Relationship Between Macular Microvasculature and Visual Acuity in Advanced and Severe Glaucoma

The association between airborne particulate matter (PM2.5) exposure level and primary open-angle glaucoma

The eye is vulnerable to the adverse effects of air pollution. Previous experimental study found that fine particulate matter (PM2.5) had a direct toxic effect on intraocular tissues. However, clinical evidence for the impact of air pollutants exposure on functional and structural changes in glaucoma remains scarce. A total of 120 patients with primary open-angle glaucoma (POAG) who met the inclusion criteria were included in this retrospective study. The standardized ophthalmic examination, such as intraocular pressure (IOP), visual field, optical coherence tomography, and comprehensive physical examination, were performed. The air pollution data, including PM2.5 concentration and air quality index (AQI), were collected. PM2.5 and AQI for the day of the medical examination, as well as one month, and three months before the medical examination date, were investigated. In our results, higher average exposure levels for one-month and three-month, were associated with increased IOP (r=0.229, P=0.013; r=0.204, P=0.028, respectively) and decreased visual field mean sensitivity (MS) (r=-0.212, P=0.037; r=-0.305, P=0.002, respectively). PM2.5 concentrations for the day of the medical examination was not significantly associated with ocular parameters. In multiple linear regression analysis adjusted for demographic and clinical factors, higher PM2.5 exposure for one month was associated with elevated IOP (P=0.040, β=0.173, 95 %CI=0.008-0.337). We also found an association between PM2.5 and MS (one-month exposure: β=-0.160, P=0.029; three-month exposure: β=-0.238, P=0.002). The logistic regression analysis found that three-month average PM2.5 exposure level was significantly associated with the disease severity (β=0.043, P=0.025, 95 %CI=1.005-1.084). In conclusion, this study is the first to investigate the relationship between air pollution and detailed ocular parameters of POAG patients in Shanghai over a three-year period, and to explore the effects of different exposure times of PM2.5 on glaucoma. This study found that PM2.5 exposure was correlated with elevated IOP and decreased MS. The one-month PM2.5 exposure level had the most significant effects on IOP. The three-month PM2.5 exposure level was an independent risk factor for POAG severity. Current evidence suggests there may be an association between PM2.5 exposure and POAG.

Glaucoma Detection through a Novel Hyperspectral Imaging Band Selection and Vision Transformer Integration

Conventional diagnostic methods for glaucoma primarily rely on non-dynamic fundus images and often analyze features such as the optic cup-to-disc ratio and abnormalities in specific retinal locations like the macula and fovea. However, hyperspectral imaging techniques focus on detecting alterations in oxygen saturation within retinal vessels, offering a potentially more comprehensive approach to diagnosis. This study explores the diagnostic potential of hyperspectral imaging for glaucoma by introducing a novel hyperspectral imaging conversion technique. Digital fundus images are transformed into hyperspectral representations, allowing for a detailed analysis of spectral variations. Spectral regions exhibiting differences are identified through spectral analysis, and images are reconstructed from these specific regions. The Vision Transformer (ViT) algorithm is then employed for classification and comparison across selected spectral bands. Fundus images are used to identify differences in lesions, utilizing a dataset of 1291 images. This study evaluates the classification performance of models using various spectral bands, revealing that the 610-780 nm band outperforms others with an accuracy, precision, recall, F1-score, and AUC-ROC all approximately at 0.9007, indicating its superior effectiveness for the task. The RGB model also shows strong performance, while other bands exhibit lower recall and overall metrics. This research highlights the disparities between machine learning algorithms and traditional clinical approaches in fundus image analysis. The findings suggest that hyperspectral imaging, coupled with advanced computational techniques such as the ViT algorithm, could significantly enhance glaucoma diagnosis. This understanding offers insights into the potential transformation of glaucoma diagnostics through the integration of hyperspectral imaging and innovative computational methodologies.

Peripapillary vessel density in eyes with cone-rod dystrophy

PURPOSE

To compared the vessel density (VD) around the optic nerve head (ONH) in eyes with cone-rod dystrophy (CORD) and healthy control eyes in a sector-wise manner and to investigate the relationship between VD around the ONH and visual function in CORD eyes.

METHODS

Twenty-six eyes in 14 CORD patients and 25 eyes in 25 healthy control subjects were examined. Using OCT angiography images, the VDs in the superficial and deep capillary plexus at the macula (sVDm and dVDm) and those around the ONH in the superior, temporal, inferior and nasal region (VDnh_s, VDnh_t, VDnh_i, and VDnh_n, respectively) were measured for each eye. Patient age, visual acuity (VA) and VDs were then compared between two groups. Moreover, the relationships between VA and the VDs were analyzed using a linear mixed model and AICc model selection.

RESULTS

No significant difference in age was seen between the CORD and control groups (p = 0.87, Wilcoxon rank sum test), but the VA was significantly lower in the CORD group (p<0.0001). Both sVDm and dVDm were significantly lower in the CORD eyes than in the control eyes (both p<0.0001). Among VDnh_s, VDnh_t, VDnh_i, and VDnh_n, however, only VDnh_t differed significantly between the CORD and control groups (p = 0.035). Among age, VDnh_t, dVDm, and sVDm, the optimal model for VA included only VDnh_t and dVDm.

CONCLUSIONS

In addition to the VD in the deep capillary plexus at the macula, the measurement of temporal VD around the ONH might be useful for predicting visual function in eyes with CORD.

Association of macular OCT and OCTA parameters with visual acuity in glaucoma

BACKGROUND/AIMS

To investigate the association of macular optical coherence tomography (OCT)/OCT angiography (OCTA) parameters with visual acuity (VA) in glaucoma.

METHODS

144 pseudophakic primary open-angle glaucoma eyes were included. Foveal (fVD), parafoveal (pf), perifoveal (perifVD) and whole-image vessel densities (wiVD) of superficial and deep layers, and their corresponding ganglion cell complex (GCC) thicknesses were obtained from OCTA 6×6 mm2 macula scans. Foveal avascular zone (FAZ) area, FAZ circumference and foveal density-300 (FD300) were measured. Correlation between OCT/OCTA parameters and Logarithm of the Minimum Angle of Resolution VA (logMAR VA) in early and moderate-advanced glaucoma was evaluated with age and Signal Strength Index-adjusted mixed models. Area under receiver operating characteristic (AUC) was used to evaluate discriminative power of OCT/OCTA for decreased VA (<20/25).

RESULTS

In early glaucoma (80 eyes), no parameter correlated with VA. In moderate-advanced glaucoma (64 eyes), greater FAZ area (β=0.228) and circumference (β=0.063) correlated with worse VA (p<0.05), but not FD300. fThinner sectoral and global GCC was associated with worse VA (β=0.002-0.003, p<0.05), except for inferior hemifield perifGCC and wiGCC. For VD, lower superior hemifield superficial perifVD and wiVD (β=0.007-0.008) and deep fVD (β=0.004) correlated with worse VA (p<0.05). OCT/OCTA parameters showed modest ability to discriminate decreased VA, with the superior hemifield performing better than the inferior hemifield. In early glaucoma, GCC and VD showed similar discrimination (AUC=0.67-0.77). In moderate-advanced glaucoma, fGCC and pfGCC yielded higher AUC (0.75-0.81) than VD (AUC=0.63-0.72).

CONCLUSIONS

Some macular OCT/OCTA parameters were associated with VA in moderate-advanced, but not early glaucoma. These structural parameters may help identify glaucoma patients with impaired vision and reduced quality of life.

TRIAL REGISTRATION NUMBER

NCT00221897.

Foveal avascular zone vessel density is associated with visual field progression in early-stage glaucoma eyes with central visual field damage

We investigated the relationship between foveal avascular zone (FAZ)-related parameters, assessed by optical coherence tomography angiography (OCT-A), and visual field (VF) progression in early-stage open-angle glaucoma (OAG) eyes with central visual field (CVF) defects. Early-stage glaucoma eyes [VF mean deviation (MD) ≥ - 6 dB] with CVF defects were included. The rates of longitudinal change in FAZ-related parameters and structural parameters were evaluated and compared between VF progressors and non-progressors, using linear mixed effects models. Cox proportional hazards model and linear regression models were used to identify factors associated with VF progression, the VF MD reduction rate and the change rate of mean total deviation in central 12 VF points (MTD10). A total of 131 eyes were included and VF progression was detected in 32 eyes (24.4%) during 3.45 years of follow-up. The rates of reduction in vessel density in the 300 µm width annular region surrounding the FAZ (FD300) and macular ganglion cell-inner plexiform layer thickness (mGCIPLT) were significantly faster in progressors than in non-progressors. The faster VF MD or MTD10 reduction rates were associated with faster rates of FD300 loss and mGCIPLT reduction. The FD300 reduction rate is significantly associated with VF progression in early-stage OAG eyes with CVF defects. FD300 may be an adjunctive biomarker of VF progression in glaucomatous eyes with CVF defects.

Relationships of Macular Functional Impairment With Structural and Vascular Changes According to Glaucoma Severity

Purpose

To determine the pointwise relationships of central visual field (VF) defects with macular ganglion cell loss and macular vessel density (VD) loss during various stages of glaucoma.

Methods

Eyes with primary open-angle glaucoma (POAG) were subjected to optical coherence tomography (OCT) and OCT angiography (OCTA) to evaluate macular ganglion cell layer (GCL) thickness and macular VD in the superficial and deep vascular complexes (SVC and DVC). OCT, OCTA, and VF locations were matched after correcting for retinal ganglion cell (RGC) displacement. Pointwise correlations of GCL thickness and VDs of the SVC and DVC with central VF sensitivity (VFS) were evaluated by Pearson's correlation analysis and compared in eyes with early and advanced POAG by Meng's test.

Results

Of the 100 eyes, 52 and 48 were classified as early and advanced POAG. Macular VD showed overall better correlation with central VFS than GCL thickness in both the early and advanced groups. SVC density showed the strongest correlation with central VFS in all groups (R = 0.327 in early group, R = 0.325 in advanced group, all P < 0.001). Although DVC density showed better correlation with VFS (R = 0.311) than GCL thickness (R = 0.212) in the early group (P < 0.001), the correlation was comparable in the advanced group (R = 0.199 and 0.176, respectively, P = 0.254).

Conclusions

After adjustment for RGC displacement, macular SVC density was better correlated with central VFS than macular GCL thickness in both early and advanced POAG. Macular DVC density showed better correlation with VFS than GCL thickness in early but not in advanced POAG, indicating that DVC loss may be involved in early central VF loss.

Factors Affecting Visual Acuity and Central Visual Function in Glaucoma Patients With Myopia

PURPOSE

To investigate associated factors including structural parameters of myopia and vessel density (VD) using optical coherence tomography angiography (OCT-A) to visual acuity (VA) and central visual function in glaucoma patients with myopia.

DESIGN

Retrospective cross-sectional study.

METHODS

Sixty-five eyes of 60 glaucoma patients with myopia and without media opacity and retinal lesions were included. Both Swedish interactive thresholding algorithm (SITA) 24-2 and 10-2 visual field (VF) testing were performed. Superficial and deep VD in the peripapillary and macular regions were evaluated using OCT-A; retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) thicknesses were measured. β-zone peripapillary atrophy (PPA) area, disc torsion, disc-fovea distance, and peripapillary choroidal thickness were measured. Decreased VA was defined as best-corrected VA <20/25.

RESULTS

The worse mean deviation of SITA 24-2, thinner GCIPL thickness, and lower deep peripapillary VD were associated with the presence of central VF damage in glaucoma patients with myopia. Thinner GCIPL thickness, lower deep peripapillary VD, and longer disc-fovea distance were associated with decreased VA in logistic regression analysis. Thinner GCIPL thickness, lower deep peripapillary VD, and larger β-zone PPA area were associated with lower VA in linear regression analysis. Deep peripapillary VD showed a positive correlation with GCIPL thickness, whereas there was no relationship between deep peripapillary VD and RNFL thickness.

CONCLUSION

Decreased VA in glaucoma patients with myopia was associated with lower deep peripapillary VD and papillomacular bundle damage. Lower deep peripapillary VD was independently associated with decreased VA along with thinner GCIPL thickness. Therefore, it could be stated that decreased VA in glaucoma patients is related to the damage location and the status of blood flow in the optic nerve head.

Optical Coherence Tomography and Optical Coherence Tomography Angiography: Essential Tools for Detecting Glaucoma and Disease Progression

Early diagnosis and detection of disease progression are critical to successful therapeutic intervention in glaucoma, the leading cause of irreversible blindness worldwide. Optical coherence tomography (OCT) is a non-invasive imaging technique that allows objective quantification in vivo of key glaucomatous structural changes in the retina and the optic nerve head (ONH). Advances in OCT technology have increased the scan speed and enhanced image quality, contributing to early glaucoma diagnosis and monitoring, as well as the visualization of critically important structures deep within the ONH, such as the lamina cribrosa. OCT angiography (OCTA) is a dye-free technique for noninvasively assessing ocular microvasculature, including capillaries within each plexus serving the macula, peripapillary retina and ONH regions, as well as the deeper vessels of the choroid. This layer-specific assessment of the microvasculature has provided evidence that retinal and choroidal vascular impairments can occur during early stages of glaucoma, suggesting that OCTA-derived measurements could be used as biomarkers for enhancing detection of glaucoma and its progression, as well as to reveal novel insights about pathophysiology. Moreover, these innovations have demonstrated that damage to the macula, a critical region for the vision-related quality of life, can be observed in the early stages of glaucomatous eyes, leading to a paradigm shift in glaucoma monitoring. Other advances in software and hardware, such as artificial intelligence-based algorithms, adaptive optics, and visible-light OCT, may further benefit clinical management of glaucoma in the future. This article reviews the utility of OCT and OCTA for glaucoma diagnosis and disease progression detection, emphasizes the importance of detecting macula damage in glaucoma, and highlights the future perspective of OCT and OCTA. We conclude that the OCT and OCTA are essential glaucoma detection and monitoring tools, leading to clinical and economic benefits for patients and society.

Relationship between the Macular Microvasculature and Central Visual Field Sensitivity in Patients with Advanced Glaucoma

PURPOSE

To evaluate the relationship between central visual field sensitivity (cVFS) and the structural parameters in patients with advanced glaucoma.

DESIGN

Cross-sectional study.

METHODS

In total, 226 eyes of 226 patients with advanced glaucoma were classified into the "minor central defect" (mean deviation on 10-2 visual field test [MD10] > -10 dB) and "significant central defect" (MD10 ≤ -10 dB) groups. We examined the structural parameters using RTVue OCT and angiography, including the retinal nerve fiber layer, ganglion cell complex, peripapillary vessel density (VD), and superficial and deep macular VD (mVD). The assessment of cVFS included MD10 and the mean deviation of the central 16 points on the 10-2 VF test (MD16). We used Pearson correlation and segmented regression to assess the global and regional relationships between the structural parameters and cVFS.

MAIN OUTCOME MEASURES

Correlation between structural parameters and cVFS.

RESULTS

In the minor central defect group, the best global correlations existed between the superficial macular and parafoveal mVD and MD16 (r = 0.52 and 0.54, P < 0.001). In the significant central defect group, superficial mVD best correlated with MD10 (r = 0.47, P < 0.001). Segmented regression between superficial mVD and cVFS revealed no breakpoint was found as MD10 declined, but a breakpoint was identified at -5.95 dB for MD16, which was statistically significant (P < 0.001). The regional correlations between the grid VD and sectors of the central 16 points were significant (r = 0.20-0.53, P= 0.010 ∼P < 0.001).

CONCLUSIONS

The fair global and regional relationships between mVD and cVFS suggest that mVD may be beneficial for monitoring cVFS in patients with advanced glaucoma.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Association Between Longitudinal 10-2 Central Visual Field Change and the Risk of Visual Acuity Loss in Mild-to-Moderate Glaucoma

PRCIS

Faster worsening of 10-2 visual field (VF) was associated with the development of visual acuity (VA) loss in mild-to-moderate glaucoma, suggesting longitudinal 10-2 VF change is associated with the risk of VA impairment.

PURPOSE

To examine whether longitudinal 10-2 central VF change is associated with the risk of VA loss in glaucoma.

PATIENTS AND METHODS

Primary open angle glaucoma and glaucoma suspect eyes with ≥3 years and 5 visits of 10-2 VF examinations were included. Cox proportional hazard modeling with shared frailty was used to evaluate the hazard ratio (HR) of 10-2 VF mean deviation (MD), superior hemifield mean sensitivity (hemi-MS), and inferior hemi-MS worsening rates for developing VA loss, defined as a change in logMAR VA ≥95% test-retest variability.

RESULTS

Among the 252 eyes (148 participants, mean follow-up = 5.8 y), 30 eyes (21 participants, mean follow-up = 4.9 y) developed VA loss. There was no difference in baseline VF between eyes with and without VA loss ( P > 0.05). Eyes with VA loss showed faster 10-2 VF MD worsening [-0.39 (95% CI: -0.60, -0.18) dB/y] and hemi-MS decrease (range: -0.42~-0.38 dB/y), as compared with no-VA loss eyes [10-2 VF MD change = -0.11 (-0.16, -0.07) dB/y; hemi-MS change: -0.12~-0.07 dB/y; P < 0.05]. In the multivariable model, faster 10-2 VF MD worsening [HR (95% CI) = 4.05 (1.61, 10.22), per 1 dB/y faster], superior hemi-MS decrease [HR (95% CI) = 7.07 (2.48, 20.14), per 1 dB/y faster], and inferior hemi-MS decrease [HR (95% CI) = 8.32 (1.99, 34.91), per 1 dB/y faster] were all associated with increased risk of developing VA loss ( P < 0.05).

CONCLUSIONS

Faster 10-2 VF MD and hemifield MS worsening are associated with the development of VA loss. Monitoring the longitudinal central 10-degree VF change may suggest that there is impending VA impairment in glaucoma.

Factors Associated with Visual Acuity in Advanced Glaucoma

This study aimed to comprehensively analyze various parameters in advanced glaucoma patients to identify the factors that can affect best-corrected visual acuity (BCVA) in advanced glaucoma. This cross-sectional retrospective study included 113 patients (mean age, 61.66 ± 13.26 years; males, 67) who had advanced glaucomatous damage (113 eyes; mean BCVA, 0.18 ± 0.38 logMAR; mean deviation of 30-2 visual field [VF], -19.08 ± 6.23 dB). Peripapillary retinal nerve fiber layer (RNFL) and total and segmented macular thickness (RNFL, ganglion cell layer (GCL), and inner plexiform layer (GCL)) were measured using Spectralis optical coherence tomography (OCT). Correlations between BCVA and OCT parameters or 30-2 VF parameters were assessed using Pearson correlation analysis. Multivariate regression analysis was performed to determine the factors associated with BCVA in advanced glaucoma patients. Peripapillary RNFL thickness, subfoveal choroidal thickness, and global macular RNFL, GCL, IPL, and total thickness were found to be significantly correlated with BCVA and central visual function. Multivariate analysis showed a significant correlation between subfoveal choroidal thickness and BCVA. In addition, central VF mean sensitivity, especially inferior hemifield, showed a significant relationship with BCVA. In conclusion, subfoveal choroidal thickness and central VF sensitivity, especially the inferior hemifield area, are factors that affect BCVA in advanced glaucoma.

Association of macular structure, function, and vessel density with foveal threshold in advanced glaucoma

Identifying new biomarkers associated with central visual function impairment is important in advanced glaucoma patients. This retrospective cross-sectional study enrolled 154 eyes from 154 subjects, consisting of 86 patients with advanced open-angle glaucoma (mean deviation of 24-2 visual field [VF] tests < - 15 dB) and 68 healthy controls. Structure, function, and vessel density (VD) parameters were obtained using optical coherence tomography (OCT), 24-2 standard automated perimetry, and OCT angiography, respectively. The relationships of macular thickness, central 5° and 10° VF mean sensitivity (MS), and macular VD parameters with foveal threshold (FT), representing central visual function, were investigated using partial correlation analyses and linear regression analyses, with age adjustment. Superficial and deep layer macular VD, central 5° and 10° VF MS, and best corrected visual acuity (BCVA) correlated significantly with FT after age adjustment (P < 0.05). In multivariate linear regression analyses, FT associated significantly with BCVA (β = - 8.80, P < 0.001), central 5° MS (β = 0.30, P = 0.037), and deep-layer global parafoveal VD (β = 0.37, P = 0.037). Thus, deep-layer parafoveal VD is an independent predictor of FT and may be a potential biomarker for central visual function in advanced glaucoma.