Analysis of choroidal thickness in age-related macular degeneration using spectral-domain optical coherence tomography

Assessment of optical coherence tomography biomarkers in patients with non-neovascular age-related macular degeneration (AMD) converting to exudative AMD according to the status of the fellow eye

OBJECTIVES

To compare optical coherence tomography (OCT) biomarkers in eyes converting from non-neovascular (nnAMD) to exudative age-related macular degeneration (eAMD) based on the status of fellow eye.

METHODS

Retrospective analysis of one year of pre-conversion data of fellow eyes of patients with nnAMD and eAMD which converted to eAMD, defined as converting eyes (CE) with fellow nnAMD and CE with fellow eAMD respectively. Demographics, best corrected visual acuity (BCVA), and OCT biomarkers including drusen type, iRORA/cRORA, subfoveal ellipsoid zone (SFEZ) disruption, central macular thickness (CMT), subfoveal choroidal thickness (SFCT), Haller vascular thickness (HVT) were evaluated. Chi-square and t-tests were employed, confidence interval of 95% and p < 0.05.

RESULTS

72 eyes of 72 patients were included: 31 CE with fellow nnAMD and 41 CE with fellow eAMD. Mean age was 81.8 ± 9.9 years, with 62.5% females. Subfoveal iRORA was more frequent in CE with fellow nnAMD (26%) compared to CE with fellow eAMD (6%) 44 weeks before conversion (p = 0.058). SFCT and HVT were higher in CE with fellow nnAMD compared to CE with fellow eAMD 19 weeks prior to conversion (213 ± 82 vs. 174 ± 63 µm, p = 0.052; 121 ± 44 vs. 104 ± 50 µm, p = 0.084 respectively). BCVA was significantly higher in CE with fellow eAMD compared to CE with fellow nnAMD every time frame (p < 0.05).

CONCLUSIONS

Although subtle distinctions, no significant differences were observed between the groups. Further research is needed to understand the influence of one eye's status on progression from nnAMD to eAMD in fellow eye.

Choroidal imaging biomarkers as predictors of conversion to exudative age-related macular degeneration

PURPOSE

Predicting the progression of intermediate AMD (iAMD) to neovascular AMD (nAMD) will help to identify high-risk patients and improve treatment outcomes. The present study assessed whether choroidal OCT biomarkers could predict conversion to nAMD.

METHODS

This retrospective study included patients with clinically stable iAMD who either converted to nAMD (C group) or did not convert (NC group) during one year of follow-up. OCT parameters included subfoveal choroidal thickness (SFCT), central macular thickness (CMT), Haller vascular thickness (HVT), inner choroidal thickness (ICT), and double-layer sign (DLS).

RESULTS

Of 116 total eyes, there were 37 in the NC group and 79 in the C group. Baseline SFCT was significantly lower in the C group compared to the NC group (169.0 ± 63.2 μm vs. 218.0 ± 97.8 μm, p = 0.01). Baseline HVT and ICT were lower in the C group (105.2 ± 40.6 μm vs. 121.0 ± 56.6 μm, p = 0.17 and 61.9 ± 35.5 μm vs. 77.5 ± 41.7 μm, p = 0.09). HVT was decreased at all time points in the C group vs NC (p > 0.05). The ICT was reduced in the C group at each time point except at conversion time (p > 0.05). Of all eight eyes who presented DLS at baseline, 100% converted to nAMD (p < 0.001).

CONCLUSION

Lower SFCT at baseline may signal conversion to nAMD within 12 months.

Choriocapillaris Impairment, Visual Function, and Distance to Fovea in Aging and Age-Related Macular Degeneration: ALSTAR2 Baseline

Purpose

In aging and early-intermediate age-related macular degeneration (AMD), rod-mediated dark adaptation (RMDA) slows more at 5° superior than at 12°. Using optical coherence tomography angiography (OCTA), we asked whether choriocapillaris flow deficits are related to distance from the fovea.

Methods

Persons ≥60 years stratified for AMD via the Age-Related Eye Disease Study's nine-step system underwent RMDA testing. Two adjacent 4.4° × 4.4° choriocapillaris OCTA slabs were centered on the fovea and 12° superior. Flow signal deficits (FD%) in concentric arcs (outer radii in mm, 0.5, 1.5, 2.2, 4.0, and 5.0 superior) were correlated with rod intercept time (RIT) and best-corrected visual acuity (BCVA).

Results

In 366 eyes (170 normal, 111 early AMD, 85 intermediate AMD), FD% was significantly worse with greater AMD severity in all regions (overall P < 0.05) and poorest under the fovea (P < 0.0001). In pairwise comparisons, FD% worsened with greater AMD severity (P < 0.05) at distances <2.2 mm. At greater distances, eyes with intermediate, but not early AMD differed from normal eyes. Foveal FD% was more strongly associated with longer RIT at 5° (r = 0.52) than RIT at 12° (r = 0.39) and BCVA (r = 0.21; all P < 0.0001). Choroidal thickness was weakly associated with longer RIT at 5° and 12° (r = 0.10-0.20, P < 0.05) and not associated with AMD severity.

Conclusions

Reduced transport across the choriocapillaris-Bruch's membrane-retinal pigment epithelium complex, which contributes to drusen formation under the macula lutea (and fovea), may also reduce retinoid resupply to rods encircling the high-risk area. FD% has potential as a functionally validated imaging biomarker for AMD emergence.

Probing Deposit-Driven Age-Related Macular Degeneration Via Thicknesses of Outer Retinal Bands and Choroid: ALSTAR2 Baseline

Purpose

We aimed to identify structural differences in normal eyes, early age-related macular degeneration (AMD), and intermediate AMD eyes using optical coherence tomography (OCT) in a well-characterized, large cross-sectional cohort.

Methods

Subjects ≥ 60 years with healthy normal eyes, as well as early or intermediate AMD were enrolled in the Alabama Study on Age-related Macular Degeneration 2 (ALSTAR2; NCT04112667). Using Spectralis HRA + OCT2, we obtained macular volumes for each participant. An auto-segmentation software was used to segment six layers and sublayers: photoreceptor inner and outer segments, subretinal drusenoid deposits (SDDs), retinal pigment epithelium + basal lamina (RPE + BL), drusen, and choroid. After manually refining the segmentations of all B-scans, mean thicknesses in whole, central, inner and outer rings of the ETDRS grid were calculated and compared among groups.

Results

This study involved 502 patients, 252 were healthy, 147 had early AMD, and 103 had intermediate AMD eyes (per Age-Related Eye Disease Study [AREDS] 9-step). Intermediate AMD eyes exhibited thicker SDD and drusen, thinner photoreceptor inner segments, and RPE compared to healthy and early AMD eyes. They also had thicker photoreceptor outer segments than early AMD eyes. Early AMD eyes had thinner photoreceptor outer segments than normal eyes but a thicker choroid than intermediate AMD eyes. Using the Beckman scale, 42% of the eyes initially classified as early AMD shifted to intermediate AMD, making thickness differences for photoreceptor outer segments and choroid insignificant.

Conclusions

With AMD stages, the most consistent structural differences involve appearance of drusen and SDD, followed by RPE + BL thickness, and then thickness of photoreceptor inner and outer segments. Structural changes in the transition from aging to intermediate AMD include alterations in the outer retinal bands, including the appearance of deposits on either side of the RPE.

C-reactive protein-complement factor H axis as a biomarker of activity in early and intermediate age-related macular degeneration

Purpose

To determine and compare the serum levels of complement Factor H (FH), monomeric C-Reactive Protein (mCRP) and pentameric C-Reactive protein (pCRP) in patients with age-related macular degeneration (AMD) and to correlate them with clinical, structural and functional parameters.

Methods

Cross-sectional observational study. One hundred thirty-nine individuals (88 patients and 51 healthy controls) from two referral centers were included and classified into three groups: early or intermediate AMD (n=33), advanced AMD (n=55), and age and sex matched healthy controls (n=51). Serum levels of FH, mCRP, and pCRP were determined and correlated with clinical and imaging parameters.

Results

Patients with intermediate AMD presented FH levels significantly lower than controls [186.5 (72.1-931.8) µg/mL vs 415.2 (106.1-1962.2) µg/mL; p=0.039] and FH levels <200 µg/mL were associated with the presence of drusen and pigmentary changes in the fundoscopy (p=0.002). While no differences were observed in pCRP and mCRP levels, and mCRP was only detected in less than 15% of the included participants, women had a significantly higher detection rate of mCRP than men (21.0% vs. 3.8%, p=0.045). In addition, the ratio mCRP/FH (log) was significantly lower in the control group compared to intermediate AMD (p=0.031). Visual acuity (p<0.001), macular volume (p<0.001), and foveal thickness (p=0.034) were significantly lower in the advanced AMD group, and choroidal thickness was significantly lower in advanced AMD compared to early/intermediate AMD (p=0.023).

Conclusion

Intermediate AMD was associated in our cohort with decreased serum FH levels together with increased serum mCRP/FH ratio. All these objective serum biomarkers may suggest an underlying systemic inflammatory process in early/intermediate AMD patients.

Comparison of choroidal thickness and choroidal vascular index in normotensive dippers and nondippers

OBJECTIVE

The aim of this study was to evaluate the choroidal thickness and choroidal vascular index in normotensive individuals with dipping and nondipping patterns.

METHODS

Patients who applied to the cardiology clinic for routine checkups and underwent 24-h blood pressure monitoring were included in our study. They were divided into two groups based on their dipper status. The patients in whom systolic blood pressure decreased during the nocturnal time by 10% or more of the daily blood pressure were defined as dippers. On the contrary, patients whose nocturnal systolic blood pressure decreased by less than 10% were defined as nondippers. Choroidal thickness and choroidal vascular index were measured by spectral-domain optical coherence tomography. Central macular thickness, retinal nerve fiber layer, and ganglion cell layer (GCL) analyses were also recorded.

RESULTS

In total, 35 patients with dipper pattern and 34 patients with nondipper pattern were recruited. The mean subfoveal choroidal thickness was 349.72±90 μm in the dipper group and 358.54±132.5 μm in the nondipper group. The groups had no significant difference in choroidal thickness, central macular thickness, retinal nerve fiber layer, and ganglion cell layer analyses. However, the choroidal vascular index was statistically significantly lower in the nondipper group when compared to the dipper group (0.61±0.02 vs. 0.64±0.02; p<0.001). Also, the choroidal vascular index was negatively correlated with subfoveal choroidal thickness in the nondipper group (Spearman; r=-0.419; p=0.033).

CONCLUSION

Our study showed that the choroidal vascular index was significantly lower in nondippers than in dippers. Nondipper individuals may be affected by vascular dysregulation, leading to alterations in the choroidal circulation.

Correlations between subfoveal choroidal thickness, macular thickness, and visual outcome in neovascular age-related macular degeneration using swept source OCT: insights from intravitreal aflibercept treatment

BACKGROUND

Age-related macular degeneration (AMD) is a leading cause of visual impairment among individuals aged 50 and above, often resulting in irreversible vision loss (1). Currently, antiangiogenic therapy is the primary treatment approach for neovascular AMD (2). The choroid has gained significant attention in recent years due to its involvement in various ocular pathologies (7). The objective of this study was to evaluate visual acuity and correlate pre-treatment variables, such as foveal thickness and choroidal thickness, with post-treatment outcomes.

MATERIALS AND METHODS

This study was designed as a prospective interventional study to investigate the changes in choroidal and macular thickness in patients with neovascular AMD who received intravitreal aflibercept injections. The study utilized medical records and employed Swept Source Optical Coherence Tomography (OCT-SS) for evaluation. The data was collected from patients treated in Presidente Prudente, Brazil, during a three-month load dose period.

RESULTS

The best-corrected mean visual acuity significantly improved from 1.0 logarithm of the minimum resolution angle (logMAR) units to 0.55 logMAR after treatment with aflibercept (p < 0.001). Patients undergoing treatment exhibited a significant decrease in average macular thickness from 323 μm to 232 μm (p = 0.001), as well as a reduction in choroidal thickness from 206 μm to 172 μm (p = 0.031), while maintaining intraocular pressure within the normal range (p = 0.719) without significant variation. Statistically significant associations were found between the difference in pre- and post-treatment choroidal thickness and the pretreatment values of macular thickness (p = 0.005) and choroidal thickness (p = 0.013). There was also a statistically significant correlation between the difference in pre- and post-treatment macular thickness and the pretreatment macular thickness value (p < 0.001).

CONCLUSION

In this study, aflibercept exhibited remarkable effectiveness in reducing macular and choroidal thickness, as evaluated using OCT-SS, and significantly improved visual acuity in patients with neovascular AMD. The assessment of both choroidal and macular changes, as well as their correlations, can provide valuable insights for clinicians, enabling them to make well-informed therapeutic decisions and effectively monitor treatment outcomes. Notably, this study contributes to the existing body of literature as the first to establish a correlation between pretreatment foveal thickness, variation in choroidal thickness, and post-treatment choroidal thickness.

Macular Pigment Optical Density in First Degree Relatives of Age-Related Macular Degeneration Patients

PURPOSE

To measure the macular pigment optical density in first-degree relatives of patients with age-related macular degeneration and compare it with a healthy control group.

METHODS

One hundred and twenty-eight healthy subjects who were first-degree relatives of age-related macular degeneration patients were included in the study (Group 1). As the control group, 74 healthy subjects were included in the study (Group 2). The right eyes of all cases were included in the study. Macular pigment optical density was measured with a commercially available device (MPSII®, Elektron Technology, Switzerland) using technology based on heterochromatic flicker photometry. Central foveal thickness and subfoveal choroidal thickness were measured with spectral-domain optical coherence tomography. Values were compared between the two groups.

RESULTS

There were 54 males and 74 females in Group 1 and 32 males and 42 females in Group 2. The mean ± SD ages of Group 1 and Group 2 were 49.0 ± 7.6 and 41.8 ± 8.6, respectively. Mean ± SD macular pigment optical density values of Group 1 and Group 2 were 0.43 ± 0.09 and 0.47 ± 0.12 (p = 0.048), mean ± SD central foveal thickness were 208 ± 19 and 216 ± 8 µm (p = 0.014), and mean ± SD subfoveal choroidal thickness were 232 ± 29 and 250 ± 21 µm (p = 0.002), respectively.

CONCLUSION

The macular pigment optical density values were significantly lower in the first-degree relatives of patients with age-related macular degeneration than in the control group. Macular pigment optical density may be a marker for the development of age-related macular degeneration in the future in the first-degree relatives of age-related macular degeneration patients. Further prospective studies with a larger number of participants will be needed to confirm our results moreover, to clarify its benefit as an early diagnostic biomarker.

Comparative assessment of choroidal thickness and choroidal vascularity index in patients with restless legs syndrome

BACKGROUND

Increased sympathetic activity has been emphasized in the pathophysiology of restless legs syndrome (RLS). This study aims to evaluate the choroidal thickness (CT) and choroidal vascularity index (CVI) values of individuals with RLS.

METHODS

A total of 60 volunteers, 30 individuals with RLS and 30 healthy individuals, were included in the study. The central macular thickness, subfoveal CT, and the CTs 1000 μm away from the fovea in the temporal and nasal regions were measured by optical coherence tomography. Total choroidal area (TCA), luminal area (LA) and stromal area (SA) were calculated using the binarization method. CVI was calculated as the ratio of lumen area to total choroidal area (LA/TCA).

RESULTS

There was no significant difference between the participants in terms of age, gender, spherical equivalent, intraocular pressure, and axial length (p>0.05). The mean LA/SA was 1.56%±0.05 in RLS group and 1.99%±0.28 in the control group. The mean CVI was 0.64%±0.02% in RLS group and 0.66%±0.03 in the control group. There was no significant difference between the groups in terms of CT, TCA and LA values. There were significant differences between the groups in SA, LA/SA and CVI values (p = 0.017, p<0.001, and p = 0.004, respectively).

CONCLUSION

SA values were significantly higher in RLS group than in control group. The LA/SA and CVI values were significantly lower in RLS group than in control group. These findings suggests that there is vascular narrowing due to sympathetic overactivity in RLS patients.

Choroidal vascularity index (CVI)-Net-based automatic assessment of diabetic retinopathy severity using CVI in optical coherence tomography images

A deep learning model called choroidal vascularity index (CVI)-Net is proposed to automatically segment the choroid layer and its vessels in overall optical coherence tomography (OCT) scans. Clinical parameters are then automatically quantified to determine structural and vascular changes in the choroid with the progression of diabetic retinopathy (DR) severity. The study includes 65 eyes consisting of 34 with proliferative DR (PDR), 17 with nonproliferative DR (NPDR), and 14 healthy controls from two OCT systems. On a dataset of 396 OCT B-scan images with manually annotated ground truths, overall Dice coefficients of 96.6 ± 1.5 and 89.1 ± 3.1 are obtained by CVI-Net for the choroid layer and vessel segmentation, respectively. The mean CVI values among the normal, NPDR, and PDR groups are consistent with reported outcomes. Statistical results indicate that CVI shows a significant negative correlation with DR severity level, and this correlation is independent of changes in other physiological parameters.

Prognostic Optical Coherence Tomography Biomarkers in Neovascular Age-Related Macular Degeneration

Optical coherence tomography has revolutionized the diagnosis and management of neovascular age-related macular degeneration. OCT-derived biomarkers have the potential to further guide therapeutic advancements with anti-vascular endothelial growth factor; however, the clinical convergence between these two tools remains suboptimal. Therefore, the aim of this review of literature was to examine the current data on OCT biomarkers and their prognostic value. Thirteen biomarkers were analyzed, and retinal fluid had the strongest-reported impact on clinical outcomes, including visual acuity, clinic visits, and anti-VEGF treatment regimens. In particular, intra-retinal fluid was shown to be associated with poor visual outcomes. Consistencies in the literature with regard to these OCT prognostic biomarkers can lead to patient-specific clinical decision making, such as early-initiated treatment and proactive monitoring. An integrated analysis of all OCT components in combination with new efforts toward automated analysis with artificial intelligence has the potential to further improve the role of OCT in nAMD therapy.

Association between lower extremity venous insufficiency and increased choroidal thickness

PURPOSE

The goal of this study is to investigate the association between the choroid and lower extremity venous insufficiency (LEVI).

METHODS

This prospective cross-sectional study includes 56 patients with LEVI and 50 age/sex-similar control subjects. Choroidal thickness (CT) measurements from 5 different points were captured from all participants by optical coherence tomography. In the group with LEVI on physical examination, reflux at the saphenofemoral junction, and the diameter of the great and small saphenous veins were evaluated via color Doppler ultrasonography.

RESULTS

The mean subfoveal CT was higher in the varicose group than in the control group (363.04±99.75μm vs. 320.30±73.46μm, P=0.013). In addition, the CTs at the temporal 3mm, temporal 1mm, nasal 1mm, and nasal 3mm distance from the fovea were higher in the LEVI group compared to the controls (for all, P<0.05). There was no correlation between CT and diameter of the great and small saphenous vein in patients with LEVI (for all, P>0.05). However, the great and small saphenous veins of patients with CT above 400μm were observed to be wider in patients with LEVI (P=0.027 and P=0.007, respectively).

CONCLUSION

Varicose veins can be a feature of systemic venous pathology. Another component of systemic venous disease may be increased CT. Patients with high CT should be investigated for susceptibility to LEVI.

Influence of Clinical and Genetic Factors on the Progression of Age-Related Macular Degeneration: A 3-Year Follow-Up

The aim of the present study was to analyze the relationship of age-related macular degeneration (AMD) progression with clinical characteristics, demographic, and environmental risk factors that would affect disease development. In addition, the influence of three genetic AMD polymorphisms (CFH Y402H, ARMS2 A69S, and PRPH2 c.582-67T>A) on AMD progression was investigated. In total, 94 participants with previously diagnosed early or intermediate AMD in at least one eye were recalled for an updated re-evaluation after 3 years. The initial visual outcomes, medical history, retinal imaging data, and choroidal imaging data were collected to characterize the AMD disease status. Among the AMD patients, 48 demonstrated AMD progression, and 46 showed no disease worsening at 3 years. Disease progression was significantly associated with worse initial visual acuity (OR = 6.74, 95% CI = 1.24-36.79, p = 0.03) and the presence of the wet AMD subtype in fellow eyes (OR = 3.79, 95%CI = 0.94-15.2, p = 0.05). In addition, a higher risk of AMD progression appeared in the patients with active thyroxine supplementation (OR = 4.77, CI = 1.25-18.25, p = 0.002). The CC variant of CFH Y402H was associated with AMD advancement compared to the TC+TT phenotype (OR = 2.76, 95% CI: 0.98-7.79, p = 0.05). Identifying risk factors of AMD progression may lead to earlier intervention and better outcomes, preventing the expansion of the late stage of the disease.

PATTERN AND CHARACTERISTICS OF DRUSEN SUBTYPES IN CHINESE AND INDIAN POPULATIONS IN SINGAPORE

PURPOSE

To report the pattern and characteristics of drusen subtypes in Asian populations and the association with choroidal thickness.

METHODS

This is the cross-sectional analysis of the population-based cohort study. Two thousand three hundred and fifty-three eyes of 1,336 Chinese and Indian participants aged older than 50 years, eyes with best-corrected visual acuity better than 20/60, and without other retinal diseases were recruited. Pachydrusen, reticular pseudodrusen, soft and hard drusen were graded on both color fundus photographs, and optical coherence tomography imaging with automated segmentation yielding and measurements of choroidal thickness.

RESULTS

Nine hundred and fifty-five Chinese and 381 Indians were included in the final analysis. The pattern of pachydrusen, soft drusen, hard drusen, and reticular pseudodrusen was 14.0%, 3.7%, 12.5%, and 0.2%, respectively. Mean choroidal thickness was the thickest in eyes with pachydrusen (298.3 μm; 95% confidence interval: 290.5-306.1), then eyes with hard (298.1 μm; 95% confidence interval: 290.6-305.5) and soft drusen (293.7 μm; 95% confidence interval: 281.9-305.4) and thinnest in eyes without drusen (284.6 μm; 95% confidence interval: 280.5-288.7). Systemic associations of the various drusen subtypes also differed.

CONCLUSION

Patterns, characterization and choroidal thickness of drusen subtypes, and their associations provide insights into the Asian phenotypic spectrum of age-related macular degeneration and the underlying pathogenesis.

Measurement of Foveal Retinal Thickness in Myopic Patients Using Different Display Modes on Optical Coherence Tomography: A Retrospective, Cross-Sectional Study

INTRODUCTION

The aim of this work is to investigate the differences in the measurement of foveal retinal thickness in myopic patients between two display modes (1:1 pixel and 1:1 micron) on optical coherence tomography (OCT).

METHODS

Horizontal OCT line scan through the central fovea was used for manual measurement of foveal retinal thickness under the two display modes, and the values were compared using Wilcoxon signed-rank test. Correlations between the OCT image tilting angle (OCT ITA) and differences in OCT measurement were analyzed by Spearman's test.

RESULTS

127 participants with a median age of 28 years, a median spherical equivalent (SE) of - 8.5 D, and a median axial length (AL) of 27.04 mm. There were significant differences between the two display modes, with a median absolute difference (median relative difference) of 13.33 μm (2.75%) for the central foveal thickness (CFT), 5.33 μm (1.28%) for the Henle fiber and outer nuclear layer thickness (HFL + ONL), 3 μm (6.47%) for the external limiting membrane to ellipsoid zone distance (ELM-EZ), and 4 μm (8.77%) for the ellipsoid zone to retinal pigment epithelium distance (EZ-RPE) (all p < 0.05). The differences in foveal retinal thickness between the two display modes were significantly correlated with the OCT ITA (r = 0.732 for CFT, 0.561 for HFL + ONL, 0.642 for ELM-EZ, and 0.471 for EZ-RPE, all p < 0.05).

CONCLUSIONS

Disparities between the two display modes were found in the manual measurement of foveal retinal thickness and correlated to the OCT ITA.

The effect of off-pump coronary bypass graft surgery on subfoveal choroidal thickness, ganglion cell complex, and retinal nerve fiber layer thickness

Background

Cardiac surgery has been associated with adverse ocular events. Off-pump coronary artery bypass graft surgery evades the systemic inflammatory response seen in extracorporeal circulation and is superior to on-pump surgery with regard to end-organ dysfunction and neurological outcomes.

Objectives

To determine the effects of off-pump (without extracorporeal circulation) coronary artery bypass graft surgery on choroidal thickness, ganglion cell complex, and the retinal nerve fiber layer.

Design

Prospective, longitudinal study.

Methods

Patients who underwent off-pump surgery were examined preoperatively and postoperatively at 1 week and 6 weeks after surgery. Choroidal thickness, ganglion cell complex, and the retinal nerve fiber layer measurements were recorded, and the effects of off-pump coronary artery bypass on these parameters were assessed.

Results

A total of 44 eyes of 44 patients were included in the study. There was a statistically significant increase in subfoveal choroidal thickness from 252.84 ± 56.24 µm preoperatively to 273.82 ± 39.76 µm at 1 week and 301.97 ± 44.83 µm at 6 weeks after off-pump coronary artery bypass graft surgery (p = 0.044; p ⩽ 0.001). Ganglion cell complex and retinal nerve fiber measurements showed no significant difference compared to preoperative values.

Conclusion

Off-pump coronary artery bypass graft surgery showed no negative effects on ganglion cell complex and retinal nerve fiber measurements. A significant increase in subfoveal choroidal thickness was seen after off-pump surgery, which might be advantageous in patients who are at high risk or have preexisting ocular diseases that are affected by the choroid.

Topography and Choroidal Thickness Measurement in Healthy Asian Indian Subjects using RTVue XR 100 Optical Coherence Tomography

PURPOSE

The purpose was to study the choroidal thickness and its profile, derived from different point locations in healthy Asian Indian subjects using RTVue XR 100 optical coherence tomography (OCT) and to determine its correlation with age, refractive error, and axial length.

METHODS

In this cross-sectional study, 300 eyes of 150 healthy subjects, with no ocular pathology, were scanned in a single session, using a line scan protocol of RTVue XR 100 OCT. Choroidal thickness was measured at the subfoveal region, and six measurements were obtained on either side of the fovea (temporal and nasal) at 500 μm interval apart, up to 3000 μm. The correlation between subfoveal choroidal thickness and age, refractive error, and axial length was assessed.

RESULTS

Three hundred eyes of 150 healthy subjects were included in the analysis. Median age of the study participants was 55 years (interquartile range [IQR]: 44-61). The median subfoveal choroidal thickness was 235 μm (IQR: 210-263). The choroidal thickness was minimum at nasal 3000 μm from the fovea, while it was maximum in the subfoveal region. The point zones which were near the fovea showed thicker choroidal thickness than the outer zones, both nasally and temporally (P < 0.00001 at all locations), and at all point locations the choroid were thicker temporally than nasally (All P < 0.00001). Subfoveal choroidal thickness showed negative correlation with age (coefficient = -0.62, P = 0.03) and axial length (correlation = -8.52, P = 0.02). A decrease in subfoveal choroidal thickness of 0.62 μm/year was found by regression analysis.

CONCLUSION

Our study provides normative database and topographic profile of choroidal thickness in the normal Asian Indian eyes using RTVue XR 100 OCT.

Choroidal thickness in eyes of migraine patients measured using spectral domain-optical coherence tomography: A meta-analysis

Recent developments in high-resolution optical coherence tomography allow evaluation of even the slightest changes of choroidal thickness in various disorders, including migraine. In this review, we analyze the choroidal thickness measurements reported in various studies that compare results between migraineurs and healthy individuals. We searched PubMed, Scopus, and EMBASE to identify relevant literature reporting choroidal thickness in the migraineurs' different macular regions compared with healthy controls. A fixed-effects or random-effects model was applied for the meta-analysis based on the heterogeneity level. Moreover, subgroup analyses, meta-regression, publication bias, and quality assessment were also performed. We identified ten studies involving 580 migraineurs (173 with aura, 128 without aura, and 279 without specification for the presence of aura) and 407 healthy controls to be included in this meta-analysis. Results indicated that average choroidal thickness was significantly decreased in the migraine cases (SMD, -1.28; 95% CI, -2.47 to -0.08; P = 0.04) compared to healthy individuals. Furthermore, both with aura (SMD, -1.16; 95% CI, -1.39 to -0.92; P < 0.0001) and without aura migraine patients (SMD, -0.81; 95% CI, -1.28 to -0.34; P < 0.001) had significantly thinner subfoveal choroid compared to healthy controls. Moreover, subfoveal choroidal thickness in the migraineurs with aura was significantly lower than those without aura (SMD, -0.45; 95% CI, -0.84 to -0.05; P = 0.03). The alterations in choroidal thickness, suggestive of migraine's neurovascular pathophysiology, were tentatively confirmed by this study's findings. Further longitudinal studies with more diverse settings are required to derive more definitive conclusions.

Relationship between ganglion cell complex thickness and vision in age-related macular degeneration treated with aflibercept

PURPOSE

This study aimed to analyze the correlation between ganglion cell complex thickness (GCCT) and vision compared with the choroidal thickness (CT) and central retinal thickness (CRT) in relation to the outcomes of intravitreal aflibercept treatment for choroidal neovascular membranes secondary to age-related macular degeneration (AMD).

METHODS

This was a prospective, observational study. Forty-three eyes of 38 patients with wet AMD received a monthly loading dose of 2 mg aflibercept by intravitreal injection (IVI) during the first 3 months and were then followed at regular monthly intervals for an average of 10 months by a pro re nata regimen. All patients were examined using spectral domain-optic coherence tomography (OCT) and enhanced depth imaging OCT. According to their response to IVI treatment in the third month, patients were divided into 2 groups, both functionally and anatomically.

RESULTS

Three-month GCCT and optic disc retinal nerve fiber layer thickness (ODRNFLT) had the most correlation with the 10-month vision (p  =  0.002, p  =  0.02, respectively). While baseline GCCT was most correlated with the functional response, baseline CRT was most correlated with the anatomical response (p  =  0.01, p  =  0.004, respectively).

CONCLUSIONS

The results suggest that a reduction in 3-month GCCT indicates a good long-term vision outcome, while a reduction in 3-month ODRNFLT shows a poor long-term vision outcome. The literature suggests that this study is the first to demonstrate that baseline GCCT is more strongly correlated with the functional response than it is with CT and CRT. Hence, GCCT has a prognostic value for vision impairment.

Optical coherence tomography angiography and Humphrey visual field in patients with obstructive sleep apnea

STUDY OBJECTIVES

To determine if obstructive sleep apnea syndrome (OSAS) predisposes patients to glaucoma and macular disease due to vascular compromise by evaluating retinal and optic nerve vasculature and function using optical coherence tomography angiography and Humphrey visual field testing, respectively.

METHODS

In this prospective, observational, cross-sectional study 45 patients undergoing polysomnography ordered per standard of care were selected and stratified based on apnea-hypopnea index (AHI). Medical history, visual acuity testing, 24-2 Humphrey visual field, intraocular pressure measurement, and optical coherence tomography angiography studies of the macular and peripapillary retina were obtained. Correlations between polysomnography parameters and imaging data were analyzed.

RESULTS

The radial peripapillary capillary vascular density demonstrated no relationship to AHI (95% confidence interval [CI] [-0.026,0.038]) or severity of OSAS (95% CI: [-0.772, 3.648]) for moderate OSAS compared to mild/normal and (-1.295, 3.1421) for severe compared to mild/normal. Optical coherence tomography angiography superficial parafoveal vascular density (95% CI: [-0.068,0.011], deep parafoveal vascular density (95% CI: [-0.080,0.009]), and foveal avascular zone (95% CI: [-0.001, 0.001]) showed no statistically significant relationship to AHI or OSAS severity after controlling for confounders. Optical coherence tomography retinal nerve fiber layer thickness increased with AHI (P = .014), but there was no statistically significant correlation with OSAS severity with retinal nerve fiber layer thickness (95% CI: [-12.543, 6.792] for moderate comparing to normal and [-2.883, 16.551] for severe comparing to normal). Visual field parameters were unaffected by OSAS (95% CI: mean deviation [-0.21,0.29], pattern standard deviation: [-0.351, 0.121], visual field index: [-0.166, 0.329]). Optical coherence tomography choroidal thickness showed a statistically significant decrease when OSAS was grouped by severity (P = .0092) but did not correlate with AHI (P = .129, 95% CI: [-1.210, 0.095]).

CONCLUSIONS

The severity of OSAS did not show a statistically significant effect on parameters associated with glaucoma or macular vascular disease. Larger cohorts may be required to determine the physiologic consequences of OSAS on the macular and optic nerve vasculature, structure, and function.

CITATION

Davanian A, Williamson L, Taylor C, et al. Optical coherence tomography angiography and Humphrey visual field in patients with obstructive sleep apnea. J Clin Sleep Med 2022;18(9):2133-2142.

Subcellular Comparison of Visible-Light Optical Coherence Tomography and Electron Microscopy in the Mouse Outer Retina

Purpose

We employed in vivo, 1.0-µm axial resolution visible-light optical coherence tomography (OCT) and ex vivo electron microscopy (EM) to investigate three subcellular features in the mouse outer retina: reflectivity oscillations inner to band 1 (study 1); hyperreflective band 2, attributed to the ellipsoid zone or inner segment/outer segment (IS/OS) junction (study 2); and the hyperreflective retinal pigment epithelium (RPE) within band 4 (study 3).

Methods

Pigmented (C57BL/6J, n = 10) and albino (BALB/cJ, n = 3) mice were imaged in vivo. Enucleated eyes were processed for light and electron microscopy. Using well-accepted reference surfaces, we compared micrometer-scale axial reflectivity of visible-light OCT with subcellular organization, as revealed by 9449 annotated EM organelles and features across four pigmented eyes.

Results

In study 1, outer nuclear layer reflectivity peaks coincided with valleys in heterochromatin clump density (-0.34 ± 2.27 µm limits of agreement [LoA]). In study 2, band 2 depth on OCT and IS/OS junction depth on EM agreed (-0.57 ± 0.76 µm LoA), with both having similar distributions. In study 3, RPE electron dense organelle distribution did not agree with reflectivity in C57BL/6J mice, with OCT measures of RPE thickness exceeding those of EM (2.09 ± 0.89 µm LoA). Finally, RPE thickness increased with age in pigmented mice (slope = 0.056 µm/mo; P = 6.8 × 10-7).

Conclusions

Visible-light OCT bands arise from subcellular organization, enabling new measurements in mice. Quantitative OCT-EM comparisons may be confounded by hydration level, particularly in the OS and RPE. Caution is warranted in generalizing results to other species.

Choroidal Thickness Changes After Intravitreal Aflibercept Injections in Treatment-Naïve Neovascular AMD

Introduction

Choroidal thickness (CT) plays an important role in the pathogenesis of various ocular diseases, including neovascular age-related macular degeneration (nAMD). Previous studies evaluated the CT variations after anti-vascular endothelial growth factor (VEGF) injections in patients with nAMD, but the results are still controversial. The present study aimed to evaluate the CT at different times (15, 30, 60, 90, and 365 days) after intravitreal aflibercept injections and its correlation with the baseline CT in treatment-naïve patients with nAMD. Secondly, the study evaluated the correlation between CT variation at 365 days and the number of intravitreal injections received.

Methods

This was a prospective, open-label, single-arm pilot study. Twenty-one treatment-naïve nAMD eyes were enrolled. The study population underwent three monthly aflibercept injections (loading phase) and additional injections as needed (pro re nata regimen). A complete ophthalmological examination, including optical coherence tomography (OCT) was performed at each visit. CT was measured manually by two independent observers. All patients were evaluated at baseline and at 15, 30, 60, 90, and 365 days after the first intravitreal injection.

Results

CT showed a statistically significant reduction at days 15, 90, and 365 in comparison to baseline. However, the major reduction of CT was observed at day 15 and in eyes with a thicker choroid at baseline. No significant correlation between CT variation and the number of injections performed was found.

Conclusion

Our findings contribute to clarifying the role of aflibercept injections in choroidal vasculature, confirming its effect after the first 2 weeks. Moreover, CT can be considered as a potential biomarker, as it reflects the pharmacological effect of anti-VEGF drugs.

Assessment of choriocapillaris/Sattler and Haller layer changes after intravitreal injection in eyes with neovascular age-related macular degeneration: aflibercept vs ranibizumab

PURPOSE

To evaluate the changes in choriocapillaris (CC)/Sattler and Haller layer thicknesses in eyes with neovascular age-related macular degeneration (nAMD) after aflibercept or ranibizumab injections.

STUDY DESIGN

Retrospective.

METHODS

A total of 70 eyes of 70 patients with treatment-naïve exudative nAMD were treated with 3 consecutive injections of aflibercept (IVA) or ranibizumab (IVR). CC/Sattler and Haller layer thicknesses were measured at the nasal and temporal regions 1000 µm from the center of the fovea by enhanced-depth imaging optical coherence tomography at baseline and after the 3 monthly intravitreal injections. In addition, the hyperfluorescence region (HF) was measured as the largest horizontal diameter of the hyperfluorescence area on the early-middle phase fluorescein angiographic images at baseline and after the 3 loading doses.

RESULTS

After the 3 consecutive injections, the mean reductions in the nasal/temporal CC/Sattler layer thicknesses in the IVR and IVA groups were  - 10.1 ± 2.3/ - 8.5 ± 1.8 and  - 25.2 ± 15.2/ - 19.4 ± 12.8 μm, respectively. Also, the mean reductions in the nasal/temporal Haller layer thicknesses in the IVR and IVA groups were  - 6.5 ± 3.6/ - 7.2 ± 7.9 and  - 9.5 ± 8.0/ - 7.0 ± 6.2 μm, respectively. The changes in the CC/Sattler layer thicknesses of the IVA group were greater than those of the IVR group (P < .001); however, the changes in the Haller layer thickness were similar between the groups (P > .05). The mean decrease in the HF size of the IVA group was greater than that of the IVR group (P < .001).

CONCLUSIONS

Aflibercept treatment has a more pronounced effect on the CC/Sattler layer. Such results may indicate that aflibercept treatment influences choroidal neovascularization, possibly by reducing the capillary permeability associated with active neovascularization in the CC layer.

Age-related macular degeneration: Epidemiology, genetics, pathophysiology, diagnosis, and targeted therapy

Age-related macular degeneration (AMD) is a complex eye disorder and is the leading cause of incurable blindness worldwide in the elderly. Clinically, AMD initially affects the central area of retina known as the macula and it is classified as early stage to late stage (advanced AMD). The advanced AMD is classified into the nonexudative or atrophic form (dry AMD) and the exudative or neovascular form (wet AMD). More severe vision loss is typically associated with the wet form. Multiple genetic factors, lipid metabolism, oxidative stress and aging, play a role in the etiology of AMD. Dysregulation in genetic to AMD is established to 46%-71% of disease contribution, with CFH and ARMS2/HTRA1 to be the two most notable risk loci among the 103 identified AMD associated loci so far. Chronic cigarette smoking is the most proven consistently risk living habits for AMD. Deep learning algorithm has been developed based on image recognition to distinguish wet AMD and normal macula with high accuracy. Currently, anti-vascular endothelial growth factor (VEGF) therapy is highly effective at treating wet AMD. Several new generation AMD drugs and iPSC-derived RPE cell therapy are in the clinical trial stage and are promising to improve AMD treatment in the near future.

Group-wise context selection network for choroid segmentation in optical coherence tomography

Choroid thickness measured from optical coherence tomography (OCT) images has emerged as a vital metric in the management of retinal diseases such as high myopia. In this paper, we propose a novel group-wise context selection network (referred to as GCS-Net) to segment the choroid of either normal or high myopia eyes. To deal with the diverse choroid thickness and the variable shape of the pathological retina, GCS-Net adopts the group-wise channel dilation (GCD) module and the group-wise spatial dilation module, which can automatically select group-wise multi-scale information under the guidance of channel attention or spatial attention, and enhance the consistency between the receptive field and the target area. Furthermore, a boundary optimization network with a new edge loss is incorporated to improve the resulting choroid boundary by deep supervision. Experimental results evaluated on a dataset composed of 1650 clinically obtained OCT B-scans show that the proposed GCS-Net can achieve a Dice similarity coefficient of 95.97 ± 0.54%, which outperforms some state-of-the-art segmentation networks.

Clinical Significance of Choroidal Thickness in Eyes with Ocular Ischemic Syndrome

Purpose

To determine the clinical significance of choroidal thickness and evaluate changes in choroidal thickness over time in eyes affected by ocular ischemic syndrome (OIS).

Methods

Medical records of 16 patients diagnosed with OIS between November 2017 and August 2019 were retrospectively reviewed. In every nine areas of the Early Treatment Diabetic Retinopathy Study (ETDRS) grid, we compared the differences in choroidal thickness between the eyes with OIS and unaffected eyes, and its change in the OIS eyes during the follow-up period using swept-source optical coherence tomography. We analyzed the best corrected visual acuity (BCVA), intraocular pressure (IOP), fluorescein angiography (FAG) parameters, systemic diseases, and the duration of symptoms. Correlation between FAG parameters and the choroidal thickness value ratio in the OIS eyes and the unaffected eyes, and changes in the choroidal thickness in the OIS eyes during follow-up were investigated.

Results

Median age of the subjects was 67.5 years. In the OIS eyes, all FAG parameters were delayed at the initial examination. BCVA and IOP were significantly different between the IOS and unaffected eyes. While the choroidal thickness in every nine areas of ETDRS in the OIS eyes was lesser than the unaffected eyes, the choroidal thickness of inner temporal, outer nasal, and outer temporal area showed statistically significant difference. During follow-up, changes in choroidal thickness of OIS eyes as well as correlation between the FAG parameters and the choroidal thickness value ratio between the OIS eyes and the unaffected eyes were not found to be statistically significant.

Conclusions

The choroidal thickness of the eyes with OIS was significantly less compared with the unaffected eyes. We inferred that choroidal thinning takes place in the early phase of the disease as the changes in choroidal thickness during the follow-up period were not significant.

Optical Coherence Tomography Prognostic Factors in AMD Patients with Peripapillary Choroidal Neovascularization

PURPOSE

To investigate the correlation between optical coherence tomography (OCT) findings and visual acuity outcomes after treatment with intravitreal bevacizumab (IVB) injections for age related macular degeneration (AMD) patients with peripapillary choroidal neovascularization (PPCNV).

METHODS

A retrospective case series of consecutive patients diagnosed with PPCNV secondary to AMD. All patients were treated with IVB injections with a follow-up time of one year. Data collected included best corrected visual acuity (BCVA), automated and manually measured OCT parameters.

RESULTS

A total of 68 eyes were diagnosed with PPMV. Of them, 30 eyes of 30 patients aged 84.3±6.9 years of which 63.3% female gender were included. Baseline BCVA was 0.46±0.62 logMAR (Snellen 20/57), average choroidal thickness was 193.2±22 µm and mean number of IVB injections was 7.2±1.9. After one year BCVA was 0.56±0.78 logMAR (Snellen 20/72) (p=0.28). Eyes with greater central retinal thickness (r=-0.36, p=0.05), greater subretinal hyperreflective material (SHRM) area (r=-0.37, p=0.05) and greater sub retinal fluid (SRF) area (r=-0.73, p<0.001) had a significantly smaller improvement in BCVA. Eyes with pigment epithelium detachment (PED) (0.68±0.90 versus 0.21±0.12, p=0.03) had a significantly worse BCVA.

CONCLUSIONS

Our data suggests that AMD related PPCNV with greater foveal thickness, PED size, SHRM and SRF areas have worse final BCVA prognosis.

Changes in choroidal and foveal retinal thickness after cataract surgery: Our results

INTRODUCTION

Cataract surgery is the most common ophthalmic surgical procedure worldwide. In addition, the retina and choroid are the tissues most susceptible to damage during cataract surgery. However, conflicting results have been found about the relationship between choroidal thickness (CT), retinal thickness (RT), and cataract surgery.

AIM

To evaluate the changes in CT and foveal retinal thickness (FT) following cataract surgery in standardized conditions.

METHODS

Twenty eyes from 20 patients who experienced uneventful cataract surgery and twenty eyes from 20 age- and sex-matched healthy volunteers were recruited in the study. Optical coherence tomography measurements were obtained for 1 day, 1 week, and 1 month postoperatively and compared with the preoperative and control values. The main outcome measure was through the mean change in CT and FT.

RESULTS

The FT values did not change throughout the follow-up. A statistically significant increase in CT at the macular (P = 0.003) and temporal 1 mm region (P = 0.04) was observed at 1 week following the surgery. However, it decreased to nearly preoperative values at 1 month postoperatively.

CONCLUSION

Although the FT remains stable following uneventful phacoemulsification, the CT changes minimally in the early postoperative period. However, this effect is transient and does not appear to be clinically significant in routine conditions.

Changes in ocular pulse amplitude and choroidal thickness in childhood obesity patients with and without insulin resistance

PURPOSE

To compare choroidal thickness (CT) and ocular pulse amplitude (OPA) in childhood obesity with insulin resistance (IR) and without IR.

METHODS

Seventy-three childhood obesity and 62 healthy children, who were both age-matched and gender-matched, comprised the study population in this prospective study. Obesity was determined as having a body mass index (BMI) - standard deviation (SD) score that was > 2 SD.Intraocular pressure (IOP) and OPA were measured using a dynamic contour tonometer. The CT measurements were performed using enhanced depth imaging optical coherence tomography at three locations, comprising at the fovea, at a position 500 µm nasal, and also at a position 500 µm temporal to the fovea.

RESULTS

Mean BMI value was 28.72 ± 4.85 in the patients with childhood obesity and 21.47 ± 1.14 in the control group. The mean IOP and OPA values were determined 15.90 ± 2.30 and 14.10 ± 2.16 mm Hg, 1.50 ± 0.28 and 1.74 ± 0.32 mm Hg in the patients with childhood obesity and the control group, respectively (p < 0.001, p < 0.001). The mean subfoveal CT value was 350.50 ± 81.51 μm in the eyes with childhood obesity and 390.02 ± 71.50 μm in those of the control group (p = 0.003). When the patient groups with and without IR were compared, no significant difference was found between CT, OPA and IOP values (p > 0.005).

CONCLUSIONS

Our results showed that both OPA and CT values were significantly decreased in childhood obesity patients. We suggest further studies to verify longitudinal changes in OPA and CT, as also the evaluation of these parameters in other populations.

The impact of vascular risk factors on the thickness and volume of the choroid in AMD patients

Disturbances in choroidal microcirculation may lead to the onset and progression of age-related macular degeneration (AMD). We aimed to assess changes in the choroidal volume and thickness in the macular region in AMD eyes and to investigate whether coexisting vascular risk factors alter choroidal status. We enrolled 354 AMD patients (175 dry, 179 wet AMD) and 121 healthy controls. All participants underwent a complete ophthalmologic examination and assessment of choroidal thickness and volume. A multivariate analysis adjusted for age, sex, and smoking status revealed that wet AMD was an independent factor associated with higher average thickness of the central ring area (ATC) and average volume of the central ring area (AVC) and lower choroidal vascularity index (CVI) compared to controls (β =  + 0.18, p = 0.0007, β =  + 0.18, p = 0.0008, respectively) and to dry AMD (β =  + 0.17, p = 0.00003 for both ATC and AVC and β =  - 0.30 p < 0.0001 for CVI). ATC, AVC and average volume (AV) were lower in AMD patients with hypertension and ischaemic heart disease (IHD). The duration of hypertension was inversely correlated with ATC, AVC and AV (Rs =  - 0.13, p < 0.05; Rs =  - 0.12; p < 0.05, Rs =  - 0.12; p < 0.05, respectively) while IHD duration negatively correlated with AV (Rs =  - 0.15, p < 0.05). No such associations were observed in the control group. Our findings show that the choroidal vascular system in eyes with AMD is much more susceptible to damage in the presence than in the absence of systemic vascular disease.

Evaluation of the Effect of a Novel β3-Adrenergic Agonist on Choroidal Vascularity

Purpose

To determine the effect of the new β₃-agonist (mirabegron), which is used for overactive bladder (OAB) treatment, on central retinal thickness (CRT) and choroidal vascularity.

Material and Methods

The 26 eyes of 26 cases using 50 mg tablet mirabegron once per day for OAB were included in this prospective case control study. The CRT, choroidal thickness (ChT), and choroidal vascularity were measured at baseline, week 1 (W1), month 1 (M1), month 2 (M2), and month 3 (M3). Subfoveal ChT measurement included the total subfoveal choroidal thickness (SFCT), and the small and large choroidal vessel layer (SCVL and LCVL) thickness. The total choroidal area (TCA), lumen area (LA), stromal area (SA), stroma/lumen ratio, and choroidal vascularity index (CVI) were measured with the Image-J software.

Results

The largest SFCT increase compared to baseline was at M1 (26.8 ± 40.8 µm, P = 0.001). The subfoveal SCVL thickness showed a significant decrease at M2 and M3 (−6.0 ± 8.9 µm, P = 0.002; −7.8 ± 13.4 µm, P = 0.046, respectively). LCVL thickness showed a significant increase at W1, M1, and M2, with the largest at M1. CVI showed a significant increase at M1, M2, and M3 (P < 0.05 for all). The TCA, LA, and SA showed a significant increasing trend at all follow-up periods. LA/SA decreased at W1 because of stromal expansion but increased at M3 with more prominent vascular dilatation. CRT values showed no significant change.

Conclusions

Mirabegron had a significant effect on choroidal thickness. Choroidal vascular response is in the form of narrowing in the choriocapillaris and enlargement in the Haller's layer.

Automated segmentation of choroidal layers from 3-dimensional macular optical coherence tomography scans

BACKGROUND

Changes in choroidal thickness are associated with various ocular diseases, and the choroid can be imaged using spectral-domain optical coherence tomography (SD-OCT) and enhanced depth imaging OCT (EDI-OCT).

NEW METHOD

Eighty macular SD-OCT volumes from 80 patients were obtained using the Zeiss Cirrus machine. Eleven additional control subjects had two Cirrus scans done in one visit along with enhanced depth imaging (EDI-OCT) using the Heidelberg Spectralis machine. To automatically segment choroidal layers from the OCT volumes, our graph-theoretic approach was utilized. The segmentation results were compared with reference standards from two independent graders, and the accuracy of automated segmentation was calculated using unsigned/signed border positioning/thickness errors and Dice similarity coefficient (DSC). The repeatability and reproducibility of our choroidal thicknesses were determined by intraclass correlation coefficient (ICC), coefficient of variation (CV), and repeatability coefficient (RC).

RESULTS

The mean unsigned/signed border positioning errors for the choroidal inner and outer surfaces are 3.39 ± 1.26 µm (mean ± standard deviation)/- 1.52 ± 1.63 µm and 16.09 ± 6.21 µm/4.73 ± 9.53 µm, respectively. The mean unsigned/signed choroidal thickness errors are 16.54 ± 6.47 µm/6.25 ± 9.91 µm, and the mean DSC is 0.949 ± 0.025. The ICC (95% confidence interval), CV, RC values are 0.991 (0.977-0.997), 2.48%, 14.25 µm for the repeatability and 0.991 (0.977-0.997), 2.49%, 14.30 µm for the reproducibility studies, respectively.

COMPARISON WITH EXISTING METHOD(S)

The proposed method outperformed our previous method using choroidal vessel segmentation and inter-grader variability.

CONCLUSIONS

This automated segmentation method can reliably measure choroidal thickness using different OCT platforms.

CHOROIDAL THICKNESS AND VASCULARITY VARY WITH DISEASE SEVERITY AND SUBRETINAL DRUSENOID DEPOSIT PRESENCE IN NONADVANCED AGE-RELATED MACULAR DEGENERATION

PURPOSE

To investigate how choroidal features vary with age-related macular degeneration (AMD) severity in early-intermediate disease.

METHODS

One hundred fifty-one eyes of 151 participants >50 years with no to intermediate AMD were analyzed with enhanced depth imaging optical coherence tomography. Mean macular choroidal thickness (CT), choroidal vascular thickness (CV), and choroidal vascularity index (CVI) were determined, and statistical associations were calculated.

RESULTS

Decreased CT and CV were associated with increased axial length (+30 and +14 µm/mm, respectively; P < 0.0001 each), whereas decreased CVI was associated with increased age (+0.1%/year; P = 0.004). Compared with eyes with no/early AMD (Group 0), eyes with large drusen without late AMD in the fellow eye (Group 1) showed increased CV and CVI (+22 µm, P = 0.03 and +2.2%, P = 0.02, respectively). However, eyes with large drusen and late AMD in the fellow eye (Group 2) resembled Group 0. Eyes with subretinal drusenoid deposits demonstrated lower mean CT/CV/CVI than Group 0 (-57 µm, P = 0.02; -31 µm, P = 0.02; -3.6%, P = 0.007).

CONCLUSION

Early AMD progression seems associated with biphasic alterations in choroidal dimensions, increasing during early drusen formation but decreasing thereafter. Subretinal drusenoid deposits are independently associated with marked reductions in all choroidal parameters. Changes in choroidal vascular anatomy may drive or reflect the pathobiology of AMD progression.

Multimodal ocular evaluation in hemodialysis patients

PURPOSE

To evaluate choroidal thickness, intraocular pressure (IOP), axial length, central corneal thickness (CCT), lens thickness, anterior chamber depth, and ocular pulse amplitude (OPA) in hemodialysis patients.

MATERIALS AND METHODS

The patients with end-stage renal disease and undergoing hemodialysis were included in the study. Immediately before and 1 hour after hemodialysis, all patients underwent measurement of choroidal thickness with spectral domain optical coherence tomography (SD-OC, Cirrus HD-OCT; Carl Zeiss Meditec Inc., Dublin, CA), IOP and OPA with Pascal dynamic contour tonometry (Ziemer Ophthalmic Systems AG, Port, Switzerland), and anterior chamber depth, lens thickness, and axial length with optical biometry (LenStar LS900; Haag-Streit AG, Koeniz, Switzerland). Data from the patients' right eyes were included in the statistical analysis.

RESULTS

The patient group included 8 (36.4%) males and 14 (63.6%) females with a mean age of 56, 14 ± 9, 96 (40-70) years. The mean subfoveal choroidal thickness before and after hemodialysis was 255.21 ± 6.15 (245-263) µm and 234.95 ± 7.89 (220-247) µm, respectively (p < 0.001). Mean choroidal thickness at 1500 µm and 3000 µm nasal and temporal of the fovea also decreased significantly after hemodialysis (p < 0.001). Mean OPA values before and after hemodialysis were 2.14 ± 1.07 (0.6-4) mmHg and 1.6 ± 0.86 (0.5-3.2) mmHg, respectively (p < 0.001). There was a statistically significant correlation between OPA and choroidal thickness measurements (p < 0.001, R = 0.923). IOP increased from 15.11 ± 2.58 (11-20) to 15.99 ± 2.21 (13-20) mmHg, but the change did not reach statistical significance (p = 0.05). There was no statistically significant change in mean axial length, anterior chamber depth, lens thickness, or CCT after hemodialysis (p > 0.05 for all).

CONCLUSION

Although choroidal thickness and OPA may be decreased immediately after hemodialysis, there may be no significant changes in IOP or avascular ocular structures such as the lens and cornea.

Choroidal vascularity index: a step towards software as a medical device

The choroidal vascularity index (CVI) is a relatively new parameter, calculated off optical coherence tomography (OCT) images, for the quantitative evaluation of choroid vascularity. It is defined as the ratio of vascular area to the total choroidal area, presented as a percentage. The choroid is an important vascular bed, often implicated in ocular and systemic conditions. Since the introduction of CVI, multiple studies have evaluated its efficacy as a tool for disease prognostication and monitoring progression, with promising results. The CVI was born out of the need for more robust and accurate evaluations of choroidal vasculature, as prior parameters such as choroidal thickness and choroidal vessel diameter had their limitations. In this review, we summarise current literature on the CVI, explain how the CVI is derived and explore its potential integration into future research and translation into clinical care. This includes the application of CVI in various disease states, and ongoing attempts to produce an automated algorithm which can calculate CVI from OCT images.

Is choroidal vascularity index a useful marker in different stages of idiopathic epiretinal membranes?

BACKGROUND

This study aims to evaluate the choroidal vascularity index in patients with idiopathic epiretinal membrane at different stages.

METHODS

This prospective study included 125 eyes of 125 patients with idiopathic epiretinal membrane and 62 eyes of 62 healthy control subjects. In this study, epiretinal membrane stages were defined based on the spectral-domain optical coherence tomography staging system. The choroidal vascularity index was measured as the ratio of the luminal area to the stromal area in the central 1500 μm after binarization on enhanced depth imaging optical coherence tomography images. Data on epiretinal membrane stages, choroidal vascularity index, and best-corrected visual acuity were noted.

RESULTS

Of 125 eyes with epiretinal membrane, 38 (30.4 %) had stage 1, 32 (25.6 %) had stage 2, and 55 (44 %) had stage 3 disease. Visual acuity was better in eyes with stage 1 or 2 epiretinal membrane than those with stage 3 epiretinal membrane (p < 0.001). The mean choroidal vascularity index was 2.29 ± 1.02 in the control, 2.23 ± 0.98 in the stage 1 epiretinal membrane, 2.22 ± 0.91 in the stage 2 epiretinal membrane, and 2.23 ± 1.11 in the stage 3 epiretinal membrane group. There was no significant difference between epiretinal membrane subgroups and the control group regarding the choroidal vascularity index (p = 0.81).

CONCLUSION

From the results obtained in the present study, the choroidal vascularity index was not effected by either the development or the progression of idiopathic epiretinal membrane.

Low incidence of pachydrusen in central serous chorioretinopathy in an Indian cohort

Purpose:

The aim of this study is to report the prevalence, clinical and swept-source optical coherence tomography (SS-OCT) characteristics of pachydrusen in eyes with central serous chorioretinopathy (CSCR) and their fellow eyes.

Methods:

A total of 264 eyes of 132 patients with a diagnosis of CSCR (acute/persistent/recurrent/chronic/inactive) in atleast one eye, were analyzed in this retrospective, cross-sectional study. SS-OCT parameters including choroidal thickness (CT), large choroidal vessel layer thickness (LCVT) at fovea and the site of pachydrusen were recorded. Paired t test and analysis of variance (ANOVA) was used to compare CT in eyes with CSCR (subfoveal and site of pachydrusen) and multiple groups respectively.

Results:

The mean age of the study patients was 42.9 ± 9.5 years with 119 males (90.15%). Bilateral CSCR was present in 31 patients. Nine eyes (chronic, 4; persistent, 2; and inactive/resolved CSCR, 3) showed presence of pachydrusen with an overall prevalence of 6.82% (9 eyes of 9 patients out of 132 patients). There was no significant difference of subfoveal CT (SFCT) in eyes with CSCR (422.4 ± 107.8 μ) vs fellow eyes (407.0 ± 96.5 μ) and eyes with CSCR associated with pachydrusen (413.7 ± 101.5 μ) vs fellow eyes of CSCR eyes with pachydrusen (431.6 ± 188.8 μ) (P = 0.71). LCVT as a percentage of CT was higher at the site of pachydrusen compared to SFCT (69.8% vs. 50.8%).

Conclusion:

CSCR can be associated with pachydrusen with a lower prevalence rate than previously reported. Whether the thickened large choroidal vessels at site of pachydrusen play any role in formation in pachydrusen needs further evaluation.

Association of Choroidal Thickness with Intermediate Age-Related Macular Degeneration in a Japanese Population

PURPOSE

To determine the relationship of choroidal thickness with the early stages of age-related macular degeneration (AMD) and their disease features in a Japanese population.

DESIGN

Cross-sectional survey.

PARTICIPANTS

A total of 1293 Japanese persons 65 to 86 years of age residing in the Saku area who underwent eye screening as part of the Japan Public Health Center-based Prospective Study.

METHODS

Comprehensive ophthalmic assessment included fundus photography, measurement of intraocular pressure, and determination of refractive status. OCT with enhanced depth imaging mode was performed and subfoveal choroidal thickness was assessed. Multinomial logistic regression models were used to assess the relationships of choroidal thickness with the early stages of AMD, namely early AMD and intermediate AMD, and their disease features, after adjustment for potential confounders.

MAIN OUTCOME MEASURES

Relationship of choroidal thickness with early AMD, intermediate AMD, and their disease features.

RESULTS

Of 1293 potential participants, 901 (mean age, 73.2 years) had choroidal thickness data, fundus photographs of sufficient quality, and no concomitant retinal disease (including 5 with late AMD). Mean choroidal thickness was 246.1 μm, 15.1% had early AMD, and 9.0% had intermediate AMD. After adjustment for age, gender, and refractive status, choroidal thickness was associated positively with presence of intermediate AMD (for each 1- standard deviation [SD] μm increase: odds ratio [OR], 1.43; 95% confidence interval [CI], 1.13-1.81), whereas no significant association was found with presence of early AMD. Among intermediate AMD features, choroidal thickness was associated positively with presence of AMD pigmentary abnormalities (associated with at least medium drusen; for each 1-SD μm increase: OR, 2.21; 95% CI, 1.42-3.42), whereas no significant association was found with presence of large drusen alone. In addition, among large drusen subtypes, choroidal thickness was associated positively with presence of pachydrusen (for each 1-SD μm increase: OR, 1.53; 95% CI, 1.10-2.13). Furthermore, exploratory analysis revealed that choroidal thickness was associated positively with presence of non-AMD pigmentary abnormalities (for each 1-SD μm increase: OR, 1.92; 95% CI, 1.31-2.18).

CONCLUSIONS

Choroidal thickness seems to be associated with the pathology of intermediate AMD and its features in Asians.

Choroidal thickness and ocular growth in childhood

The involvement of the choroid in ocular growth regulation has been postulated in studies showing that refractive errors correlate with alterations in choroidal thickness (ChT). The advent of optical coherence tomography imaging has enabled qualitative and quantitative assessment of the choroid. In children, ChT changes correlate with a number of ocular pathologies, including myopia, retinopathy of prematurity, and amblyopia. We synthesize mechanisms and evidence regarding choroidal thickness variation during childhood. Subfoveal ChT is influenced by a number of factors including age, ethnicity, gender, axial length, and intraocular pressure. Myopic eyes have thinner choroids compared to emmetropic and hyperopic eyes. ChT may in fact serve as a marker of myopic progression, as ChT thinning occurs early during myopic development, but this association has not been established quantitatively. In addition, subfoveal ChT appears thicker in amblyopic eyes, while prematurity and retinopathy of prematurity may be associated with thinner ChT. Overall, both animal models and clinical research indicate that ChT induces or reflects physiological changes in the eye pertaining to ocular growth or maturation.

Characteristics of Pachychoroid Diseases and Age-Related Macular Degeneration: Multimodal Imaging and Genetic Backgrounds

The emergence of pachychoroid disease is changing the concept of age-related macular degeneration (AMD). The concept of pachychoroid diseases was developed through clinical observation of multimodal images of eyes with AMD and central serous chorioretinopathy; however, recent genetic studies have provided a proof of concept for pachychoroid spectrum disease, which should be differentiated from drusen-driven AMD. The genetic confirmation of pachychoroid concept further provides novel viewpoints to decode previously reported findings, which facilitates an understanding of the true nature of pachychoroid diseases and AMD. The purpose of this review was to elucidate the relationship between pachychoroid diseases and AMD by interpreting previous findings on pachychoroid diseases and AMD from the novel viewpoints of genetic associations. We confirmed that previous genetic studies supported the concept of pachychoroid diseases. From a genetic viewpoint, the presence of thick choroid and the presence of choroidal vascular hyperpermeability were important characteristics of pachychoroid spectrum diseases. Previous studies have also suggested the classification of polypoidal choroidal vasculopathy (PCV) into two subtypes, pachychoroid neovasculopathy and drusen-driven PCV. Genetic viewpoints will be beneficial to rearrange subtypes of drusen-driven AMD and pachychoroid spectrum diseases. Further genetic studies are needed to investigate pachyvessels, pachydrusen and the significance of polypoidal lesions in pachychoroid neovasculopathy and drusen-driven AMD/PCV.

Retinal, choroidal and optic disc analysis in patients with Graves' disease with or without orbitopathy

PURPOSE

To compare optic disc, retinal and choroidal measurements in patients with Graves' disease with or without orbitopathy, and healthy controls.

METHODS

Optical coherence tomography and Heidelberg retinal tomography were performed in 40 patients with Graves' orbitopathy (GO), 40 subjects with Graves's disease (GD) with no sign of orbitopathy and 40 healthy controls. Degree of exophthalmos, ocular alignment, clinical activity score (CAS), choroidal thickness, retinal thickness, ganglion cell layer (GCL) thickness, disc area, cup area, rim area, cup/disc area ratio, linear cup/disc ratio and mean peripapillary retinal nerve fibre layer thickness were analysed.

RESULTS

GO patients and healthy controls significantly differ regarding mean central retinal thickness (275 ± 19 µm and 285 ± 20 µm, P = 0.017); mean central GCL thickness (14.87 ± 3.0 µm and 17.92 ± 5.02 µm, P = 0.001); mean disc area (2.00 ± 0.44 mm² and 1.72 ± 0.37 mm², P = 0.003); mean cup area (0.53 ± 0.52 mm² and 0.31 ± 0.20 mm², P = 0.003); cup/disc area ratio (0.22 ± 0.10 and 0.17 ± 0.08, P = 0.010); and linear cup/disc ratio (0.47 ± 0.15 and 0.40 ± 0.13, respectively, P = 0.011). No difference was found between patients without orbitopathy and healthy controls. No significant difference was found regarding the choroidal thickness between the three groups. There was no statistically significant relationship between retinal thickness, ganglion cell layer thickness, mean disc area, mean cup area, cup/disc area ratio, linear cup/disc ratio, CAS, exophthalmometric value and ocular alignment.

CONCLUSION

GO patients showed significant changes in foveal and GCL thickness, and optic nerve head morphology suggesting a possible influence of the orbital inflammatory process.

Choroidal vascularity index determined by binarization of enhanced depth imaging optical coherence tomography images in eyes with intermediate age-related macular degeneration

Purpose

To evaluate choroidal structural changes in patients with intermediate age-related macular degeneration using choroidal vascularity index.

Methods

The eyes of patients with intermediate age-related macular degeneration and controls were evaluated with enhanced depth imaging optical coherence tomography images. Subfoveal choroidal area was segmented into luminal area and stromal area by the binarization technique on enhanced depth imaging optical coherence tomography images using ImageJ software. Choroidal vascularity index was defined as the ratio of luminal area to total circumscribed subfoveal choroidal area.

Results

Fifty-seven eyes with intermediate age-related macular degeneration and 60 healthy control eyes were included in the study. The choroidal vascularity index was computed as 59.53% ± 4.9% in the intermediate age-related macular degeneration group and as 62.7% ± 4.3% in the control group ( p = 0.002). Patients with age-related macular degeneration showed significantly lower values of stromal area and higher values of luminal area compared to control subjects (0.51 ± 0.22 vs 0.87 ± 0.21, p < 0.001 and 0.74 ± 0.22 vs 0.52 ± 0.18, p < 0.001, respectively).

Conclusion

Eyes with intermediate age-related macular degeneration demonstrated reduced choroidal vascularity index compared to healthy eyes. Choroidal vascularity index seems to be a potential non-invasive quantitative method for studying structural changes of the choroid in patients with intermediate age-related macular degeneration.

Comparison of Choroidal Thickness Measurements Using Semiautomated and Manual Segmentation Methods

SIGNIFICANCE

This study demonstrated that a semiautomated segmentation method could help inexperienced practitioners to obtain choroidal thickness as good as experienced practitioners.

PURPOSE

The purpose of this study was to compare choroidal thickness measurements obtained by semiautomated and manual segmentation methods.

METHODS

Optical coherence tomography images of 37 eyes from 37 healthy young subjects acquired by a spectral-domain optical coherence tomography device were reviewed retrospectively. Two naive examiners measured choroidal thickness using manual and semiautomated methods, whereas two experienced examiners used only the semiautomated method. The semiautomated method referred to a fully automated segmentation program customized based on MATLAB and followed manual verification. After highlighting the inner and outer choroidal boundaries through automated segmentation, examiners reviewed these boundaries in each B-scan and conducted manual revisions if segmentation errors occurred. After selecting points where correct boundary was located, the software used a spline fit to blend the corrected region with the rest of the boundary. All measurements were summarized in a 6-mm Early Treatment Diabetic Retinopathy Study grid. Operation time spent to complete retinal and choroidal segmentation on each eye was recorded. Between-examiner agreements, that is, intraclass correlation coefficient and coefficient of reproducibility (CoR), were calculated among four sets of semiautomated measurements, and within-examiner agreements were comparisons between manual and semiautomated results from the same naive examiners. Eyes with thin or thick choroids were also analyzed separately.

RESULTS

The between-examiner and within-examiner agreements were excellent with intraclass correlation coefficient of 0.976 or greater. Pairwise within-examiner CoRs ranged from 17.4 to 47.1 μm. Pairwise between-examiner CoRs were between 13.0 and 38.9 μm. Eyes with thin choroid had better agreements than those with thick choroids. On average, naive examiners saved 3 to 5 minutes per eye using the semiautomated method.

CONCLUSIONS

With the help of a dedicated software, inexperienced practitioners could obtain choroidal thickness measurements with accuracy similar to experienced practitioners. Processing time with the semiautomated method was also reduced.

FEATURES OF THE MACULAR AND PERIPAPILLARY CHOROID AND CHORIOCAPILLARIS IN EYES WITH NONEXUDATIVE AGE-RELATED MACULAR DEGENERATION

PURPOSE

We investigated macular and peripapillary choroidal thickness (CT) and flow voids in the choriocapillaris in eyes with nonexudative age-related macular degeneration.

METHODS

We retrospectively reviewed the medical records of patients with nonexudative age-related macular degeneration and classified their eyes into three categories: pachydrusen, drusen, and subretinal drusenoid deposit. Mean macular and peripapillary CT and choriocapillaris flow void area were compared among the three groups.

RESULTS

The three groups included 29, 33, and 33 patients, respectively. The mean macular and peripapillary CT findings were 260.64 ± 75.85 µm and 134.47 ± 46.28 µm for the pachydrusen group; 163.63 ± 64.08 µm and 93.47 ± 39.07 µm for the drusen group; and 95.33 ± 28.87 µm and 56.06 ± 11.64 µm for the subretinal drusenoid deposit group (all, P < 0.001). Mean macular and peripapillary flow void area varied among the subretinal drusenoid deposit group (57.07 ± 6.16% and 55.38 ± 6.65%), drusen group (58.30 ± 6.98% and 49.11 ± 9.11%) and pachydrusen group (50.09 ± 5.77% and 45.47 ± 8.06%) (all P < 0.001).

CONCLUSION

The peripapillary CT and flow voids in the choriocapillaris varied according to the features of drusen in nonexudative age-related macular degeneration eyes. Greater flow voids and thinner CT in eyes with subretinal drusenoid deposits may suggest that these eyes have diffuse choroidal abnormalities both in and outside the macula.

Exploring choroidal angioarchitecture in health and disease using choroidal vascularity index

The choroid is one of the most vascularized structures of the human body and plays an irreplaceable role in nourishing photoreceptors. As such, choroidal dysfunction is implicated in a multitude of ocular diseases. Studying the choroid can lead to a better understanding of disease pathogenesis, progression and discovery of novel management strategies. However, current research has produced inconsistent findings, partly due to the physical inaccessibility of the choroid and the lack of reliable biomarkers. With the advancements in optical coherence tomography technology, our group has developed a novel quantitative imaging biomarker known as the choroidal vascularity index (CVI), defined as the ratio of vascular area to the total choroidal area. CVI is a potential tool in establishing early diagnoses, monitoring disease progression and prognosticating patients. CVI has been reported in existing literature as a robust marker in numerous retinal and choroidal diseases. In this review, we will discuss the current role of CVI with reference to existing literature, and make postulations about its potential and future applications.

Macular Choroidal Thickness Changes in Development, Progression, and Spontaneous Resolution of Epiretinal Membrane

BACKGROUND AND OBJECTIVE

To evaluate the association between macular choroidal thickness and the development, progression, and resolution of epiretinal membrane (ERM).

PATIENTS AND METHODS

The patients (n = 38) with unilateral ERM eyes with definitive changes on optical coherence tomography (OCT) and healthy fellow eyes were observed retrospectively. ERM eyes were divided into three groups: Development/new-onset group (n = 14), progression group (n = 13), and resolution group (n = 11). In each group, the average changes of macular choroidal thickness over time in ERM eyes were compared with those in the fellow eyes RESULTS: Choroidal thickness significantly decreased from 174.0 μm at baseline to 132.3 μm at event time (P = .001) in the development group, and from 140.0 μm ± 30.0 μm to 120.5 μm (P = .002) in the progression group. Conversely, a significant increase in choroidal thickness was observed in the resolution group (from 205.2 μm to 222.6 μm; P = .004). The fellow eyes showed no significant changes in choroidal thickness in all three groups.

CONCLUSION

Choroidal thinning in newly developed or significantly progressed ERM eyes and choroidal thickening in spontaneously resolved ERM eyes suggest a clinical implication of choroidal changes in ERM. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:627-634.].