Association between Primary Open-Angle Glaucoma and Cognitive Impairment as Measured by the Montreal Cognitive Assessment

Association Analysis between Cognitive Function Score and Inner Macular Thickness/Visual Field Sensitivity in Glaucoma Patients

(1) Background: Previous research has investigated the relationship between cognitive impairment, optical coherence tomography (OCT), visual fields (VF), and VF reliability in smaller patient samples using various cognitive assessment tools. This study analyzed the relationship between cognitive function scores using the Mini-Cog test and inner macular thickness (IMT) and VF sensitivity in glaucoma patients. (2) Methods: A retrospective analysis was conducted on 984 patients with 1897 eyes. Assessments included age, sex, intraocular pressure (IOP), and Mini-Cog test scores. Abnormal Mini-Cog scores were observed in 89 patients (9%). Using a mixed-effects model adjusted for background factors, the association between Mini-Cog scores and IMT, parafoveal (PF)-IMT, mean deviation (MD), pattern standard deviation, fixation losses (FL), false negatives (FN), and false positives (FP) was analyzed. (3) Results: Abnormal Mini-Cog scores (≤2) were associated with thinning of the IMT and PF-IMT, worse MDs, and higher FN and FP rates but not with PSD or FL. (4) Conclusions: Glaucoma patients with low cognitive function scores exhibited more advanced glaucoma-related changes in VF testing and morphological tests. Further longitudinal studies are needed to explore the relationship between glaucoma and cognitive impairment.

Risk of glaucoma to subsequent dementia or cognitive impairment: a systematic review and meta-analysis

BACKGROUND

Substantial evidence supports that glaucoma and dementia share pathological mechanisms and pathogenic risk factors. However, the association between glaucoma, cognitive decline and dementia has yet to be elucidated.

OBJECTIVE

This study was aimed to assess whether glaucoma increase the risk of dementia or cognitive impairment.

METHODS

PubMed, Cochrane Library, Web of Science, and EMBASE databases for cohort or case-control studies were searched from inception to March 10, 2024. The Newcastle-Ottawa Quality Assessment Scale (NOS) was used to the risk of bias. Heterogeneity was rigorously evaluated using the I2 test, while publication bias was assessed by visual inspection of the funnel plot and by Egger' s regression asymmetry test. Subgroup analyses were applied to determine the sources of heterogeneity.

RESULTS

Twenty-seven studies covering 9,061,675 individuals were included. Pooled analyses indicated that glaucoma increased the risk of all-cause dementia, Alzheimer's disease, vascular dementia, and cognitive impairment. Subgroup analysis showed that the prevalence of dementia was 2.90 (95% CI: 1.45-5.77) in age ≥ 65 years and 2.07 (95% CI: 1.18-3.62) in age<65 years; the incidence rates in female glaucoma patients was 1.46 (95% CI: 1.06-2.00), respectively, which was no statistical significance in male patients. Among glaucoma types, POAG was more likely to develop dementia and cognitive impairment. There were also differences in regional distribution, with the highest prevalence in the Asia region, while glaucoma was not associated with dementia in Europe and North America regions.

CONCLUSION

Glaucoma increased the risk of subsequent cognitive impairment and dementia. The type of glaucoma, gender, age, and region composition of the study population may significantly affect the relationship between glaucoma and dementia.

Primary Open-Angle Glaucoma Is Associated with Short-Term Memory Decline and Dementia in Individuals of African Ancestry

Background: Over the last decade, studies have suggested that primary open-angle glaucoma (POAG) may be associated with cognitive impairment and dementia, as both pathologies are age-related neurodegenerative processes. It remains unclear to what extent neurodegeneration in POAG extends to other neurological functions beyond vision, such as cognition. This follow-up study examined the potential association between POAG and cognitive decline in an African ancestry population. Methods: The Telephone-Montreal Cognitive Assessment (T-MoCA) was administered to POAG cases and controls previously enrolled in the Primary Open-Angle African American Glaucoma Genetics (POAAGG) study. Cases were assessed for retinal nerve fiber layer (RNFL) thickness and for the presence of dementia via chart review. Comparisons between POAG cases and controls were performed using two-sample t-tests for the T-MoCA total score and five subsection scores, and using chi-squared tests for incidence of dementia. Current scores were compared to scores from this same cohort from 7 years prior. Results: The T-MoCA was administered to 13 cases and 20 controls. The mean ± standard deviation (SD) T-MoCA total score was 15.5 ± 4.0 in cases and 16.7 ± 3.5 in controls (p = 0.36). However, there was a borderline significant difference in the delayed recall sub-score (2.3 ± 1.6 for cases vs. 3.4 ± 1.5 for controls, p = 0.052) and a significant difference in its sub-domain, the memory index score (MIS, 9.1 ± 4.3 for cases vs. 12.1 ± 3.0 for controls, p = 0.02). There were no significant differences between cases and controls for the remaining subsections. During 7 years of follow-up, a higher incidence of dementia was noted in POAG cases (7.1% for cases vs. 0% for controls, p = 0.058). Over 7 years, there was no significant deterioration in the cognitive performance of cases versus controls, and no association was seen between RNFL thinning and cognitive impairment. Conclusions: In this small-sample follow-up study of African ancestry individuals, POAG cases demonstrated worse short-term memory and higher incidence of dementia compared to controls. Future larger studies are needed to further investigate the presence and impact of neurodegeneration in POAG.

Roles of Cognitive Function on Visual Field Reliability Indices among Glaucoma Patients

This study reports the prevalence of cognitive impairment (CI) in patients attending a glaucoma outpatient clinic at a tertiary hospital. It also comprehensively assesses possible associations between CI and visual field (VF) reliability indices among glaucoma patients. The retrospective analysis included 1464 eyes from 746 subjects (mean age, 70.6 ± 11.9; 401 males and 345 females). CI was evaluated using the Mini-Cog test, revealing a suspected prevalence of 8.0% (60 out of 746) among the patients. After adjusting for various background parameters using a mixed effects regression model, an abnormal Mini-Cog score was linked to higher false negative (FN) (p = 0.0034) and false positive (FP) (p = 0.0051) but not fixation loss (FL) (p = 0.82). Among the Mini-Cog components, a lower word recall test score was associated with higher FN (p < 0.0001), with a borderline difference in FP (p = 0.054) and no significant effect on FL (p = 0.09). Conversely, a lower clock drawing test score was associated with higher FP (p = 0.038), while FL (p = 0.49) and FN (p = 0.12) remained unaffected. These findings suggest that CI can impact the reliability of VF testing among glaucoma patients, highlighting the importance of assessing cognitive function in glaucoma care.

Glaucoma and cognitive function trajectories in a population-based study: Findings from the health and retirement study

INTRODUCTION

Prior studies on the association of glaucoma and cognitive function have reported mixed results.

METHODS

The Health and Retirement Study (HRS) is a nationally representative panel survey of Americans age ≥ 51 years. HRS-linked Medicare claims data were used to identify incident glaucoma cases (by glaucoma type). Cognitive function was measured using the Telephone Interview for Cognitive Status (TICS), administered in each wave (every 2 years). Separate linear mixed models were fitted with either prevalent or incident glaucoma as a predictor of TICS trajectories and adjusting for age, race/ethnicity, educational attainment, gender, and medical history. Negative model estimates indicate associations of glaucoma with worse cognitive function scores or steeper per-year declines in cognitive function scores.

RESULTS

Analyses of prevalent glaucoma cases included 1344 cases and 5729 controls. Analyses of incident glaucoma included 886 cases and 4385 controls. In fully-adjusted models, those with prevalent glaucoma had similar TICS scores to controls (β = 0.01; 95% Confidence Interval [CI]: -0.15, 0.18; p = 0.86). However, in those with incident glaucoma, we detected a statistically significant association between glaucoma and lower TICS scores (β = -0.29; 95% CI: -0.50, -0.08; p = 0.007). However, there was no statistically significant association between either prevalent or incident glaucoma and per-year rates of change in TICS scores. When categorizing glaucoma by type (primary open angle glaucoma, normal tension glaucoma, or other glaucoma), no significant associations were detected between either prevalent or incident glaucoma and levels of or rates of change in TICS scores in fully covariate adjusted models.

CONCLUSION

The observed associations between glaucoma and cognitive function were small and unlikely to be clinically meaningful. Compared to prior studies on this topic, this investigation provides robust evidence based on its larger sample size, longitudinal follow-up, and repeated measures of cognitive function in a population-based sample.

Cognitive Performance on the Montreal Cognitive Assessment Test and Retinal Structural and Functional Measures in Glaucoma

Background: Glaucoma, the leading cause of irreversible blindness, is classified as a neurodegenerative disease, and its incidence increases with age. Pathophysiological changes, such as the deposition of amyloid-beta plaques in the retinal ganglion cell layer, as well as neuropsychological changes, including cognitive decline, have been reported in glaucoma. However, the association between cognitive ability and retinal functional and structural measures in glaucoma, particularly glaucoma subtypes, has not been studied. We studied the association between cognitive ability and the visual field reliability indices as well as the retinal ganglion cell (RGC) count estimates in a cohort of glaucoma patients. Methods: A total of 95 eyes from 61 glaucoma patients were included. From these, 20 were normal-tension glaucoma (NTG), 25 were primary open-angle glaucoma (POAG), and 16 were glaucoma suspects. All the participants had a computerised Humphrey visual field (HVF) assessment and optical coherence tomography (OCT) scan and were administered the written Montreal Cognitive Assessment (MoCA) test. RGC count estimates were derived based on established formulas using the HVF and OCT results. A MoCA cut-off score of 25 and less was designated as cognitive impairment. Student’s t-test was used to assess differences between the groups. The Pearson correlation coefficient was used to assess the association between MoCA scores and retinal structural and functional measures. Results: Significant associations were found between MoCA scores and the false-negative and pattern standard deviation indices recorded on the HVF (r = −0.19, r = −0.22, p < 0.05). The mean IOP was significantly lower in the cognitively impaired group (i.e., MOCA ≤ 25) (13.7 ± 3.6 vs. 15.7 ± 4.5, p < 0.05). No significant association was found between RGC count estimates and MoCA scores. Analysis of these parameters in individual glaucoma subtypes did not reveal any group-specific significant associations either.

Exploring the effect of glaucomatous visual field defects of current drivers on a neuropsychological test battery

PURPOSE

This study explores the effect of glaucomatous visual field defects on several neuropsychological tests that are often used in research and in clinical settings.

METHODS

Nineteen glaucoma patients and nineteen healthy participants, which are current drivers and older than 65 years old were included. All participants completed the Montreal Cognitive Assessment (MoCA), the Trail Making Test (TMT), the Benton Visual Retention Test (BVRT), the Snellgrove Maze Task (SMT) and the Digit Span Test (DST). All participants were also tested on contrast sensitivity and near and far visual acuity. For the glaucoma patients, visual field tests were downloaded from hospital servers.

RESULTS

On the MoCA test, glaucoma patients scored lower than the healthy group, but not significantly. On the MoCA-Blind, the difference was statistically significant. Glaucoma patients also had lower percentile scores on the TMT, with a significant difference in the TMT-A, but this difference largely disappeared in the calculated TMT B-A index, which isolates the cognitive component. The BVRT and SMT showed no significant differences between both groups. In the only non-visual test, the DST, glaucoma patients outperformed the healthy group. Glaucoma severity did not influence results, except for the BVRT on which the moderate/severe group has better scores.

CONCLUSION

Using visual items might lead to conclusions about cognition when it should be one about vision. Therefore, careful selection of tests is needed when examining cognition in glaucoma patients.

Individuals with and without normal tension glaucoma exhibit comparable performance on tests of cognitive function

AIM

To evaluate aspects of cognition impacted by individuals with and without normal tension glaucoma.

METHODS

Fifty normal tension glaucoma (NTG) and 50 control patients ≥50y of age were recruited from the UCSF Department of Ophthalmology. Demographic data and glaucoma parameters were extracted from electronic medical records for both groups. Tests of executive function [Executive Abilities: Measures and Instruments for Neurobehavioral Evaluation and Research (EXAMINER)] and learning and memory [California Verbal Learning Test-Second Edition (CVLT-II)] were administered to both NTG and controls. Race, handedness, best-corrected visual acuity, maximum intraocular pressure, optic nerve cup-to-disc ratio, visual field and optic nerve optical coherence tomography parameters, and a measure of general health (Charlson Comorbidity Index) were compared between NTG and controls as well as within NTG subgroups. Multivariate linear regression was used to compare group performances on the EXAMINER battery and CVLT-II while controlling for age, sex, and years of education.

RESULTS

NTG and controls were comparable with respect to age, sex, race, education, handedness, and the Charlson Comorbidity Index (P>0.05 for all). Performance on the EXAMINER composite score and the CVLT-II did not differ between NTG and controls (P>0.05 for both).

CONCLUSION

This is the first prospective study in which the cognitive function of subject with NTG were evaluated using a comprehensive, computerized neurocognitive battery. Subjects with NTG do not perform worse than unaffected controls on tests of executive function, learning, and memory. Results do not support the hypothesis that individuals with NTG are at higher risk for cognitive dysfunction and/or dementia.

Cognitive Dysfunctions in Glaucoma: An Overview of Morpho-Functional Mechanisms and the Impact on Higher-Order Visual Function

Background: Glaucoma is a chronic, vision-threatening disease, and a major cause of legal blindness. The current view is no longer limited to the progressive optic nerve injury, since growing evidence strongly support the interpretation of glaucoma as a complex neurodegenerative disease. However, the precise pathogenic mechanisms leading to the onset and progression of central nervous system (CNS) impairment, and the functional consequences of this damage, are still partially understood. The main aim of this review is to provide a complete and updated overview of the current knowledge regarding the CNS involvement in glaucoma, and the possible therapeutic perspectives. Methods: We made a careful survey of the current literature reporting all the relevant findings related to the cognitive dysfunctions occurring in glaucoma, with specific remarks dedicated on the higher-order visual function impairment and the possible employment of neuroprotective agents. Results: The current literature strongly support the interpretation of glaucoma as a multifaceted chronic neurodegenerative disease, widely affecting the CNS. The cognitive impairment may vary in terms of higher-order functions involvement and in the severity of the degeneration. Although several neuroprotective agents are currently available, the development of new molecules represents a major topic of investigation for future clinical trials. Conclusions: Glaucoma earned the right to be fully considered a neurodegenerative disease. Glaucomatous patients may experience a heterogeneous set of visual and cognitive symptoms, progressively deteriorating the quality of life. Neuroprotection is nowadays a necessary therapeutic goal and a future promising way to preserve visual and cognitive functions, thus improving patients' quality of life.

Changes in retinal multilayer thickness and vascular network of patients with Alzheimer's disease

BACKGROUND

Retinal biomarkers of Alzheimer's disease (AD) have been extensively investigated in recent decades. Retinal nervous and vascular parameters can reflect brain conditions, and they can facilitate early diagnosis of AD.

OBJECTIVE

Our study aimed to evaluate the difference in retinal neuro-layer thickness and vascular parameters of patients with AD and healthy controls (HCs).

METHODS

Non-invasive optical coherence tomography angiography (OCTA) was used to determine the combined thickness of the retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL), as well as the full retinal thickness (FRT). The vascular branching (VB), vascular curvature (VC), and vascular density (VD) for AD and HC groups were also obtained. The Mini-Mental State Examination (MMSE) was used to evaluate the cognitive performance of all the participants. After obtaining all the parameters, two-way analysis of variance (ANOVA) was used to compare the mean values of all the retinal parameters of the patients with AD and the HCs. Pearson's correlation was used to test the association between retinal parameters, MMSE scores, and vascular parameters.

RESULTS

Seventy-eight eyes from 39 participants (19 AD and 20 HC; male, 52.6% in AD and 45.0% in HC; mean [standard deviation] age of 73.79 [7.22] years in AD and 74.35 [6.07] years in HC) were included for the analysis. The average RNFL + GCL thickness (106.32 ± 7.34 μm), FRTs of the four quadrants (290.35 ± 13.05 μm of inferior quadrant, 294.68 ± 9.37 μm of superior quadrant, 302.97 ± 6.52 μm of nasal quadrant, 286.02 ± 13.74 μm of temporal quadrant), and retinal VD (0.0148 ± 0.003) of patients with AD, compared with the HCs, were significantly reduced (p < 0.05). Retinal thickness was significantly correlated with the MMSE scores (p < 0.05). Meanwhile, retinal VD was significantly correlated with the average RNFL + GCL thickness (r2 = 0.2146, p < 0.01). When the vascular parameters were considered, the sensitivity of the AD diagnosis was increased from 0.874 to 0.892.

CONCLUSION

Our study suggested that the patients with AD, compared with age-matched HCs, had significantly reduced RNFL + GCL thickness and vascular density. These reductions correlated with the cognitive performance of the participants. By combining nerve and vessel parameters, the diagnosis of AD can be improved using OCTA technology. Trail registration Name of the registry: Chinese Clinical Trail Registry, Trial registration number: ChiCTR2000035243, Date of registration: Aug. 5, 2020. URL of trial registry record: http://www.chictr.org.cn/index.aspx.

Lower Cognitive Function in Patients with Functionally and Structurally Severe Glaucoma: The LIGHT Study

PRECIS

This cross-sectional study of 172 patients with glaucoma showed that functional and structural glaucoma damage was significantly associated with cognitive impairment independent of age and visual acuity.

PURPOSE

The aim of this study was to determine whether functional and structural glaucoma damage is associated with cognitive function.

PATIENTS AND METHODS

This was a cross-sectional analysis comprising 172 patients with glaucoma with a mean age of 70.6 years. Functional glaucoma severity was evaluated according to the visual field mean deviation (severe, mean deviation ≤ -12▒dB; mild, mean deviation > -12▒dB), and structural glaucoma severity was determined based on circumpapillary retinal nerve fiber layer (RNFL) thickness. The main outcome measure was cognitive impairment defined by a mini-mental state examination (MMSE) score of ≤26 and MMSE-blind score of ≤16.

RESULTS

The prevalence of patients with cognitive impairment (MMSE score ≤26) was significantly higher in the severe glaucoma group than in the mild glaucoma group (33.3% vs. 15.7%; P=0.010, respectively). Similar results were obtained in the analyses with MMSE-blind score of ≤16 (14.7% vs. 1.4%; P=0.003, respectively). Multivariable logistic regression analysis adjusted for potential confounders, including age, body mass index, education, visual acuity, hypertension, diabetes, and depressive symptoms, indicated a higher odds ratio for cognitive impairment (MMSE score ≤26) in patients with severe glaucoma than in those with mild glaucoma (odds ratio, 2.62; 95% confidence interval, 1.006-6.84; P=0.049) and in relation to a 10-μm thinning of the RNFL (odds ratio, 1.42; 95% confidence interval, 1.05-1.93; P=0.025).

CONCLUSION

Functional and structural glaucoma damage was significantly associated with lower cognitive function independent of age and visual acuity in a glaucoma cohort.

The Bidirectional Relationship between Vision and Cognition: A Systematic Review and Meta-analysis

TOPIC

Visual impairment (VI) and cognitive impairment (CIM) are prevalent age-related conditions that impose substantial burden on the society. Findings on the hypothesized bidirectional association of VI and CIM remains equivocal. Hence, we conducted a systematic review and meta-analysis to examine this bidirectional relationship.

CLINICAL RELEVANCE

Sixty percent risk of CIM has not been well elucidated in the literature. A bidirectional relationship between VI and CIM may support the development of strategies for early detection and management of risk factors for both conditions in older people.

METHODS

PubMed, Embase, and Cochrane Central registers were searched systematically for observational studies, published from inception until April 6, 2020, in adults 40 years of age or older reporting objectively measured VI and CIM assessment using clinically validated cognitive screening tests or diagnostic evaluation. Meta-analyses on cross-sectional and longitudinal associations between VI and CIM outcomes (any CIM assessed using screening tests and clinically diagnosed dementia) were examined. Random effect models were used to generate pooled odds ratios (ORs) and 95% confidence intervals (CIs). We also examined study quality, publication bias, and heterogeneity.

RESULTS

Forty studies were included (n = 47 913 570). Meta-analyses confirmed that persons with VI were more likely to have CIM, with significantly higher odds of: (1) any CIM (cross-sectional: OR, 2.38 [95% CI, 1.84-3.07]; longitudinal: OR, 1.66 [95% CI, 1.46-1.89]) and (2) clinically diagnosed dementia (cross-sectional: OR, 2.43 [95% CI, 1.48-4.01]; longitudinal: OR, 2.09 [95% CI, 1.37-3.21]) compared with persons without VI. Significant heterogeneity was explained partially by differences in age, sex, and follow-up duration. Also, some evidence suggested that individuals with CIM, relative to cognitively intact persons, were more likely to have VI, with most articles (8/9 [89%]) reporting significantly positive associations; however, meta-analyses on this association could not be conducted because of insufficient data.

DISCUSSION

Overall, our work suggests that VI is a risk factor of CIM, although further work is needed to confirm the association of CIM as a risk factor for VI. Strategies for early detection and management of both conditions in older people may minimize individual clinical and public health consequences.

Trans-synaptic degeneration in the visual pathway: Neural connectivity, pathophysiology, and clinical implications in neurodegenerative disorders

There is a strong interrelationship between eye and brain diseases. It has been shown that neurodegenerative changes can spread bidirectionally in the visual pathway along neuronal projections. For example, damage to retinal ganglion cells in the retina leads to degeneration of the visual cortex (anterograde degeneration) and vice versa (retrograde degeneration). The underlying mechanisms of this process, known as trans-synaptic degeneration (TSD), are unknown, but TSD contributes to the progression of numerous neurodegenerative disorders, leading to clinical and functional deterioration. The hierarchical structure of the visual system comprises of a strong topographic connectivity between the retina and the visual cortex and therefore serves as an ideal model to study the cellular effect, clinical manifestations, and deterioration extent of TSD. With this review we provide comprehensive information about the neural connectivity, synapse function, molecular changes, and pathophysiology of TSD in visual pathways. We then discuss its bidirectional nature and clinical implications in neurodegenerative diseases. A thorough understanding of TSD in the visual pathway can provide insights into progression of neurodegenerative disorders and its potential as a therapeutic target.

Glaucoma as Neurodegeneration in the Brain

Glaucoma, a group of diseases characterized by progressive optic nerve degeneration that results in irreversible blindness, can be considered a neurodegenerative disorder of both the eye and the brain. Increasing evidence from human and animal studies have shown that glaucoma shares some common neurodegenerative pathways with Alzheimer’s disease (AD) and other tauopathies, such as chronic traumatic encephalopathy (CTE) and frontotemporal dementia. This hypothesis is based on the focal adhesion pathway hypothesis and the spreading hypothesis of tau. Not only has the Apolipoprotein E (APOE) gene been shown to be associated with AD, but also with primary open angle glaucoma (POAG). This review will highlight the relevant literature in the past 20 years from PubMed that show the pathogenic overlap between POAG and AD. Neurodegenerative pathways that contribute to transsynaptic neurodegeneration in AD and other tauopathies might also be similar to those in glaucomatous neurodegeneration.

Association between cognitive performance and self-reported glaucoma in middle-aged and older adults: a cross-sectional analysis of ELSA-Brasil

Recent evidence suggests that glaucoma and Alzheimer's disease are neurodegenerative diseases sharing common pathophysiological and etiological features, although findings are inconclusive. We sought to investigate whether self-reported glaucoma patients without dementia present poorer cognitive performance, an issue that has been less investigated. We employed cross-sectional data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) and included participants ≥50 years of age without a known diagnosis of dementia and a self-reported glaucoma diagnosis. We excluded those with previous stroke, other eye conditions, and using drugs that could impair cognition. We evaluated cognition using delayed word recall, phonemic verbal fluency, and trail making (version B) tests. We used multinomial linear regression models to investigate associations between self-reported glaucoma with cognition, adjusted by several sociodemographic and clinical variables. Out of 4,331 participants, 139 reported glaucoma. Fully-adjusted models showed that self-reported glaucoma patients presented poorer performance in the verbal fluency test (β=-0.39, 95%CI=-0.64 to -0.14, P=0.002), but not in the other cognitive assessments. Thus, our results support the hypothesis that self-reported glaucoma is associated with poor cognitive performance; however, longitudinal data are necessary to corroborate our findings.

Impact of glaucoma on executive function and visual search

PURPOSE

Executive function and visual search are linked to a number of activities of daily living including driving and mobility. Using a computerised version of the Trail Making Test B (TMT-B), we compared the executive function and visual search ability of older adults with glaucoma to age-similar controls and identified which visual function tests best predict TMT-B performance. Novel low-contrast and shifting-target variations of the test were incorporated to explore the effects of different levels of test complexity.

METHODS

Thirty-one older adults with mild to moderate glaucoma (mean age = 71.2 years [SD 6.9]; better-eye mean deviation [MD]: median = -1.9 dB [IQR = -1.2 to 0.4], worse-eye MD: median = -11.1 dB [IQR = -14.0 to -7.7]) and 24 age-similar controls (mean age = 71.9 years [SD 6.6]) with normal vision participated. The groups were matched in age, sex, and cognitive status (mini-mental state examination [MMSE]). Participants underwent measurements of visual acuity, contrast sensitivity (CS), visual fields, and visual processing speeds using the useful field-of-view (UFoV). Participants then completed four variations of a computerised TMT-B test, with different levels of complexity based on target contrast (high/low-contrast) and shifts in target position (fixed/shifting locations). Linear mixed-effect models were used to explore the effects of group, target contrast and shift on TMT-B completion time.

RESULTS

The glaucoma group took 17.3s longer than controls to complete the TMT-B (P = 0.028). All participants took 6.5s longer to complete the low- compared to the high-contrast tests (P = 0.012), and 10.6s longer for the shifting TMT-B compared to the fixed version (P < 0.001). There was no interaction effect between group, contrast, or target shift on completion time. Across all tests and participant groups, longer completion time was associated with slower UFoV processing speeds (divided attention: P = 0.003; selective attention: P = 0.006). Poorer CS was associated with longer completion times for the low (P = 0.007), but not the high-contrast tests.

CONCLUSIONS

Our findings suggest that older adults with mild to moderate glaucoma have poorer visual search ability and executive function relative to controls. However, decreasing target contrast or shifting target position did not exacerbate the effects of glaucomatous visual impairment on performance. The UFoV was a strong predictor of TMT-B performance.