Rapid initial OCT RNFL thinning is predictive of faster visual field loss during extended follow-up in glaucoma

Biological and Methodological Variability in Retinal Nerve Fiber Layer OCT: The Framingham Heart Study

Objective

To explore participant-level biological attributes and scan-level methodological attributes associated with retinal nerve fiber layer (RNFL) thickness variability in a population-based sample of elderly United States adults.

Design

Cross-sectional analysis using data from the Framingham Heart Study.

Participants

One thousand three hundred forty-seven eyes from 825 participants with ≥1 OCT scan and axial length data were included.

Methods

Three or more successive RNFL scans of each eye of each participant were obtained in a single session. Multivariable linear mixed models were employed to explore the associations between average RNFL thickness with participant-level biological attributes (age, gender, race, ethnicity, and axial length) and scan-level attributes (signal strength [SS]) as independent variables in the whole population as well as a subsample of adults with no self-reported history of glaucoma. Similar analyses were designed to assess methodological variability with average within-eye standard deviation (SD) for repeated scans as the dependent variable.

Main Outcomes Measures

(1) Biological variability: average RNFL thickness, and (2) methodological variability: average within-participant SD across repeated scans.

Results

Age (β =  - 0.19 microns/year, [95% confidence interval {CI}: - 0.29, - 0.09]), female gender (β = +1.48 microns vs. male, [95% CI: 0.09, 2.86]), axial length (β =  - 1.24 microns/mm of greater length, [95% CI: - 1.80, - 0.67]), and SS (β = +1.62 microns/1 unit greater SS, [95% CI: 1.16, 2.09]) were significantly associated with RNFL thickness, while race and ethnicity were not (P > 0.05). In analyses designed to assess methodological variability, higher RNFL thickness (β = +0.02 per micron increase, [95% CI: 0.01, 0.03]), and lower SS (β = +0.19 per 1 unit lower SS, [95% CI: 0.10, 0.27]) were significantly associated with greater RNFL variability. In adults with no self-reported history of glaucoma (n of eyes = 1165, n of participants = 712), female gender was not associated with RNFL, while African American race was associated with thicker RNFL (β = +4.65 microns vs. Whites, [95% CI: 1.28, 8.03]).

Conclusions

Retinal nerve fiber layer thickness is lower with older age, male gender, greater axial length, lower SS, and Whites (as compared with African Americans) without self-reported glaucoma. Measurement variability (SD) is higher with greater RNFL thickness and lower SS. Understanding these biological and methodological variations is important to aid in OCT interpretation.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Impact of Social Vulnerability Index on the Development of Severe Visual Impairment or Blindness From Glaucoma

PURPOSE

To evaluate whether geocoded social risk factor data predict the development of severe visual impairment or blindness due to glaucoma during follow-up using a large electronic health record (EHR) database.

DESIGN

Cohort study.

METHODS

Patients diagnosed with open-angle glaucoma (OAG) at a tertiary care institution. All eyes had glaucomatous visual field defects at baseline. Sociodemographic and ocular data were extracted from the EHR, including age, gender, self-reported race and ethnicity, insurance status, OAG type, prior glaucoma laser or surgery, baseline disease severity using Hodapp-Anderson-Parrish criteria, mean intraocular pressure (IOP) during follow-up, and central corneal thickness. Social vulnerability index (SVIndex) data at the census tract level were obtained using geocoded patient residences. Mixed-effects Cox proportional hazard models were completed to assess for the development of severe visual impairment or blindness during follow-up, defined as BCVA ≤ 20/200 at least at the last two clinic visits or standard automated perimetry (SAP) mean deviation (MD) ≤ -22dB confirmed on two tests.

RESULTS

A total of 4,046 eyes from 2,826 patients met inclusion criteria and were followed for an average of 4.3 ± 2.2 years. Severe visual impairment or blindness developed in 79 eyes (2.0%) from 76 patients (2.7%) after an average of 3.4 ± 1.8 years, leading to an incidence rate of severe visual impairment or blindness of 0.5% per year. Older age (adjusted hazards ratio [HR] 1.36 per decade, P = .007), residence in areas with higher SVIndex (HR 1.56 per 25% increase, P < .001), higher IOP during follow-up (HR 3.01 per 5 mmHg increase, P < .001), and moderate or severe glaucoma at baseline (HR 7.31 and 26.87, P < .001) were risk factors for developing severe visual impairment or blindness. Concordance index of the model was 0.88. Socioeconomic, minority status/language, and housing type/transportation SVIndex themes were key contributors to developing severe visual impairment or blindness.

CONCLUSIONS

Risk factors for developing glaucoma-related severe visual impairment or blindness included older age, elevated IOP during follow-up, moderate or severe disease at baseline, and residence in areas associated with greater social vulnerability. In addition to ocular risk factors, geocoded EHR data regarding social risk factors could help identify patients at high risk of developing glaucoma-related visual impairment.

The Impact of Social Vulnerability on Structural and Functional Glaucoma Severity, Worsening, and Variability

PURPOSE

To determine the associations between social vulnerability index (SVI) and baseline severity, worsening, and variability of glaucoma, as assessed by visual field (VF) and OCT.

DESIGN

Retrospective longitudinal cohort study.

PARTICIPANTS

Adults with glaucoma or glaucoma suspect status in 1 or both eyes. Visual fields were derived from 7897 eyes from 4482 patients, while OCTs were derived from 6271 eyes from 3976 patients. All eyes had a minimum of 5 tests over follow-up using either the Humphrey Field Analyzer or the Cirrus HD-OCT.

METHODS

Social vulnerability index, which measures neighborhood-level environmental factors, was linked to patients' addresses at the census tract level. Rates of change in mean deviation (MD) and retinal nerve fiber layer (RNFL) thickness were computed using linear regression. The slope of the regression line was used to assess worsening, while the standard deviation of residuals was used as a measure of variability. Multivariable linear mixed-effects models were used to investigate the impact of SVI on baseline, worsening, and variability in both MD and RNFL. We further explored the interaction effect of mean intraocular pressure (IOP) and SVI on worsening in MD and RNFL.

MAIN OUTCOME MEASURES

Glaucoma severity defined based on baseline MD and RNFL thickness. Worsening defined as MD and RNFL slope. Variability defined as the standard deviation of the residuals obtained from MD and RNFL slopes.

RESULTS

Increased (worse) SVI was significantly associated with worse baseline MD (β = -1.07 dB, 95% confidence interval [CI]: [-1.54, -0.60]), thicker baseline RNFL (β = 2.46 μm, 95% CI: [0.75, 4.17]), greater rates of RNFL loss (β = -0.12 μm, 95% CI: [-0.23, -0.02]), and greater VF variability (β = 0.16 dB, 95% CI: [0.07, 0.24]). Having worse SVI was associated with worse RNFL loss with increases in IOP (βinteraction = -0.07, 95% CI: [-0.12, -0.02]).

CONCLUSIONS

Increased SVI score is associated with worse functional (VF) loss at baseline, higher rates of structural (OCT) worsening over time, higher VF variability, and a greater effect of IOP on RNFL loss. Further studies are needed to enhance our understanding of these relationships and establish their cause.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

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.

Rate of Initial Optic Nerve Head Capillary Density Loss and Risk of Visual Field Progression

Importance

Rapid initial optic nerve head capillary density loss may be used to assess the risk of glaucoma visual field progression.

Objective

To investigate the association between the rate of initial optic nerve head capillary density loss from optical coherence tomography angiography (OCTA) and visual field progression.

Design, Setting, Participants

This was a retrospective study of a longitudinal cohort at a glaucoma referral center. A total of 167 eyes (96 with primary open-angle glaucoma and 71 with glaucoma suspect) of 109 patients were monitored for a mean (SD) of 5.7 (1.4) years from January 2015 to December 2022. Data analysis was undertaken in April 2023.

Main Outcomes and Measures

The rates of initial capillary density and average retinal nerve fiber layer loss were calculated from the first 3 optic nerve head OCTA and OCT scans, respectively, during the initial follow-up (mean [SD], 2.0 [1.0] years). Based on the median rate, eyes were categorized into fast and slow progressor groups. The association between initial capillary density change or retinal nerve fiber layer thinning and visual field progression was evaluated using linear-mixed and time-varying Cox models.

Results

A total of 167 eyes of 109 patients (mean [SD] age, 69.0 [11.1] years; 56 [51.4%] female and 53 [48.6%] male) were assessed. Eighty-three eyes were slow OCTA progressors, while 84 eyes were fast with mean capillary density loss of -0.45% per year and -1.17% per year, respectively (mean difference, -0.72%/year; 95% CI,-0.84 to -0.60; P < .001). Similarly, 83 eyes were slow OCT progressors, while 84 eyes were fast with mean retinal nerve fiber layer thinning of -0.09 μm per year and -0.60 μm per year, respectively (mean difference, -0.51 μm/year; 95% CI,-0.59 to -0.43; P < .001). The fast OCTA and OCT progressors were associated with more rapid visual field loss (mean difference, -0.18 dB/year; 95% CI,-0.30 to -0.06; P = .004 and -0.17 dB/year; 95% CI,-0.29 to -0.06; P = .002, respectively). Fast OCTA progressing eyes were more likely to have visual field progression (hazard ratio, 1.96; 95% CI, 1.04-3.69; P = .04). Seventeen of 52 eyes (32.7%; 95% CI, 32.5-32.8) with fast OCTA and OCT progression developed subsequent visual field likely progression.

Conclusion and Relevance

Rapid initial optic nerve head capillary density loss from OCTA was associated with a faster rate of visual field progression and a doubling of the risk of developing event progression in this study. These findings may support clinical use of OCTA and OCT optic nerve head measurements for risk assessment of glaucoma progression.

Racial-ethnic disparities in concurrent rates of peripapillary & macular OCT parameters among a large glaucomatous clinical population

OBJECTIVES

To compare rates of change in peripapillary retinal nerve fibre layer (pRNFL) and macular ganglion cell-inner plexiform layer (mGCIPL) parameters among different race-ethnicities from a large electronic health record database of subjects with or suspected of glaucoma.

METHODS

In this retrospective cohort study, rates of change were obtained using joint longitudinal linear mixed models for eyes with ≥3 visits and ≥1 year of follow-up, adjusting for age, sex, intraocular pressure, central corneal thickness, and baseline pRNFL and mGCIPL thickness. Best linear unbiased predictor estimates of various parameters were stratified by baseline glaucoma severity and analysed by racial-ethnic group.

RESULTS

A total of 21,472 spectral domain optical coherence tomography (OCT) pRNFL scans and 14,431 mGCIPL scans from 2002 eyes were evaluated. A total of 200 (15.6%) and 601 (46.8%) subjects identified as non-Hispanic Black (NHB) and Hispanic, respectively. NHB eyes exhibited faster rates of change in pRNFL among glaucoma suspect (global pRNFL -0.57 ± 0.55 µm/year vs. -0.37 ± 0.62 µm/year among Hispanics, p < 0.001), mild glaucoma (superior pRNFL quadrant -1.20 ± 1.06 µm/year vs. -0.75 ± 1.51 µm/year among non-Hispanic Whites (NHW), p = 0.043), and moderate glaucoma eyes (superior pRNFL quadrant -1.31 ± 1.49 µm/year vs. -0.52 ± 1.26 µm/year among Hispanics, p = 0.003). NHB eyes exhibited faster rates of mGCIPL loss corresponding to pRNFL rates. Global pRNFL and mGCIPL rates were strongly correlated (R2 = 0.70).

CONCLUSIONS

Adjusted rates of pRNFL and mGCIPL loss significantly differed between racial-ethnic groups when stratified by glaucoma severity, with faster rates among NHB patients. These differences highlight key racial-ethnic disparities in adjusted rates of glaucoma OCT parameters.

Performance of Linear Mixed Models in Estimating Structural Rates of Glaucoma Progression Using Varied Random Effect Distributions

Purpose

To compare how linear mixed models (LMMs) using Gaussian, Student t, and log-gamma (LG) random effect distributions estimate rates of structural loss in a glaucomatous population using OCT and to compare model performance to ordinary least squares (OLS) regression.

Design

Retrospective cohort study.

Subjects

Patients in the Bascom Palmer Glaucoma Repository (BPGR).

Methods

Eyes with ≥ 5 reliable peripapillary retinal nerve fiber layer (RNFL) OCT tests over ≥ 2 years were identified from the BPGR. Retinal nerve fiber layer thickness values from each reliable test (signal strength ≥ 7/10) and associated time points were collected. Data were modeled using OLS regression as well as LMMs using different random effect distributions. Predictive modeling involved constructing LMMs with (n - 1) tests to predict the RNFL thickness of subsequent tests. A total of 1200 simulated eyes of different baseline RNFL thickness values and progression rates were developed to evaluate the likelihood of declared progression and predicted rates.

Main Outcome Measures

Model fit assessed by Watanabe-Akaike information criterion (WAIC) and mean absolute error (MAE) when predicting future RNFL thickness values; log-rank test and median time to progression with simulated eyes.

Results

A total of 35 862 OCT scans from 5766 eyes of 3491 subjects were included. The mean follow-up period was 7.0 ± 2.3 years, with an average of 6.2 ± 1.4 tests per eye. The Student t model produced the lowest WAIC. In predictive models, all LMMs demonstrated a significant reduction in MAE when estimating future RNFL thickness values compared with OLS (P < 0.001). Gaussian and Student t models were similar and significantly better than the LG model in estimating future RNFL thickness values (P < 0.001). Simulated eyes confirmed LMM performance in declaring progression sooner than OLS regression among moderate and fast progressors (P < 0.01).

Conclusions

LMMs outperformed conventional approaches for estimating rates of OCT RNFL thickness loss in a glaucomatous population. The Student t model provides the best model fit for estimating rates of change in RNFL thickness, although the use of the Gaussian or Student t distribution in models led to similar improvements in accurately estimating RNFL loss.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Visual Field Outcomes in the Primary Tube Versus Trabeculectomy Study

PURPOSE

To describe visual field outcomes in the Primary Tube Versus Trabeculectomy (PTVT) Study.

DESIGN

Cohort analysis of a prospective multicenter randomized clinical trial.

SUBJECTS

A total of 155 eyes from 155 subjects randomly assigned to treatment with tube shunt surgery (n=84) or trabeculectomy with mitomycin C (n=71).

METHODS

The PTVT Study was a multicenter randomized clinical trial comparing the safety and efficacy of trabeculectomy and tube shunt surgery in eyes without prior intraocular surgery. Subjects underwent standard automated perimetry (SAP) at baseline and annually for five years. SAP tests were deemed reliable if the false positive rate was ≤15%. Tests were excluded if visual acuity was ≤20/400 or loss of ≥2 Snellen lines from baseline were attributed to a non-glaucomatous etiology. Linear mixed-effects models were used to compare rates of change in SAP mean deviation (MD) between the two treatment groups. Intraocular pressure (IOP) control was assessed by percentage of visits with IOP <18 mmHg and mean IOP.

OUTCOME MEASURES

Rate of change in SAP MD during follow-up.

RESULTS

A total of 730 SAP tests were evaluated, with an average of 4.7 tests per eye. The average SAP MD at baseline was -12.8±8.3 dB in the tube group and -12.0±8.4 dB in the trabeculectomy group (p=0.57). The mean rate of change in SAP MD was -0.32±0.39 dB/year in the trabeculectomy group and -0.47±0.43 dB/year in the tube group (p=0.23). Eyes with mean IOP 14-17.5 mmHg had significantly faster rates of SAP MD loss compared to eyes with mean IOP <14 mmHg (-0.59±0.13 vs. -0.27±0.08 dB/year, p=0.012) and eyes with only 50-75% of visits with IOP <18 mmHg had faster rates than those with 100% of visits with IOP <18 mmHg (-0.90±0.16 vs. -0.29±0.08 dB/year, p<0.001). Multivariable analysis identified older age and worse IOP control as risk factors for faster progression in both treatment groups.

CONCLUSIONS

No statistically significant difference in mean rates of visual field change was observed between trabeculectomy and tube shunt surgery in the PTVT Study. Worse IOP control was significantly associated with faster rates of SAP MD loss during follow-up. Older patients were also at risk for faster progression.

Phenotypic expressions of the optic disc in primary open-angle glaucoma

BACKGROUND

Which phenotypes are we able to recognize in the optic nerve of patients with primary open angle glaucoma?

METHODS

Retrospective interventional case series. 885 eyes from 885 patients at an outpatient tertiary care centre who met specified criteria for POAG were included. Disc photographs were classified by three glaucoma specialists into the following phenotypes according to their predominant characteristics: (1) concentric rim thinning, (2) focal rim thinning, (3) acquired pit of the optic nerve (APON), (4) tilted, (5) extensive peripapillary atrophy (PPA), and (6) broad rim thinning. Demographic, medical, and ocular data were collected. Kruskal-Wallis was used as a non-parametric test and pairwise comparison was performed by using Wilcoxon rank sum test corrected.

RESULTS

Phenotypic distribution was as follows: 398(45%) focal thinning, 153(18%) concentric thinning, 153(17%) broad thinning, 109(12%) tilted, 47(5%) extensive PPA and 25(3%) APON. Phenotypic traits of interest included a higher proportion of female patients with the focal thinning phenotype (p = 0.015); myopia (p = 0.000), Asian race (OR: 8.8, p = 0.000), and younger age (p = 0.000) were associated with the tilted phenotype; the concentric thinning patients had thicker RNFL (p = 0.000), higher MD (p = 0.008) and lower PSD (p = 0.043) than broad thinning, despite no difference in disc sizes (p = 0.849). The focal thinning group had a localized VF pattern with high PSD compared to concentric thinning (p = 0.005).

CONCLUSION

We report six phenotypic classifications of POAG patients with demographic and ocular differences between phenotypes. Future refinement of phenotypes should allow enhanced identification of genetic associations and improved individualization of patient care.

Secondhand smoke exposure and ocular health: A systematic review

The toxicology of secondhand smoke (SHS), along with the harm of its exposure to human health, has been generally acknowledged; however, specific evidence is lacking on the association between SHS exposure and ocular health. In this systematic review (PROSPERO registration number: CRD42022247992), we included 55 original articles published by 12 May 2023, which dealt with SHS exposure and ocular disorders, such as eye irritation, conjunctivitis, dry eye diseases, uveitis, myopia, astigmatism, contact lens discomfort, age-related macular degeneration, glaucoma, and thyroid eye disease that addressed the ocular neurovascular structures of the macular, retinal nerve fiber layer, choroid, and corneal biomechanical parameters. We found compelling correlational evidence for eye irritation, conjunctivitis, and dry eye symptoms-supporting that SHS exposure was positively associated with inflammatory and allergic changes in the eyes. Yet, evidence about the associations between SHS exposure and other ocular disorders, structures, and parameters is still limited or controversial. Given the limitations of existing literature, more investigations with high quality and rigorous design are warranted to elucidate the potentially harmful effects of SHS exposure on ocular health.

Association of baseline optical coherence tomography angiography with the development of glaucomatous visual field defects in preperimetric glaucoma eyes

AIMS

To evaluate whether baseline vessel density (VD) parameters derived from optical coherence tomography angiography (OCT-A) is associated with the development of glaucomatous visual field (VF) defects in preperimetric glaucoma (PPG) patients.

METHODS

One eye from each of 200 consecutive PPG patients with a normal standard automated perimetry and OCT-A at baseline was retrospectively analysed. OCT-A was used to measure the circumpapillary VD (cpVD) and the parafoveal and perifoveal VD. The retinal nerve fibre layer (RNFL) and macular ganglion cell-inner plexiform layer thicknesses were measured as reference standards. Two patient groups were stratified based on the development of repeatable glaucomatous VF loss. A Cox proportional hazards model was constructed to determine the predictive ability of OCT-A parameters for VF defects. The correlation between these baseline OCT-A parameters and the rate of global VF sensitivity loss (dB/year) was calculated using linear regression analysis.

RESULTS

During a 3.1-year average follow-up period, 18 eyes (9.0%) developed glaucomatous VF defects. At baseline, the lower inferior temporal cpVD (HR (95% CI)=0.934 (0.883 to 0.988); p=0.017) and thinner inferior RNFL (HR (95% CI)=0.895 (0.839 to 0.956); p=0.001) were predictive of glaucomatous VF loss. A lower inferior temporal cpVD and thinner RNFL at baseline were associated with faster rate of global VF sensitivity loss (β=0.015; p=0.001).

CONCLUSION

In PPG eyes, a lower baseline inferior temporal cpVD is significantly associated with glaucomatous VF defect development and a faster rate of global VF loss.

Endpoints for clinical trials in ophthalmology

With the identification of novel targets, the number of interventional clinical trials in ophthalmology has increased. Visual acuity has for a long time been considered the gold standard endpoint for clinical trials, but in the recent years it became evident that other endpoints are required for many indications including geographic atrophy and inherited retinal disease. In glaucoma the currently available drugs were approved based on their IOP lowering capacity. Some recent findings do, however, indicate that at the same level of IOP reduction, not all drugs have the same effect on visual field progression. For neuroprotection trials in glaucoma, novel surrogate endpoints are required, which may either include functional or structural parameters or a combination of both. A number of potential surrogate endpoints for ophthalmology clinical trials have been identified, but their validation is complicated and requires solid scientific evidence. In this article we summarize candidates for clinical endpoints in ophthalmology with a focus on retinal disease and glaucoma. Functional and structural biomarkers, as well as quality of life measures are discussed, and their potential to serve as endpoints in pivotal trials is critically evaluated.

Smoking and progressive retinal nerve fibre layer thinning in glaucoma

BACKGROUND/AIMS

To investigate the relationship between smoking and smoking intensity, and the rate of retinal nerve fibre layer (RNFL) thinning in patients with primary open angle glaucoma (POAG).

METHODS

In this longitudinal study, patients with POAG who had at least 3 years of follow-up with a minimum of 5 visits of optical coherence tomography (OCT) were enrolled. The smoking intensity was calculated as the pack-year at the baseline OCT. Univariable and multivariable linear mixed models were used to determine the effect of each parameter on the rates of RNFL thinning over time. Non-linear least-squares estimation with piecewise regression model was used to investigate the cut-off point for the relationship between circumpapillary RNFL thinning and smoking intensity.

RESULTS

A total of 466 eyes of 314 patients were included over the mean (95% CI) follow-up of 6.6 (6.4 to 6.7) years. Of the 314 patients, 121 (39%) had reported any history of smoking. Greater smoking intensity was associated with faster RNFL thinning (-0.06 (95% CI -0.11 to 0.00) µm/year per 10 pack-year higher; p=0.031) after adjusted for confounding factors. RNFL thinning became significantly faster when smoking intensity was >8 pack-year.

CONCLUSIONS

Smoking intensity is associated with faster rates of RNFL thinning. Evaluation of smoking intensity might add information to the assessment of risk of glaucoma progression. Future studies are required to explore if withdrawing smoking as a modifiable risk factor can decrease progression in patients with glaucoma.

Improved Prediction of Perimetric Loss in Glaucomatous Eyes Using Latent Class Mixed Modeling

PURPOSE

To evaluate whether the identification of distinct classes within a population of glaucoma patients improves estimates of future perimetric loss.

DESIGN

Longitudinal cohort study.

PARTICIPANTS

A total of 6558 eyes of 3981 subjects from the Duke Ophthalmic Registry with ≥ 5 reliable standard automated perimetry (SAP) tests and ≥ 2 years of follow-up.

METHODS

Standard automated perimetry mean deviation (MD) values were extracted with associated timepoints. Latent class mixed models (LCMMs) were used to identify distinct subgroups (classes) of eyes according to rates of perimetric change over time. Rates for individual eyes were then estimated by considering both individual eye data and the most probable class membership for that eye. Data were split into training (80%) and test sets (20%), and test set mean squared prediction errors (MSPEs) were estimated using LCMM and ordinary least squares (OLS) regression.

MAIN OUTCOME MEASURES

Rates of change in SAP MD in each class and MSPE.

RESULTS

The dataset contained 52 900 SAP tests with an average of 8.1 ± 3.7 tests per eye. The best-fitting LCMM contained 5 classes with rates of -0.06, -0.21, -0.87, -2.15, and +1.28dB/year (80.0%, 10.2%, 7.5%, 1.3%, and 1.0% of the population, respectively) labeled as slow, moderate, fast, catastrophic progressors, and "improvers" respectively. Fast and catastrophic progressors were older (64.1 ± 13.7 and 63.5 ± 16.9 vs. 57.8 ± 15.8, P < 0.001) and had generally mild-moderate disease at baseline (65.7% and 71% vs. 52%, P < 0.001) than slow progressors. The MSPE was significantly lower for LCMM compared to OLS, regardless of the number of tests used to obtain the rate of change (5.1 ± 0.6 vs. 60.2 ± 37.9, 4.9 ± 0.5 vs. 13.4 ± 3.2, 5.6 ± 0.8 vs. 8.1 ± 1.1, 3.4 ± 0.3 vs. 5.5 ± 1.1 when predicting the fourth, fifth, sixth, and seventh visual fields (VFs) respectively; P < 0.001 for all comparisons). MSPE of fast and catastrophic progressors was significantly lower with LCMM versus OLS (17.7 ± 6.9 vs. 48.1 ± 19.7, 27.1 ± 8.4 vs. 81.3 ± 27.1, 49.0 ± 14.7 vs. 183.9 ± 55.2, 46.6 ± 16.0 vs. 232.4 ± 78.0 when predicting the fourth, fifth, sixth, and seventh VFs respectively; P < 0.001 for all comparisons).

CONCLUSIONS

Latent class mixed model successfully identified distinct classes of progressors within a large glaucoma population that seemed to reflect subgroups observed in clinical practice. Latent class mixed models were superior to OLS regression in predicting future VF observations.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosuremay be found after the references.

Risk factors for structural and functional progression of primary open-angle glaucoma in an African ancestry cohort

BACKGROUND/AIMS

To investigate the rates of structural and functional progression of primary open-angle glaucoma in an African ancestry cohort and identify risk factors for progression.

METHODS

This retrospective study included 1424 eyes from glaucoma cases in the Primary Open-Angle African American Glaucoma Genetics cohort, with ≥2 visits for retinal nerve fibre layer (RNFL) thickness and mean deviation (MD) measurements over ≥6-month follow-up. The rates of structural progression (change in RNFL thickness/year) and functional progression (change in MD/year) were calculated from linear mixed effects models, accounting for intereye correlation and longitudinal correlation. Eyes were categorised as slow, moderate or fast progressors. Risk factors for progression rates were assessed using univariable and multivariable regression models.

RESULTS

The median (interquartile) rates of progression were -1.60 (-2.05 to -1.15) µm/year for RNFL thickness and -0.40 (-0.44 to -0.34) decibels/year for MD. Eyes were categorised as slow (structural: 19%, functional: 88%), moderate (structural: 54%, functional: 11%) and fast (structural: 27%, functional: 1%) progressors. In multivariable analysis, faster RNFL progression was independently associated with thicker baseline RNFL (p<0.0001), lower baseline MD (p=0.003) and beta peripapillary atrophy (p=0.03). Faster MD progression was independently associated with higher baseline MD (p<0.0001), larger cup-to-disc ratios (p=0.02) and lower body mass index (p=0.0004).

CONCLUSION

The median rates of structural and functional progression in this African ancestry cohort were faster than the rates reported from previously published studies in other ethnic groups. Higher baseline RNFL thickness and MD values were associated with faster progression rates. Results highlight the importance of monitoring structural and functional glaucoma progression to provide timely treatment in early disease.

Detecting disease progression in mild, moderate and severe glaucoma

PURPOSE OF REVIEW

The purpose of this review is to examine contemporary techniques for detecting the progression of glaucoma. We provide a general overview of detection principles and review evidence-based diagnostic strategies and specific considerations for detecting glaucomatous progression in patients with mild, moderate and severe disease.

RECENT FINDINGS

Diagnostic techniques and technologies for glaucoma have dramatically evolved in recent years, affording clinicians an expansive toolkit with which to detect glaucoma progression. Each stage of glaucoma, however, presents unique diagnostic challenges. In mild disease, either structural or functional changes can develop first in disease progression. In moderate disease, structural or functional changes can occur either in tandem or in isolation. In severe disease, standard techniques may fail to detect further disease progression, but such detection can still be measured using other modalities.

SUMMARY

Detecting disease progression is central to the management of glaucoma. Glaucomatous progression has both structural and functional elements, both of which must be carefully monitored at all disease stages to determine when interventions are warranted.

Application of diffusion tensor imaging technology in glaucoma diagnosis

Glaucoma is the first major category of irreversible blinding eye illnesses worldwide. Its leading cause is the death of retinal ganglion cells and their axons, which results in the loss of vision. Research indicates that glaucoma affects the optic nerve and the whole visual pathway. It also reveals that degenerative lesions caused by glaucoma can be found outside the visual pathway. Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique that can investigate the complete visual system, including alterations in the optic nerve, optic chiasm, optic tract, lateral geniculate nuclear, and optic radiation. In order to provide a more solid foundation for the degenerative characteristics of glaucoma, this paper will discuss the standard diagnostic techniques for glaucoma through a review of the literature, describe the use of DTI technology in glaucoma in humans and animal models, and introduce these techniques. With the advancement of DTI technology and its coupling with artificial intelligence, DTI represents a potential future for MRI technology in glaucoma research.

Association Between Rate of Ganglion Cell Complex Thinning and Rate of Central Visual Field Loss

Importance

Whether rapid ganglion cell complex (GCC) thinning during an initial follow-up period is associated with rates of central visual field loss over time is unclear but important to understand because risk of glaucoma progression can help guide treatment intensity.

Objective

To investigate the association between the rate of GCC thinning during initial follow-up and the rate of central visual field loss.

Design, Setting, and Participants

This retrospective cohort study assessed patients older than 18 years with glaucoma at a tertiary glaucoma center who were followed up from June 18, 2014, to January 11, 2019. Data analysis for the current study was undertaken in March 2022.

Main Outcomes and Measures

Initial rates of GCC thinning were obtained from global GCC thickness values of the first 3 optical coherence tomography (OCT) scans. Rates of central visual field loss were assessed as the change in central (10-2) visual field mean deviation during the 4.7-year follow-up period by univariable and multivariable linear mixed-effects models. Eyes were categorized as slow (>-1 μm/y) or fast (≤-1 μm/y) progressors based on rates of GCC thinning.

Results

The cohort consisted of 202 eyes of 139 patients (mean [SD] age, 68.7 [10.0] years; 72 male [51.8%]); 44 African American patients (31.7%), 13 Asian patients (9.4%), 80 White patients (57.6%), and 2 patients who identified as other race and ethnicity (1.4%) were analyzed. The rate of GCC change was -0.56 μm/y (95% CI, -0.66 to -0.46 μm/y) during a mean initial follow-up of 1.8 years (95% CI, 1.7-2.0 years). A total of 163 eyes (80.7%) were slow OCT progressors, and 39 (19.3%) were fast OCT progressors, with rates of GCC thinning of -0.3 μm/y (95% CI, -0.4 to -0.2 μm/y) and -1.6 μm/y (-1.8 to -1.3 μm/y), respectively. The rates of 10-2 visual field mean deviation worsening among slow and fast OCT progressors were -0.10 dB/y (95% CI, -0.16 to 0.00 dB/y) and -0.34 dB/y (95% CI, -0.51 to -0.16 dB/y), respectively (difference, -0.26 dB/y; 95% CI, -0.45 to -0.07 dB/y; P = .008).

Conclusions and Relevance

In this cohort study, rapid GCC thinning during an initial follow-up period was associated with faster rates of central visual field decline. These findings support use of longitudinal macular OCT scans assisting clinical decision-making for glaucoma and also may guide possible intensification of therapy in high-risk patients.

Restless Legs Syndrome and the Eyes: Spectral-Domain Optic Coherence Tomography Study

BACKGROUND

Restless legs syndrome (RLS) is a movement disorder thought to be caused by impaired dopamine action. This study aimed to evaluate possible changes in ocular biometric and optic coherence tomography (OCT) parameters in RLS patients.

METHODS

This is a prospective, cross-sectional comparative study. Consecutive primary and secondary (with iron-deficiency anemia) RLS patients and age-matched and sex-matched controls were enrolled in the study. All participants underwent comprehensive neurological and ophthalmological examinations. Ocular biometric and OCT parameters, such as choroidal thickness, macular thickness, macular volume, ganglion cell layer thickness, inner nuclear cell layer thickness, and retinal nerve fiber layer thickness, were compared.

RESULTS

Fifty-one RLS patients and 50 healthy controls were included in this study. There was no difference between the groups' refraction status, ocular biometric data (axial length, anterior chamber depth, central corneal thickness), or OCT parameters (choroidal thickness, macular thickness, macular volume, ganglion cell layer thickness, inner nuclear cell layer thickness). Primary and secondary (with only iron-deficiency anemia) RLS patients were compared, and there was no difference in their axial length, anterior chamber depth, central corneal thickness or OCT parameters. No significant relationship was found between disease severity or duration and OCT parameters.

CONCLUSIONS

Disease severity and disease duration do not affect OCT parameters in primary or secondary RLS patients. OCT data do not seem to provide information about the course of this disease.

Impact of Smoking on Visual Field Progression in a Long-term Clinical Follow-up

PURPOSE

To investigate the effect of smoking on rates of progressive visual field (VF) damage over time in glaucoma.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Five hundred eleven eyes of 354 patients with glaucoma followed up from multicenter glaucoma registries.

METHODS

In this longitudinal study, 354 patients with primary open-angle glaucoma with a minimum of 3 years of follow-up and 5 VF tests were enrolled from the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation Study. Univariate and multivariate linear mixed models were used to investigate the effects of smoking on rates of 24-2 VF mean deviation loss. Visual field progression was defined using pointwise linear and significant negative VF mean deviation loss. Logistic regression was used to identify baseline factors and whether different levels of smoking intensity were associated with VF progression. Kaplan-Meier survival analysis and the log-rank test were used to compare the cumulative risk ratio of progression between smoker and never smoker groups.

MAIN OUTCOME MEASURES

Visual field progression.

RESULTS

Five hundred eleven eyes of 354 patients were included over the median follow-up of 12.5 years. Median baseline age was 64.8 years. Of the 354 patients, 124 (35%) were Black, and 149 (42.1%) and 168 (59.8%) had reported a history of smoking or alcohol consumption, respectively. In a multivariate model, higher smoking intensity was associated with faster VF loss (coefficient, -0.05 decibels (dB)/year per 10 pack-years; 95% confidence interval [CI], -0.08 to -0.01 dB/year per 10 pack-years; P = 0.010). Developing VF progression in eyes of heavy smokers (≥ 20 pack-years) was 2.2 times more than in eyes of patients without smoking history (odds ratio, 2.21; 95% CI, 1.02-4.76; P = 0.044). Statistically significant differences were found between heavy smokers (≥ 20 pack-years) and never smokers by Kaplan-Meier analysis (P = 0.011, log-rank test).

CONCLUSIONS

Heavy smokers are more likely to sustain VF loss in eyes with glaucoma. The prospective longitudinal design of this study supports the hypothesis that levels of smoking may be a significant predictor for glaucoma progression. Additionally, this information can be used for clinically relevant tobacco prevention and intervention messages.

Smoking Cessation May Reduce Risk of Visual Field Progression in Heavy Smokers

PRCIS

The earlier a person quits smoking the more likely is the optic nerve be spared from damage.

PURPOSE

To investigate the effect of smoking cessation on visual field (VF) progression in glaucoma.

METHODS

Primary open angle glaucoma patients with a minimum of 3 years follow-up and 5 VFs were included. Linear mixed models were used to investigate the effects of smoking on the rates of 24-2 VF mean deviation loss after adjusting for confounding factors. Cox proportional hazard regression was used to identify whether different levels of smoking intensity were associated with VF progression with respect to different duration of quitting.

RESULTS

Five hundred eleven eyes of 354 patients were included over the mean follow-up of 12.4 years. Mean baseline age (95% confidence interval) was 62.3 (61.2, 63.4) years. One hundred forty nine (42.1%) patients were smokers. In a multivariable model, smoking intensity was associated with faster VF loss (-0.06, 95% confidence interval (-0.10, -0.01) dB/year per 10 pack-years, P =0.01) among smokers. Heavy smokers (≥20 pack-years) who had quit ˂25 years prior had significantly greater odds of VF progression compared with never smokers (odds ratio=2.49 (1.01, 6.08); P =0.046). There was no significant difference in odds of VF progression in heavy smokers who had quit smoking more than 25 years compared with never smokers ( P =0.43). A significantly higher proportion of VF progression was found in heavy smokers who quit < 25 years compared with heavy smokers who quit ≥25 years by Kaplan-Meier analysis ( P =<0.001).

CONCLUSIONS

After ≥25 years of smoking cessation, the risk of VF progression in former heavy smokers becomes similar to never smokers. Long-term smoking cessation may be associated with lower VF progression in glaucoma patients.

Corneal Hysteresis and Rates of Neuroretinal Rim Change in Glaucoma

PURPOSE

To evaluate the impact of corneal hysteresis (CH) as a risk factor for progressive neuroretinal rim loss in glaucoma, as measured by spectral-domain OCT of the Bruch's membrane opening minimum rim width (MRW).

DESIGN

Prospective, observational cohort study.

PARTICIPANTS

The study group included 118 eyes of 70 subjects with glaucoma. The average follow-up time for the cohort was 3.9 ± 1.3 years, with an average of 6.4 ± 2.0 spectral-domain OCT tests, ranging from 4 to 12.

METHODS

Corneal hysteresis measurements were acquired at baseline using the Ocular Response Analyzer (Reichert Instruments). Linear mixed models were used to investigate the relationship between the rates of MRW loss and baseline CH. Multivariable analyses adjusted for other putative predictive factors for progression, including mean intraocular pressure (IOP), central corneal thickness (CCT), age, race, and baseline disease severity.

MAIN OUTCOME MEASURES

Effects of CH on the rate of MRW change over time.

RESULTS

Corneal hysteresis had a significant effect on rates of MRW progression over time. Each 1-mmHg lower CH was associated with -0.38 μm/year faster MRW loss (95% confidence interval [CI], -0.70 to -0.06; P = 0.019), after adjustment for other predictive factors. The mean IOP was also significantly associated with progression, with -0.35 μm/year (95% CI, -0.47 to -0.23 μm/year) faster MRW change for each 1-mmHg higher pressure (P < 0.001). In the analysis of predictive strength, the mean IOP was the strongest predictive factor (R2 = 23%), followed by CH (R2 = 14%) and baseline disease severity (R2 = 6%). Central corneal thickness explained only 3% of the variability in slopes of change in global MRW.

CONCLUSIONS

Lower CH measurements were associated with faster loss of the neuroretinal rim in glaucoma, as measured by MRW. The predictive ability of CH was superior to that of CCT. These findings suggest that CH is an important parameter to be considered in assessing the risk of glaucoma progression.

Association of Initial Optical Coherence Tomography Angiography Vessel Density Loss With Faster Visual Field Loss in Glaucoma

IMPORTANCE

Rapid vessel density loss during an initial follow-up period may be associated with the rates of visual field loss over time.

OBJECTIVES

To evaluate the association between the rate of vessel density loss during initial follow-up and the rate of visual field loss during an extended follow-up period in patients suspected of having glaucoma and patients with primary open-angle glaucoma.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study assessed 124 eyes (86 with primary open-angle glaucoma and 38 suspected of having glaucoma) of 82 patients who were followed up at a tertiary glaucoma center for a mean of 4.0 years (95% CI, 3.9-4.1 years) from January 1, 2015, to February 29, 2020. Data analysis for the current study was undertaken in March 2021.

MAIN OUTCOMES AND MEASURES

The rate of vessel density loss was derived from macular whole-image vessel density values from 3 optical coherence tomography angiography scans early during the study. The rate of visual field loss was calculated from visual field mean deviation during the entire follow-up period after the first optical coherence tomography angiography visit. Linear mixed-effects models were used to estimate rates of change.

RESULTS

A total of 124 eyes from 82 patients (mean [SD] age, 69.2 [10.9] years; 41 female [50.0%] and 41 male [50.0%]; and 20 African American [24.4%], 10 Asian [12.2%], 50 White [61.0%], and 2 other race or ethnicity [2.4%]) were assessed. The annual rate of vessel density change was -0.80% (95% CI, -0.88% to -0.72%) during a mean initial follow-up of 2.1 years (95% CI, 1.9-2.3 years). Eyes with annual rates of vessel density loss of -0.75% or greater (n = 62) were categorized as fast progressors, and eyes with annual rates of less than -0.75% (n = 62) were categorized as slow progressors. The annual rate of visual field loss was -0.15 dB (95% CI, -0.29 to -0.01 dB) for the slow optical coherence tomography angiography progressors and -0.43 dB (95% CI, -0.58 to -0.29 dB) for the fast optical coherence tomography angiography progressors (difference, -0.28 dB; 95% CI, -0.48 to -0.08 dB; P = .006). The fast optical coherence tomography angiography progressor group was associated with the faster overall rate of visual field loss in a multivariable model after adjusting to include concurrent visual field mean deviation rate (-0.17 dB; 95% CI, -0.33 to -0.01 dB; P = .04).

CONCLUSIONS AND RELEVANCE

The findings of this cohort study suggest that faster vessel density loss during an initial follow-up period was associated with faster concurrent and subsequent rates of visual field loss during an extended period.

Optical Microangiography and Progressive Retinal Nerve Fiber Layer Loss in Primary Open Angle Glaucoma

PURPOSE

To evaluate the association between optical microangiography (OMAG) measurements and progressive retinal nerve fiber layer (RNFL) loss in primary open angle glaucoma (POAG).

DESIGN

Prospective case series.

METHODS

Sixty-four eyes of 40 patients with POAG (108 quadrants) with mild to moderate functional damage were longitudinally studied for at least 2 years and with a minimum of 3 optical coherence tomography examinations. OMAG imaging was performed at the baseline visit. Effect of clinical parameters (age, sex, presence of systemic diseases, central corneal thickness, presence of disc hemorrhage, and mean and fluctuation of intraocular pressure during follow-up), baseline hemifield mean deviation, baseline quadrant optical coherence tomography RNFL and ganglion cell inner plexiform layer thickness), and OMAG (peripapillary and macular perfusion density [PD] and vessel density [VD]) on the rate of RNFL change was evaluated using linear mixed models.

RESULTS

Average (±SD) mean deviation, RNFL, and ganglion cell inner plexiform layer thickness of the analyzed quadrants at baseline were -5.5 ± 2.9 dB, 96.5 ± 17.9 µm, and 73.8 ± 8.6 µm, respectively. Peripapillary PD and VD in the quadrant were 44.6% ± 5.9% and 17.5 ± 2.2 mm/mm², respectively. Rate of quadrant RNFL change was -1.8 ± 0.6 µm/y. Multivariate mixed models showed that lower peripapillary PD (coefficient = 0.08, P = .01) and lower VD (coefficient = 0.21, P = .02) were significantly associated with a faster rate of RNFL loss.

CONCLUSIONS

Lower baseline peripapillary PD and VD measured using OMAG were significantly associated with a faster rate of RNFL loss in POAG. OMAG imaging provides useful information about the risk of glaucoma progression and the rate of disease worsening.