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.

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 (ß = -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 , ß = 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.

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.

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.].

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.

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.

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.

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.

Study of the Natural Crystalline Lens Characteristics Using Dual-Energy Computed Tomography.

There is a paucity of radiologic literature regarding age-related cataract, and little is known about any differences in the imaging appearance of the natural crystalline lens on computed tomography (CT) exams among different demographic groups. In this retrospective review of 198 eyes in 103 adults who underwent dual-energy computed tomography (DECT) exams of the head, regions of interest spanning 3−5 mm were placed over the center of the lens, and the x-ray attenuation of each lens was recorded in Hounsfield Units (HU) at 3 energy levels: 40 keV, 70 keV, and 190 keV. Generalized estimating equations (GEEs) were used to assess the association of clinical or demographic data with lens attenuation. The mean HU values were significantly lower for the older vs. younger group at 40 keV (GEE p-value = 0.022), but there was no significant difference at higher energy levels (p > 0.05). Mean HU values were significantly higher for females vs. males and non-whites vs. non-Hispanic whites at all 3 energy levels in bivariate and multivariable analyses (all p-value < 0.05). There was no significant association between lens attenuation and either diabetes or smoking status. The crystalline lens of females and non-whites had higher attenuation on DECT which may suggest higher density or increased concentration of materials like calcium and increased potential for cataract formation. Given the large scope of cataracts as a cause of visual impairment and the racial disparities that exist in its detection and treatment, further investigation into the role of opportunistic imaging to detect cataract formation is warranted.

Retinal and Choroidal Changes in Men Compared with Women with Alzheimer's Disease: A Case-Control Study.

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.

Factors Associated with Ophthalmology Referral and Adherence in a Teleretinal Screening Program: Insights from a Federally Qualified Health Center.

Background: Early detection of ophthalmic conditions such as diabetic retinopathy (DR) and glaucoma is crucial to preventing vision loss. Previous studies have evaluated teleretinal screening programs for DR in well-insured populations. The purpose of this retrospective study was to evaluate a teleretinal screening program in a population of uninsured and underinsured patients seen in a Federally Qualified Health Center (FQHC). Methods: We conducted a retrospective chart review of patients (age ≥18) who underwent teleretinal imaging (TRI) at a FQHC between January 2015 and September 2019. TRI gradings and patient demographic and clinical information were abstracted. Factors associated with referral for a dilated eye exam by an ophthalmologist, adherence to recommended follow-up dilated eye exam, and ophthalmology visit attendance were examined. Results: 3130 TRIs were graded in 2216 eyes (1107 patients). 65.2% (N = 722) self-identified as Hispanic and 56.3% (N = 623) required interpreter services. Follow-up dilated fundus examination (DFE) was recommended for 388 TRIs, 49% (N = 190) of which were completed within 1 year. Adherence to the recommended ophthalmology exam was not associated with any baseline clinical or demographic characteristics (p > 0.05). Older age, male sex, hypertension, proteinuria, and higher A1c were significantly associated with greater odds of ophthalmology referral based on TRI (all p < 0.05), after adjusting for covariates. Less severe diabetic retinopathy, no insurance coverage, and Hispanic ethnicity were associated with lower odds of attending an ophthalmology visit, regardless of follow-up recommendations based on TRI (all p < 0.05). Conclusion: In an FQHC serving predominantly uninsured and underinsured patients, only 49% of recommended DFE were completed within one year. Less severe diabetic retinopathy, lack of insurance coverage, and Hispanic ethnicity were associated with a lower likelihood of having a DFE regardless of recommendation. These results suggest that greater system-level efforts are needed to increase adherence to follow-up eye exams after TRI to ensure sight-saving care for underserved populations.

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.

Clinical characteristics and mortality rates for suprachoroidal hemorrhage: seven-year experience at a tertiary eye center.

PURPOSE: To investigate comorbidities and medications associated with acute (ASCH) and delayed (DSCH) suprachoroidal hemorrhage (SCH), and to explore visual outcomes and mortality following SCH. METHODS: Retrospective review of SCH cases diagnosed at a tertiary center between 2013 and 2019. Demographics, history, surgery type, visual acuity, intraocular pressure (IOP), and mortality data were reviewed. RESULTS: Fifty eyes of 50 patients experienced SCH related to surgery: 15 (30%) ASCH and 35 (70%) DSCH. Glaucoma surgery was the most common preceding surgery, and SCH was more likely to be delayed in glaucoma surgery relative to other surgeries (p = 0.001). The proportions of patients on anticoagulant, antiplatelet, or NSAID medications were 30% (n = 15), 52% (n = 26), and 12% (n = 6), respectively. The mean preoperative IOP was 25.0 ± 10.2 mmHg. The mean final best corrected visual acuity did not significantly differ between DSCH and ASCH (logMAR 1.92 vs. 2.36; p = 0.39). After controlling for pre-drainage visual acuity, final visual acuity was not statistically significantly different between eyes that were drained versus those that were not drained (p = 0.06). Of all 50 patients, the mortality rate was 12% with a mean time to mortality after SCH of 754 ± 564 days for those who died. CONCLUSION: DSCH was more common than ASCH, with glaucoma surgery being the most common procedure to result in SCH. Visual outcomes and mortality rate were comparable between ASCH and DSCH. Further research is needed regarding the role of surgical drainage on improving visual outcomes in eyes with SCH.

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.

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.].

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.

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.