using a 24--2 stimulus presentation pattern.

PURPOSE: To assess whether smaller targets and a 24-2 stimulus presentation pattern would improve the ability of frequency doubling technology (FDT) perimetry to detect and characterize early glaucomatous visual field loss. METHODS: One hundred normal subjects between the ages of 20 and 85 participated in this study. In addition, 53 patients who either had early glaucomatous visual field loss (n = 23) or were high-risk glaucoma suspects with normal conventional visual fields (n = 30) were evaluated with the commercial version of FDT perimetry (full threshold test) with 17 stimuli (four 10 degrees diameter square targets per quadrant and a central 5 degrees circular target) and a custom version of FDT perimetry using 54 stimuli (4 degrees targets with 6 degrees grid spacing) arranged in a 24-2 stimulus presentation pattern. RESULTS: The custom FDT test using a 24-2 stimulus presentation pattern had a similar dynamic range, and demonstrated normal aging characteristics and test-retest reliability that were similar to the commercial version of FDT perimetry using 17 larger stimuli. Both FDT tests showed an age-related sensitivity reduction of approximately 0.6 dB per decade, and exhibited an average test-retest reliability of 1 to 1.5 dB. The custom 24-2 FDT perimetry test had a greater variation of sensitivity with eccentricity than the commercial version of FDT perimetry that was probably related to the difference in stimulus size. The custom 24-2 FDT perimetry test had a greater percentage of abnormal test locations than the commercial FDT test for both early glaucomas and high-risk glaucoma suspects. CONCLUSIONS: FDT perimetry can be performed with smaller targets using a presentation pattern that is similar to conventional automated perimetry. In comparison to the commercially available 17 target display, the 24-2 stimulus pattern appears to have modestly higher sensitivity for detection of early glaucomatous loss and provides better characterization of the pattern of visual field loss, but the test takes approximately twice as long.     

Testing for glaucoma with frequency-doubling perimetry in normals, ocular hypertensives, and glaucoma patients

BACKGROUND: The aim of this study was to evaluate the diagnostic usefulness of the FDT perimeter protocol (C-20-5) in combination with a database system for analysis of single test locations. METHODS: One hundred seventy-three ocular hypertensive eyes, 116 "preperimetric" open-angle glaucoma eyes (glaucomatous optic disc atrophy, elevated intraocular pressure, no visual field defects in standard white-on-white perimetry), 199 "perimetric" open-angle glaucoma eyes (glaucomatous optic disc atrophy and visual field defects), and 151 control eyes underwent FDT screening and conventional white-on-white perimetry. Four repeated measurements were carried out in 15 glaucoma patients at 2-h intervals to judge reproducibility of all test locations. The present screening strategy begins testing at the normal 5% probability level. If a stimulus is not detected, further targets are presented. FDT-Viewfinder and statistics software were used for case-wise recalculation of all missed localized probability levels and correlation with corresponding test locations using conventional perimetry. RESULTS: Analysis of repeated measurements in patients reveals that variation of single test points can be considerable. However, the numbers of missed test-stimuli calculated globally or in quadrants are significantly correlated with corresponding Octopus visual field defects (Spearman rank correlation P<0.001). Using a predefined specificity of 96% in control eyes, 11% of ocular hypertensive eyes, 28.5% of "preperimetric" glaucoma eyes and 86.9% of "perimetric" glaucoma eyes have been classified glaucomatous using an overall score and with consideration of different cut-off points in right and left eyes. CONCLUSION: Point-wise analysis of FDT screening results can be helpful for classification of patient groups and consideration of the individual learning curve in repeated measurements. The C-20-5 protocol of the FDT perimeter is able to detect a considerable proportion of glaucomatous patients.     

Frequency doubling technology perimetry abnormalities as predictors of glaucomatous visual field loss

PURPOSE: To determine whether frequency doubling technology (FDT) perimetry results predict glaucomatous visual field defects, as assessed by standard automated perimetry (SAP), in a glaucoma suspect population. DESIGN: Longitudinal observational study. METHODS: The study included 105 eyes of 105 glaucoma suspect patients, with a mean follow-up time of 41 +/- 17 months. Glaucoma suspects had either intraocular pressure (IOP) higher than or equal to 23 mm Hg or glaucomatous optic neuropathy by stereophotograph assessment. All patients had normal SAP visual fields at baseline. A baseline FDT test was performed within 3 months of the normal SAP examination. Several baseline FDT parameters and other variables (age, gender, IOP, central corneal thickness, SAP visual field indices, and stereophotograph assessment) were investigated by univariate and multivariate Cox proportional hazards models to obtain hazard ratios (HR) and identify factors that predicted which patients had SAP glaucomatous visual field loss during follow-up. RESULTS: Seventeen patients (16%) developed repeatable SAP visual field abnormality during follow-up. An abnormal FDT examination at baseline predicted the development of SAP visual field conversion in both univariate (HR = 3.17; 95% confidence interval [CI] = 1.22-8.25; P =.018) and multivariate models (Adjusted HR = 3.68; 95% CI = 1.06-12.8; P =.04). The analysis of FDT examinations during follow-up revealed that in 59% of converters the FDT abnormalities preceded SAP visual field loss by as much as 4 years. Also, the initial development of glaucomatous visual field loss as measured by SAP occurred in regions that had previously demonstrated abnormalities on FDT testing. CONCLUSION: Functional abnormalities detected by FDT perimetry were predictive of the future onset and location of SAP visual field loss among glaucoma suspect patients.     

Learning effects among perimetric novices in frequency doubling technology perimetry

PURPOSE: To investigate learning effects, including improvements in reliability indices, in frequency doubling technology (FDT) perimetry in subjects without glaucoma who have not undergone previous automated perimetry. DESIGN: Prospective consecutive case series. PARTICIPANTS: Eighty-one normal subjects. METHODS: Normal subjects were recruited from the University of Washington Eye Clinic who had no history of automated visual field testing. All eyes underwent complete ophthalmic examination. The C-20-5 screening mode of FDT perimetry (Zeiss-Humphrey, San Leandro, CA) was performed after appropriate instruction, including a demonstration of the frequency doubling phenomenon. If any abnormal areas were identified or there were greater than 33% fixation losses or false-positive results, then the test was readministered up to three times or until a normal result was returned. MAIN OUTCOME MEASURES: Normal FDT test. RESULTS: The mean age was 54.8 years (range, 19-94). Sixty-nine subjects (85.2%) returned a normal test after a single test administration. Nine subjects (11.1%) required two administrations, and two subjects (2.5%) required three or more administrations to return a normal test. One subject still tested unreliably after four tests. The number or severity of abnormal locations did not predict the number of trials necessary to overcome learning effects. Fixation loss was the most common reliability problem. Subjects who demonstrated learning effects did not differ significantly in age, visual acuity, refraction, or test time from those who did not. CONCLUSIONS: Some perimetric novices demonstrate learning effects in C-20-5 screening-mode FDT perimetry. Learning effects in FDT perimetry must be considered during screening for glaucoma or other ocular disease.     

Corneal thickness measurements and frequency doubling technology perimetry abnormalities in ocular hypertensive eyes

OBJECTIVE: It has been suggested that some patients currently diagnosed with ocular hypertension (OHT) may have thicker than average corneas that result in an overestimation of their true intraocular pressure. Consequently, patients with OHT with greater corneal thickness may be at a lower risk for functional glaucomatous damage, including visual field loss measured with frequency doubling technology (FDT) perimetry. The purpose of this study was to evaluate the frequency of FDT perimetry deficits in patients with OHT and to correlate these findings with central corneal thickness (CCT) measurements. DESIGN: Observational case control study. PARTICIPANTS AND CONTROLS: Sixty-five patients with OHT with normal optic discs and normal standard achromatic automated perimetry (SAP) visual fields and 52 normal control subjects. METHODS: All participants underwent SAP, FDT perimetry, and CCT measurements using ultrasound pachymetry. MAIN OUTCOME MEASURES: CCT measurements in patients with OHT with abnormal repeatable FDT test results were compared with CCT measurements in patients with OHT with normal FDT results. In addition, CCT measurements in patients with OHT were compared with CCT measurements in normal control subjects. RESULTS: Fourteen of 65 patients with OHT (21.5%) demonstrated repeatable FDT abnormalities. The mean CCT of patients with OHT with abnormal FDT results was significantly lower than the mean CCT of patients with OHT with normal FDT results (542+/-35 microm versus 575+/-35 microm; P = 0.003). The mean CCT in the normal control group was 556+/-36 microm. The mean CCT in patients with OHT with normal FDT results was significantly higher than in normal subjects (P = 0.008). No statistically significant difference was found between mean CCT in normal subjects and in patients with OHT with abnormal FDT results (P = 0.18). CONCLUSIONS: Patients currently diagnosed with OHT, but with visual field loss detected by FDT perimetry, had significantly lower CCT measurements than patients with OHT with normal FDT results. These findings suggest that patients with OHT with thinner corneas are more likely to develop early glaucomatous functional damage and that CCT measurements should be taken into account when assessing risk for the development of glaucoma among OHT subjects.     

Frequency doubling technique in patients with ocular hypertension and glaucoma: correlation with octopus perimeter indices

PURPOSE: To ascertain whether frequency doubling technique (FDT) (Welch-Allyn, Skaneateles, NY; Zeiss-Humphrey, San Leandro, CA) indices provide results comparable with those of standard Octopus threshold perimeters (Interzeag AG, CH-8952 Schlieren, CH) in patients with glaucoma and in patients suspected of having ocular hypertension, glaucoma, or both. DESIGN: A comparative, consecutive, case series. PARTICIPANTS: Thirty-nine glaucomatous patients and 41 patients with ocular hypertension or suspected glaucoma were recruited consecutively. METHODS: The visual field of the study participants were assessed by FDT program C-20 full threshold and Octopus program dG1X. Only one eye of each participant was selected randomly. Pearson's r correlation coefficient was calculated among the FDT and Octopus indices. MAIN OUTCOME MEASURES: Using Octopus perimeter, mean defect (MD), mean sensitivity (MS), loss variance (LV), and corrected loss variance (CLV) were calculated and used for correlation. For the FDT, mean deviation (FDT-MD) and pattern standard deviation (FDT-PSD) were calculated and used for correlation. Also, the time required to perform the visual field test was considered. RESULTS: In the entire population, a statistically significant correlation (Pearson's r, P<0.001) was found between FDT-MD and both MS (0.77) and MD (-0.80) and between FDT-PSD and both LV (0.50) and CLV (0.45). When the glaucoma group was considered alone, similar significant correlation was found between the indices. In the suspected ocular hypertension and glaucoma suspect group, no significant correlation was found. A significant (P<0.001) difference was found between FDT and Octopus for the time needed to perform the visual field test. CONCLUSIONS: This new technique could be used both to screen populations and to observe glaucomatous visual field progression in early and moderate stages. The FDT is a faster way to analyze the visual field and captures threshold values for each point, but it is important to remember that this is a new technique and its limits are still unknown.     

Prediction of visual field defects on standard automated perimetry by screening C-20-1 frequency doubling technology perimetry

PURPOSE: To determine if perimetric defects, initially seen with C-20-1 frequency doubling technology (FDT) in eyes with normal standard automated perimetry (SAP), will subsequently develop on standard automated perimetry. METHODS: Review of patients considered high-risk glaucoma suspects (GS) or with ocular hypertension (OHT), who underwent one C-20-1 FDT in 1997 or 1998. An abnormal frequency doubling technology was defined in two ways, as having either at least one, or at least two abnormal locations. An abnormal standard automated perimetry was defined as fulfilling two of three modified Anderson criteria for abnormality on two consecutive tests and at final standard automated perimetry. RESULTS: Of 63 eyes (50 patients), 18 (28.6%) had >or=1 FDT defects, and 12 (19.0%) had >or=2 defects. After follow-up of 62 +/- 26 months, an abnormal standard automated perimetry developed in 5 eyes (28%) with frequency doubling technology defects at 22 +/- 13 months (28% of eyes with >or=1 defect and 42% of eyes with >or=2 FDT defects), and in 4 of 45 eyes (9%) with normal frequency doubling technology at 32 +/- 30 months. Kaplan-Meier survival analysis revealed the risk of an abnormal standard automated perimetry at 5 years with or=1 defects, and >or=2 defects, was 10.3%, 11.8%, 30.6%, and 46.4% respectively (P = 0.060 for >or=1 defects compared with no defects; P = 0.002 for >or=2 defects compared with 相似文献   

Application of frequency doubling technology perimetry in the diagnosis of glaucoma

PURPOSE: Evaluation of the frequency doubling technology perimetry in the detection of an early glaucomatous field loss. MATERIAL AND METHODS: Twenty-two patients (40 eyes), who were diagnosed with ocular hypertension were enrolled in the study. The diagnosis was made based on slit lamp examination, 3 measurements of intraocular pressure (IOP) over 21 mmHg. Standard perimetry was performed with Humphrey perimeter and SITA program (30-2 threshold). Then, all patients underwent FDT perimetry with 30-2 threshold program. Patients, who had any changes in FDT visual field had to repeat the test, to confirm the results. RESULTS: Out of 40 eyes with the normal white on white perimetry 5 eyes (5 patients) presented defects in FDT perimetry. They had optic disc c/d asymmetry > 0.1 and the nerve fiber layer defects corresponding to the visual field defects in FDT perimetry. CONCLUSION: Frequency Doubling Technology perimetry may be useful as a supplemental method of the visual field evaluation, particularly in patients where standard perimetry does not show any functional damage.     

Correlation between confocal tomography of the optic nerve (HRT) and the perimetric frequency doubling technology

PURPOSE AND METHODS: To correlate the five phases of optic nerve (ON) damage staging, as assessed by means of confocal tomography (HRT) with the five stages of visual field, assessed by conventional perimetry (standard automatic perimetry, SAP) and classified in five stages according to the "GLAUCOMA STAGING SYSTEM". The second step was to correlate the same optic nerve staging system with the results of the visual field tested with non-conventional perimetry using the frequency doubling technology (FDT) employing the Humphrey-Zeiss and Welch-Allyn perimeter. The five stages of FDT visual field data evolution were classified according to the new "FDT STAGING SYSTEM". MATERIAL: 58 visual fields of 58 consecutive selected patients with either ocular hypertension or glaucoma with an age-range between 15 and 65 years. METHOD: Visual field examination was performed with conventional (Octopus G2 threshold test) and non-conventional perimetry (FDT N30 threshold test), and the ON was assessed with confocal tomography (Heidelberg Retina Tomograph). RESULTS: In 40 % of the visual fields tested normal with conventional perimetry, non-conventional perimetry (FDT) detected glaucomatous visual field defects corresponding topographically with the optic nerve damage revealed by HRT. CONCLUSIONS: New non-conventional perimetric techniques such as FDT enable the very early detection of visual field defects topographically correlated to optic nerve damage.     

Learning effect of Humphrey Matrix perimetry

BACKGROUND: Humphrey Matrix perimetry is a recent development in automated perimetry that uses frequency-doubling technology (FDT). We evaluated the learning effect of Humphrey Matrix perimetry with a full-threshold 30-2 strategy. METHODS: Twenty-four patients with primary open-angle glaucoma and early visual field defects as assessed by standard automated perimetry and 24 healthy control subjects participated. All subjects had no prior experience with FDT visual field tests. Humphrey Matrix perimetry using a full-threshold 30-2 strategy was performed 3 times within 1 month. Various visual field indices were compared across multiple tests. RESULTS: Mean deviation (MD) showed a larger defect at the first test than at the second and third tests (p < 0.001), and the mean total improvement of the MD was 2.80 decibels (dB) in the glaucoma group and 1.71 dB in the control group. Pattern standard deviations (PSDs) were decreased as the tests were repeated, but test duration, fixation losses, and false-positive or false-negative rate were not changed significantly. Additionally, the Glaucoma Hemifield Test (GHT) showed unstable results. INTERPRETATION: In patients naive to the FDT test, Humphrey Matrix perimetry showed a large learning effect on MD and PSD among the various visual field indices. The GHT results of Humphrey Matrix perimetry showed a large instability.