Age-dependent normative values for differential luminance sensitivity in automated static perimetry using the Octopus 101

Multicenter Normative Data for Mesopic Microperimetry

Purpose

The purpose of this study was to provide a large, multi-center normative dataset for the Macular Integrity Assessment (MAIA) microperimeter and compare the goodness-of-fit and prediction interval calibration-error for a panel of hill-of-vision models.

Methods

Microperimetry examinations of healthy eyes from five independent study groups and one previously available dataset were included (1137 tests from 531 eyes of 432 participants [223 women and 209 men]). Linear mixed models (LMMs) were fitted to the data to obtain interpretable hill-of-vision models. A panel of regression models to predict normative data was compared using cross-validation with site-wise splits. The mean absolute error (MAE) and miscalibration area (area between the calibration curve and the ideal diagonal) were evaluated as the performance measures.

Results

Based on the parameters "participant age," "eccentricity from the fovea," "overlap with the central fixation target," and "eccentricity along the four principal meridians," a Bayesian mixed model had the lowest MAE (2.13 decibel [dB]; 95% confidence interval [CI] = 1.9-2.36 dB) and miscalibration area (0.13; 95% CI = 0.07-0.19). However, a parsimonious linear model provided a comparable MAE (2.17 dB; 95% CI = 1.93-2.4 dB) and a similar miscalibration area (0.14; 95% CI = 0.08-0.2).

Conclusions

Normal variations in visual sensitivity on mesopic microperimetry can be effectively explained by a linear model that includes age and eccentricity. The dataset and a code vignette are provided for estimating normative values across a large range of retinal locations, applicable to customized testing patterns.

Aging-associated changes of optical coherence tomography-measured ganglion cell-related retinal layer thickness and visual sensitivity in normal Japanese

PURPOSE

To report aging-associated change rates in circumpapillary retinal nerve fiber layer thickness (cpRNFLT) and macular ganglion cell-inner plexiform layer and complex thickness (MGCIPLT, MGCCT) in normal Japanese eyes and to compare the data in linear scaled visual field (VF) sensitivity of central 4 points of Humphrey Field Analyzer (HFA) 24-2 test (VF4TestPoints) to that in MGCIPLT in four 0.6-mm-diameter circles corresponding to the four central points of HFA 24-2 adjusted for retinal ganglion cell displacement (GCIPLT4TestPoints).

STUDY DESIGN

Prospective observational study METHODS: HFA 24-2 tests and spectral-domain optical coherence tomography (SD-OCT) measurements of cpRNFLT, MGCIPLT, MGCCT and GCIPLT4TestPoints were performed every 3 months for 3 years in 73 eyes of 37 healthy Japanese with mean age of 50.4 years. The time changes of SD-OCT-measured parameters and VF4TestPoints were analyzed using a linear mixed model.

RESULTS

The aging-associated change rates were -0.064 μm/year for MGCIPLT and and -0.095 for MGCCT (P=0.020 and 0.017), but could not be detected for cpRNFLT. They accelerated with aging at -0.009μm/year/year of age for MGCIPLT (P<0.001), at 0.011 for MGCCT (P<0.001) and at 0.013 for cpRNFLT(0.031). The aging-associated decline of -82.1 [1/Lambert]/year of VF4TestPoints corresponded to -0.095 μm/year of GCIPLT4TestPoints.

CONCLUSION

We report that aging-associated change rates of cpRNFLT, MGCIPLT and MGCCT in normal Japanese eyes were found to be significantly accelerated along with aging. Relationship between VF sensitivity decline rates and SD-OCT measured GCIPLT decline rates during physiological aging in the corresponding parafoveal retinal areas are also documented.

Online Circular Contrast Perimetry via a Web-Application: Establishing a Normative Database for Central 10-Degree Perimetry

Purpose

To establish a normative database using a central 10-degree grid pattern for the online circular contrast perimetry (OCCP) application.

Participants

Fifty participants with mean age 65 ± 13 years were selected for this study. One eye from each participant that met inclusion criteria was randomly included in the cohort.

Methods

The web-application delivered online 52-loci perimetry in a central 10-degree pattern using circular flickering targets. These targets consist of concentric sinusoidal alternating contrast rings. Users were guided by the application to the correct viewing distance and head position using in-built blind spot localization and webcam monitoring. A spinning golden star was used as the fixation target and patients performed the test in a darkened room following standard automated perimetry (SAP).

Results

The reliability rates and global indices for OCCP were similar to SAP. OCCP mean sensitivity reduced with age at a similar rate to SAP. Mean sensitivity per loci of 10-degree OCCP was greater than SAP by 1.24 log units (95% CI 1.23 to 1.26) and obeyed a physiological hill of vision. Small differences existed in mean sensitivities between OCCP and SAP which increased with increasing spot eccentricity. Mean deviation (MD) displayed good agreement between the two tests.

Conclusion

Central 10-degree online circular contrast perimetry via a computer-based application has comparable perimetric results to standard automated perimetry in a normal cohort.

Spatial Cluster Patterns of Retinal Sensitivity Loss in Intermediate Age-Related Macular Degeneration Features

Purpose

To examine spatial patterns of retinal sensitivity loss in the three key features of intermediate age-related macular degeneration (iAMD).

Methods

One-hundred individuals (53 iAMD, 47 normal) underwent 10-2 mesopic microperimetry testing in one eye. Pointwise sensitivities (dB) were corrected for age, sex, iAMD status, and co-presence of co-localized key iAMD features: drusen load, pigmentary abnormalities, and reticular pseudodrusen (RPD). Clusters (labeled by ranks of magnitude C-2, C-1, C0) were derived from pointwise sensitivities and then assessed by quadrants and eccentricity/rings.

Results

Two clusters of decreased sensitivities were evident in iAMD versus normal: C-2, -1.67 dB (95% CI (confidence intervals), -2.36 to -0.98; P < 0.0001); C-1, -0.93 dB (95% CI, -1.5 to -0.36; P < 0.01). One cluster of decreased sensitivity was independently associated each with increased drusen load (13.57 µm increase per -1 dB; P < 0.0001), pigmentary abnormalities (C-1: -2.23 dB; 95% CI, -3.36 to -1.1; P < 0.01), and RPD (C-1: -1.07 dB; 95% CI, -2 to -0.14; P < 0.01). Sensitivity loss in iAMD was biased toward the superior and central macula (P = 0.16 to <0.0001), aligning with structural distributions of features. However, sensitivity loss associated with drusen load also extended to the peripheral macula (P < 0.0001) with paracentral sparing, which was discordant with the central distribution of drusen.

Conclusions

Drusen load, pigmentary abnormalities, and RPD are associated with patterns of retinal sensitivity loss commonly demonstrating superior and central bias. Results highlighted that a clinical focus on these three key iAMD features using structural measures alone does not capture the complex, spatial extent of vision-related functional impairment in iAMD.

Translational Relevance

Defining the spatial patterns of retinal sensitivity loss in iAMD can facilitate a targeted visual field protocol for iAMD assessment.

Online circular contrast perimetry via a web-application: optimising parameters and establishing a normative database

PURPOSE

To establish a normative database and optimise parameters for personal-computer based perimetry via a web-application using circular contrast targets.

METHODS

Online 24-degree 52-loci perimetry was delivered through a web-application using circular flickering contrast targets. Embedding contrast differentials within targets allows calculation of relative decibel (rdB) per 256-bit greyscale level differential. Target light-band maximum brightness colour was fixed, while the dark-band varied to achieve the desired rdB level. A staircase system was used with two reversals ranging from 0 to 36 rdB levels. Blind spot localisation at the start of the test was used to optimise viewing distance and subsequently count fixation losses. Gaze was maintained on a spinning golden star which moves mid-test to maximise sampling area. Patients performed the test to each eye separately using a computer in a darkened room at 40-45 cm.

RESULTS

158 eyes of 101 patients completed the Online Circular Contrast Perimetry (OCCP) test. Mean age was 62.9 ± 14.3 years old. Mean sensitivity reduced with age, at 1.0 relative decibel per decade. Mean sensitivity per locus correlated with standard automated perimetry (SAP) in a physiological hill of vision, with an average difference of 4.02 decibels (95% confidence interval (CI) = 3.77-4.27, p < 0.001) and good agreement between tests.

CONCLUSIONS

Online circular contract perimetry provides accurate perimetric testing with comparable results to standard automated perimetry.

Three-Year Changes in Visual Function in the Placebo Group of a Randomized Double-Blind International Multicenter Safety Study: Analysis of Electroretinography, Perimetry, Color Vision, and Visual Acuity in Individuals With Chronic Stable Angina Pectoris

Purpose

To determine whether significant deteriorations in objective (electroretinography [ERG]) and subjective (standard automated and semi-automated kinetic perimetry; color discrimination; and best-corrected visual acuity) tests of visual function, potentially attributable to aging, occurred in the group randomized to placebo of a 3-year prospective multicenter ocular safety study of ivabradine for chronic stable angina pectoris.

Methods

The multicenter trial was conducted at 11 international ophthalmic centers. Changes in visual function between baseline and month 36 were analyzed by means of a two-tailed Wilcoxon signed-rank test, based on the Hodges and Lehman estimator of the median difference, with the 95% confidence intervals derived by Walsh averages.

Results

Thirty-eight participants from the placebo group completed the study (mean [SD], age, 62.7 [8.1] years). The group exhibited in each eye small, but statistically significant, reductions in the amplitudes of the dark-adapted (DA) ERG 3.0 a-wave, and light-adapted (LA) 3.0 b-wave, as well as increases in peak time for the DA 0.01 b-wave, DA 3.0 a-wave, LA 3.0 b-wave, and LA 3.0 30-Hz flicker response and in the isopter area I3e of the visual field.

Conclusions

Statistically significant deteriorations occurred in visual function over a period of 3 years, potentially attributable to age, within a group of individuals with chronic stable angina pectoris and unremarkable ophthalmological findings other than those attributable to age.

Translational Relevance

A longitudinal correction factor for age-related change in visual function may be useful in future trials to determine whether an observed deterioration in visual function is related to intervention or to aging.

Effects of Physiologic Myopia and Aging on Visual Fields in Normal Eyes

PURPOSE

The purpose of this study was to investigate how mild-to-moderate myopia and aging affect visual field sensitivity (VF-S) in normal eyes, correcting for effects of each.

DESIGN

Combined cross-sectional and cohort study.

METHODS

Two normal groups, a cross-sectional group (n = 703; 1,051 eyes; mean age, 52.6 years) and a longitudinal group (n = 44; 83 eyes; mean age, 52.3 years; follow-up, 4.2 years; VF tests, 12) were included. In the cross-sectional group, the mean VF-S of the entire field and 3 disc portion-oriented subfields of the Humphrey Field Analyzer 24-2 program were correlated with subjects' age, axial length (AL), disc, rim and β-peripapillary area, and disc ovality and torsion, using linear mixed-regression models. Their time changes in the longitudinal group were correlated with time, subjects' ages, and AL using linear mixed-regression models.

RESULTS

In the cross-sectional group, the VF-S correlated negatively with age (-0.081 decibel [dB]/year; P < .001), which was more negative (P = .020) in the midperipheral than the central subfield, and with AL (P = .049) without intersubfield differences. In the longitudinal group, no changes in the ocular media were significant, and the VF-S declined by 0.074 dB/year (P = .007), which accelerated with higher age (P < .002) and baseline VF-S (P < .001) without intersubfield differences. The AL showed little effects on the VF-S longitudinal changes.

CONCLUSIONS

In normal eyes with mild-to-moderate myopia, the VF-S was lower subfield-independently with longer AL, whereas the AL had little effect on the aging-associated VF-S reduction. The VF-S decreased with aging with intersubfield differences. The aging-associated VF-S reduction accelerated with higher age, to which the ocular media changes were unrelated.

Retinal Differential Light Sensitivity Variation Across the Macula in Healthy Subjects: Importance of Cone Separation and Loci Eccentricity

Purpose

Microperimetry measures differential light sensitivity (DLS) at specific retinal locations. The aim of this study is to examine the variation in DLS across the macula and the contribution to this variation of cone distribution metrics and retinal eccentricity.

Methods

Forty healthy eyes of 40 subjects were examined by microperimetry (MAIA) and adaptive optics imaging (rtx1). Retinal DLS was measured using the grid patterns: foveal (2°–3°), macular (3°–7°), and meridional (2°–8° on horizontal and vertical meridians). Cone density (CD), distribution regularity, and intercone distance (ICD) were calculated at the respective test loci coordinates. Linear mixed-effects regression was used to examine the association between cone distribution metrics and loci eccentricity, and retinal DLS.

Results

An eccentricity-dependent reduction in DLS was observed on all MAIA grids, which was greatest at the foveal-parafoveal junction (2°–3°) (−0.58 dB per degree, 95% confidence interval [CI]; −0.91 to −0.24 dB, P < 0.01). Retinal DLS across the meridional grid changed significantly with each 1000 cells/deg² change in CD (0.85 dB, 95% CI; 0.10 to 1.61 dB, P = 0.03), but not with each arcmin change in ICD (1.36 dB, 95% CI; −2.93 to 0.20 dB, P = 0.09).

Conclusions

We demonstrate significant variation in DLS across the macula. Topographical change in cone separation is an important determinant of the variation in DLS at the foveal-parafoveal junction. We caution the extrapolation of changes in DLS measurements to cone distribution because the relationship between these variables is complex.

Translational Relevance

Cone density is an independent determinant of DLS in the foveal-parafoveal junction in healthy eyes.

Contrast Sensitivity on 1/f Noise Is More Greatly Impacted by Older Age for the Fovea Than Parafovea

SIGNIFICANCE

Contrast sensitivity changes across the visual field with age and is often measured clinically with various forms of perimetry on plain backgrounds. In daily life, the visual scene is more complicated, and therefore, the standard clinical measures of contrast sensitivity may not predict a patient's visual experience in more natural environments.

PURPOSE

This study aims to determine whether contrast thresholds in older adults are different from younger adults when measured on a 1/f noise background (a nonuniform background whose spatial frequency content is similar to those present in the natural vision environments).

METHODS

Twenty younger (age range, 20 to 35 years) and 20 older adults (age range, 61 to 79 years) with normal ocular health were recruited. Contrast thresholds were measured for a Gabor patch of 6 cycles per degree (sine wave grating masked by a Gaussian envelope of standard deviation 0.17°) presented on 1/f noise background (root-mean-square contrast, 0.05 and 0.20) that subtended 15° diameter of the central visual field. The stimulus was presented at four eccentricities (0°, 2°, 4°, and 6°) along the 45° meridian in the noise background, and nine contrast levels were tested at each eccentricity. The proportion of correct responses for detecting the target at each eccentricity was obtained, and psychometric functions were fit to estimate the contrast threshold.

RESULTS

Older adults demonstrate increased contrast thresholds compared with younger adults. There was an eccentricity-dependent interaction with age, with the difference between groups being highest in the fovea compared with other eccentricities. Performance was similar for the two noise backgrounds tested.

CONCLUSIONS

Our results revealed a strong eccentricity dependence in performance between older and younger adults, highlighting age-related differences in the contrast detection mechanisms between fovea and parafovea for stimuli presented on nonuniform backgrounds.

Age- and Gender-Related Characteristics of Corneal Refractive Parameters in a Large Cohort Study

PURPOSE

To characterize age- and sex-related changes in corneal refractive parameters in myopic and hyperopic patients undergoing refractive surgery.

DESIGN

A retrospective cross-sectional study.

METHODS

Analysis of demographic and refractive parameters of myopic and hyperopic patients who underwent laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) between January 2000 and December 2014 at the Care-Vision Laser Centers, Tel-Aviv, Israel.

RESULTS

A total of 62,422 eyes of 31,211 patients were included. With advancing age, refractive surgery was performed for lower magnitudes of myopia and hyperopia. The magnitude of cylinder was higher in men than in women in both myopic and hyperopic patients. In comparison, women were significantly more myopic than men (spherical equivalent of -3.73 diopter [D] versus -4.07 D; P < 0.01). The myopic group sphere (r = 0.044; P < 0.001) had a positive correlation with age, whereas other parameters had a negative correlation with age: astigmatism (r = -0.09; P < 0.001), best-correct visual acuity (BCVA) (r = -0.04; P < 0.001), flat K (r = -0.09; P < 0.001), steep K (r = -0.06; P < 0.001), average K (r = -0.07; P < 0.001), and J0 (r = -0.05; P < 0.001). For hyperopic patients, astigmatism (r = 0.35; P < 0.001), BCVA (r = 0.11; P < 0.001), flat K (r = 0.30; P < 0.001), average K (0.14; P < 0.001), and central corneal thickness (r = 0.10; P < 0.001) correlated positively with age, whereas sphere (r = -0.23; P < 0.001), J0 (r = -0.31; P < 0.001), and overall blurring strength (r = -0.31; P < 0.001) had negative correlations with age.

CONCLUSIONS

This large cohort study shows age- and sex-related refractive parameters among myopic and hyperopic patients seeking refractive surgery. These parameters can explain and predict trends in patients attending refractive surgery.

Microperimetry in Age-Related Macular Degeneration: An Evidence-Base for Pattern Deviation Probability Analysis in Microperimetry

Purpose

The “traffic light” color designation of differential light sensitivity used in a number of microperimeters does not encompass the conventional Total and Pattern Deviation probability analyses adopted by standard automated perimetry. We determined whether the color designation is indicative of abnormality as represented by the “gold standard” Pattern Deviation probability analysis.

Methods

Total and Pattern Deviation probability levels, using two different methods, were derived at each of 40 stimulus locations, within 7° eccentricity, from 66 ocular healthy individuals (66 eyes) who had undergone microperimetry with the Macular Integrity Assessment microperimeter. The probability levels were applied to the corresponding fields from each of 45 individuals (45 eyes) with age-related macular degeneration (AMD) and evaluated in relation to the color designation.

Results

Sensitivities designated in orange encompassed the entire range of Pattern Deviation probability levels (from normal to P ≤ 1%). Those designated in green were mostly normal; those in red/black generally corresponded to the ≤1% probability level.

Conclusions

The green and the red/black designations are generally indicative of normal and abnormal probability values, respectively. The orange designation encompassed all probability outcomes and should not be relied upon for visual field interpretation. The evidence base indicates replacement of the color designation of sensitivity in AMD by Total Deviation and Pattern Deviation analyses.

Translational Relevance

The use of Total and Pattern Deviation probability analyses is not universal in all microperimeters, and the derivation of these values indicates that color coding will lead to errors in evaluating visual field loss.

Development of a Spatial Model of Age-Related Change in the Macular Ganglion Cell Layer to Predict Function From Structural Changes

PURPOSE

To develop location-specific models of normal, age-related changes in the macular ganglion cell layer (GCL) from optical coherence tomography (OCT). Using these OCT-derived models, we predicted visual field (VF) sensitivities and compared these results to actual VF sensitivities.

DESIGN

Retrospective cohort study.

METHODS

Single eyes of 254 normal participants were retrospectively enrolled from the Centre for Eye Health (Sydney, Australia). Macular GCL measurements were obtained using Spectralis OCT. Cluster algorithms were performed to identify spatial patterns demonstrating similar age-related change. Quadratic and linear regression models were subsequently used to characterize age-related GCL decline. Forty participants underwent additional testing with Humphrey VFs, and 95% prediction intervals were calculated to measure the predictive ability of structure-function models incorporating cluster-based pooling, age correction, and consideration of spatial summation.

RESULTS

Quadratic GCL regression models provided a superior fit (P value <.0001-.0066), establishing that GCL decline commences in the late 30s across the macula. The equivalent linear rates of GCL decline showed eccentricity-dependent variation (0.13 μm/yr centrally vs 0.06 μm/yr peripherally); however, average, normalized GCL loss per year was consistent across the 64 macular measurement locations at 0.26%. The 95% prediction intervals describing predicted VF sensitivities were significantly narrower across all cluster-based structure-function models (3.79-4.99 dB) compared with models without clustering applied (5.66-6.73 dB, P < .0001).

CONCLUSIONS

Combining spatial clustering with age-correction based on regression models allowed the development of robust models describing GCL changes with age. The resultant superior predictive ability of VF sensitivity from ganglion cell measurements may be applied to future models of disease development to improve detection of early macular GCL pathology.

Regional Variations and Intra-/Intersession Repeatability for Scotopic Sensitivity in Normal Controls and Patients With Inherited Retinal Degenerations

Purpose

Dark-adapted visual fields were obtained from patients with inherited retinal degeneration (IRD) and controls to evaluate the effect that age, retinal region, and disease had on scotopic sensitivity. Intra- and intersession test–retest repeatabilities for patients and controls were measured to establish significant change for longitudinal studies.

Methods

A total of 41 patients with IRD and 30 controls had one eye dilated and dark-adapted for 40 minutes. Scotopic sensitivity was measured with a Medmont dark-adapted chromatic (DAC) perimeter (size V stimulus, 200-ms duration, background luminance < 0.0001 cd/m², dynamic range 0–75 decibel [dB]). Mixed effects analysis was performed to analyze age, retinal eccentricity, and sensitivity. The intra-/intersession coefficients of repeatability (CR) were calculated for controls and patients with IRD.

Results

Each additional year was associated with lower sensitivity (−0.22 dB) per year in normal controls over age 50 compared to younger controls (12–49 years). The superior field had lower sensitivity than the inferior, but the nasal field was not different compared to the temporal field in normal controls. The CR for intra- and intersession testing on mean sensitivity (MS)/pointwise sensitivity (PWS) were ±1.5/±8.5 and ±3.3/±9.8 dB, respectively, for patients with IRD. Control MS/PWS CR were ±1.5/±6.1 dB for intrasession and ±1.7/±6.8 dB for intersession DAC perimetry.

Conclusions

The DAC perimeter is an important asset because it tests a wide field of scotopic vision. The CR are comparable to those of other perimetry devices. Effects of age and retinal region should be considered when assessing scotopic sensitivity measured with the DAC perimeter.

Contrast sensitivity isocontours of the central visual field

Standard automated perimetry (SAP), the most common form of perimetry used in clinical practice, is associated with high test variability, impacting clinical decision making and efficiency. Contrast sensitivity isocontours (CSIs) may reduce test variability in SAP by identifying regions of the visual field with statistically similar patterns of change that can be analysed collectively and allow a point (disease)-to-CSI (normal) comparison in disease assessment as opposed to a point (disease)-to-point (normal) comparison. CSIs in the central visual field however have limited applicability as they have only been described using visual field test patterns with low, 6° spatial sampling. In this study, CSIs were determined within the central 20° visual field using the 10-2 test grid paradigm of the Humphrey Field Analyzer which has a high 2° sampling frequency. The number of CSIs detected in the central 20° visual field was greater than previously reported with low spatial sampling and stimulus size dependent: 6 CSIs for GI, 4 CSIs for GII and GIII, and 3 CSIs for GIV and GV. CSI number and distribution were preserved with age. Use of CSIs to assess visual function in age-related macular degeneration (AMD) found CSI guided analysis detected a significantly greater deviation in sensitivity of AMD eyes from normal compared to a standard clinical pointwise comparison (−1.40 ± 0.15 dB vs −0.96 ± 0.15 dB; p < 0.05). This work suggests detection of CSIs within the central 20° is dependent on sampling strategy and stimulus size and normative distribution limits of CSIs can indicate significant functional deficits in diseases affecting the central visual field such as AMD.

Pattern Recognition Analysis Reveals Unique Contrast Sensitivity Isocontours Using Static Perimetry Thresholds Across the Visual Field

Purpose

To determine the locus of test locations that exhibit statistically similar age-related decline in sensitivity to light increments and age-corrected contrast sensitivity isocontours (CSIs) across the central visual field (VF). We compared these CSIs with test point clusters used by the Glaucoma Hemifield Test (GHT).

Methods

Sixty healthy observers underwent testing on the Humphrey Field Analyzer 30-2 test grid using Goldmann (G) stimulus sizes I-V. Age-correction factors for GI-V were determined using linear regression analysis. Pattern recognition analysis was used to cluster test locations across the VF exhibiting equal age-related sensitivity decline (age-related CSIs), and points of equal age-corrected sensitivity (age-corrected CSIs) for GI-V.

Results

There was a small but significant test size–dependent sensitivity decline with age, with smaller stimuli declining more rapidly. Age-related decline in sensitivity was more rapid in the periphery. A greater number of unique age-related CSIs was revealed when using smaller stimuli, particularly in the mid-periphery. Cluster analysis of age-corrected sensitivity thresholds revealed unique CSIs for GI-V, with smaller stimuli having a greater number of unique clusters. Zones examined by the GHT consisted of test locations that did not necessarily belong to the same CSI, particularly in the periphery.

Conclusions

Cluster analysis reveals statistically significant groups of test locations within the 30-2 test grid exhibiting the same age-related decline. CSIs facilitate pooling of sensitivities to reduce the variability of individual test locations. These CSIs could guide future structure-function and alternate hemifield asymmetry analyses by comparing matched areas of similar sensitivity signatures.

Incorporating Spatial Models in Visual Field Test Procedures

Purpose

To introduce a perimetric algorithm (Spatially Weighted Likelihoods in Zippy Estimation by Sequential Testing [ZEST] [SWeLZ]) that uses spatial information on every presentation to alter visual field (VF) estimates, to reduce test times without affecting output precision and accuracy.

Methods

SWeLZ is a maximum likelihood Bayesian procedure, which updates probability mass functions at VF locations using a spatial model. Spatial models were created from empirical data, computational models, nearest neighbor, random relationships, and interconnecting all locations. SWeLZ was compared to an implementation of the ZEST algorithm for perimetry using computer simulations on 163 glaucomatous and 233 normal VFs (Humphrey Field Analyzer 24-2). Output measures included number of presentations and visual sensitivity estimates.

Results

There was no significant difference in accuracy or precision of SWeLZ for the different spatial models relative to ZEST, either when collated across whole fields or when split by input sensitivity. Inspection of VF maps showed that SWeLZ was able to detect localized VF loss. SWeLZ was faster than ZEST for normal VFs: median number of presentations reduced by 20% to 38%. The number of presentations was equivalent for SWeLZ and ZEST when simulated on glaucomatous VFs.

Conclusions

SWeLZ has the potential to reduce VF test times in people with normal VFs, without detriment to output precision and accuracy in glaucomatous VFs.

Translational Relevance

SWeLZ is a novel perimetric algorithm. Simulations show that SWeLZ can reduce the number of test presentations for people with normal VFs. Since many patients have normal fields, this has the potential for significant time savings in clinical settings.

The effect of duration post-migraine on visual electrophysiology and visual field performance in people with migraine

Purpose:

In between migraine attacks, some people show visual field defects that are worse when measured closer to the end of a migraine event. In this cohort study, we consider whether electrophysiological responses correlate with visual field performance at different times post-migraine, and explore evidence for cortical versus retinal origin.

Methods:

Twenty-six non-headache controls and 17 people with migraine performed three types of perimetry (static, flicker and blue-on-yellow) to assess different aspects of visual function at two visits conducted at different durations post-migraine. On the same days, the pattern electroretinogram (PERG) and visual evoked response (PVER) were recorded.

Results:

Migraine participants showed persistent, interictal, localised visual field loss, with greater deficits at the visit nearer to migraine offset. Spatial patterns of visual field defect consistent with retinal and cortical dysfunction were identified. The PERG was normal, whereas the PVER abnormality found did not change with time post-migraine and did not correlate with abnormal visual field performance.

Conclusions:

Dysfunction on clinical tests of vision is common in between migraine attacks; however, the nature of the defect varies between individuals and can change with time. People with migraine show markers of both retinal and/or cortical dysfunction. Abnormal visual field sensitivity does not predict abnormality on electrophysiological testing.

Comparing the Nidek MP-1 and Humphrey field analyzer in normal subjects

PURPOSE

To compare visual fields on the Nidek MP-1 to those obtained on the Humphrey field analyzer (HFA) in healthy volunteers and assess the effects of differences in stimulus parameters and testing strategies that may influence the interpretation of results in patients. A secondary aim was to establish MP-1 normative data to calculate the total deviation analyses and global indices analogous to those used by the HFA.

METHODS

Fifty healthy volunteers (age 43.5 ± 13.9 years, range, 18 to 68 years) underwent repeat MP-1 and HFA visual field testing, using the 10-2 pattern. MP-1 data were converted to HFA equivalent dB units. Between instrument comparisons of HFA and MP-1 sensitivities, regression of sensitivity with age and examination duration were assessed. Test-retest variability was examined between visits.

RESULTS

MP-1 (mean = 32.82 dB, SD = 1.92 dB) and HFA sensitivities (mean = 32.84 dB, SD = 1.83 dB) were not significantly different (p = 0.759). SD values for the HFA (range, 1.11 to 3.30 dB) were similar to the MP-1 (range, 0.14 to 2.75 dB). However, asymmetry comparisons between instruments showed significantly decreased superior rather than inferior retinal values for the MP-1. There was a small but significant difference (p = 0.004) in mean test duration between the MP-1 (mean = 6:11 min, SD = 1:49 min) and the HFA (mean = 5:14 min, SD = 0:42 min). There was also a difference in the decline of mean sensitivity with age, a decline of 0.1 and 0.4 dB per decade was noted in MP-1 and HFA sensitivity, respectively. Test-retest variability was similar between instruments. A small but non-significant increase in mean sensitivity at the second visit for both the MP-1 (p = 0.060) and HFA (p = 0.570) was found.

CONCLUSIONS

Both instruments showed similar variability and test-retest variability when results were compared using equivalent units. However, there are important differences in sensitivity values, stimulus parameters, and testing strategies that have to be taken into account when comparisons are made.

Normative data set identifying properties of the macula across age groups: integration of visual function and retinal structure with microperimetry and spectral-domain optical coherence tomography

PURPOSE

A normative database of functional and structural parameters of the macula from normal subjects was established to identify reference points for the diagnosis of patients with macular disease using microperimetry and scanning laser ophthalmoscope/spectral-domain optical coherence tomography (SD-OCT).

METHODS

This was a community-based, prospective, cross-sectional study of 169 eyes from subjects aged 21 years to 85 years with best-corrected visual acuity of 20/25 or better and without any ocular disease. Full-threshold macular microperimetry combined with the acquisition of structural parameters of the macula with scanning laser ophthalmoscope/SD-OCT was recorded (SD-OCT/scanning laser ophthalmoscope with add-on Microperimetry module; OPKO). Fixation, central, subfield, and mean retinal thickness were acquired together with macular sensitivity function. Thickness and sensitivity as primary outcome measures were mapped and superimposed correlating topographically differentiated macular thickness with sensitivity. Statistical evaluation was performed with age, gender, and ethnicity as covariates.

RESULTS

Subfield and mean retinal thickness and sensitivity were measured with macular microperimetry combined with SD-OCT and differentiated by macular topography and subjects' age, gender, and ethnicity. Mean retinal sensitivity and thickness were calculated for 169 healthy eyes (mean age, 48 ± 17 years). A statistically significant decrease in sensitivity was found only in the age group of participants ≥ 70 years and in peripheral portions of the macula in individuals aged ≥60 years and was more pronounced in the area surrounding the fovea than in the center of the macula, while retinal thickness did not change with age. No statistically significant differences in the primary outcome measures or their correlations were found when using gender or ethnicity as a covariate.

CONCLUSION

A database for normal macular thickness and sensitivity was generated with a combined microperimetry SD-OCT system as the basis for comparison of outcome parameters in patients with macular abnormality. Mean retinal sensitivity decreased significantly only in the age group of participants ≥ 70 years and in peripheral portions of the macula in individuals aged ≥60 years, with increasing distance from the fovea, while other parameters, their correlations and covariates, were not affected within the normative data set. No relationship was detected between retinal thickness and retinal sensitivity in the healthy macula.

Volume of visual field assessed with kinetic perimetry and its application to static perimetry

Background:

The purpose of this study was to quantify the volume of the kinetic visual field with a single unit that accounts for visual field area and differential luminance sensitivity.

Methods:

Kinetic visual field perimetry was performed with a Goldmann perimeter using I4e, I3e, I2e, and I1e targets. The visual fields of 25 normal volunteers (17 women, eight men) of mean age 33.9 ± 10.1 (range 17–64) years were obtained and digitized. Isopter areas were measured with a method devised to correct cartographic distortion due to polar projection inherent in perimetry and are expressed in steradians. The third dimension of each isopter represents sensitivity to target luminance and was calculated as log (target luminance⁻¹). If luminance is expressed in cd/m², the values for the third dimension are 0.5 for I4e, 1.0 for I3e, 1.5 for I2e, and 2.0 for I1e. The resulting unit is a steradian (log 10³ (cd/m²)⁻¹ which is referred to as a Goldmann. In addition, the visual fields of four patients with representative visual defect patterns were examined and compared with normal subjects.

Results:

Mean isopter areas for normal subjects were 3.092 ± 0.242 steradians for I4e, 2.349 ± 0.280 steradians for I3e, 1.242 ± 0.263 steradians for I2e, and 0.251 ± 0.114 steradians for the I1e target. Isopter volumes were 1.546 ± 0.121 Goldmanns for the I4e target, 1.174 ± 0.140 Goldmanns for I3e, 0.621 ± 0.131 Goldmanns for I2e, and 0.126 ± 0.057 Goldmanns for I1e. The total mean visual field volume in our study for the I target was 3.467 ± 0.371 Goldmanns.

Conclusion:

The volume of the island of vision may be used to quantify a visual field with a single value which contains information about both visual field extension and differential luminance sensitivity. This technique may be used to assess the progression or stability of visual field defects over time. A similar method may be applied to static perimetry.

The decline in visual acuity in elderly people with healthy eyes or eyes with early age-related maculopathy in two Scandinavian population samples

PURPOSE

This study aimed to analyse the decline in visual acuity (VA) during normal ageing in two Scandinavian population samples of subjects aged ≥ 70 years and to study the age-specific decline in VA in eyes with early age-related maculopathy (ARM).

METHODS

We carried out a cross-sectional analysis of data pertaining to VA in the better eye in one population sample from Oulu (OU), Finland (aged 70-82 years) and a second population sample from Gothenburg (GG), Sweden (aged 82 or 88 years). The change in VA with age was evaluated in healthy eyes (OU, n = 119; GG, n = 40) and in eyes with early ARM (OU-ARM, n = 22; GG-ARM, n = 114) using linear regression or logistic regression. The results were compared with those of previous reports.

RESULTS

Our population samples showed a significant decrease with age in VA in healthy eyes in subjects aged ≥ 44 years using both statistical models. Comparisons with previous reports demonstrated a homogeneity in the decline in VA with age. On average, 0.3 logMAR are lost from middle age up to 88 years, presumably as a result of physiological ageing. In early ARM, the rate of age-specific decline in VA more than doubled and the prevalence of VA < 0.5 markedly increased.

CONCLUSIONS

Visual acuity in healthy eyes declines with age from middle age onwards. The decrease in VA possibly accelerates in subjects aged > 70 years, although no significant evidence for this was found. An age-specific decline in VA is shown in eyes with early ARM. These results are important for the evaluation of age-specific treatment results.

Specification of progression in glaucomatous visual field loss, applying locally condensed stimulus arrangements

Purpose

The goal of this work was to (i) determine patterns of progression in glaucomatous visual field loss, (ii) compare the detection rate of progression between locally condensed stimulus arrangements and conventional 6° × 6° grid, and (iii) assess the individual frequency distribution of test locations exhibiting a local event (i.e., an abrupt local deterioration of differential luminance sensitivity (DLS) by more than -10dB between any two examinations).

Methods

The visual function of 41 glaucomatous eyes of 41 patients (16 females, 25 males, 37 to 75 years old) was examined with automated static perimetry (Tuebingen Computer Campimeter or Octopus 101-Perimeter). Stimuli were added to locally enhance the spatial resolution in suspicious regions of the visual field. The minimum follow-up was four subsequent sessions with a minimum of 2-month (median 6-month) intervals between each session. Progression was identified using a modified pointwise linear regression (PLR) method and a modified Katz criterion. The presence of events was assessed in all progressive visual fields.

Results

Eleven eyes (27%) showed progression over the study period (median 2.5 years, range 1.3–8.6 years). Six (55%) of these had combined progression in depth and size and five eyes (45%) progressed in depth only. Progression in size conformed always to the nerve fiber course. Seven out of 11 (64%) of the progressive scotomata detected by spatially condensed grids would have been missed by the conventional 6° × 6° grid. At least one event occurred in 64% of all progressive eyes. Five of 11 (46%) progressive eyes showed a cluster of events.

Conclusions

The most common pattern of progression in glaucomatous visual fields is combined progression in depth and size of an existing scotoma. Applying individually condensed test grids remarkably enhances the detection rate of glaucomatous visual field deterioration (at the expense of an increased examination time) compared to conventional stimulus arrangements.

Comparison of the new perimetric GATE strategy with conventional full-threshold and SITA standard strategies

PURPOSE

A new, fast-threshold strategy, German Adaptive Thresholding Estimation (GATE/GATE-i), is compared to the full-threshold (FT) staircase and the Swedish Interactive Thresholding Algorithm (SITA) Standard strategies. GATE-i is performed in the initial examination and GATE refers to the results in subsequent examinations.

METHODS

Sixty subjects were recruited for participation in the study: 40 with manifest glaucoma, 10 with suspected glaucoma, and 10 with ocular hypertension. The subjects were evaluated by each threshold strategy on two separate sessions within 14 days in a randomized block design.

RESULTS

SITA standard, GATE-i, and GATE thresholds were 1.2, 0.6, and 0.0 dB higher than FT. The SITA standard tended to have lower thresholds than those of FT, GATE-i, and GATE for the more positive thresholds, and also in the five seed locations. For FT, GATE-i, GATE, and SITA Standard, the standard deviations of thresholds between sessions were, respectively, 3.9, 4.5, 4.2, and 3.1 dB, test-retest reliabilities (Spearman's rank correlations) were 0.84, 0.76, 0.79, and 0.71, test-retest agreements as measured by the 95% reference interval of differences were -7.69 to 7.69, -8.76 to 9.00, -8.40 to 8.56, and -7.01 to 7.44 dB, and examination durations were 9.0, 5.7, 4.7, and 5.6 minutes. The test duration for SITA Standard increased with increasing glaucomatous loss.

CONCLUSIONS

The GATE algorithm achieves thresholds that are similar to those of FT and SITA Standard, with comparable accuracy, test-retest reliability, but with a shorter test duration than FT.