Association of fractal dimension and other retinal vascular network parameters with cognitive performance and neuroimaging biomarkers: The Multi-Ethnic Study of Atherosclerosis (MESA)

INTRODUCTION

Retinal vascular network changes may reflect the integrity of the cerebral microcirculation, and may be associated with cognitive impairment.

METHODS

Associations of retinal vascular measures with cognitive function and MRI biomarkers were examined amongst Multi-Ethnic Study of Atherosclerosis (MESA) participants in North Carolina who had gradable retinal photographs at Exams 2 (2002 to 2004, n = 313) and 5 (2010 to 2012, n = 306), and detailed cognitive testing and MRI at Exam 6 (2016 to 2018).

RESULTS

After adjustment for covariates and multiple comparisons, greater arteriolar fractal dimension (FD) at Exam 2 was associated with less isotropic free water of gray matter regions (β = -0.0005, SE = 0.0024, p = 0.01) at Exam 6, while greater arteriolar FD at Exam 5 was associated with greater gray matter cortical volume (in mm3 , β = 5458, SE = 20.17, p = 0.04) at Exam 6.

CONCLUSION

Greater arteriolar FD, reflecting greater complexity of the branching pattern of the retinal arteries, is associated with MRI biomarkers indicative of less neuroinflammation and neurodegeneration.

A Comparison of Black and Non-Black Patients in the Presentation and Treatment of Keratoconus

Purpose

Patients with advanced keratoconus (KCN) are less likely to benefit from corneal cross-linking and may require a partial or full thickness keratoplasty. This study aimed to determine whether racial disparities exist in the clinical presentation and initial treatment recommendations for patients evaluated for KCN.

Methods

A single-center retrospective review was conducted on all patients who presented to the cornea department for initial evaluation of KCN between 2018 and 2020. Patients who had undergone prior corneal procedures or surgeries were excluded. Baseline sociodemographic and clinical information was collected and stratified according to black versus non-black race. Generalized estimating equations were used to examine the association between black race and presenting corrected distance visual acuity (CDVA), presence of corneal scarring, keratometry values, Belin ABCD score, and treatment recommendations. Multivariate models were adjusted for patient demographics.

Results

A total of 128 patients (251 eyes) were included in this study. In fully adjusted models, black individuals presented with significantly worse CDVA (p < 0.0001) and worse tomographic KCN staging according to the Belin ABCD criteria (p = 0.002) compared to non-blacks. Blacks were also more than four times as likely to present with a thinnest pachymetry <400 µm (p < 0.0001) and more than three times as likely to have corneal scarring (p = 0.001). Blacks were more than seven times more likely to have keratoplasty recommended as treatment than conservative management such as corneal cross-linking or contact lenses (p = 0.004).

Conclusion

Compared with their non-black counterparts, blacks presented with significantly more advanced KCN, which placed them at risk of requiring more invasive treatment plans. Future studies should investigate reasons for such late presentations and aim to mitigate disparities in the presentation and management of KCN.

Relationship of Self-reported and Performance-based Visual Function With Performance-based Measures of Physical Function: The Health ABC Study

BACKGROUND

To assess the relationship between self-reported and performance-based visual impairment (VI) and lower extremity physical function.

METHODS

Cross-sectional analysis of 2 219 Health ABC participants who completed vision testing and the Short Physical Performance Battery (SPPB). Linear regression models used either self-reported (weighted visual function question [VFQ] score) or performance-based (visual acuity [VA], log contrast sensitivity [LCS], Frisby stereoacuity [SA]) to predict SPPB or its components-gait speed, chair stands, or standing balance-with and without covariate adjustment.

RESULTS

Mean age was 73.5 years (range 69-80); 52.4% were female and 37.4% African American. All VI measures were strongly associated with SPPB in unadjusted and adjusted models (p < .001). A self-reported VFQ score 1 standard deviation lower than the mean (mean 87.8 out of 100) demonstrated a -0.241 (95% confidence interval [CI]: -0.325, -0.156) adjusted difference in SPPB. After controlling for covariates, VA of <20/40 (41%) demonstrated a -0.496 (-0.660, -0.331) lower SPPB score while SA score>85 arcsec (30%) had a -0.449 (-0.627, -0.271) adjusted SPPB score versus those with better visual function. LCS < 1.55 (28.6%) was associated with a -0.759 (-0.938, -0.579) lower and LCS ≤ 1.30 (8%) with a -1.216 (-1.515, -0.918) lower adjusted SPPB score relative to better LCS. In a final multivariable model containing multiple vision measures, LCS remained independently associated with SPPB and all components, while SA remained associated with balance (all p < .05).

CONCLUSIONS

Both self-reported and performance-based VI are strongly associated with poor lower extremity physical function. These findings may identify a subgroup of older adults with co-existing visual and physical dysfunction who may benefit from targeted screening and intervention to prevent disability.

The relationship between visual function and physical performance in the Study of Muscle, Mobility and Aging (SOMMA)

PURPOSE

The relationship of types of visual function to different aspects of physical function, especially strength and coordination, has been understudied, but delineation of these relationships could suggest potentially modifiable targets prior to the onset of disability.

METHODS

Cross-sectional analysis of visual function (self-reported eyesight and eye disease, visual acuity, contrast sensitivity) and physical function tests in 877 older adults (mean age 76.36±5.01 years, 59.2% women, and 13.3% Black race). Separate linear regression models were constructed for short physical performance battery (SPPB), expanded SPPB (eSPPB), their components (gait speed, chair stand, balance, narrow walk), stair climb, four-square step, leg extension peak power and strength, and grip strength.

RESULTS

In adjusted models, worse acuity, worse contrast sensitivity, and self-reported poor vision were significantly associated with worse performance on the eSPPB and four-square step test. Worse contrast sensitivity, but not acuity, was significantly associated with shorter balance times, slower chair stand pace, longer stair climb time, and worse SPPB score. Associations of worse acuity and contrast sensitivity with weaker leg extension power, leg strength, and grip strength were attenuated by covariate adjustment. Self-reported macular degeneration, but not cataract or glaucoma, was associated with worse performance on SPPB, eSPPB, balance, stair climb, and four-square step tests in adjusted models. Worse contrast sensitivity and macular degeneration remained associated with worse SPPB and balance after controlling for visual acuity and self-reported eyesight.

CONCLUSIONS

Poor contrast sensitivity was more strongly associated with worse physical performance than acuity, especially for complex tasks that dynamically challenge coordination and balance. Future studies should examine if older adults with contrast sensitivity impairment would benefit from targeted intervention to decrease their risk of disability.

Association Between Contrast Sensitivity and Physical Function in Cognitively Healthy Older Adults: The Brain Networks and Mobility Function Study

BACKGROUND

To evaluate whether contrast sensitivity is associated with lower extremity physical function in cognitively intact older adults.

METHODS

Cross-sectional analysis of the relationship of binocular and worse eye log contrast sensitivity (LCS) to expanded Short Physical Performance Battery (eSPPB) and its components (gait speed, narrow walking speed, chair stand pace, and balance) in 192 cognitively healthy older adults. The association of LCS with postural sway and gait was also tested with tasks that further challenged functional reserve.

RESULTS

Mean age was 76.4 years with 56% identifying as female and over 98.5% having good corrected visual acuity. Lower LCS was significantly associated with worse performance on the eSPPB, 4-M gait speed, narrow walking speed, and balance time in unadjusted and adjusted models. The relationship between worse eye LCS and larger postural sway was 3 times greater on a foam surface (beta 1.07, 95% CI [0.35, 1.80]) than a firm surface (beta 0.35, 95% CI [0.05, 0.65]), and both were robust to adjustment for confounders; similar findings were observed with binocular LCS. Lower binocular LCS had a greater decremental effect on gait velocity during the fast pace (beta -0.58, 95% CI [-0.90, -0.27]) than the usual pace (Beta -0.39 [-0.63, -0.15]) gait task.

CONCLUSIONS

These findings suggest that cognitively unimpaired older adults without significant visual acuity impairment can have subtle preclinical deficits in contrast sensitivity and physical function that could place them at risk of mobility and balance issues. Future studies should determine whether this subset of older adults may benefit from targeted intervention to prevent disability.

Corrigendum: Examining the intersection of cognitive and physical function measures: Results from the brain networks and mobility (B-NET) study

[This corrects the article DOI: 10.3389/fnagi.2023.1090641.].

Retinal Vascular Changes in Alzheimer's Dementia and Mild Cognitive Impairment: A Pilot Study Using Ultra-Widefield Imaging

Purpose

Retinal microvascular abnormalities measured on retinal images are a potential source of prognostic biomarkers of vascular changes in the neurodegenerating brain. We assessed the presence of these abnormalities in Alzheimer's dementia and mild cognitive impairment (MCI) using ultra-widefield (UWF) retinal imaging.

Methods

UWF images from 103 participants (28 with Alzheimer's dementia, 30 with MCI, and 45 with normal cognition) underwent analysis to quantify measures of retinal vascular branching complexity, width, and tortuosity.

Results

Participants with Alzheimer's dementia displayed increased vessel branching in the midperipheral retina and increased arteriolar thinning. Participants with MCI displayed increased rates of arteriolar and venular thinning and a trend for decreased vessel branching.

Conclusions

Statistically significant differences in the retinal vasculature in peripheral regions of the retina were observed among the distinct cognitive stages. However, larger studies are required to establish the clinical importance of our findings. UWF imaging may be a promising modality to assess a larger view of the retinal vasculature to uncover retinal changes in Alzheimer's disease.

Translational Relevance

This pilot work reports an investigation into which retinal vasculature measurements may be useful surrogate measures of cognitive decline, as well as technical developments (e.g., measurement standardization), that are first required to establish their recommended use and translational potential.

Examining the intersection of cognitive and physical function measures: Results from the brain networks and mobility (B-NET) study

Background and objectives

Although evidence exists that measures of mobility and cognition are correlated, it is not known to what extent they overlap, especially across various domains. This study aimed to investigate the intersection of 18 different objective cognitive and physical function measures from a sample of unimpaired adults aged 70 years and older.

Research design and methods

Canonical correlation analysis was utilized to explore the joint cross-sectional relationship between 13 cognitive and 6 physical function measures in the baseline visit of the Brain Networks and Mobility Function (B-NET) Study (n = 192).

Results

Mean age of participants was 76.4 years. Two synthetic functions were identified. Function 1 explained 26.3% of the shared variability between the cognition and physical function variables, whereas Function 2 explained 19.5%. Function 1 termed "cognitive and physical speed" related the expanded Short Physical Performance Battery (eSPPB), 400-m walk speed, and Dual Task gait speed measures of physical function to semantic fluency animals scores, Digit Symbol Coding (DSC), and Trail Making Test B. Function 2 termed "complex motor tasks and cognitive tasks" related the Force Plate Postural Sway Foam Task and Dual Task to the following cognitive variables: MoCA Adjusted Score, Verbal Fluency L words, Craft story immediate and delayed recall, and Trail Making Test B.

Discussion and implications

We identified groups of cognitive and physical functional abilities that were linked in cross-sectional analyses, which may suggest shared underlying neural network pathway(s) related to speed (Function 1) or complexity (Function 2).

Translational significance

Whether such neural processes decline before measurable functional losses or may be important targets for future interventions that aim to prevent disability also remains to be determined.

Retinal and Choroidal Changes in Men Compared with Women with Alzheimer’s Disease

Purpose

To evaluate differences in the retinal microvasculature and structure and choroidal structure among men and women with Alzheimer’s disease (AD) compared with age-matched cognitively normal male and female controls.

Design

Case-control study of participants ≥ 50 years of age.

Participants

A total of 202 eyes of 139 subjects (101 cases and 101 controls).

Methods

All participants and controls underwent OCT and OCT angiography (OCTA), and parameters of subjects with AD were compared with those of cognitively normal controls.

Main Outcome Measures

The foveal avascular zone (FAZ) area, vessel density (VD), and perfusion density (PD) in the superficial capillary plexus within the 3- and 6-mm circle and ring using Early Treatment Diabetic Retinopathy Study (ETDRS) grid overlay on OCTA; central subfield thickness (CST), retinal nerve fiber layer (RNFL) thickness, ganglion cell-inner plexiform layer (GCIPL) thickness, and choroidal vascularity index (CVI) on OCT.

Results

No significant sex differences in VD or PD were found in the AD or control cohorts; however, there were greater differences in VD and PD among AD female participants than AD male participants compared with their respective controls. The CST and FAZ area were not different between male and female AD participants. Among controls, men had a thicker CST (P < 0.001) and smaller FAZ area (P = 0.003) compared with women. The RNFL thickness, GCIPL thickness, and CVI were similar among male and female AD participants and controls.

Conclusions

There may be a loss of the physiologic sex-related differences in retinal structure and microvasculature in those with AD compared with controls. Further studies are needed to elucidate the pathophysiological basis for these findings.

Refractive Outcomes Using Intraoperative Aberrometry for Highly Myopic, Highly Hyperopic, and Post-refractive Eyes

PURPOSE

To evaluate whether intraoperative aberrometry improves the accuracy of refractive outcomes after cataract surgery in highly myopic, highly hyperopic, and post-refractive eyes.

METHODS

This single-center, retrospective review compared the spherical equivalent of postoperative refraction to that predicted by the Barrett Universal II formula versus Optiwave Refractive Analysis (ORA) (Alcon Laboratories, Inc) for highly myopic and hyperopic eyes and to the Barrett True K formula versus ORA for post-refractive eyes. The number and magnitude of lens changes were analyzed and used to determine in how many cases refractive surprises were affected by ORA, with additional subanalysis of outcomes based on average keratometry values.

RESULTS

ORA led to a change in the lens power implanted in 48% (96 of 198) of eyes, and prevented hyperopic surprise in 27% (15 of 55) and excess myopia in 46% (19 of 41). Steeper keratometry values correlated with more frequent changes on ORA-recommended implanted intraocular lens (P = .0031). ORA led to a similar percentage of eyes falling within ±0.50, ±0.75, and ±1.00 diopters compared to the Barrett Universal II and Barrett True K formulas. In post-refractive eyes, ORA led to a similar mean absolute error when compared to the Barrett True K formula (P = .62). For highly myopic eyes with an axial length of greater than 27 mm, ORA demonstrated a trend toward lower mean absolute error when compared to the Barrett Universal II formula (P = .076).

CONCLUSIONS

ORA demonstrated similar refractive results to the Barrett True K formula in post-refractive eyes and to the Barrett Universal II formula in highly myopic and hyper-opic eyes and may provide additional benefit for eyes with steeper corneas or an axial length of greater than 27 mm. [J Refract Surg. 2021;37(9):609-615.].

A case of metastatic primary cardiac angiosarcoma

We report a 49-year-old Southeast Asian woman diagnosed with metastatic primary right atrial angiosarcoma (PCA) and the difficulties encountered in this diagnosis and its subsequent management. Diagnosis of PCA is often delayed due to non-specific clinical presentation of patients. These tumours often present once metastatic spread has occurred, restricting treatment options and leading to very poor prognosis. Patients undergo a multidisciplinary team (MDT) approach involving chemotherapy, radiotherapy and, if eligible, surgery, but evidence-based treatment guidelines have yet to be established due to the rarity of the tumour.

Agreement Between Trend-Based and Qualitative Analysis of the Retinal Nerve Fiber Layer Thickness for Glaucoma Progression on Spectral-Domain Optical Coherence Tomography

INTRODUCTION

To evaluate the agreement between trend-based analysis and qualitative assessment of the retinal nerve fiber layer (RNFL) thickness for glaucomatous progression on spectral-domain optical coherence tomography (SDOCT).

METHODS

Retrospective review of 190 eyes from 103 patients with glaucoma or suspected glaucoma that underwent SDOCT imaging during four consecutive clinic visits. Trend-based progression was characterized by a significantly negative slope. Progression by qualitative analysis was determined by review of raw SDOCT B-scans.

RESULTS

The slope was significantly greater in those with progression than without progression for both trend-based and qualitative analysis (p < 0.001). However, the qualitative grading classified a significantly greater proportion of eyes as progressing compared to trend-based analysis in both the superotemporal (ST) (23.2% vs. 10.5%, p = 0.001) and inferotemporal (IT) RNFL (27.4% vs 8.4%, p < 0.001). The trend-based and qualitative classifications of progression showed poor agreement in both the ST (kappa = 0.0135) and IT RNFL (kappa = 0.1222). The agreement between trend-based and qualitative analysis was lower for eyes with artifacts (ST = 58.11%; IT = 68.7%) than those without artifacts (ST = 80.2%; IT = 74.8%). Moreover, among eyes with artifacts, there was no significant difference in slope between those qualitatively categorized as progressing versus not progressing (p > 0.05).

CONCLUSIONS

Poor agreement was found between a trend-based and qualitative analysis of change in RNFL on SDOCT. Careful qualitative review of SDOCT imaging may identify specific areas of glaucoma progression not captured by trend-based methods, especially in the presence of artifacts. Such an approach may also prove useful for detecting glaucoma progression in a clinical setting when there are few data points available.

The Effect of Age on Increasing Susceptibility to Retinal Nerve Fiber Layer Loss in Glaucoma

Purpose

To determine whether aging modifies the effect of intraocular pressure (IOP) on progressive glaucomatous retinal nerve fiber layer (RNFL) thinning over time.

Methods

This was a retrospective cohort study involving patients with glaucoma or suspected of having glaucoma who were followed over time from the Duke Glaucoma Registry. Rates of RNFL loss from spectral-domain optical coherence tomography (SD-OCT) were used to assess disease progression. Generalized estimating equations with robust sandwich variance estimators were used to investigate the effects of the interaction of age at baseline and mean IOP on rates of RNFL loss over time. Models were adjusted for gender, race, diagnosis, central corneal thickness, follow-up time, and baseline disease severity.

Results

The study included 85,475 IOP measurements and 60,026 SD-OCT tests of 14,739 eyes of 7814 patients. Eyes had a mean follow-up time of 3.5 ± 1.9 years. The average rate of change in RNFL thickness was –0.70 µm/year (95% confidence interval, –0.72 to –0.67). There was a significant interaction between age and mean IOP and the rate of RNFL loss (P = 0.001), with older eyes having significantly faster rates of RNFL loss than younger ones for the same level of IOP. The effect of IOP on rates of change was greater in the inferior and superior regions of the optic disc.

Conclusions

Age is a significant modifier of the relationship between IOP and glaucomatous loss in RNFL thickness over time. Older patients may be more susceptible to glaucomatous progression than younger patients at the same level of IOP.

Co-Prevalence of Alzheimer's Disease and Age-Related Macular Degeneration Established by Histopathologic Diagnosis

BACKGROUND

Previous epidemiologic studies have suggested an association between AMD and AD, and several therapeutic agents are being developed based on this principle. However, prior studies have provided conflicting results due in part to their reliance on clinical diagnoses that are not based on gold-standard histopathology.

OBJECTIVE

To use histopathologic standards for diagnosis in order to determine the co-prevalence of AD among patients with and without AMD.

METHODS

This is a cross-sectional study of 157 autopsy ocular specimens from patients with and without AMD that were greater than 75 years of age at death. Sarks staging was used to document the severity of AMD, and Braak and Braak staging was used to assess the severity of AD in corresponding brain specimens. The prevalence of AD within different severities of AMD was determined using univariable and multivariable logistic regression.

RESULTS

58% of autopsy eyes had AMD. The prevalence of AD was lower in AMD subjects (63%) compared to non-AMD subjects (73%), even when grouped by severity (all p > 0.15). The likelihood of AD was significantly less in AMD subjects, even after adjusting for age and sex in multivariable analysis (OR 0.47, p = 0.049).

CONCLUSION

Histopathologic diagnoses fail to support an increase in prevalence of AD among subjects with AMD, even when disease severity is considered.

Repeatability of Peripapillary Optical Coherence Tomography Angiography Parameters in Older Adults

Purpose:

This work assesses the intrasession repeatability of capillary perfusion density (CPD) and capillary flux index (CFI) measurements on peripapillary optical coherence tomography angiography (OCTA) in healthy eyes of older adults.

Methods:

In this cross-sectional study, healthy volunteers aged 50 years or older underwent 4.5 × 4.5 mm OCTA imaging centered on the optic nerve head using Zeiss Cirrus HD-5000 AngioPlex (Carl Zeiss Meditec). Two consecutive images were acquired in the same eye during a single study session. CPD and CFI were assessed using AngioPlex Software (version 11.0.0.29946) for the radial peripapillary capillary plexus (average over whole scan area) and 4 quadrants (superior, inferior, temporal, and nasal). CPD and CFI repeatability was assessed by intraclass correlation (ICC), mean interocular differences using 2-tailed t test, and association with age using generalized estimating equations.

Results:

A total of 150 images were acquired from 75 eyes of 47 patients. For CPD, ICC results ranged from 0.7160 (nasal CPD) to 0.9218 (average CPD). For CFI, ICC results ranged from 0.6167 (temporal CFI) to 0.8976 (inferior CFI). Temporal CFI was significantly different between right and left eyes of the same patient ( P = .03). CPD and CFI decreased with age in all analyses (average CPD β coefficient –0.00172, P < .001; average CFI β coefficient −0.00278, P < .001).

Conclusions:

Moderate to good repeatability was observed for most peripapillary OCTA metrics; temporal measurements were least repeatable for CPD and CFI. Peripapillary CPD and CFI decrease with age even beyond the fifth decade in healthy older adults.

Characterization of Retinal Microvascular and Choroidal Structural Changes in Parkinson Disease

Importance

Noninvasive retinal imaging may detect structural changes associated with Parkinson disease (PD) and may represent a novel biomarker for disease detection.

Objective

To characterize alterations in the structure and microvasculature of the retina and choroid in eyes of individuals with PD and compare them with eyes of age- and sex-matched cognitively healthy control individuals using optical coherence tomography (OCT) and OCT angiography (OCTA).

Design, Setting, and Participants

This cross-sectional study was conducted at the Duke Neurological Disorders Clinic in Durham, North Carolina. Individuals aged 50 years or older with a diagnosis of PD were eligible for inclusion and underwent an evaluation and diagnosis confirmation before enrollment. Control individuals aged 50 years or older and without subjective cognitive dysfunction, a history of tremor, or evidence of motor dysfunction consistent with parkinsonism were solicited from the clinic or the Duke Alzheimer's Disease Prevention Registry. Individuals with diabetes, glaucoma, retinal pathology, other dementias, and corrected Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity worse than 20/40 Snellen were excluded. Data were analyzed between January 1, 2020, and March 30, 2020.

Exposures

All participants underwent OCT and OCTA imaging.

Main Outcomes and Measures

Generalized estimating equation analysis was used to characterize the association between imaging parameters and PD diagnosis. Superficial capillary plexus vessel density (VD) and perfusion density (PFD) were assessed within the ETDRS 6 × 6-mm circle, 6 × 6-mm inner ring, and 6 × 6-mm outer ring, as was the foveal avascular zone area. Peripapillary retinal nerve fiber layer thickness, macular ganglion cell-inner plexiform layer thickness, central subfield thickness, subfoveal choroidal thickness, total choroidal area, luminal area, and choroidal vascularity index (CVI) were measured.

Results

A total of 124 eyes of 69 participants with PD (39 men [56.5%]; mean [SD] age, 71.7 [7.0] years) and 248 eyes of 137 control participants (77 men [56.2%]; mean [SD] age, 70.9 [6.7] years) were analyzed. In the 6 × 6-mm ETDRS circle, VD (β coefficient = 0.37; 95% CI, 0.04-0.71; P = .03) and PFD (β coefficient = 0.009; 95% CI, 0.0003-0.018; P = .04) were lower in eyes of participants with PD. In the inner ring of the 6 × 6-mm ETDRS circle, VD (β coefficient = 0.61; 95% CI, 0.20-1.02; P = .003) and PFD (β coefficient = 0.015; 95% CI, 0.005-0.026; P = .004) were lower in eyes of participants with PD. Total choroidal area (β coefficient = -1.74 units2; 95% CI, -3.12 to -0.37 units2; P = .01) and luminal area (β coefficient = -1.02 units2; 95% CI, -1.86 to -0.18 units2; P = .02) were greater, but CVI was lower (β coefficient = 0.5%; 95% CI, 0.2%-0.8%; P < .001) in eyes of individuals with PD.

Conclusions and Relevance

This study found that individuals with PD had decreased retinal VD and PFD as well as choroidal structural changes compared with age- and sex-matched control participants. Given the observed population differences in these noninvasive retinal biomarkers, further research into their clinical utility in PD is needed.

Identifying Peripapillary Radial Capillary Plexus Alterations in Parkinson's Disease Using OCT Angiography

PURPOSE

To compare radial peripapillary capillary (RPC) plexus vascular parameters and retinal nerve fiber layer (RNFL) thickness between those with Parkinson's disease (PD) and controls.

DESIGN

Prospective, cross-sectional study.

PARTICIPANTS

A total of 151 eyes of 81 PD participants and 514 eyes of 266 controls.

METHODS

Participants underwent OCT angiography (OCTA) imaging using the Zeiss Cirrus HD-5000 AngioPlex (Carl Zeiss AG). Capillary perfusion density (CPD) and capillary flux index (CFI) were assessed using a 4.5 × 4.5-mm peripapillary scan, and RNFL thickness was assessed using a 200 × 200-μm optic nerve cube OCT scan. Hoehn and Yahr clinical staging for PD was determined by an experienced movement disorders specialist. Generalized estimating equations adjusted for age and sex were used for analysis.

MAIN OUTCOME MEASURES

Differences in RNFL thickness, CPD, and CFI as assessed using multivariable generalized estimating equations between individuals with PD and controls.

RESULTS

After adjustment for age and sex, average CPD (0.446% ± 0.018% vs. 0.439% ± 0.017%, P < 0.001) and CFI (0.434 ± 0.031 vs. 0.426 ± 0.036, P = 0.008) were significantly higher in PD eyes. Average RNFL thickness was similar between groups (PD 89.71 ± 10.45 μm vs. control 88.20 ± 10.33 μm, P = 0.19). Significant correlations between Hoehn and Yahr stage and OCTA parameters were not observed. The OCTA parameters were not significantly different between eyes of the same patient.

CONCLUSIONS

Increased peripapillary microvascular density and flux were detected in a large cohort of individuals with PD compared with controls after adjusting for age and sex; however, RNFL thickness was similar between groups. Peripapillary OCTA parameters may not correlate with the severity of PD. OCTA may serve as a noninvasive method to identify novel biomarkers for the early diagnosis of PD; as such, this methodology deserves further investigation.

Choroidal Structural Analysis in Alzheimer Disease, Mild Cognitive Impairment, and Cognitively Healthy Controls

PURPOSE

To assess choroidal structural parameters in symptomatic Alzheimer disease (AD), mild cognitive impairment (MCI), and cognitively healthy control subjects.

DESIGN

Prospective cross-sectional study.

METHODS

This study took place in an outpatient neurological disorders clinic. Participants included 67 patients (112 eyes) with AD, 74 patients (143 eyes) with MCI, and 137 (248 eyes) control subjects. Subjects with diabetes, glaucoma, or retinal pathology were excluded. High-definition enhanced depth imaging foveal scans were obtained using Zeiss Cirrus HD-5000 AngioPlex. Subfoveal choroidal thickness (SFCT) was measured by 2 masked graders with a third adjudicator. Total choroidal area (TCA), luminal area (LA), and the choroidal vascularity index (CVI) were calculated after image binarization. Association of choroidal parameters with AD, MCI, or control subjects was assessed using multivariable generalized estimating equations, adjusted for age, sex, and visual acuity.

RESULTS

After adjustment for age, sex, and visual acuity, TCA was significantly greater in patients with AD (ß = 2.73; p = .001) and MCI (ß = 4.38; p < .001) compared with control subjects. LA was significantly greater in patients with AD (ß = 1.68; p = .001) and MCI (ß = 2.69; p < .001) compared with control subjects, and CVI was significantly lower in patients with MCI (ß = -0.58; p = .002) compared with control subjects. SFCT was similar among patients with AD and MCI and control subjects on multivariable analysis (p > .05).

CONCLUSIONS

TCA, LA, and CVI may differ between patients with AD, MCI, and healthy cognition, whereas SFCT may not differ among these groups. TCA, LA, and CVI deserve further study in subjects on the Alzheimer continuum.

Rates of Glaucomatous Structural and Functional Change From a Large Clinical Population: The Duke Glaucoma Registry Study

PURPOSE

To investigate rates of structural and functional change in a large clinical population of glaucoma and glaucoma suspect patients.

DESIGN

Retrospective cohort.

METHODS

Twenty-nine thousand five hundred forty-eight spectral-domain optical coherence tomography (OCT) and 19,812 standard automated perimetry (SAP) tests from 6138 eyes of 3669 patients with ≥6 months of follow-up, 2 good quality spectral-domain OCT peripapillary retinal nerve fiber layer scans, and 2 reliable SAP tests were included. Data were extracted from the Duke Glaucoma Registry, a large database of electronic health records of patients from the Duke Eye Center and satellite clinics. Rates of change for the 2 metrics were obtained using linear mixed models, categorized according to pre-established cutoffs, and analyzed according to the severity of the disease.

RESULTS

Average rates of change were -0.73 ± 0.80 μm per year for global retinal nerve fiber layer thickness and -0.09 ± 0.36 dB per year for SAP mean deviation. More than one quarter (26.6%) of eyes were classified as having at least a moderate rate of change by spectral-domain OCT vs 9.1% by SAP (P < .001). In eyes with severe disease, 31.6% were classified as progressing at moderate or faster rates by SAP vs 26.5% by spectral-domain OCT (P = .055). Most eyes classified as fast by spectral-domain OCT were classified as slow by SAP and vice versa.

CONCLUSION

Although most patients under routine care had slow rates of progression, a substantial proportion had rates that could potentially result in major losses if sustained over time. Both structural and functional tests should be used to monitor glaucoma, and spectral-domain OCT still has a relevant role in detecting fast progressors in advanced disease.

Optical Coherence Tomography in Patients with Alzheimer's Disease: What Can It Tell Us?

PURPOSE

Although Alzheimer's disease (AD) is a leading cause of dementia worldwide, its clinical diagnosis remains a challenge. Optical coherence tomography (OCT) and OCT with angiography (OCTA) are non-invasive ophthalmic imaging tools with the potential to detect retinal structural and microvascular changes in patients with AD, which may serve as biomarkers for the disease. In this systematic review, we evaluate whether certain OCT and OCTA parameters are significantly associated with AD and mild cognitive impairment (MCI).

METHODS

PubMed database was searched using a combination of MeSH terms to identify studies for review. Studies were organized by participant diagnostic groups, type of imaging modality, and OCT/OCTA parameters of interest. Participant demographic data was also collected and baseline descriptive statistics were calculated for the included studies.

RESULTS

Seventy-one studies were included for review, representing a total of 6757 patients (2350 AD, 793 MCI, 2902 healthy controls (HC), and 841 others with a range of other neurodegenerative diagnoses). The mean baseline ages were 72.78±3.69, 71.52±2.88, 70.55±3.85 years for AD, MCI and HC groups, respectively. The majority of studies noted significant structural and functional decline in AD patients when compared to HC. Although analysis of MCI groups yielded more mixed results, a similar pattern of decline was often noted amongst patients with MCI relative to HC. OCT and OCTA measurements were also shown to correlate with established measures of AD such as neuropsychological testing or neuroimaging.

CONCLUSION

OCT and OCTA show great potential as non-invasive technologies for the diagnosis of AD. However, further research is needed to determine whether there are AD-specific patterns of structural or microvascular change in the retina and optic nerve that distinguish AD from other neurodegenerative diseases. Development of sensitive and specific OCT/OCTA parameters will be necessary before they can be used to detect AD in clinical settings.

Impact of Artifacts From Optical Coherence Tomography Retinal Nerve Fiber Layer and Macula Scans on Detection of Glaucoma Progression

PURPOSE

To determine the prevalence of artifacts on segmented spectral-domain optical coherence tomography (SDOCT) images and assess their impact on the interpretation of glaucomatous progression in the retinal nerve fiber layer (RNFL) profile and macular thickness map.

DESIGN

Retrospective reliability analysis.

METHODS

Retrospective review of glaucoma and glaucoma suspect eyes imaged with SDOCT during a 1-month period. All cases had at least 4 sets of RNFL and macular images at 6-month intervals. SDOCT raw B-scans were examined to determine true progression and whether artifacts impacted the original interpretation of progression based on auto-segmented change maps. The co-prevalence of artifacts in the RNFL and macula was assessed, as well as the association of clinical factors with the likelihood of artifacts.

RESULTS

A total of 190 eyes with 760 sets of OCT RNFL and macular scans were included. Fifty percent (96/190) of eyes had artifacts, either in the circumpapillary RNFL (83/190; 43.68%) or the macula (57/190; 30.0%). Epiretinal membrane and vitreomacular traction were the most common artifacts. True progression was present on 39.5% (75/190) of scans overall. Among scans with artifacts, 23.9% (23/96) of artifacts masked true progression (ie, false-negative), 36.5% (35/96) led to an interpretation of false progression (ie, false-positive), and 39.6% (38/96) had no effect on the interpretation of progression. The presence of true progression on the RNFL scan was significantly associated with the presence of true progression on the macular scan (P < .001). Similarly, the presence of artifacts on the RNFL scan was significantly associated with artifacts on the macular scan (P < .001). In multivariable analysis, severe glaucoma, hypertension, and age were significantly associated with the presence of artifacts on RNFL (P < .05).

CONCLUSIONS

Artifacts are highly prevalent on both circumpapillary RNFL and macular scans on SDOCT images acquired in a glaucoma clinic. Artifacts can lead to false-positive and false-negative interpretation of progression when using only the auto-segmentation change maps. Thus, careful examination of the raw B-scan images of both the RNFL and macula is critical to identify artifacts and true glaucoma progression.

Predicting Age From Optical Coherence Tomography Scans With Deep Learning

Purpose

To assess whether age can be predicted from deep learning analysis of peripapillary spectral-domain optical coherence tomography (SD-OCT) B-scans and to determine the importance of specific retinal areas on the predictions.

Methods

Deep learning (DL) convolutional neural networks were developed to predict chronological age in healthy subjects using peripapillary SD-OCT B-scan images. Models were built using the whole B-scan, as well as using specific regions through image ablation. Cross-validation was used for training and testing the model. Mean absolute error (MAE) and correlations between predicted and observed age were used to evaluate model performance.

Results

A total of 7271 images from 542 eyes of 278 healthy subjects were included. DL predictions of age using the whole B-scan were strongly correlated with chronological age (MAE = 5.82 years; r = 0.860, P < 0.001). The model also accurately discriminated between the lowest and highest tertiles of age, with an area under the receiver operating characteristic curve of 0.962. In general, class activation maps tended to show a diffuse pattern of activation throughout the scan image. For specific structures of the B-scan, the layers with the strongest correlations with chronological age were the choroid and vitreous (both r = 0.736), whereas retinal nerve fiber layer had the lowest correlation (r = 0.492).

Conclusions

A DL algorithm was able to accurately predict age from whole peripapillary SD-OCT B-scans.

Translational Relevance

DL models applied to SD-OCT scans suggest that aging appears to affect several layers in the posterior eye segment.

Creating a model to predict time intervals from induction of labor to induction of anesthesia and delivery to coordinate workload

BACKGROUND

Induction of labor continues to become more common. We analyzed induction of labor and timing of obstetric and anesthesia work to create a model to predict the induction-anesthesia interval and the induction-delivery interval in order to co-ordinate workload to occur when staff are most available.

METHODS

Patients who underwent induction of labor at a single medical center were identified and multivariable linear regression was used to model anesthesia and delivery times. Data were collected on date of birth, race/ethnicity, body mass index, gestational age, gravidity, parity, indication for labor induction, number of prior deliveries, time of induction, induction agent, cervical dilation, effacement, and fetal station on admission, date and time of anesthesia administration, date and time of delivery, and delivery type.

RESULTS

A total of 1746 women met inclusion criteria. Associations which significantly influenced time from induction of labor to anesthesia and delivery included maternal age (anesthesia P <0.001, delivery P =0.002), body mass index (both P <0.001), prior vaginal delivery (both P <0.001), gestational age (anesthesia P <0.001, delivery P <0.018), simplified Bishop score (both P <0.001), and first induction agent (both P <0.001). Induction of labor of nulliparous women at 02:00 h and parous women at 04:00 or 05:00 h had the highest estimated probability of the mother having her first anesthesia encounter and delivering during optimally staffed hours when our institution's specialty personnel are most available.

CONCLUSIONS

Time to obstetric and anesthesia tasks can be estimated to optimize induction of labor start times, and shift anesthesia and delivery workload to hours when staff are most available.

Applications of deep learning in detection of glaucoma: A systematic review

Glaucoma is the leading cause of irreversible blindness and disability worldwide. Nevertheless, the majority of patients do not know they have the disease and detection of glaucoma progression using standard technology remains a challenge in clinical practice. Artificial intelligence (AI) is an expanding field that offers the potential to improve diagnosis and screening for glaucoma with minimal reliance on human input. Deep learning (DL) algorithms have risen to the forefront of AI by providing nearly human-level performance, at times exceeding the performance of humans for detection of glaucoma on structural and functional tests. A succinct summary of present studies and challenges to be addressed in this field is needed. Following PRISMA guidelines, we conducted a systematic review of studies that applied DL methods for detection of glaucoma using color fundus photographs, optical coherence tomography (OCT), or standard automated perimetry (SAP). In this review article we describe recent advances in DL as applied to the diagnosis of glaucoma and glaucoma progression for application in screening and clinical settings, as well as the challenges that remain when applying this novel technique in glaucoma.

Association of OCT Angiography Parameters With Age in Cognitively Healthy Older Adults

BACKGROUND AND OBJECTIVE

To evaluate the association of changes in retinal anatomy and microvasculature with age and sex in cognitively healthy older adults.

PATIENTS AND METHODS

Cross-sectional study of cognitively healthy subjects aged 50 years and older who underwent optical coherence tomography angiography (OCTA) to estimate the association between age and sex with ganglion cell layer-inner plexiform layer (GC-IPL); central subfield thickness (CST); subfoveal choroidal thickness (CT); foveal avascular zone (FAZ) size; and superficial (SCP), deep (DCP), and whole capillary plexus (WCP) vessel density (VD) and perfusion density (PD) measured in the ETDRS 3-mm and 6-mm circle and rings.

RESULTS

Among 141 older adults (72.9% female; median age: 69 years), 282 eyes were imaged. Females had a greater CT, GC-IPL thickness, and FAZ size and a lower CST than males. After controlling for sex, both CT (P = .001) and GC-IPL thickness (P < .001) decreased with age, whereas FAZ size and CST did not. There was a reduction in VD and PD in SCP, DCP, and WCP with age in the 3-mm circle, 3-mm ring, and 6-mm circle (all P < .05).

CONCLUSIONS

There is a significant reduction in both VD and PD, as well as decreased choroidal and GC-IPL thickness associated with aging, even beyond the fifth decade, in cognitively healthy adults. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:706-714.].

Convolutional neural network to identify symptomatic Alzheimer’s disease using multimodal retinal imaging

Background/Aims

To develop a convolutional neural network (CNN) to detect symptomatic Alzheimer’s disease (AD) using a combination of multimodal retinal images and patient data.

Methods

Colour maps of ganglion cell-inner plexiform layer (GC-IPL) thickness, superficial capillary plexus (SCP) optical coherence tomography angiography (OCTA) images, and ultra-widefield (UWF) colour and fundus autofluorescence (FAF) scanning laser ophthalmoscopy images were captured in individuals with AD or healthy cognition. A CNN to predict AD diagnosis was developed using multimodal retinal images, OCT and OCTA quantitative data, and patient data.

Results

284 eyes of 159 subjects (222 eyes from 123 cognitively healthy subjects and 62 eyes from 36 subjects with AD) were used to develop the model. Area under the receiving operating characteristic curve (AUC) values for predicted probability of AD for the independent test set varied by input used: UWF colour AUC 0.450 (95% CI 0.282, 0.592), OCTA SCP 0.582 (95% CI 0.440, 0.724), UWF FAF 0.618 (95% CI 0.462, 0.773), GC-IPL maps 0.809 (95% CI 0.700, 0.919). A model incorporating all images, quantitative data and patient data (AUC 0.836 (CI 0.729, 0.943)) performed similarly to models only incorporating all images (AUC 0.829 (95% CI 0.719, 0.939)). GC-IPL maps, quantitative data and patient data AUC 0.841 (95% CI 0.739, 0.943).

Conclusion

Our CNN used multimodal retinal images to successfully predict diagnosis of symptomatic AD in an independent test set. GC-IPL maps were the most useful single inputs for prediction. Models including only images performed similarly to models also including quantitative data and patient data.

Assessment of a Segmentation-Free Deep Learning Algorithm for Diagnosing Glaucoma From Optical Coherence Tomography Scans

Importance

Conventional segmentation of the retinal nerve fiber layer (RNFL) is prone to errors that may affect the accuracy of spectral-domain optical coherence tomography (SD-OCT) scans in detecting glaucomatous damage.

Objective

To develop a segmentation-free deep learning (DL) algorithm for assessment of glaucomatous damage using the entire circle B-scan image from SD-OCT.

Design, Setting, and Participants

This cross-sectional study at a single institution used data from SD-OCT images of eyes with glaucoma (perimetric and preperimetric) and normal eyes. The data set was randomly split at the patient level into a training (50%), validation (20%), and test data set (30%). Data were collected from March 2008 to April 2019, and analysis began April 2018.

Exposures

A convolutional neural network was trained to discriminate glaucomatous from normal eyes using the SD-OCT circle B-scan without segmentation lines.

Main Outcomes and Measures

The ability to discriminate glaucoma from healthy eyes was evaluated by comparing the area under the receiver operating characteristic curve and sensitivity at 80% or 95% specificity for the DL algorithm's predicted probability of glaucoma vs conventional RNFL thickness parameters given by SD-OCT software. The performance was also assessed in preperimetric glaucoma, as well as by visual field severity using Hodapp-Parrish-Anderson criteria.

Results

A total of 20 806 SD-OCT images from 1154 eyes of 635 individuals (612 [53%] with glaucoma and 542 normal eyes [47%]) were included. The mean (SD) age at SD-OCT scan was 70.8 (10.4) years in individuals with glaucoma and 55.8 (14.1) years in controls. There were 187 women (53.3%) in the glaucoma group and 165 (59.8%) in the control group. Of 612 eyes with glaucoma, 432 (70.4%) had perimetric and 180 (29.6%) had preperimetric glaucoma. The DL algorithm had a significantly higher area under the receiver operating characteristic curve than global RNFL thickness (0.96 vs 0.87; difference = 0.08 [95% CI, 0.04-0.12]) and each RNFL thickness sector for discriminating between glaucoma and controls (all P < .001). At 95% specificity, the DL algorithm (81%; 95% CI, 64%-97%) was more sensitive than global RNFL thickness (67%; 95% CI, 58%-76%). The areas under the receiver operating characteristic curve were also significantly greater for the DL algorithm compared with RNFL thickness at each stage of disease, especially preperimetric and mild perimetric glaucoma.

Conclusions and Relevance

A segmentation-free DL algorithm performed better than conventional RNFL thickness parameters for diagnosing glaucomatous damage on OCT scans, especially in early disease. Future studies should investigate how such an approach contributes to diagnostic decisions when combined with other relevant clinical information, such as risk factors and perimetry results.

Optical Quality and Tear Film Analysis Before and After Intranasal Stimulation in Patients with Dry Eye Syndrome

Purpose

To evaluate the optical quality and tear film quality in patients with dry eye syndrome (DES) before and after using an intranasal neurostimulation device to stimulate tear production.

Methods

Cross-sectional review of 33 eyes in 21 patients with DES who underwent optical quality and tear film analysis as part of their routine dry eye evaluation pre- and post-neurostimulation trial in office. Optical quality was assessed by measuring the objective scattering index (OSI) and modulation transfer function (MTF). The time to blink and mean tear film OSI were used to analyze the tear film.

Results

Optical quality after the use of the intranasal neurostimulator improved with an average decrease (improvement) in OSI of 0.30±0.68 (P=0.015) and an average increase (improvement) in MTF of 2.12±9.2 (P=0.15). Pre-intranasal neurostimulation OSI had a positive correlation with age (Spearman’s rho 0.60, p < 0.001), while MTF had a negative correlation (Spearman’s rho −0.38, p = 0.03). Pre-intranasal neurostimulation OSI had a negative correlation with MTF (Spearman’s rho −0.85, p < 0.001) and a positive correlation with tear film mean OSI (Spearman’s rho 0.85, p <0.001).

Conclusion

The optical quality of patients with DES is improved with the use of intranasal neurostimulation for tear production, and there was a trend towards improved MTF though not statistically significant. Future studies are needed to follow patients longitudinally.

Comparing the Rule of 5 to Trend-based Analysis for Detecting Glaucoma Progression on OCT

PURPOSE

The rule of 5 is a simple rule for detecting retinal nerve fiber layer (RNFL) change on spectral-domain OCT (SD-OCT), in which a loss of 5 μm of global RNFL on a follow-up test is considered evidence of significant change when compared with the baseline. The rule is based on short-term test-retest variability of SD-OCT and is often used in clinical practice. The purpose of this study was to compare the rule of 5 with trend-based analysis of global RNFL thickness over time for detecting glaucomatous progression.

DESIGN

Prospective cohort.

PARTICIPANTS

A total of 300 eyes of 210 glaucoma subjects followed for an average of 5.4±1.5 years with a median of 11 (interquartile range, 7-14) visits.

METHODS

Trend-based analysis was performed by ordinary least-squares (OLS) linear regression of global RNFL thickness over time. For estimation of specificity, false-positives were obtained by assessing for progression on series of randomly permutated follow-up visits for each eye, which removes any systematic trend over time. The specificity of trend-based analysis was matched to that of the rule of 5 to allow meaningful comparison of the "hit rate," or the proportion of glaucoma eyes categorized as progressing at each time point, using the original sequence of visits.

MAIN OUTCOME MEASURES

Comparison between hit rates of trend-analysis versus rule of 5 at matched specificity.

RESULTS

After 5 years, the simple rule of 5 identified 37.5% of eyes as progressing at a specificity of 81.1%. At the same specificity, the hit rate for trend-based analysis was significantly greater than that of the rule of 5 (62.9% vs. 37.5%; P < 0.001). If the rule of 5 was required to be repeatable on a consecutive test, specificity improved to 93.4%, but hit rate decreased to 21.0%. At this higher specificity, trend-based analysis still had a significantly greater hit rate than the rule of 5 (47.4% vs. 21.0%, respectively; P < 0.001).

CONCLUSIONS

Trend-based analysis was superior to the simple rule of 5 for identifying progression in glaucoma eyes and should be preferred as a method for longitudinal assessment of global SD-OCT RNFL change over time.

A Review of Deep Learning for Screening, Diagnosis, and Detection of Glaucoma Progression

Because of recent advances in computing technology and the availability of large datasets, deep learning has risen to the forefront of artificial intelligence, with performances that often equal, or sometimes even exceed, those of human subjects on a variety of tasks, especially those related to image classification and pattern recognition. As one of the medical fields that is highly dependent on ancillary imaging tests, ophthalmology has been in a prime position to witness the application of deep learning algorithms that can help analyze the vast amount of data coming from those tests. In particular, glaucoma stands as one of the conditions where application of deep learning algorithms could potentially lead to better use of the vast amount of information coming from structural and functional tests evaluating the optic nerve and macula. The purpose of this article is to critically review recent applications of deep learning models in glaucoma, discussing their advantages but also focusing on the challenges inherent to the development of such models for screening, diagnosis and detection of progression. After a brief general overview of deep learning and how it compares to traditional machine learning classifiers, we discuss issues related to the training and validation of deep learning models and how they specifically apply to glaucoma. We then discuss specific scenarios where deep learning has been proposed for use in glaucoma, such as screening with fundus photography, and diagnosis and detection of glaucoma progression with optical coherence tomography and standard automated perimetry.

Translational Relevance

Deep learning algorithms have the potential to significantly improve diagnostic capabilities in glaucoma, but their application in clinical practice requires careful validation, with consideration of the target population, the reference standards used to build the models, and potential sources of bias.

Impact of Intraocular Pressure Control on Rates of Retinal Nerve Fiber Layer Loss in a Large Clinical Population

PURPOSE

To investigate the impact of intraocular pressure (IOP) control on rates of change of spectral-domain OCT (SD-OCT) retinal nerve fiber layer (RNFL) thickness in a large clinical population.

DESIGN

Retrospective cohort study.

PARTICIPANTS

A total of 85 835 IOP measurements and 60 223 SD-OCT tests from 14 790 eyes of 7844 patients.

METHODS

Data were extracted from the Duke Glaucoma Registry, a large database of electronic medical records of patients with glaucoma and suspected disease followed over time at the Duke Eye Center and satellite clinics. All records from patients with a minimum of 6 months of follow-up and at least 2 good-quality SD-OCT scans and 2 clinical visits with Goldmann applanation tonometry were included. Eyes were categorized according to the frequency of visits with IOP below cutoffs of 21 mmHg, 18 mmHg, and 15 mmHg over time. Rates of change for global RNFL thickness were obtained using linear mixed models and classified as slow if change was slower than -1.0 μm/year; moderate if between -1.0 and -2.0 μm/year; and fast if faster than -2.0 μm/year. Multivariable models were adjusted for age, gender, race, diagnosis, central corneal thickness, follow-up time, and baseline disease severity.

MAIN OUTCOME MEASURES

Rates of change in SD-OCT RNFL thickness according to levels of IOP control.

RESULTS

Eyes had a mean follow-up of 3.5±1.9 years. Average rate of change in RNFL thickness was -0.68±0.59 μm/year. Each 1 mmHg higher mean IOP was associated with 0.05 μm/year faster RNFL loss (P < 0.001) after adjustment for potentially confounding variables. For eyes that had fast progression, 41% of them had IOP <21 mmHg in all visits during follow-up, whereas 20% of them had all visits with IOP <18 mmHg, but only 9% of them had all visits with IOP <15 mmHg.

CONCLUSIONS

Intraocular pressure was significantly associated with rates of progressive RNFL loss in a large clinical population. Eyes with stricter IOP control over follow-up visits had a smaller chance of exhibiting fast deterioration. Our findings may assist clinicians in establishing target pressures in clinical practice.

Human Versus Machine: Comparing a Deep Learning Algorithm to Human Gradings for Detecting Glaucoma on Fundus Photographs

PURPOSE

To compare the diagnostic performance of human gradings vs predictions provided by a machine-to-machine (M2M) deep learning (DL) algorithm trained to quantify retinal nerve fiber layer (RNFL) damage on fundus photographs.

DESIGN

Evaluation of a machine learning algorithm.

METHODS

An M2M DL algorithm trained with RNFL thickness parameters from spectral-domain optical coherence tomography was applied to a subset of 490 fundus photos of 490 eyes of 370 subjects graded by 2 glaucoma specialists for the probability of glaucomatous optical neuropathy (GON), and estimates of cup-to-disc (C/D) ratios. Spearman correlations with standard automated perimetry (SAP) global indices were compared between the human gradings vs the M2M DL-predicted RNFL thickness values. The area under the receiver operating characteristic curves (AUC) and partial AUC for the region of clinically meaningful specificity (85%-100%) were used to compare the ability of each output to discriminate eyes with repeatable glaucomatous SAP defects vs eyes with normal fields.

RESULTS

The M2M DL-predicted RNFL thickness had a significantly stronger absolute correlation with SAP mean deviation (rho=0.54) than the probability of GON given by human graders (rho=0.48; P < .001). The partial AUC for the M2M DL algorithm was significantly higher than that for the probability of GON by human graders (partial AUC = 0.529 vs 0.411, respectively; P = .016).

CONCLUSION

An M2M DL algorithm performed as well as, if not better than, human graders at detecting eyes with repeatable glaucomatous visual field loss. This DL algorithm could potentially replace human graders in population screening efforts for glaucoma.

Correlation of OCTA and Volumetric MRI in Mild Cognitive Impairment and Alzheimer's Disease

BACKGROUD AND OBJECTIVE

To evaluate the relationship between retinal microvascular parameters on optical coherence tomography angiography (OCTA) and neurodegenerative changes assessed by measurement of brain volume on volumetric magnetic resonance imaging (MRI) in Alzheimer's disease (AD) and mild cognitive impairment (MCI).

PATIENTS AND METHODS

Sixteen subjects with AD and MCI underwent OCTA imaging (3 mm × 3 mm and 6 mm × 6 mm scans) and volumetric brain MRI imaging with automated volumetric segmentation and quantification. Spearman's correlation (ρ) was performed between forebrain parenchyma, cortical gray matter, inferolateral ventricle (ILV), lateral ventricle (LV), and hippocampus (HP) MRI volumes and vessel density (VD), along with perfusion density (PD) for the 6-mm circle, 6-mm ring, 3-mm circle, and 3-mm ring Early Treatment Diabetic Retinopathy Study regions of the superficial capillary plexus.

RESULTS

Thirty eyes of 16 patients (seven MCI and nine AD) with good-quality OCTA images were analyzed. ILV volume inversely correlated with the VD in the 6-mm circle (ρ = -0 .565, P = .028) and 3-mm ring (ρ = -0.569, P = .027) and PD in the 3-mm ring (ρ = -0.605, P = .0169). Forebrain, cortical gray matter, LV, and HP volumes did not significantly correlate with either VD or PD (P > .05).

CONCLUSIONS

In this pilot investigation, the authors found a significant correlation between reduction in the superficial capillary plexus VD and PD on OCTA and expansion of the ILV in MCI and AD. This relationship between the retinal microvasculature and cerebral volumetric changes deserves further investigation. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:709-718.].

Comparison of Short- And Long-Term Variability in Standard Perimetry and Spectral Domain Optical Coherence Tomography in Glaucoma

PURPOSE

To assess short- and long-term variability on standard automated perimetry (SAP) and spectral domain optical coherence tomography (SD-OCT) in glaucoma.

DESIGN

Prospective cohort.

METHODS

Ordinary least squares linear regression of SAP mean deviation (MD) and SD-OCT global retinal nerve fiber layer (RNFL) thickness were fitted over time for sequential tests conducted within 5 weeks (short-term testing) and annually (long-term testing). Residuals were obtained by subtracting the predicted and observed values, and each patient's standard deviation (SD) of the residuals was used as a measure of variability. Wilcoxon signed-rank test was performed to test the hypothesis of equality between short- and long-term variability.

RESULTS

A total of 43 eyes of 43 glaucoma subjects were included. Subjects had a mean 4.5 ± 0.8 SAP and OCT tests for short-term variability assessment. For long-term variability, the same number of tests were performed and results annually collected over an average of 4.0 ± 0.8 years. The average SD of the residuals was significantly higher in the long-term than in the short-term period for both tests: 1.05 ± 0.70 dB vs. 0.61 ± 0.34 dB, respectively (P < 0.001) for SAP MD and 1.95 ± 1.86 μm vs. 0.81 ± 0.56 μm, respectively (P < 0.001) for SD-OCT RNFL thickness.

CONCLUSIONS

Long-term variability was higher than short-term variability on SD-OCT and SAP. Because current event-based algorithms for detection of glaucoma progression on SAP and SD-OCT have relied on short-term variability data to establish their normative databases, these algorithms may be underestimating the variability in the long-term and thus may overestimate progression over time.

Evaluation of contrast sensitivity in patients with advanced glaucoma: comparison of two tests

AIMS

To evaluate contrast sensitivity (CS) in patients with advanced glaucomatous visual field damage, and to compare two clinical CS tests.

METHODS

This was a cross-sectional test-retest study. Twenty-eight patients with open-angle glaucoma, visual acuity (VA) better than 20/40 and visual field mean deviation (MD) worse than -15 dB were enrolled. Patients underwent VA, visual field and CS testing with the Pelli-Robson (PR) chart and the Freiburg Visual Acuity and Contrast Test (FrACT). Retest measurements were obtained within 1 week to 1 month.

RESULTS

Median (IQR) age and MD were 61.5 (55.5 to 69.2) years and -27.7 (-29.7 to -22.7) dB, respectively. Median (IQR) VA was 0.08 logarithm minimum angle of resolution (0.02 to 0.16), corresponding to 20/25 (20/20 to 20/30). Median (IQR) CS was 1.35 (1.11 to 1.51) log units with the PR chart and 1.39 (1.24 to 1.64) log units with FrACT. VA explained less than 40% of the variance in CS (adjusted R²=0.36). CS estimates of both tests were closely related (rho=0.88, p=0.001), but CS was 0.09 log units higher with FrACT compared with the PR chart, and the 95% repeatability intervals (Bland-Altman) were 46% tighter with the PR chart.

CONCLUSIONS

Despite near-normal VA, almost all patients showed moderate to profound deficits in CS. CS measurement provides additional information on central visual function in patients with advanced glaucoma.

Quantification of Retinal Nerve Fibre Layer Thickness on Optical Coherence Tomography with a Deep Learning Segmentation-Free Approach

This study describes a segmentation-free deep learning (DL) algorithm for measuring retinal nerve fibre layer (RNFL) thickness on spectral-domain optical coherence tomography (SDOCT). The study included 25,285 B-scans from 1,338 eyes of 706 subjects. Training was done to predict RNFL thickness from raw unsegmented scans using conventional RNFL thickness measurements from good quality images as targets, forcing the DL algorithm to learn its own representation of RNFL. The algorithm was tested in three different sets: (1) images without segmentation errors or artefacts, (2) low-quality images with segmentation errors, and (3) images with other artefacts. In test set 1, segmentation-free RNFL predictions were highly correlated with conventional RNFL thickness (r = 0.983, P < 0.001). In test set 2, segmentation-free predictions had higher correlation with the best available estimate (tests with good quality taken in the same date) compared to those from the conventional algorithm (r = 0.972 vs. r = 0.829, respectively; P < 0.001). Segmentation-free predictions were also better in test set 3 (r = 0.940 vs. r = 0.640, P < 0.001). In conclusion, a novel segmentation-free algorithm to extract RNFL thickness performed similarly to the conventional method in good quality images and better in images with errors or other artefacts.

Factors Impacting Outcomes and the Time to Recovery From Malignant Glaucoma

PURPOSE

To identify factors associated with the successful treatment of malignant glaucoma (MG).

DESIGN

Retrospective case series.

METHODS

Setting: single institution; study population: 64 eyes (55 subjects) with MG; observation procedure(s): chart review; main outcome measures: anatomy, intraocular pressure (IOP), best visual acuity (BVA).

RESULTS

87.5% (n=56/64) of eyes with MG required surgical intervention. Vitrectomy was more likely to be successful in eyes with a history of <3 incisional surgeries, <3 glaucoma drops, or IOP ≤30 mm Hg (P < .05). If vitrectomy was performed within 30 days, recovery of anatomy, BVA, and IOP occurred sooner (P < .05). IOP reduction was greater in subjects treated with oral carbonic anhydrase inhibitors (P = .016) or Nd:YAG laser hyaloidotomy (P = .007), and without a history of MG (P = .007). Time to maximal improvement was significantly longer for IOP and BVA than anatomy (P < .001). Treatment of MG with an oral carbonic anhydrase inhibitor hastened anatomic recovery (P = .01). Time to improvement in BVA was significantly faster in men and African Americans (P < .05). Time to maximal reduction in IOP occurred sooner in eyes that underwent anterior chamber reformation in clinic (P < .002). Trabeculectomy surgery prior to MG was associated with prolonged recovery of anatomy, BVA, and IOP (P < .05).

CONCLUSIONS

Earlier vitrectomy may shorten recovery times for MG. Nd:YAG laser hyaloidotomy and oral carbonic anhydrase inhibitors may lead to greater IOP reduction. The time to maximal improvement in IOP and BVA may be longer than the time to anatomic resolution. Although trabeculectomy may impede time to recovery from MG, oral carbonic anhydrase inhibitors may shorten the time to anatomic recovery and anterior chamber reformation may hasten IOP recovery.

Performance of the Rule of 5 for Detecting Glaucoma Progression between Visits with OCT

PURPOSE

To evaluate whether loss of 5 μm or more in global retinal nerve fiber layer (RNFL) thickness on spectral-domain (SD) between 2 consecutive visits is specific for glaucoma progression.

DESIGN

Prospective cohort.

PARTICIPANTS

Ninety-two eyes of 49 control participants and 300 eyes of 210 glaucoma patients.

METHODS

Patients completed at least 5 standard automated perimetry and SD OCT examinations at 6-month intervals over at least 2 years. Eyes were categorized as progressing from glaucoma if the average RNFL declined by 5 μm or more between 2 consecutive visits. The false-positive proportion was estimated by 2 methods: (1) 5-μm or more loss in control participants and (2) 5-μm or more gain in glaucoma. The false-positive proportion was subtracted from the cumulative proportion of eyes categorized with glaucoma progression to estimate the true progression prevalence.

MAIN OUTCOME MEASURES

False-positive and true progression prevalence of patients with glaucoma detected as progressing on SD OCT.

RESULTS

After 5 years of semiannual testing, the cumulative proportion of false-positive results based on 5-μm or more RNFL losses between visits was 24.8% in the control participants. Although 40.6% of glaucoma eyes were diagnosed with progression at 5 years, only 15.8% would have been considered to show true progression based on the expected false-positive ratio from the control participants (i.e., 40.6%-24.8%). The cumulative proportion of an intervisit gain of 5 μm or more at 5 years was 27.4% in glaucoma eyes, suggesting that only 13.2% of eyes with glaucoma truly had progressed (i.e., 40.6%-27.4%).

CONCLUSIONS

Loss of 5 μm or more in average RNFL thickness between consecutive SD OCT tests is not specific for glaucoma progression. Application of this intervisit rule of 5 can result in a high cumulative proportion of false-positive results over time, which could lead to unnecessary interventions in patients whose disease is stable. More specific diagnostic criteria are needed to help clinicians determine whether patients with glaucoma are progressing so that therapy escalation is both timely and appropriate.

Longitudinal Study of Visual Function in Dry Age-Related Macular Degeneration at 12 Months

PURPOSE

To report the 1-year progression of visual impairment on psychophysical tests of visual function in patients with early and intermediate age-related macular degeneration (AMD).

DESIGN

Prospective, observational study.

PARTICIPANTS

Patients with early and intermediate AMD were enrolled from the existing population at the Duke Eye Center, and healthy age-matched control participants were recruited from family members or friends of the AMD patients and from the Duke Optometry and Comprehensive Eye Clinics.

METHODS

Patients and control participants recruited during the baseline study were assessed at both 6 and 12 months after the initial study visit. Measurements of visual function included best-corrected visual acuity (BCVA), low-luminance visual acuity (LLVA), low-luminance deficit (LLD), microperimetry percent-reduced threshold (PRT), microperimetry average threshold (AT), and cone contrast tests (CCTs).

MAIN OUTCOME MEASURES

Changes in BCVA, LLVA, LLD, microperimetry PRT, microperimetry AT, and CCT results from baseline to 6 months and to 12 months were assessed.

RESULTS

Eighty-five patients completed the 12-month examination (19 control participants, 27 early AMD patients, and 39 intermediate AMD patients). Longitudinal analysis detected significant changes from baseline within each group in microperimetry PRT and AT and in the intermediate AMD group only for BCVA and CCT results (P < 0.05).

CONCLUSIONS

Microperimetry and CCT are able to detect functional changes resulting from progression of dry AMD within a period as short as 12 months. These functional markers may be useful end points in future clinical trials that assess the effect of potential treatments for AMD.

Retinal Microvascular and Neurodegenerative Changes in Alzheimer's Disease and Mild Cognitive Impairment Compared with Control Participants

PURPOSE

Evaluate and compare the retinal microvasculature in the superficial capillary plexus (SCP) in Alzheimer's disease (AD), mild cognitive impairment (MCI), and cognitively intact controls using OCT angiography. OCT parameters were also compared.

DESIGN

Cross-sectional study.

PARTICIPANTS

Seventy eyes from 39 AD participants, 72 eyes from 37 MCI participants, and 254 eyes from 133 control participants were enrolled.

METHODS

Participants were imaged using Zeiss Cirrus HD-5000 with AngioPlex (Carl Zeiss Meditec, Dublin, CA) and underwent cognitive evaluation with Mini-Mental State Examination.

MAIN OUTCOME MEASURES

Vessel density (VD) and perfusion density (PD) in the SCP within the Early Treatment Diabetic Retinopathy Study 6-mm circle, 3-mm circle, and 3-mm ring were compared between groups. Foveal avascular zone (FAZ) area, central subfield thickness (CST), macular ganglion cell-inner plexiform layer (GC-IPL) thickness, and peripapillary retinal nerve fiber layer (RNFL) thickness were also compared.

RESULTS

Alzheimer's participants showed significantly decreased SCP VD and PD in the 3-mm ring (P = 0.001 and P = 0.002, respectively) and 3-mm circle (P = 0.003 and P = 0.004, respectively) and decreased SCP VD in the 6-mm circle (P = 0.047) compared with MCI and significantly decreased SCP VD and PD in the 3-mm ring (P = 0.008 and P = 0.004, respectively) and 3-mm circle (P = 0.015 and P = 0.009, respectively) and SCP PD in the 6-mm circle (P = 0.033) when compared with cognitively intact controls. There was no difference in SCP VD or PD between MCI and controls (P > 0.05). FAZ area and CST did not differ significantly between groups (P > 0.05). Alzheimer's participants showed significantly decreased GC-IPL thickness over the inferior (P = 0.032) and inferonasal (P = 0.025) sectors compared with MCI and significantly decreased GC-IPL thickness over the entire (P = 0.012), superonasal (P = 0.041), inferior (P = 0.004), and inferonasal (P = 0.006) sectors compared to controls. MCI participants showed significantly decreased temporal RNFL thickness (P = 0.04) compared with controls.

CONCLUSIONS

Alzheimer's participants showed significantly reduced macular VD, PD, and GC-IPL thickness compared with MCI and controls. Changes in the retinal microvasculature may mirror small vessel cerebrovascular changes in AD.

A Deep Learning Algorithm to Quantify Neuroretinal Rim Loss From Optic Disc Photographs

PURPOSE

To train a deep learning (DL) algorithm that quantifies glaucomatous neuroretinal damage on fundus photographs using the minimum rim width relative to Bruch membrane opening (BMO-MRW) from spectral-domain optical coherence tomography (SDOCT).

DESIGN

Cross-sectional study.

METHODS

A total of 9282 pairs of optic disc photographs and SDOCT optic nerve head scans from 927 eyes of 490 subjects were randomly divided into the validation plus training (80%) and test sets (20%). A DL convolutional neural network was trained to predict the SDOCT BMO-MRW global and sector values when evaluating optic disc photographs. The predictions of the DL network were compared to the actual SDOCT measurements. The area under the receiver operating curve (AUC) was used to evaluate the ability of the network to discriminate glaucomatous visual field loss from normal eyes.

RESULTS

The DL predictions of global BMO-MRW from all optic disc photographs in the test set (mean ± standard deviation [SD]: 228.8 ± 63.1 μm) were highly correlated with the observed values from SDOCT (mean ± SD: 226.0 ± 73.8 μm) (Pearson's r = 0.88; R² = 77%; P < .001), with mean absolute error of the predictions of 27.8 μm. The AUCs for discriminating glaucomatous from healthy eyes with the DL predictions and actual SDOCT global BMO-MRW measurements were 0.945 (95% confidence interval [CI]: 0.874-0.980) and 0.933 (95% CI: 0.856-0.975), respectively (P = .587).

CONCLUSIONS

A DL network can be trained to quantify the amount of neuroretinal damage on optic disc photographs using SDOCT BMO-MRW as a reference. This algorithm showed high accuracy for glaucoma detection, and may potentially eliminate the need for human gradings of disc photographs.

Factors Associated with Interventions after Laser Peripheral Iridotomy for Primary Angle-Closure Spectrum Diagnoses

PURPOSE

To assess factors associated with receipt of subsequent medical, laser, or surgical interventions after laser peripheral iridotomy (LPI).

DESIGN

Retrospective review.

PARTICIPANTS

A total of 1271 eyes in 692 subjects with narrow angles (NAs) that were treated with LPI.

METHODS

Demographic and clinical factors associated with primary angle-closure (PAC) or PAC glaucoma (PACG) versus PAC suspect (PACS) diagnosis and use of glaucoma medications at the time of LPI, as well as factors predictive of subsequent addition of glaucoma medications, and receipt of selective laser trabeculoplasty (SLT), cataract surgery, and glaucoma surgery were assessed using logistic regression with generalized estimating equations. Kaplan-Meier curves and Cox proportional-hazards regression analysis were used to assess baseline factors affecting the time to SLT, cataract surgery, or glaucoma surgery.

MAIN OUTCOME MEASURES

Diagnosis of PAC/PACG and medical, laser, or surgical interventions after LPI.

RESULTS

African Americans (odds ratio [OR], 2.12; P < 0.001) were significantly more likely than whites to have PAC/PACG than PACS and to already be taking glaucoma medications (OR, 2.25, P < 0.001) at the time of LPI. In multivariable logistic regression analysis, African Americans were significantly more likely to be prescribed additional glaucoma medications after LPI (OR, 1.73; P = 0.025) and receive glaucoma surgery (OR, 2.7; P = 0.007), but were less likely to receive SLT (OR, 0.37; P = 0.009). In multivariate Cox proportional-hazards regression analysis, African Americans had longer time to SLT than whites (hazard ratio [HR], 0.41; P = 0.022), but a shorter time to glaucoma surgery (HR, 2.57; P = 0.004). There was no significant association between race and the likelihood of cataract surgery or time to cataract surgery (P > 0.10).

CONCLUSIONS

African Americans were more likely than whites to carry a diagnosis of PAC or PACG at the time of LPI and were significantly more likely to be prescribed additional glaucoma medications and require glaucoma surgery after LPI. Improved screening methods that target African Americans with NAs are needed so that preventive interventions such as LPI can be performed earlier to decrease the risk of progression.

Beneath the Retinal Pigment Epithelium: Histopathologic Findings in Metastatic Extranodal Natural Killer/T-Cell Lymphoma, Nasal Type

Purpose

To report a case of extranodal natural killer/T-cell lymphoma (ENKTCL), nasal type metastatic to the space beneath the retinal pigment epithelium (RPE) with coincident paraneoplastic lymphoma-associated retinopathy.

Methods

Findings of clinical and histopathologic examination are presented with differential diagnoses and a literature review.

Case Report

A 53-year-old man presented with bilateral blindness and had exudative retinal detachments overlying subretinal masses in both eyes. Flow cytometry of pericardial fluid revealed malignant T lymphocytes. After two cycles of chemotherapy, the patient was hospitalized and quickly expired. Autopsy revealed lymphoma involving the eyes, heart, right lung, and two subcarinal lymph nodes focally. Histopathologic examination of the eyes revealed intraocular metastases from ENKTCL, nasal type. Expression of CD3 and CD56, along with expression of Epstein-Barr virus by in situ hybridization, confirmed the diagnosis. Lymphomatous infiltrates were confined to the space beneath the neurosensory retina and between the RPE and the Bruch membrane, sparing the uveal tissue, similar to other metastatic T-cell lymphomas. Extensive RPE and photoreceptor loss in regions with and without underlying tumor was typical of a concurrent paraneoplastic lymphoma-associated retinopathy.

Conclusion

Patients diagnosed with ENKTCL should be evaluated by an ophthalmologist, as ophthalmic involvement portends a poor prognosis.