Perceived spatial frequency of sinusoidal gratings

Should clinical automated perimetry be considered for routine functional assessment of early/intermediate age-related macular degeneration (AMD)? A systematic review of current literature

Purpose

There is growing interest in functional testing for early/intermediate age‐related macular degeneration (iAMD). However, systematic evaluation of existing clinical functional tests is lacking. This systematic review examines evidence for using clinical automated perimetry in routine assessment of early/iAMD.

Recent findings

PubMed, Web of Science Core Collection, and Embase were searched from inception to October 2020 to answer, is there evidence of visual field defects in early/iAMD, and if so, are early/iAMD visual field defects linked to real‐world patient outcomes? Articles using clinical automated perimetry (commercially accessible and non‐modified devices/protocols) were included. Microperimetry was excluded as this has yet to be incorporated into clinical guidelines. The primary outcome was global visual field indices including mean deviation (MD), pattern standard deviation (PSD), mean sensitivity (MS) and frequency of defects. The secondary outcome was any real‐world patient outcome including quality of life and/or activities of daily living indices. Twenty‐six studies were eligible for inclusion and all studies were observational. There was consistent evidence of worsened MD, PSD, MS and frequency of defects for early/iAMD compared to normal eyes under photopic, low‐photopic and scotopic conditions. Meta‐analysis of studies using standard automated perimetry (SAP) under photopic conditions revealed worsened MD (−1.52dB [−2.27, −0.78 dB]) and MS (−1.47dB [−2, −0.94 dB]) in early/iAMD compared to normal eyes, representing large statistical effect sizes but non‐clinically meaningful reductions. There was insufficient data for meta‐analyses regarding other clinical automated perimetry protocols. Only one study assessed a real‐world patient outcome (on‐road driving performance), with no significant link to visual field outcomes in early/iAMD.

Summary

Significant reduction of global visual field indices is present in early/iAMD, but not clinically meaningful using SAP under photopic conditions. Translational relevance of visual field outcomes to patient outcomes in early/iAMD remains unclear. Thus, SAP under photopic conditions is unlikely to be useful for routine assessment of early/iAMD.

Functional assessment of glaucoma: Uncovering progression

Clinicians who manage glaucoma patients carefully monitor the visual field to determine if treatments are effective or interventions are needed. Visual field tests may reflect disease progression or variability among examinations. We describe the approaches and perimetric tests used to evaluate glaucomatous visual field progression and factors that are important for identifying progression. These include stimulus size, which area of the visual field to assess (central versus peripheral), and the testing frequency, evaluating which is important to detect change early while minimizing patient testing burden. We also review the different statistical methods developed to identify change. These include trend- and event-based analyses, parametric and nonparametric tests, population-based versus individualized approaches, as well as pointwise and global analyses. We hope this information will prove useful and important to enhance the management of glaucoma patients. Overall, analysis procedures based on series of at least 5 to 6 examinations that require confirmation and persistence of changes, that are guided by the pattern and shape of the glaucomatous visual field deficits, and that are consistent with structural defects provide the best clinical performance.

Development of a new algorithm based on FDT Matrix perimetry and SD-OCT to improve early glaucoma detection in primary care

Purpose

The purpose of this study was to develop an objective algorithm to discriminate the earliest stages of glaucoma using frequency doubling technology (FDT) Matrix perimetry and spectral domain-optical coherence tomography (OCT) technology to improve primary care detection.

Materials and methods

Three hundred six eyes (mean age 58.67±15.12) from 161 patients were included and classified in the following three groups: 101 nonglaucoma (GI-NG), 100 glaucoma suspect (GII-SG), and 105 open-angle glaucoma (GIII-OAG). All participants underwent a visual field exploration using the Humphrey Matrix visual field instrument and retinal nerve fiber layer evaluation using the Topcon 3D OCT-2000. Pattern deviation plot was divided into 19 areas and five aggrupation or quadrants and ranked with a value between 0 and 4 according to its likelihood of normality, and differences among three groups were analyzed. Principal component analysis (PCA) was also used to extract the most notable features of FDT and OCT, and a logistic regression analysis was applied to obtain the classification rules.

Results

Only area numbers 7 and 12 and the central zone of FDT Matrix showed statistical differences (P<0.05) between GI-NG and GII-SG. The classification rules were estimated by the four PCA obtained from FDT Matrix and 3D OCT-2000 in a separate and combined use. Area under the receiver operating characteristic curve was 78.88% with FDT-PCA, 82.09% with OCT-PCA, and 94.27% with combined use of FDT and OCT-PCA to discriminate GI-NG and GII-SG.

Conclusion

The predictive rules based on FDT-PCA or OCT-PCA provide a high sensitivity and specificity to detect the earliest stages of glaucoma and even better in combined use. These predictive rules may help the future development of software for FDT Matrix perimetry and 3D OCT-2000, which will greatly improve their diagnostic ability, making them useful in daily practice in a primary care setting.

SITA-Standard perimetry has better performance than FDT2 matrix perimetry for detecting glaucomatous progression

PURPOSE

The Humphrey Matrix (FDT2) may be more sensitive in detecting glaucomatous visual field loss than SITA standard automated perimetry (SAP) performed on the Humphrey Field Analyzer (HFA). Therefore, FDT may be a good candidate to determine disease progression in patients with glaucoma. Our aim was to test the hypothesis that automated perimetry using the FDT2 would be equal to, or more effective than, HFA SITA-Standard, in identifying glaucomatous progression.

METHODS

One hundred and twenty patients with glaucoma were tested twice at baseline and every 6 months for 4 years with HFA SITA-Standard and FDT2. FDT2 values were standardised to HFA SAP values. We used pointwise linear regression (PLR) over the full data series to identify glaucomatous progression and generated an array of results using three different criteria: (1) three or more clustered test locations progressing, (2) three or more non-clustered test locations progressing and (3) total number of progressing test locations. We compared HFA SAP and FDT2 for the number of locations signalled by the PLR detection algorithm.

RESULTS

Regardless of the criteria, HFA SAP with SITA-Standard testing detected visual field progression at a higher rate than the FDT2 overall (P<0.001).

CONCLUSION

HFA SAP identifies glaucomatous visual field progression at a rate at least as high if not higher than FDT2.

Test Conditions in Macular Visual Field Testing in Glaucoma

PURPOSE

The purpose of this study is to evaluate the suitable visual field (VF) test conditions (target size, test type, and eccentricity) for the macular region, we investigated the correlations between the ganglion cell layer (GCL) thickness and 6 VF test results.

METHODS

We tested 32 eyes of patients (61.1±9.2 y) with preperimetric (6), early-stage (16), and moderate-stage (10) glaucoma. The VF tests included 3 SAP (the 10-2 HFA using SITA with target size III [HFA SITA (III)], full threshold with size III [HFA FULL (III)] and size I [HFA FULL (I)]) and 3 visual function-specific perimetry tests (the 10-2 SWAP, 10-2 flicker, and 10-2 Humphrey Matrix). The GCL and inner plexiform layer (GCL+IPL) thickness was measured by Spectral Domain Optical Coherence Tomography (SD-OCT) with a macular 7×7 mm cube scan (3D OCT-2000, Topcon). The coefficient of determination (r) for the correlation between visual sensitivity and the GCL+IPL thickness was calculated for each test at eccentricities 0 to 5 degrees, 5 to 7 degrees, and 7 to 10 degrees using linear and quadratic regressions.

RESULTS

All 6 tests showed the strongest correlation with the GCL+IPL thickness at 5 to 7 degrees. The respective r (linear) and R (quadratic) for HFA SITA (III), HFA FULL (III), HFA FULL (I), SWAP, Flicker, and Matrix were (0.40, 0.50), (0.43, 0.53), (0.44, 0.46), (0.51, 0.51), (0.33, 0.34), and (0.52, 0.52).

CONCLUSIONS

As compared with the frequently-used SAP with a size III, SAP with size I and the function-specific perimetry tests (especially the Matrix) could be more suitable for testing the macular region.

Comparison of matrix frequency-doubling technology perimetry and standard automated perimetry in monitoring the development of visual field defects for glaucoma suspect eyes

BACKGROUND

Perimetry is indispensable for the clinical management of glaucoma suspects. Our goal is to compare the performance of standard automated perimetry (SAP) and Matrix frequency-doubling technology (FDT) perimetry in monitoring the development of visual field (VF) defects in glaucoma suspect eyes.

METHODS

Longitudinal data of paired SAP and FDT from 221 eyes of 155 glaucoma suspects enrolled in the Diagnostic Innovations in Glaucoma Study or the African Descent and Glaucoma Evaluation Study were included. All eyes had glaucomatous optic neuropathy or ocular hypertension, but normal SAP and FDT results at baseline. The development of glaucomatous VF defects was defined as the presence of a cluster of ≥ 3 (less conservative) or ≥ 4 (more conservative) locations confirmed on ≥ 2 additional consecutive tests. Risk factors for the development of VF defects were analyzed by COX proportional hazard models. After conversion into common logarithmic units, the rates of change of global VF indices were fitted with linear mixed models.

RESULTS

FDT detected more eyes that developed VF defects than SAP using the less conservative criterion, and no significant difference was observed using the more conservative criterion. For those eyes detected by both SAP and FDT, FDT detected the development of VF defects either earlier than SAP or simultaneously in most cases. Baseline structural measurements were not significantly associated with an increased risk for the development of glaucomatous VF defects on either SAP or FDT. Older age was significantly associated with the development of VF defects on FDT but not on SAP. Both SAP and FDT detected a progressing worsening trend of pattern standard deviation over time with a similar rate of change between these test types.

CONCLUSIONS

Matrix FDT would be useful to monitor the onset of VF defects in glaucoma suspects and may outperform SAP in the early stage of glaucomatous VF damage.

Predicting conversion to glaucoma using standard automated perimetry and frequency doubling technology

PURPOSE

To test the hypothesis that development of glaucomatous visual fields can be predicted several years earlier from prior visual field information.

METHODS

One-hundred and seven eyes with glaucomatous optic neuropathy (n = 47 eyes) or which were suspicious for glaucoma (n = 60) were prospectively enrolled in a longitudinal study. Visual fields were evaluated on an annual basis using standard automated perimetry (SAP), the original version of frequency doubling technology (FDT) perimetry, and a custom version of FDT that used the 24-2 stimulus pattern. All SAP fields were within normal limits at the initial visit. When the SAP glaucoma hemifield test was 'outside normal limits' or the pattern standard deviation probability was worse than the lower 5th percentile or more than two clustered locations at the p < 0.05 level were present on the pattern deviation probability plot, an eye was defined as being abnormal. We used a classification tree analysis to predict which eyes would convert, using only baseline test results.

RESULTS

Classification trees that were constructed using only baseline data had excellent specificity (near 100%) but worse sensitivity (25-50%) for predicting which eyes would convert during follow-up.

CONCLUSIONS

Predictive information is present in visual field results, even when they are still within normal limits.

Steady-state pattern electroretinogram and frequency doubling technology in anisometropic amblyopia

Background

Steady-state pattern electroretinogram (PERG) and frequency doubling technology (FDT) perimetry can be used to selectively investigate the activity of the M-Y ganglion cells in adult anisometropic amblyopes.

Methods

Fifteen normal subjects (mean 27.8±4.1 years) and 15 adults with anisometropic amblyopia (mean 28.7±5.9 years) were analyzed using steady-state PERG and FDT.

Results

The amplitude of steady-state PERG was significantly different not only among the control group and both the amblyopic eye (P=0.0001) and the sound eye group (P=0.0001), but also between the latter two groups (P=0.006). The difference in FDT mean deviation was statistically significant not only between the control group and amblyopic eye group (P=0.0002), but also between the control group and the sound eye group (P=0.0009). The FDT pattern standard deviation was significantly higher in the control group rather than in the amblyopic eye (P=0.0001) or the sound eye group (P=0.0001). A correlation was found between the reduction in PERG amplitude and the increase in FDT-pattern standard deviation index not only in amblyopic (P=0.0025) and sound (P=0.0023) eyes, but also in the healthy control group (P=0.0001).

Conclusion

These data demonstrate that in anisometropic amblyopia, there is an abnormal functionality of a subgroup of the magnocellular ganglion cells (M-Y), and the involvement of these cells, together with the parvocellular pathway, may play a key role in the clinical expression of the disease.

Comparison of Standard Automated Perimetry, Short-Wavelength Automated Perimetry, and Frequency-Doubling Technology Perimetry to Monitor Glaucoma Progression

Detection of progression is paramount to the clinical management of glaucoma. Our goal is to compare the performance of standard automated perimetry (SAP), short-wavelength automated perimetry (SWAP), and frequency-doubling technology (FDT) perimetry in monitoring glaucoma progression.Longitudinal data of paired SAP, SWAP, and FDT from 113 eyes with primary open-angle glaucoma enrolled in the Diagnostic Innovations in Glaucoma Study or the African Descent and Glaucoma Evaluation Study were included. Data from all tests were expressed in comparable units by converting the sensitivity from decibels to unitless contrast sensitivity and by expressing sensitivity values in percent of mean normal based on an independent dataset of 207 healthy eyes with aging deterioration taken into consideration. Pointwise linear regression analysis was performed and 3 criteria (conservative, moderate, and liberal) were used to define progression and improvement. Global mean sensitivity (MS) was fitted with linear mixed models.No statistically significant difference in the proportion of progressing and improving eyes was observed across tests using the conservative criterion. Fewer eyes showed improvement on SAP compared to SWAP and FDT using the moderate criterion; and FDT detected less progressing eyes than SAP and SWAP using the liberal criterion. The agreement between these test types was poor. The linear mixed model showed a progressing trend of global MS overtime for SAP and SWAP, but not for FDT. The baseline estimate of SWAP MS was significantly lower than SAP MS by 21.59% of mean normal. FDT showed comparable estimation of baseline MS with SAP.SWAP and FDT do not appear to have significant benefits over SAP in monitoring glaucoma progression. SAP, SWAP, and FDT may, however, detect progression in different glaucoma eyes.

Screening for Patients with Mild Alzheimer Disease Using Frequency Doubling Technology Perimetry

We compared the visual field performances of patients with mild Alzheimer disease (AD) with normal subjects and detected visual field impairment attributable to the magnocellular pathway using frequency doubling technology-Matrix (FDT-Matrix). We recruited 43 patients with mild AD (mean age: 68.0 ± 7.2 years) and 33 controls who are visually and cognitively normal (mean age: 64.1 ± 6.4 years). All participants had at least two reliable FDT-Matrix 30-2 tests. Reliability indices, global indices (mean deviation and pattern standard deviation), and glaucoma hemifield test results were measured with FDT-Matrix. The mean test duration was significantly longer in patient group compared with controls (p = 0.002). Among the reliability indices, false negatives were higher in patient group than controls (p = 0.003). There were statistically significant differences in mean deviation and pattern standard deviation values (p < 0.0001 and p < 0.0001, respectively) and glaucoma hemifield test results (p < 0.001) between the patient and the control group. Our results imply that the pathogenesis of cognitive deterioration may not only be confined to the cortical area but also to the magnocellular pathway. We underline that FDT testing can be useful for the identification of early impairment and the follow-up of patients with AD.

Visual field loss in schizophrenia: evaluation of magnocellular pathway dysfunction in schizophrenic patients and their parents

Purpose:

We sought to evaluate the visual pathway deficits in schizophrenic patients, compared with their parents and healthy controls, using Matrix frequency doubling technology (FDT) perimetry. Matrix FDT is an ophthalmic test used to detect visual field loss.

Method:

A total of 13 patients, 13 parents, and 12 healthy controls were enrolled in the study. Participants were subjected to Matrix FDT perimetry in a single test session. We analyzed the mean deviation for each eye and used a generalized estimated equation to evaluate differences among the groups and correct the dependency between the eyes.

Results:

The global mean deviation (presented as the mean of both eyes) was significantly lower in the schizophrenic patients than in their parents or controls. Analysis of the general sensitivity of the fibers crossing the optic chiasm showed a difference between the groups (P = 0.006), indicating that the sensitivity of the fibers crossing the optic chiasm was lower than those which did not cross. But when we analyzed the specific groups, the difference between the fibers was not considerable. Comparison of the right and left hemispheres showed that general sensitivity was lower for the left hemisphere, but when we analyzed specific groups, the difference was not significant (P = 0.29).

Conclusion:

These findings are suggestive of a lower global sensitivity in schizophrenic patients and their parents compared with controls. This difference may be an endophenotype of schizophrenia. The present study adds to a growing body of research on early-stage visual processing deficits in schizophrenia.

Psychophysical and electrophysiological testing in ocular hypertension

PURPOSE

The purpose of this study was to compare psychophysical and electrophysiological testings in early optic nerve dysfunction in a group of clinically asymptomatic subjects with suspect ocular hypertension (OHT).

METHODS

Forty eyes of 40 patients with suspect OHT and asymmetrical horizontal cup/disc ratio (0.2/0.4), 22 eyes of 22 patients with open-angle glaucoma (OAG), and 40 eyes of 40 healthy controls were evaluated by using frequency-doubling technology perimetry (FDT), contrast sensitivity (CS), pattern electroretinography (PERG), and pattern visual-evoked potentials (VEP). The VEP were elicited by checkerboard stimuli with large (VEP 120), medium (VEP 45), and small (VEP 15) checks; then the values of the amplitude (A) and latency (L) of P100 peaks were studied. Receiver operator characteristic (ROC) curves were calculated to determine the sensitivity, specificity, and optimal cutoff points of abnormal values. A logistic regression analysis was performed to determine which tests were providing the most useful information. In addition, Kruskal-Wallis test was performed to test the differences between the control group and the OHT group.

RESULTS

VEP P100 peak latency (VEP L15 and VEP L45) and amplitude (VEP A120), PERG N95 peak amplitude, CS at medium spatial frequencies (CS 4SF), and FDT pattern standard deviation (PSD) yielded the greatest sensitivity (85.0 to 60.0%) and specificity (80.0 to 60.0%) ratio, displaying the largest ROC curve areas; whereas PERG N95 peak latency ROC curve had the smallest areas. Kruskal-Wallis test showed that most diagnostic tests were able to differentiate the OHT group from the control group. Stepwise logistic regression analysis identified VEP L15 (p < 0.001), CS 4SF (p = 0.023), FDT PSD (p = 0.032), and VEP A120 (p = 0.072) as tests that could be useful to distinguish controls from OHT.

CONCLUSIONS

Our data confirm that psychophysical and electrophysiological tests are useful for early detection of patients at risk of developing OAG.

[Importance of flicker contrast tests in functional glaucoma diagnostics]

One of the many unsolved problems concerning glaucoma is early detection and many different methodologies have been developed. This article concentrates on methodologies belonging to the class of flicker contrast tests which present dynamic stimuli (with temporal frequencies generally above 10 Hz) and assess the perceptual thresholds for contrast, be it global or locally resolved. The tests include global flicker sensitivity, flicker perimetry (current embodiment: Pulsar), Rauschfeld campimetry, frequency doubling perimetry and flicker-defined edge perimetry. These different approaches are placed into historical perspective and are critically assessed.

Usefulness of frequency-doubling technology for perimetrically normal eyes of open-angle glaucoma patients with unilateral field loss

PURPOSE

To determine whether frequency-doubling technology (FDT) perimetry detects visual field loss in perimetrically normal eyes of patients with open-angle glaucoma (OAG) and whether these visual field defects subsequently are detected by standard automated perimetry (SAP), and to explore the relating factors of the progression from abnormalities based on FDT to visual field loss based on SAP.

DESIGN

Prospective cohort study.

PARTICIPANTS

Sixty-eight OAG patients with unilateral field loss detected by SAP (Octopus, G2 program; Interzeig, Schlieren, Switzerland).

METHODS

Perimetrically normal eyes of participants were examined with the FDT N-30 threshold program (Humphrey Instruments, Welch-Allyn, Skaneateles, NY). The visual field examination was followed by a series of SAP examinations administered over 3 years.

MAIN OUTCOME MEASURES

The relationship between FDT and subsequent SAP results in perimetrically normal eyes was analyzed. Glaucomatous optic neuropathy (GON), visual field indices, intraocular pressure (IOP), and central corneal thickness (CCT) were compared between converters (eyes with subsequent SAP abnormality) and nonconverters within perimetrically normal eyes with abnormal FDT results. Finally, the SAP test points were matched to the abnormal FDT sectors. The relative risk (RR) of subsequent SAP abnormality corresponding to FDT abnormal sectors was calculated.

RESULTS

Sixty perimetrically normal eyes of 60 participants had complete data and a qualifying follow-up. Baseline FDT results were abnormal in 65%. Of the eyes with abnormal FDT results, 51% developed abnormal SAP results after 4 to 27 months, whereas none of the eyes with normal FDT results developed abnormal SAP results (P<0.05). In perimetrically normal eyes with abnormal FDT results, converters had a greater cup-to-disc ratio, more eyes with GON, larger and deeper cups, and worse FDT mean deviation than nonconverters (P<0.05). The IOP and CCT did not differ between the 2 groups. The RR of subsequent SAP abnormality corresponding to abnormal FDT sectors was 5.38 (95% confidence interval, 3.61-8.04; P<0.05).

CONCLUSIONS

In perimetrically normal eyes of OAG patients, FDT detected visual field loss in almost 2 of every 3 of these eyes and also predicted to some extent future visual field loss on SAP. Severity of glaucomatous neuropathy at baseline was related to conversion of abnormalities on FDT to visual field loss on SAP.

Non-conventional perimetric methods in the detection of early glaucomatous functional damage

PURPOSE

To compare the ability of frequency-doubling technology (FDT), rarebit perimetry (RBP), and pulsar perimetry (PP) in detecting early glaucomatous functional damage.

METHODS

This prospective observational cross-sectional case study included 52 patients with early primary open-angle glaucoma (mean deviation -2.3+/-1.1 dB; pattern standard deviation 3.0+/-1.2 dB) and 53 healthy controls. Visual field (VF) testing included standard automated perimetry (SAP) Humphrey Field Analyzer 30-2, FDT N-30, RBP (version 4.0), and PP T30W. One eye per patient was considered. Sensitivity at fixed specificities and area under the receiver operating characteristic curve (AROC) for discriminating between healthy and glaucomatous eyes were calculated and compared.

RESULTS

The parameters associated with the largest AROC, which were not statistically different (Hanley-McNeil method, P0.42-0.71) were as follows: number of locations in the pattern deviation probability (PDP) plot with P<5% for FDT (0.93); mean hit rate for RBP (0.95); and mean defect for PP (0.94). PP test duration was significantly shorter than FDT and RBP (P<0.002).

CONCLUSIONS

FDT, PP, and RBP are useful non-conventional VF methods in detecting early glaucomatous VF defects with similar AROCs. The methods were rapid and easy, and PP took less than half the time than SAP. These non-conventional testing may prove to be useful in providing additional information in the diagnosis of glaucoma suspect with normal SAP results, in the therapeutic decision-making process of early glaucomatous patients, and in subjects unable to perform VF testing with SAP.