Peripapillary Choroidal Thickness and Open-Angle Glaucoma: A Meta-Analysis

Comparison of Peripapillary Choroidal Thickness Between Primary Open-angle Glaucoma, Normal Tension Glaucoma, and Normal Eyes: A Systematic Review and Meta-analysis

TOPIC

To investigate differences in peripapillary choroidal thickness (PPCT) between primary open-angle glaucoma (POAG), normal tension glaucoma (NTG), and healthy eyes, additionally comparing differences between POAG and NTG eyes.

CLINICAL RELEVANCE

Peripapillary choroidal thickness is a well-established OCT parameter in eyes with glaucoma and other ocular pathologies. The relationship between PPCT and glaucoma, if better understood, may facilitate the development of PPCT as a potential diagnostic and monitoring metric for glaucoma. In particular, there has yet to be a synthesis that directly compares PPCT between POAG eyes and NTG eyes.

METHODS

A comprehensive literature search was performed on PubMed, EMBASE, and Cochrane Library, identifying studies from inception to December 2022. We included studies that measured PPCT using OCT in POAG, NTG, and healthy eyes. Mean difference (MD) among groups was calculated. Statistical analysis was performed using R version 4.2.0. Risk of bias of included studies was assessed using the Newcastle Ottawa Scale (NOS).

RESULTS

Eighteen studies were included in this meta-analysis, with a pooled total of 935 healthy control eyes, 446 NTG eyes, and 934 POAG eyes. There was a significant reduction of PPCT in POAG eyes compared with healthy eyes [MD = -16.32; 95% confidence interval (CI) (-27.55 to -5.09)]. Reduction in PPCT was also significant in NTG eyes compared with healthy eyes [MD = -34.96; 95% CI (-49.97 to -19.95)]. NTG eyes had significantly reduced PPCT compared with POAG eyes [MD = -26.64; 95% CI (-49.00 to -4.28)].

CONCLUSIONS

Glaucomatous eyes appear to have significantly reduced PPCT compared with normal healthy eyes. In addition, PPCT in NTG eyes appear significantly thinner compared with that in POAG eyes.

FINANCIAL DISCLOSURE(S)

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

Impact of obesity on peripapillary choroidal thickness, macular choroidal thickness, and lamina cribrosa morphology

BACKGROUND

Obesity is known to be a significant risk factor for many ocular diseases. In order to understand the mechanism of obesity-related ocular diseases, we examined the lamina cribrosa morphology, peripapillary choroidal thickness (PPCT), and macular choroidal thickness (MCT) in obese women using optical coherence tomography (OCT).

METHODS

This comparative cross-sectional study included the right eyes of 72 obese women and 63 healthy women classified based on body mass index (BMI). Each participant underwent a thorough ophthalmological examination and enhanced depth (EDI) OCT imaging, including measurements of PPCT from a total of 12 regions, MCT from a total of 7 regions, Bruch's membrane opening (BMO), lamina cribrosa thickness (LCT), lamina cribrosa depth (LCD), intraocular pressure (IOP), and central corneal thickness (CCT).

RESULTS

The mean age and BMI of the obese group were 32.36±7.38 years and 35.11±4.39 kg/m², while those of the control group were 31.64±7.78 years and 20.88±1.72 kg/m² (p = 0.658, and p<0.001, respectively). PPCT N1000, PPCT N1500, PPCT S1500, and PPCT T1500 were statistically significantly thinner in the obese group than the control group (p values were 0.039, 0.012, 0.027, and 0.036, respectively). IOP and CCT were significantly higher in the obese group than the control group (p = 0.016, and p = 0.019, respectively). There was no statistically significant difference between the two groups in terms of MCT, BMO, LCT, and LCD.

CONCLUSION

We discovered thinning in the PPCT, which indicates microvascular abnormalities in the optic disc head. Microvascular alteration in the peripapillary region may be a potential initial event in the pathogenesis of several obesity-related ocular diseases, especially glaucoma.

A comprehensive enhanced depth imaging spectral-domain optical coherence tomography analysis of pseudoexfoliation spectrum from non-glaucomatous to advanced stage glaucoma in the aspect of Bruch's membrane opening-minimum rim width

PURPOSE

To compare the correlations between lamina cribrosa (LC) and related structures with Bruch's membrane opening-minimum rim width (BMO-MRW) and retinal nerve fiber layer (RNFL) thickness in pseudoexfoliation syndrome (PXS) and different stages of pseudoexfoliation glaucoma (PXG).

METHODS

This prospective cross-sectional study included 32 PXS eyes of 24 patients and 94 PXG eyes (early-stage (n: 55) and advanced-stage glaucoma (n: 39) of 78 patients. Global and six sectors of RNFL thicknesses and BMO-MRW parameters were measured with enhanced depth imaging (EDI) mode of SD-OCT. Structural parameters; lamina cribrosa thickness (LCT), lamina cribrosa depth (LCD), prelaminar tissue thickness (PLTT), four quadrants of peripapillary choroidal thicknesses (PPCT), and subfoveal choroidal thickness (SFCT) were measured and statistical relationships between the structural parameters have been laid out. We apply the generalized estimating equations method to take into account dependency of right and left eyes.

RESULTS

From PXS to mild and advanced PXG groups LCT and PLTT decrease from 147.29 ± 33.10, 145.62 ± 30.64, 126.30 ± 29.14 and 260.93 ± 185.07, 247.27 ± 142.58, 159.89 ± 86.84, respectively, and LCD varies as 159.89 ± 86.84, 420.88 ± 117.80, and 505.64 ± 183.25. The correlations between LCD, LCT, and PLTT and the stage of the disease are significant. BMO-MRW shows slightly stronger correlations than the RNFL with LC related parameters. SFCT does not exhibit any significant relationship with the stage of the disease. However, PPCT in only the interior quadrant does. The significant correlations between LCD and all quadrants of PPCT is the sign of important anatomic relationship.

CONCLUSION

These findings show that the BMO-MRW parameter may be more sensitive than RNFL and can safely be used in the diagnosis and follow-up in PXS and PXG, but this result should be supported with longer and larger series.

Peripapillary choroidal thickness assessed by spectral-domain optical coherence tomography in normal Japanese

PURPOSE

To investigate peripapillary choroidal thickness (PPCT) in normal Japanese subjects by using spectral-domain optical coherence tomography (SD-OCT) with enhanced depth imaging (EDI) technique and evaluate its association with ocular and systemic factors.

STUDY DESIGN

Cross-sectional study.

METHODS

This study included 85 eyes of 85 normal Japanese subjects. Normal subjects were defined as those without retinal and optic nerve disorders of any kind. The PPCT was measured at the location of 3.4 mm diameter peripapillary circle centered on the optic nerve head. It was measured as the distance between the retinal pigment epithelium and scleral-choroidal interface at the following six sectors; temporal, supra-temporal, supra-nasal, nasal, infero-nasal, and infero-temporal. Global PPCT was calculated based on these sectorial data. In addition, association between the PPCT and ocular and systemic factors were evaluated.

RESULTS

Among the included subjects, 39 (45.9%) were men and mean age was 51.4 ± 17.6 years. The mean global PPCT was 135.8 ± 40.6 µm. The infero-nasal and infero-temporal sectors were significantly thinner than other sectors (all, P < 0.05). In multiple regression analysis, thinner global PPCT was significantly associated with older age (P < 0.0001) and female sex (P = 0.0330) after considering effects of other confounders.

CONCLUSIONS

This study provided global PPCT and its profile in normal Japanese subjects by using EDI SD-OCT. These results may be used as a reference in the assessment of normal status of the PPCT. The age and sex of the subjects should be considered in interpreting the PPCT data.

Towards label-free 3D segmentation of optical coherence tomography images of the optic nerve head using deep learning

Recently proposed deep learning (DL) algorithms for the segmentation of optical coherence tomography (OCT) images to quantify the morphological changes to the optic nerve head (ONH) tissues during glaucoma have limited clinical adoption due to their device specific nature and the difficulty in preparing manual segmentations (training data). We propose a DL-based 3D segmentation framework that is easily translatable across OCT devices in a label-free manner (i.e. without the need to manually re-segment data for each device). Specifically, we developed 2 sets of DL networks: the 'enhancer' (enhance OCT image quality and harmonize image characteristics from 3 devices) and the 'ONH-Net' (3D segmentation of 6 ONH tissues). We found that only when the 'enhancer' was used to preprocess the OCT images, the 'ONH-Net' trained on any of the 3 devices successfully segmented ONH tissues from the other two unseen devices with high performance (Dice coefficients > 0.92). We demonstrate that is possible to automatically segment OCT images from new devices without ever needing manual segmentation data from them.

Peripapillary choroidal thickness in patients with vitamin D deficiency

AIM

To investigate the effects of vitamin D deficiency on peripapillary choroidal thickness and retinal nerve fiber layer thickness.

MATERIALS AND METHODS

Patients diagnosed with vitamin D deficiency but not yet treated for it (Group 1) and patients with normal vitamin D levels (Group 2) were included in this study. Subjects with any kind of eye disease and/or systemic disease were excluded from this study. Demographic characteristics of the patients were collected, and the subfoveal choroidal thickness, central foveal thickness, retinal nerve fiber layer thickness, and peripapillary choroidal thickness were measured using optical coherence tomography.

RESULTS

The mean ages in Groups 1 and 2 were 30.5 ± 6.7 and 28 ± 5.78 years (p = 0.12), respectively, and female to male ratios were 19/11 and 17/13, respectively (p = 0.59). The mean vitamin D levels were 8.2 ± 2.5 and 28 ± 4.9 ng/mL in Groups 1 and 2, respectively (p <0.001). In Group 1, subfoveal choroidal thickness and nasal and inferior peripapillary choroidal thicknesses at 500 µm were 327.5 ± 81.4, 142.9 ± 40, and 140.66 ± 38.74 µm, respectively. For Group 2, these values were 407.1 ± 85.5, 189.3 0 ± 57.18, and 195.93 ± 67.58 µm, respectively (p <0.001, p = 0.001, and p <0.001, respectively). In addition, a positive correlation was found between vitamin D levels and the subfoveal choroidal thickness and nasal and inferior peripapillary choroidal thicknesses in all patients (r = 0.365, p = 0.005; r = 0.341, p = 0.008; and r = 0.370, p = 0.004, respectively).

CONCLUSION

Subfoveal choroidal thickness and inferior and nasal peripapillary choroidal thicknesses decreased in patients with vitamin D deficiency.

Factors Influencing Optical Coherence Tomography Peripapillary Choroidal Thickness: A Multicenter Study

Purpose

To quantify peripapillary choroidal thickness (PCT) and the factors that influence it in healthy participants who represent the racial and ethnic composition of the U.S. population.

Methods

A total of 362 healthy participants underwent optical coherence tomography (OCT) enhanced depth imaging of the optic nerve head with a 24 radial B-scan pattern aligned to the fovea to Bruch's membrane opening axis. Bruch's membrane, anterior scleral canal opening (ASCO), and the anterior scleral surface were manually segmented. PCT was measured at 100, 300, 500, 700, 900, and 1100 μm from the ASCO globally and within 12 clock-hour sectors. The effects of age, axial length, intraocular pressure, ethnicity, sex, sector, and ASCO area on PCT were assessed by ANOVA and univariable and multivariable regressions.

Results

Globally, PCT was thicker further from the ASCO border and thinner with older age, longer axial length, larger ASCO area, European descent, and female sex. Among these effectors, age and axial length explained the greatest proportion of variance. The rate of age-related decline increased further from the ASCO border. Sectorally, the inferior-temporal sectors were thinnest (10.7%-20.0% thinner than the thickest sector) and demonstrated a higher rate of age-related loss (from 15.6% to 20.7% faster) at each ASCO distance.

Conclusions

In healthy eyes, PCT was thinnest in the inferior temporal sectors and thinner PCT was associated with older age, European descent, longer axial length, larger ASCO area, and female sex. Among these associations, age had the strongest influence, and its effect was greatest within the inferior temporal sectors.

Comparison of peripapillary and subfoveal choroidal thickness in normal versus primary open-angle glaucoma (POAG) subjects using spectral domain optical coherence tomography (SD-OCT) and swept source optical coherence tomography (SS-OCT)

Objective

To elucidate the difference between choroidal thickness (CT) in primary open-angle glaucoma (POAG) and normal subjects and to compare the CT measured using spectral domain optical coherence tomography (SD-OCT) and swept source optical coherence tomography (SS-OCT).

Methods and analysis

This cross-sectional observational study included 25 eyes of 17 POAG subjects (cases) and 31 eyes of 20 normal subjects (controls). All the patients underwent complete ophthalmologic examination, enhanced depth imaging, SD-OCT and SS-OCT. In both controls and cases, the CT was measured in seven predetermined points in macular and peripapillary area and were compared.

Results

Choroid was significantly thicker on SS-OCT compared with SD-OCT in peripapillary and macular area in both cases and controls, except for inferior peripapillary in controls. The CT was not different from glaucoma and controls in peripapillary or macular area on SD-OCT (p>0.05), however, the CT was significantly thicker in glaucoma compared with controls in peripapillary area on SS-OCT (p<0.05) except inferior peripapillary (p=0.13). There was good intraobserver (±20 µm) and interobserver (±55 µm and ±45 µm) agreement on both SD-OCT and SS-OCT respectively.

On SD-OCT, choroid was thinnest at the temporal peripapillary and thickest at subfoveal location in controls. In POAG, choroid was thinnest at inferior peripapillary region and thickest (500 µm) nasal to the fovea. On SS-OCT, choroid was thinnest at inferior peripapillary and thickest at the temporal peripapillary area in both cases and controls.

Conclusion

CT measurements on SS-OCT were higher than the SD-OCT measurements possibly due to better delineation of the sclerochoroidal junction on SS-OCT. CT was significantly thicker in glaucoma subjects compared with controls in peripapillary area on SS-OCT but not in macular area.

DRUNET: a dilated-residual U-Net deep learning network to segment optic nerve head tissues in optical coherence tomography images

Given that the neural and connective tissues of the optic nerve head (ONH) exhibit complex morphological changes with the development and progression of glaucoma, their simultaneous isolation from optical coherence tomography (OCT) images may be of great interest for the clinical diagnosis and management of this pathology. A deep learning algorithm (custom U-NET) was designed and trained to segment 6 ONH tissue layers by capturing both the local (tissue texture) and contextual information (spatial arrangement of tissues). The overall Dice coefficient (mean of all tissues) was 0.91 ± 0.05 when assessed against manual segmentations performed by an expert observer. Further, we automatically extracted six clinically relevant neural and connective tissue structural parameters from the segmented tissues. We offer here a robust segmentation framework that could also be extended to the 3D segmentation of the ONH tissues.

The diagnostic use of choroidal thickness analysis and its correlation with visual field indices in glaucoma using spectral domain optical coherence tomography

PURPOSE

To evaluate the quantitative characteristics of choroidal thickness in primary open-angle glaucoma (POAG), normal tension glaucoma (NTG) and in normal eyes using spectral-domain optical coherence tomography (SD-OCT). To evaluate the diagnostic ability of choroidal thickness in glaucoma and to determine the correlation between choroidal thickness and visual field parameters in glaucoma.

METHODS

A total of 116 subjects including 40 POAG, 30 NTG and 46 healthy subjects were enrolled in this study. Choroidal thickness measurements were acquired in the macular and peripapillary regions using SD-OCT. All subjects underwent white-on-white (W/W) and blue-on-yellow (B/Y) visual field tests using Humphrey Field Analyzer. The receiver operating characteristic (ROC) curve and the area under curve (AUC) were generated to assess the discriminating power of choroidal thickness for glaucoma. Pearson's correlation coefficients were calculated to assess the structure function correlation for glaucoma patients.

RESULTS

No significant differences were observed for macular choroidal thickness among the different groups (all P > 0.05). Regarding the peripapillary choroidal thickness (PPCT), significant differences were observed among the three groups (all P < 0.05). Post hoc tests for multiple comparisons revealed a significant difference in the NTG-normal comparison group (all P < 0.01). The inferior and temporal PPCT in POAG patients were significantly thinner than those in normal subjects (P = 0.007, P = 0.002, respectively). Different parameters of PPCT showed significantly low diagnostic values to detect POAG from normal subjects (AUC: 0.555 to 0.652) and to discriminate NTG from POAG (AUC: 0.462 to 0.702), but moderate diagnostic power to detect NTG from normal subjects (AUC: 0.708 to 0.771). Regarding the diagnosis of early glaucoma, different parameters of PPCT showed relatively low diagnostic power (AUC: 0.606 to 0.698). In all the glaucoma subjects, PPCT was not significantly correlated with W/W mean deviation (MD) (all P > 0.05), but showed significant correlations with B/Y MD (all P < 0.05). In the early glaucomatous eyes, PPCT showed significant correlations with W/W MD and B/Y MD (all P < 0.05).

CONCLUSIONS

In our study, peripapillary choroidal thickness measured on OCT showed a low to moderate but statistically significant diagnostic power and a significant correlation with blue-on-yellow visual field indices in glaucoma. This may indicate a potential adjunct for peripapillary choroidal thickness in glaucoma diagnosis.

Biometric Differences between Unilateral Chronic Primary Angle Closure Glaucoma and Fellow Non-Glaucomatous Eyes

PURPOSE

To compare biometric differences between eyes with unilateral chronic primary angle-closure glaucoma (PACG) and fellow non-glaucomatous eyes in the same patient.

METHODS

Clinical data and imaging records of 17 patients with unilateral PACG were retrospectively reviewed. The fellow eyes with primary angle-closure (PAC) or primary angle-closure suspected (PACS) were grouped in Group 1. The PACG eyes were set as Group 2. The biometric parameters of both eyes were measured by IOL-Master, anterior segment optical coherence tomography (AS-OCT), and swept source OCT.

RESULTS

The iris area in Group 1 was significantly thicker than that in Group 2 (1.590 ± 0.267 versus 1.365 ± 0.352, P = 0.016). Choroidal thickness in the macular region was thicker in Group 1 than in Group 2, with statistical significance at inner temporal grid (282.7 ± 121.1 versus 191.6 ± 90.3, P = 0.036), central field (297.4 ± 130.6 versus 200.1 ± 96.3, P = 0.029), inner nasal grid (283.1 ± 128.3 versus 194.8 ± 91.8, P = 0.040), and average value (265.3 ± 105.6 versus 191.1 ± 87.0, P = 0.049). Group 1 also had thicker peripapillary choroidal thickness at 1 o'clock (141.4 ± 68.4 versus 101.8 ± 39.0, P = 0.025) and 12 o'clock (141.5 ± 82.3 versus 104.5 ± 44.6, P = 0.037) compared to Group 2. The multivariate logistic regression analyses showed that only intraocular pressure was independently associated with PACG and explained 58.3% variance of PACG.

CONCLUSIONS

In unilateral PACG, there was significant inter-eye difference in anterior and posterior segment parameters. Longitudinal comparisons are required to further understand the differences in pathology of angle closures.

[Suprachoroidal minimally invasive glaucoma surgery : Procedures and clinical outcome]

The uveoscleral outflow route is via the ciliary muscles into the suprachoroidal spaces and then to the orbital blood and lymph systems. The main driving force behind this uveoscleral outflow is the high oncotic pressure in the choroidal vessels. Currently, the CyPass microstent is the only available suprachoroidal device for ab interno minimally invasive glaucoma surgery. The CyPass achieves a maximum reduction of intraocular pressure (IOP) to 16-17 mm Hg over 12-24 months and is approved for mild to moderate primary open-angle glaucoma. The CyPass is an easy to use minimally invasive glaucoma surgery stent operation and has few intraoperative as well as short and long-term complications. Postoperative management is unproblematic and the postoperative burden for patients is low, which leads to rapid recovery of patients; however, the correct selection of glaucoma patients is crucial for maintaining a sustainable success rate. Long-term studies are necessary to demonstrate the persistence of the IOP lowering effect.

Analysis of choroidal thickness in ocular hypertensive patients using enhanced depth imaging optical coherence tomography

This study aimed to compare choroidal thickness between subjects with ocular hypertension (OHT) and normal individuals and explore factors affecting choroidal thickness. This study included 60 untreated newly diagnosed OHT eyes and 60 normal eyes. Choroidal thickness obtained from Cirrus HD-OCT was measured at different locations in the macular and peripapillary regions and compared between the two groups before and after adjusting for potential confounding variables. Regression analysis was performed to figure out factors influencing choroidal thickness. The macular choroidal thickness did not vary significantly between OHT patients and normal controls regardless of locations (all P > 0.05). The average peripapillary choroidal thickness was 167 ± 53 μm in OHT eyes and 185 ± 63 μm in the normal eyes; no significant differences were identified (P = 0.107). Only one of the locations in the temporal area in the OHT group demonstrated significantly thinner peripapillary choroidal thickness as compared to the normal group (P = 0.033). Age was the only significant factor affecting choroidal thickness on multivariate analysis regardless of locations (all P < 0.001). Choroidal thickness of the macular and peripapillary regions in OHT patients is not decreased significantly except one location in the temporal area of the optic disc when comparing with the normal subjects. Anatomic peripapillary choroidal thickness measurements with SD-OCT might be one more tool to track changes in OHT patients.