Frequency Doubling Technology Perimetry Testing Research Articles

Increased Incidence of Visual Field Abnormalities as Determined by Frequency Doubling Technology Perimetry in High Computer Users Among Japanese Workers: A Retrospective Cohort Study.

BackgroundThis retrospective cohort study primarily aimed to investigate the possible association of computer use with visual field abnormalities (VFA) among Japanese workers.MethodsThe study included 2,377 workers (mean age 45.7 [standard deviation, 8.3] years; 2,229 men and 148 women) who initially exhibited no VFA during frequency doubling technology perimetry (FDT) testing. Subjects then underwent annual follow-up FDT testing for 7 years, and VFA were determined using a FDT-test protocol (FDT-VFA). Subjects with FDT-VFA were examined by ophthalmologists. Baseline data about the mean duration of computer use during a 5-year period and refractive errors were obtained via self-administered questionnaire and evaluations for refractive errors (use of eyeglasses or contact lenses), respectively.ResultsA Cox proportional hazard analysis demonstrated that heavy computer users (>8 hr/day) had a significantly increased risk of FDT-VFA (hazard ratio [HR] 2.85; 95% confidence interval [CI], 1.26–6.48) relative to light users (<4 hr/day), and this association was strengthened among subjects with refractive errors (HR 4.48; 95% CI, 1.87–10.74). The computer usage history also significantly correlated with FDT-VFA among subject with refractive errors (P < 0.05), and 73.1% of subjects with FDT-VFA and refractive errors were diagnosed with glaucoma or ocular hypertension.ConclusionsThe incidence of FDT-VFA appears to be increased among Japanese workers who are heavy computer users, particularly if they have refractive errors. Further investigations of epidemiology and causality are warranted.

Frequency Doubling Technology Perimetry for Detection of Visual Field Progression in Glaucoma: A Pointwise Linear Regression Analysis

We compared the detection of visual field progression and its rate of change between standard automated perimetry (SAP) and Matrix frequency doubling technology perimetry (FDTP) in glaucoma. We followed prospectively 217 eyes (179 glaucoma and 38 normal eyes) for SAP and FDTP testing at 4-month intervals for ≥36 months. Pointwise linear regression analysis was performed. A test location was considered progressing when the rate of change of visual sensitivity was ≤-1 dB/y for nonedge and ≤-2 dB/y for edge locations. Three criteria were used to define progression in an eye: ≥3 adjacent nonedge test locations (conservative), any three locations (moderate), and any two locations (liberal) progressed. The rate of change of visual sensitivity was calculated with linear mixed models. Of the 217 eyes, 6.1% and 3.9% progressed with the conservative criteria, 14.5% and 5.6% of eyes progressed with the moderate criteria, and 20.1% and 11.7% of eyes progressed with the liberal criteria by FDTP and SAP, respectively. Taking all test locations into consideration (total, 54 × 179 locations), FDTP detected more progressing locations (176) than SAP (103, P < 0.001). The rate of change of visual field mean deviation (MD) was significantly faster for FDTP (all with P < 0.001). No eyes showed progression in the normal group using the conservative and the moderate criteria. With a faster rate of change of visual sensitivity, FDTP detected more progressing eyes than SAP at a comparable level of specificity. Frequency doubling technology perimetry can provide a useful alternative to monitor glaucoma progression.

Frequency-Doubling Technology Perimetry for Detection of the Development of Visual Field Defects in Glaucoma Suspect Eyes

While standard automated perimetry (SAP) remains the reference standard for evaluation of visual field (VF) defects in glaucoma, this study demonstrates that frequency-doubling technology (FDT) perimetry is effective in monitoring visual field progression and may detect the onset of visual field defects earlier than SAP. To compare detection of the development of VF defects, rate of change of VF loss, and risk factors for progression between SAP and matrix FDT perimetry in glaucoma suspect and ocular hypertensive eyes. A total of 113 glaucoma suspect and ocular hypertensive eyes from 76 patients with normal SAP and FDT perimetry results at baseline were prospectively followed up for SAP and FDT perimetry testing at approximately 4-month intervals for 30 months or longer. Patients were consecutively enrolled and followed up from January 2, 2008, to February 28, 2012, at the Hong Kong Eye Hospital, Chinese University of Hong Kong. Visual field progression was defined by the development of VF defects confirmed by 3 or more consecutive examinations at a cluster of 3 or more (less conservative) or 4 or more (more conservative) locations. The rates of change of mean deviation and pattern standard deviation were evaluated with linear mixed models and the risk factors for VF progression were computed with Cox proportional hazard models. During a median study period of 3.4 years, 8.0% of eyes developed VF defects detected by FDT perimetry, 6.2% by SAP, and 4.4% by both using the less-conservative criteria. The detection dropped to 6.2%, 4.4%, and 2.7%, respectively, when the more-conservative criteria were applied. The rate of change of pattern standard deviation was significantly faster for FDT perimetry than SAP (P < .001). Baseline average retinal nerve fiber layer thickness and the number of clock hours of abnormal retinal nerve fiber layer measurement were associated with increased risk for VF progression for both SAP and FDT perimetry. Frequency-doubling technology perimetry would be useful to monitor the onset of VF defects in glaucoma and may detect VF defects not evident in SAP.

The Validity of Screening For Open-angle Glaucoma in High-risk Populations With Single-test Screening Mode Frequency Doubling Technology Perimetry (FDT)

To evaluate whether a single frequency doubling perimetry (FDT) test is a valid screening tool to detect open-angle glaucoma (OAG) in high-risk populations. All participants underwent frequency doubling Technology perimetry (FDT C-20-5 algorithm, Carl Zeiss Meditec Inc, Dublin, CA) and complete ophthalmic examination. FDT printouts were classified according to Iwasaki and Patel protocols. Gold-standard was clinical diagnosis of glaucomatous optic nerve damage. Sensitivity, specificity, positive predictive value, negative predictive value, positive, and negative likelihood ratios of a single-test screening FDT. Data of 445 right eyes and 408 left eyes of participants were analyzed. On the basis of clinical diagnosis, 19 right eyes (4.3%) and 20 left eyes (4.9%) had glaucoma. Depending on the gold standard used, the range of sensitivity was between 40.7% and 78.9%, 66% and 70% for specificity, 7.7% and 25.2% for positive predictive value, 82.3% and 98.6% for negative predictive value, 1.25 and 2.37 for positive likelihood ratio, and 0.32 and 0.87 for negative likelihood ratio. The κ coefficient of agreement between the FDT classifications as described by Iwasaki et al and Patel et al was 0.936 in right eyes and 0.935 in left eyes. The sensitivity and specificity of a single reliable screening FDT test were low. Thus, a single screening FDT test in even a high-risk population has poor validity and steps should be taken to better define the target population before testing, and enhance the FDT screening strategy.

Optimizing the Use of Frequency Doubling Technology Perimetry in Community Vision Screenings

In recent years, Frequency Doubling Technology perimetry (FDT) has been added to traditional ocular health testing in screening for glaucoma. This study examines a number of strategies to employ FDT in an effort to determine its optimal use in large community screenings. In Part I, 1253 persons participated in a free, community vision screening in a large metropolitan area. FDT testing was limited to those in a high-risk group, defined as individuals over age 45 and either black or having a family history of glaucoma that passed the eye health part of the screening. In Part II, a simulated screening performed at the same location examined four different strategies for utilizing FDT: (1) FDT limited to the high risk group passing eye health testing; (2) FDT on all persons passing eye health testing; (3) FDT and eye health testing on all persons; and (4) FDT on all persons, without eye health testing. In the community screening, 1043 persons (83.2%) passed the eye health testing. 159 (15.2%) of the 1043 were in the high risk group and were tested with FDT. 19 (1.5%) of these tests resulted in failure. There were few unreliable tests (5.0%). For the simulated screening, specificity and sensitivity with 95% confidence intervals for strategies one through four were, respectively, 83.3% (64.5 to 93.7) and 77.8% (51.9 to 92.6); 80.0% (60.9 to 91.6) and 88.9% (63.9 to 98.1); 76.7% (57.3 to 89.4) and 94.4% (70.6 to 99.7); 90.0% (72.3 to 97.4) and 38.9% (18.3 to 63.9). In the community screening, FDT performed reliably and identified abnormalities in a significant number of persons in the high-risk group passing the eye health part of the screening. However, with the exception of the poor sensitivity shown by strategy 4, results from the simulated screening did not support the usefulness of one strategy over another.

The association of office intraocular pressure fluctuation in ocular hypertension with frequency doubling technology perimetry abnormality

To characterize intraocular pressure (IOP) and central corneal thickness (CCT) measurements of ocular hypertension (OHT) patients with and without frequency doubling technology (FDT) perimetry test abnormalities. In this prospective, observational, cross-sectional, comparative case series, one eye of 33 OHT patients was randomly chosen. All OHT patients had IOP > or = 23 mmHg in 2 out of 3 measurements on the test day, normal appearing discs and nerve fiber layer, and normal white on white standard automated perimetry (SAP). Several IOP calculations (outpatient IOP, highest office IOP, mean office IOP, office IOP fluctuation, and office IOP peak), CCT, SAP and FDT parameters were compared between OHT patients with repeatable FDT perimetry abnormality and normal FDT perimetry. Eight (24%) of 33 OHT patients had an abnormal FDT perimetry test. The median office IOP fluctuation (5.0 vs 2.0, P = 0.007), office IOP peak (3.2 vs 1.0, P = 0.004), and FDT pattern standard deviation (PSD) (5.03 v 3.32, P = 0.000) were significantly higher in OHT patients with repeatable FDT perimetry test abnormalities compared to OHT patients with normal FDT perimetry test. Office IOP fluctuation and office IOP peak were significantly correlated with both number of significantly depressed FDT points and FDT PSD index. CCT measurements and SAP global indices did not differ significantly in OHT patients with and without FDT perimetry test abnormality. Our results suggest that currently diagnosed OHT patients who have large office IOP fluctuations and office IOP peaks are more likely to have repeatable FDT perimetry test abnormalities. These results suggest that OHT patients with large IOP fluctuations and IOP peaks are more likely to have early glaucomatous damage, and this should be taken into account when assessing the risk of conversion to primary open angle glaucoma.

Laterality of the performance of glaucoma mass screening using frequency-doubling technology.

This study investigated laterality during the performance of glaucoma mass screening with a frequency-doubling technology perimetry test. A frequency-doubling technology screening mode (C-20-1, version 2.6) test was performed on both eyes of 14,784 persons. Subjects with visual field abnormalities detected by the frequency-doubling technology test or with fixation error underwent retesting without a specified interval for rest. Consequently, 206 subjects who fulfilled the screening criteria of the frequency-doubling technology-based glaucoma screening protocol [FDT-GSP(+)] were further investigated using the Humphrey visual field analyzer (30-2). As a result, 74 right eyes and 57 left eyes were shown to have definite glaucoma. Frequency-doubling technology data for the left eye demonstrated a significantly (P<0.001) higher rate of artifacts, such as no reproducibility of results between the first and second tests (left/right: 2.4%/1.7%) as well as fixation errors (left/right: 2.8%/1.0%). The false-positive rate of the FDT-GSP for glaucoma was more than 1.5-fold higher in the left eye than in the right eye (16.3%/9.8%). In the case that either eye exhibited FDT-GSP(+), the positive predictive value of the FDT-GSP for definite glaucoma in the left eye was almost half of that in the right eye (28.4% vs. 53.8%). Specificity of the FDT-GSP for detection of definite glaucoma also exhibited a lower trend (P = 0.097) in the left eye (44.6%) than in the right eye (55.3%), but the sensitivity of the test was similar in both eyes (91.2% vs. 90.5%, respectively). When frequency-doubling technology-based mass screening is performed on the general population, performance is lower for the left eye than for the right eye. This performance disparity is likely to be primarily associated with a difference in specificity.

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

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. 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. 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. 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.