DETAILED CHARACTERIZATION OF CHOROIDAL MORPHOLOGIC AND VASCULAR FEATURES IN AGE-RELATED MACULAR DEGENERATION AND POLYPOIDAL CHOROIDAL VASCULOPATHY

Trends in application of fundus fluorescein angiography in fundus diseases during a recent ten-year period

PURPOSE

To analyze the trends in the application of fundus fluorescein angiography (FFA) in fundus diseases over ten years.

METHOD

It was a retrospective study. Patients who underwent FFA examinations between Jan 2012 and Dec 2021 in Eye Hospital of Wenzhou Medical University were included, excluding infants. Data included the fundus disease and examination time of FFA.

RESULTS

A total of 37,038 cases underwent FFA examinations in our hospital in the past decade, and the number of each year was 3,628, 2,232, 2,230, 2,351, 3,546, 3,924, 5,325, 4,202, 4,432 and 5,168 from 2012 to 2021, respectively. The top three diseases were central serous chorioretinopathy (CSC), diabetic retinopathy (DR) and retinal vein occlusion (RVO) over the years from 2012 to 2021. The fourth to eighth ranked diseases were uveitis, age-related macular degeneration (AMD), choroidal neovascularization (CNV), optic neuropathy (ON) and polypoid choroidal vasculopathy (PCV) 9 years from 2012 to 2020; while retinal artery occlusion (RAO) ranked eighth and PCV fell out of the first eight in 2021. Tumor, Eale's disease, macular hemorrhage (MH), epiretinal retinal membrane (ERM) and Coat's disease had consistent proportions over the years. There was a significant statistical difference in the proportion of disease components over the years from 2012 to 2021(p = 0.000).

CONCLUSION

Despite changes in annual distribution, CSC, DR, and RVO consistently ranked as the top three diseases requiring FFA examination. Changes might be related to the development of non-invasive fundus examination instruments and technologies. Indicated that FFA still hold its irreplaceable nature in diagnosing and understanding fundus diseases.

A study of the relationship between cytokine levels and the response to anti-VEGF therapy in polypoid choroidal vasculopathy with different choroidal thicknesses

Purpose

Polypoidal choroidal vasculopathy (PCV) is an irreversible retinal choroidal disease. Individuals with PCV exhibit diverse baseline characteristics, including systemic characteristics, ocular traits, metabolic factor levels, and different responses to intravitreal anti-VEGF therapy. This study aims to investigate the pathogenesis of PCV by analyzing the systemic characteristics, ocular traits, and cytokine levels at baseline within a cohort of patients who exhibit different responses to anti-VEGF treatment.

Methods

We conducted a retrospective analysis involving 80 eyes diagnosed with PCV. Patients were categorized into two groups based on responses to suboptimal intravitreal ranibizumab injection therapy: those with suboptimal responses and optimal responses. Aqueous humor samples were collected from the experimental eyes, and cytokine expression levels were assessed using cytometric bead array analysis. All subjects were further stratified into two groups according to the median choroidal thickness. Subsequently, logistic regression analysis and the ROC curve were employed to examine the relationship between cytokine expression levels, choroidal thickness, and anti-VEGF response.

Results

The results revealed that compared to the group of optimal anti-VEGF response, the choroid in the suboptimal response group exhibited a significantly greater thickness. Additionally, compared to the suboptimal anti-VEGF response group, the expression levels of VEGF and VCAM-1 were markedly lower observed in the optimal anti-VEGF response group, while TNF-α showed the opposite trend. Logistic regression analysis indicated that VEGF, VCAM-1, and TNF-α in the aqueous humor were independent risk factors for a suboptimal anti-VEGF response. After adjusting other risk factors, the risk of suboptimal anti-VEGF response decreased to 0.998-fold, 0.997-fold, and 1.294-fold. The AUC values for VEGF, VCAM-1, and TNF-α were determined to be 0.805, 0.846, and 0.897, respectively. Furthermore, the risk of VEGF, VCAM-1, and TNF-α were significantly associated with an increased risk of suboptimal anti-VEGF response after correction for risk factors in the thick choroid group.

Conclusions

Our study demonstrated that PCV exhibits systemic and ocular characteristics variations based on different anti-VEGF responses. The levels of cytokines in aqueous humor were found to have a significant correlation with the anti-VEGF response in PCV. VEGF, VCAM-1, and TNF-α are potential targets for assessing treatment response in thick choroidal PCV.

Factors Influencing Visual Acuity in Patients with Active Subfoveal Circumscribed Polypoidal Choroidal Vasculopathy and Changes in Imaging Parameters

We performed a retrospective, observational study of 51 eyes in 51 treatment-naïve patients with polypoidal choroidal vasculopathy (PCV), whose lesion ranged within the 6 × 6 mm scope of optical coherence tomography angiography (OCTA). The patients were divided into an ill-defined group and a well-defined group based on the pattern of branching vascular network (BVN) on OCTA. BVN morphology was not related to baseline best-corrected visual acuity (BCVA). However, the BCVA in the ill-defined BVN group (-0.18 [interquartile range: -0.40 to 0.00]) was significantly improved after anti-vascular endothelial growth factor (VEGF) injections, compared with that (0.00 [interquartile range: -0.18 to 0.00]) in the well-defined group (z = 2.143, p = 0.032). Multiple logistic regression analysis showed that male sex, fewer injections, and the presence of polypoidal lesions on OCTA images at baseline predicted a poor prognosis in patients with polypoidal lesions on OCTA images after anti-VEGF therapy (all p < 0.05). Finally, BCVA at baseline and the number of injections were protective factors for BCVA after anti-VEGF therapy (all p < 0.05). In contrast, a history of hypertension and macular edema at baseline were risk factors for BCVA after anti-VEGF injections (all p < 0.05). Our results revealed the visual and morphological prognosis of patients with active subfoveal circumscribed PCV after anti-VEGF therapy.

Vortex vein engorgement and different shapes of venous drainage systems in polypoid choroidal vasculopathy vs. age‑related macular degeneration on indocyanine green angiography

There are differences in vortex vein engorgement and appearance in polypoid choroidal vasculopathy (PCV), age-related macular degeneration (AMD), and healthy eyes. The present study aimed to use indocyanine green angiography (ICGA) to find a simple, clinically meaningful method for evaluating the filling degree of vortex veins in various eye diseases. Participant clinical characteristics were recorded. The number of vortex veins (NVV), central vortex vein diameter (CVVD), mean root area of the vortex vein (MRAVV), mean diameter of the thickest peripheral branch (MDPTB), subfoveal choroidal thickness and percentage of vortex vein anastomosis (PVVA) were obtained by marking the vortex veins on ICGA. The proportion of subretinal haemorrhage and the numbers and types of vortex veins in each quadrant were counted separately. The CVVD and MDPTB were significantly increased in the PCV compared with those in the AMD group (P<0.05). The CVVD, MRAV, and PVVA were significantly increased in the PCV compared with those in the healthy group (P<0.05). The type IV vortex vein (complete with ampulla) proportion was the lowest while the type I (vortex vein absent) proportion was the highest in the PCV group (P<0.001). NVV in the inferior-temporal region was increased in the PCV compared with that in the AMD group (P=0.034). Subretinal haemorrhage occurred in the inferior temporal choroid in 47.62% of examined eyes in PCV group, and in the superior temporal choroid in 23.81% of the PCV group, with significant differences between the quadrants (P<0.001). Vortex vein engorgement and shape differed significantly between PCV, AMD and healthy eyes. The vortex vein branches in PCV eyes were significantly dilated in the posterior pole; moreover, the peripheral choroid and the lower proportion of type IV vortex veins may be pathognomonic for PCV.

Peripheral and macular polypoidal choroidal vasculopathy: A retrospective comparative case series

PURPOSE

To compare clinical and imaging features and treatment outcomes between eyes having peripheral polypoidal choroidal vasculopathy (PCV) and macular PCV.

METHODS

In this retrospective comparative case series, confirmed cases of peripheral and macular PCV cases on indocyanine green angiography (ICGA) were included. The various demographic features, imaging characteristics and clinical course between cases with peripheral and macular PCV were compared and analysed.

RESULTS

Fifteen eyes of 12 patients and 22 eyes of 20 patients were diagnosed with peripheral PCV and macular PCV respectively based on polyps seen on ICGA. Mean age at presentation in peripheral and macular PCV groups were 76.3 ± 8.78 and 69.1 ± 8.64 years respectively (p = 0.038). Mean logMAR visual acuity in the peripheral and macular PCV group was 0.423 ± 0.568 and 0.535 ± 0.513 respectively (p = 0.595). Peripheral subretinal hemorrhage was noted commonly in the peripheral PCV group (n = 10, 66%) and hard exudates were common in the macular PCV (19, 86%) group. Subfoveal choroid was significantly thinner in peripheral PCV group compared to macular PCV group (215.2 ± 39.94 vs 283.3 ± 50.08; p = 0.001). At final follow-up visit, 50% eyes (n = 11) in macular PCV group were still active and 87% (n = 13) eyes in the peripheral PCV showed an inactive disease (p = 0.035).

CONCLUSION

Peripheral and macular PCV cases are two separate clinical entities having distinct pathogenesis, clinical and imaging features and treatment outcomes. Further studies are needed for understanding the pathomechanism in these distinct disease entities.

A Comparative Study of Choroidal Vascular and Structural Characteristics of Typical Polypoidal Choroidal Vasculopathy and Polypoidal Choroidal Neovascularization: OCTA-Based Evaluation of Intervortex Venous Anastomosis

BACKGROUND

The aim of this study was to compare the choroidal characteristics of typical polypoidal choroidal vasculopathy (T-PCV) and polypoidal choroidal neovascularization (P-CNV) cases, and to investigate the presence of intervortex venous anastomoses in these PCV subtypes by using en face optical coherence tomography angiography (OCTA).

METHODS

A total of 35 eyes of 33 PCV cases were included. The PCV cases were divided into T-PCV and P-CNV groups. The choroidal vascularity index (CVI) was calculated. En face OCTA images were evaluated for the presence of intervortex venous anastomoses. The diameter of the largest anastomotic Haller vessel was measured.

RESULTS

T-PCV cases had significantly higher mean CVI values (73.9 ± 3.7 vs. 70.8 ± 4.5%) than P-CNV cases (p = 0.039). Intervortex venous anastomoses were observed in 85.7% of T-PCV eyes and in 91.7% of P-CNV eyes on en face OCTA (p = 1.000). In the cases with intervortex venous anastomosis, the mean diameter of the largest anastomotic vessel on en face OCTA was 341.2 ± 109.1 µm in the T-PCV and 280.4 ± 68.4 µm in the P-CNV group (p = 0.048).

CONCLUSIONS

The higher CVI value in T-PCV may be an important feature concerning the pathogenesis and classification of PCV. Although there was no difference between the two subtypes in terms of intervortex anastomosis, more dilated anastomotic vessels were observed in the T-PCV.

Pachychoroid neovasculopathy can mimic wet type age-related macular degeneration

Purpose

to determine the percentage of patients with pachychoroid neovasculopathy (PNV) among patients who have been misdiagnosed and treated with wet age-related macular degeneration (AMD).

Methods

In this retrospective cross-sectional study, patients over 55 years old, who were diagnosed with wet AMD, were re-evaluated. All patients were recalled for examination and imaging. Patients with PNV were differentiated form wet AMD based on inclusion and exclusion criteria.

Results

Overall, 120 patients (137 eyes) were recorded with wet AMD in the clinic. Finally, after complete re-evaluation, 94 (106 eyes) and 26 patients (31 eyes) were assigned to the AMD and the PNV group, respectively. Thus, a total of 20% of patients with primary mistake diagnosis of wet AMD, actually had PNV. The mean sub field choroidal thickness (SFCT) in the AMD and PNV groups was 173.8 ± 69 μm and 342 ± 27 μm, respectively. Drusen and pachydrusen were found in 69.9% and 24% of the cases with AMD and PNV, respectively (P = 0.001). The average number of intravitreal injections of anti-VEGF (vascular endothelial growth factor) required in the AMD and PNV groups was about 5 and 3, respectively, which was statistically significant (P-value 0.02).

Conclusion

This study revealed that about a one-fifth of wet AMD patients are actually pachychoroid neovasculopathy. These patients were younger and had thicker SFCT, and developed less subretinal scarring. Thus, the disorder must be considered as an important differential diagnosis of AMD-CNV.

Quantitative Assessment of the Choroidal Vessel Diameter during the Recovery of Form-Deprivation Myopia in Guinea Pigs

PURPOSE

The development and recovery (REC) of myopia is associated with changing of choroidal thickness (CT) in the model of guinea pigs. Nitric oxide synthase (NOS) is an enzyme which can affect choroidal vasodilatation. This study wants to investigate the changes of choroidal vessel diameter (CVD) and NOS during the REC of form-deprivation (FD) myopia in guinea pigs.

METHODS

Forty-eight guinea pigs were randomly assigned to the normal control (NC) group, FD group (FD for 21 d), and four REC groups: REC1/2 group (removal the deprivation and re-exposure to the normal environment for 1/2 d), REC1 group (1 d), REC 2 group (2 d), and REC7 group (7 d). CT was measured by optical coherence tomography (OCT), and CVD of foveal choroid was quantitatively assessed on OCT angiography images using MATLAB software at each time point. NOS in choroid was measured using enzyme-linked immunosorbent assays. Measurements were compared between groups and correlations between CT, CVD, and NOS were assessed using regression analyses.

RESULTS

CVD and CT in FD group were significantly smaller than in NC group (both p < .05), while the NOS significantly larger (p < .001). When deprivation was removed, CVD and NOS were significantly larger and reached a peak in the REC1 group, while CT reached the peak in the REC2 group, then all gradually decreased, and no significant differences were observed in NC and REC7 group (all p > .05). In the REC and NC groups, there was a significant positive correlation between CVD and NOS (p < .001), CVD and CT (p = .0092), but no correlation was found between NOS and CT (p > .05).

CONCLUSIONS

This study indicated that the CVD in guinea pigs could be significantly dilated following myopia REC, and this change coincides with changes in NOS and CT.

Characterization of Choroidal Morphology and Vasculature in the Phenotype of Pachychoroid Diseases by Swept-Source OCT and OCTA

The objective of this study was to characterize the choroidal morphology and vasculature in pachychoroid diseases (PCD). A total of 49 eyes with polypoidal choroidal vasculopathy (PCV), 43 eyes with neovascular age-related macular degeneration (nAMD), and 50 eyes with central serous chorioretinopathy (CSC), along with 80 healthy eyes, were enrolled in this nested case-control study. The swept-source optical coherent tomography (OCT), OCT angiography, and En face images were quantitatively analyzed. Multivariate logistic regression models showed that older age and increased vessel density (VD) in the choriocapillaris (CC) layer were independent risk factors for both PCV (page < 0.001, pVD = 0.004), and nAMD (page < 0.001, pVD = 0.005). Decreased VD in the Sattler’s layer was an independent risk factor for PCV (p = 0.014). Increased VD in the Haller’s layer was an independent risk factor for CSC (p = 0.001). The proportion of the diffuse type of collateral circulation in the Sattler’ layer in CSC group was significantly higher than in the other three groups (p < 0.001). We concluded that the involvement of the blood flow in the CC, Haller’s, and Sattler’s layers are differently affected in CSC, nAMD, and PCV eyes, indicating the different pathological mechanism underlying the phenotype of PCD. The age-dependent establishment of collateral circulation in the Sattler’s layer may play a compensatory role regarding ischemic injury in the development of PCD.

Recurrence and visual prognostic factors of polypoidal choroidal vasculopathy: 5-year results

This retrospective study aimed to evaluate the factors affecting recurrence and visual prognosis in patients with treatment-naïve subfoveal polypoidal choroidal vasculopathy (PCV). Patients who had received three consecutive intravitreal injections of ranibizumab or aflibercept and had reached remission were enrolled. They were divided into a group without recurrence (group 1, 26 eyes) and a group with recurrence (group 2, 121 eyes) and followed up for at least 5 years. Patients in group 2 received additional treatment for worsening. Logistic regression analysis revealed that a young age of onset (P = 0.001), high choroidal vascularity index (CVI; P = 0.019), and presence of choroidal vascular hyperpermeability (CVH; P = 0.037) were associated with a low risk of recurrence. Multiple regression analysis revealed that recurrence (P = 0.001), greatest linear dimension (P = 0.003), and polyp configuration (single or cluster; P = 0.043) were associated with final visual acuity. Patients without recurrence had a lower age of onset and higher CVI than those with recurrence, and they tended to have CVH. In addition, patients with recurrence, large lesion, and cluster polyps had worse final visual acuity than those without these factors. CVI and CVH may be used to predict recurrence of PCV.

Pachychoroid disease spectrum: review article

PURPOSE

The aim of this article is to do a comprehensive literature review about the current understandings of the pachychoroid disease spectrum, describing its multimodal imaging analysis, pathophysiology, differential diagnosis, and current types of management.

METHODS

This comprehensive literature review was performed based on a search on the PubMed database, of relevant pachychoroid published papers according to our current knowledge.

DISCUSSION

The pachychoroid disease spectrum, according to some authors, includes the following: pachychoroid pigment epitheliopathy (PPE), central serous chorioretinopathy (CSC), pachychoroid neovasculopathy (PNV), polypoidal choroidal vasculopathy (PCV)/aneurysmal type 1 neovascularization (AT1), and more recently focal choroidal excavation (FCE) and peripapillary pachychoroid syndrome (PPS). Each one of these entities will be described and discussed in this article.

CONCLUSION

Significant advances in multimodal imaging have enabled a better understanding of the typical choroidal changes in pachychoroid disease spectrum. The clinical knowledge and managing options about this disease significantly increased in the last years. However, it is still unclear why some eyes with typical pachychoroid disease phenotype show no evidence of RPE damage and subretinal fluid (uncomplicated pachychoroid) while others present progressive tissue damage, neovascularization, and atrophy.

OCT Biomarkers in Neovascular Age-Related Macular Degeneration: A Narrative Review

Age-related macular degeneration (AMD) is the leading cause of legal blindness in elderly people. Neovascular AMD (nAMD) is responsible for the majority of cases of severe visual loss in eyes with AMD. Optical coherence tomography (OCT) is the most widely used technology for the diagnosis and follow-up of nAMD patients, which is widely used to study and guide the clinical approach, as well as to predict and evaluate treatment response. The aim of this review is to describe and analyze various structural OCT-based biomarkers, which have practical value during both initial assessment and treatment follow-up of nAMD patients. While central retinal thickness has been the most common and one of the first OCT identified biomarkers, today, other qualitative and quantitative biomarkers provide novel insight into disease activity and offer superior prognostic value and better guidance for tailored therapeutic management. The key importance of retinal fluid compartmentalization (intraretinal fluid, subretinal fluid, and subretinal pigment epithelium (RPE) fluid) will be discussed firstly. In the second part, the structural alterations of different retinal layers in various stages of the disease (photoreceptors layer integrity, hyperreflective dots, outer retinal tubulations, subretinal hyperreflective material, and retinal pigment epithelial tears) will be analyzed in detail. The last part of the review will focus on how alterations of the vitreoretinal interface (vitreomacular adhesion and traction) and of the choroid (sub-RPE hyperreflective columns, prechoroidal clefts, choroidal caverns, choroidal thickness and choroidal volume, and choroidal vascular index) interact with nAMD progression. OCT technology is evolving very quickly, and new retinal biomarkers are continuously described. This up-to-date review article provides a comprehensive description on how structural OCT-based biomarkers provide a valuable tool to monitor the progression of the disease and the treatment response in nAMD patients. Thus, in this perspective, clinicians will be able to allocate hospital resources in the best possible way and tailor treatment to the individual patient's needs.

PERIPHERAL EXUDATIVE HEMORRHAGIC CHORIORETINOPATHY-A NEW ADDITION TO THE SPECTRUM OF PACHYCHOROID DISEASE?

PURPOSE

To demonstrate choroidal vascular changes and report a novel choroidal thickness contour in eyes with peripheral exudative hemorrhagic chorioretinopathy (PEHCR).

METHODS

Retrospective, observational, comparative case series. Fourteen eyes of nine patients with PEHCR and 14 eyes of 14 age-matched and sex-matched controls underwent swept-source optical coherence tomography. Choroidal thickness was measured from posterior edge of the retinal pigment epithelium-Bruch membrane to choroidoscleral interface at 11 points 1,000 µm apart. Large choroidal vessel thickness was also measured.

RESULTS

In PEHCR group, the choroid was thinnest at 3 mm nasal to fovea (mean 95.3 ± 33.5 µm) and thickest at 7 mm temporal to fovea (mean 272.7 ± 80.2 µm), with gradual increase in choroidal thickness from nasal to temporal periphery. The choroid was thickest subfoveally (259.7 ± 63.8 µm) in the control group. The choroid was significantly thicker in temporal periphery in PEHCR eyes as compared to controls (P = 0.0002). The mean large choroidal vessel thickness was 202.4 ± 50.8 µm in the PEHCR group and 160.6 ± 40.5 µm in the control group (P = 0.0235).

CONCLUSION

Peripheral exudative hemorrhagic chorioretinopathy eyes showed progressively increasing choroidal thickness toward the temporal periphery, compared with age-matched and sex-matched controls. This gave rise to a club-shaped choroidal contour compared with the bowl-shaped contour seen in control eyes. Thicker choroid and pachyvessels favor inclusion of PEHCR in the pachychoroid disease spectrum.

A comparative study on the choroidal vascularity index and the determination of cut-off values in the pachychoroid spectrum diseases

PURPOSE

To determine the cut-off levels for choroidal thickness and choroidal vascularity index (CVI) to differentiate among pachychoroid spectrum diseases.

STUDY DESIGN

A retrospective comparative study METHODS: A total of 143 eyes were included. Of these 29 had uncomplicated pachychoroid (UCP), 29 had pachychoroid pigment epitheliopathy (PPE), 25 had pachychoroid neovasculopathy (PNV), 30 had central serous chorioretinopathy (CSC), and 30 had polypoidal choroidal vasculopathy (PCV). The choroidal areas were measured with ImageJ software. The CVI, the proportion of the luminal area to the total choroidal area, was assessed.

RESULTS

The cut-off points of central choroidal thickness were determined as 360 µm for the PPE and PCV group pair (p < 0.001), 422 µm for the PNV and CSC group pair (p = 0.026), 271 µm for the PNV and PCV group pair (p < 0.001), and 341 µm for the CSC and PCV group pair (p < 0.001). The cut-off points of CVI were 72.7 for the PPE and PCV group pair (p < 0.001), 74.7 for the PNV and CSC group pair (p = 0.005), 72.6 for the PNV and PCV group pair (p = 0.001), and 73.6 for the CSC and PCV group pair (p < 0.001).

CONCLUSION

Pachychoroid spectrum may be composed of a combination of distinct choroidal diseases with different vascular and structural characteristics.

Clustering of eyes with age-related macular degeneration or pachychoroid spectrum diseases based on choroidal thickness profile

Choroidal changes have been suggested to be involved in the pathophysiology of both age-related macular degeneration (AMD) and pachychoroid spectrum diseases (PSD). To find out the choroidal characteristics of each disease groups, various groups of AMD and PSD were classified into several clusters according to choroidal profiles based on subfoveal choroidal thickness (CT), peripapillary CT, the ratio of subfoveal CT to peripapillary CT and age. We retrospectively analyzed 661 eyes, including 190 normal controls and 471 with AMD or PSDs. In the AMD groups, eyes with soft drusen or reticular pseudodrusen were belonged to the same cluster as those with classic exudative AMD (all p < 0.001). However, eyes with pachydrusen were not clustered with eyes from other AMD groups; instead, they were classified in the same cluster as eyes from the PSD group (all p < 0.001). In the PSD group, eyes with pachychoroid neovasculopathy were grouped in the same cluster of those with polypoidal choroidal vasculopathy (p < 0.001). The cluster analysis based on the CT profiles, including subfoveal CT, peripapillary CT, and their ratio, revealed a clustering pattern of eyes with AMD and PSDs. These findings support the suggestion that pachydrusen has the common pathogenesis as PSD.

Choroidal thickness profile and clinical outcomes in eyes with polypoidal choroidal vasculopathy

PURPOSE

To investigate the relationship between choroidal thickness (CT) profile and clinical outcomes after anti-vascular endothelial growth factor (VEGF) treatment in polypoidal choroidal vasculopathy (PCV).

METHODS

Medical records of patients diagnosed with PCV who received anti-VEGF treatment over 12 months were reviewed. Subfoveal CT (SFCT) and peripapillary CT (PCT) were measured on swept-source optical coherence tomography images. Patients were divided into various groups based on choroidal profiles including SFCT, nasal PCT (nPCT) and ratio of SFCT to nPCT (SFCT/nPCT). Clinical outcomes were compared between the thin and thick CT groups.

RESULTS

A total of 65 patients with PCV patients were included. After ant-VEGF treatment, SFCT was significantly decreased after anti-VEGF treatment (P = 0.001), but nasal PCT (nPCT) was not. Clinical outcomes were not different between the thin and thick SFCT groups. Total number of injections during the 12 months was significantly fewer in the thin nPCT group (3.4 ± 1.3) than in the thick nPCT group (4.5 ± 1.8) (P = 0.020). Complete resolution after loading injections was more frequently observed in the high SFCT/nPCT ratio (> 1.9) group (87.9%) than in the low SFCT/nPCT ratio (≤ 1.90) group (59.4%) (P = 0.009). The ratio of SFCT/nPCT showed the best predictive ability for poor responders (area under curve = 0.771).

CONCLUSION

These results suggest that baseline nPCT and SFCT/nPCT ratio could be a good biomarker that reflects clinical outcomes after anti-VEGF treatment in PCV.

Quantitative analysis of choroidal vasculature in polypoidal choroidal vasculopathy using ultra-widefield indocyanine green angiography

Polypoidal choroidal vasculopathy (PCV) is a common choroidal vascular disease particularly in Asians. However, the underlying pathogenesis of PCV is still yet to be fully elucidated, and the correlation between choroidal vasculature and treatment response of PCV are poorly understood. Accordingly, we sought to find clues to understand the pathogenesis and prognosis of PCV by quantitatively evaluating choroidal vasculature from the entire fundus using ultra-widefield (UWF) indocyanine green angiography (ICGA). In this study, 32 eyes from 29 patients with treatment naïve PCV and 30 eyes from 30 healthy control participants were enrolled. Choroidal vascular density (CVD) of PCV eyes was higher than normal eyes in majority regions including the periphery. CVD was positively correlated with choroidal thickness and choroidal hyperpermeability, supporting that the pathogenesis of PCV may include choroidal congestion and dilatation. Thicker choroid and higher CVD were also correlated with poor treatment response after anti-VEGF injections. The CVD, quantified from UWF ICGA can also be used as an effective image biomarker to predict the treatment response in PCV.

Decrease in Choroidal Vascularity Index of Haller's layer in diabetic eyes precedes retinopathy

INTRODUCTION

The study aimed to evaluate Choroidal Vascularity Index (CVI) of Haller's and Sattler's layers and their relationships with choroidal and retinal thickness, volumes measured on enhanced depth imaging-optical coherence tomography (OCT) scans in the eyes of patients without diabetes, patients with diabetes with no diabetic retinopathy (DR) and patients with diabetes and DR.

RESEARCH DESIGN AND METHODS

Retrospective analysis of 165 eyes from 84 Singapore Indian Eye Study-2 study participants (group 1: no diabetes, group 2: diabetes with no DR and group 3: with DR). Groups 1 and 2 were matched by age and gender from group 3.

RESULTS

In the eyes of patients with diabetes without DR, the macular CVI of Haller's but not Sattler's layer was significantly reduced compared with eyes of patients without diabetes. Eyes with >5 years of diabetes have significantly decreased CVI of Sattler's layers (mean difference=0.06 ± 0.10, p=0.04) and also decreased subfoveal choroidal volume (mean difference=0.89 ± 0.16 mm³, p=0.02), compared with those with ≤5 years of diabetes.

CONCLUSION

Diabetic eyes without DR had significantly lower CVI of macular Haller's layer than those of healthy controls. With a longer duration of diabetes, CVI of subfoveal Sattler's layer and choroidal volume continue to decrease, irrespective of diabetic control, suggesting that early diabetic choroidopathy mainly affects larger choroidal veins initially before medium-sized arterioles. The CVI of macular Haller's layer could potentially be used as a marker on spectral domain OCT imaging in newly diagnosed patients with diabetes for the onset of DR and as a possible prognostication tool in diabetic eyes. Future prospective longitudinal studies in diabetic eyes would be useful in establishing the relationship between CVIs of Haller's and Sattler's layer with visual acuity as a marker of photoreceptor health and visual prognosis.

Polypoidal Choroidal Vasculopathy: Consensus Nomenclature and Non-Indocyanine Green Angiograph Diagnostic Criteria from the Asia-Pacific Ocular Imaging Society PCV Workgroup

PURPOSE

To develop consensus terminology in the setting of polypoidal choroidal vasculopathy (PCV) and to develop and validate a set of diagnostic criteria not requiring indocyanine green angiography (ICGA) for differentiating PCV from typical neovascular age-related macular degeneration (nAMD) based on a combination of OCT and color fundus photography findings.

DESIGN

Evaluation of diagnostic test results.

PARTICIPANTS

Panel of retina specialists.

METHODS

As part of the Asia-Pacific Ocular Imaging Society, an international group of experts surveyed and discussed the published literature regarding the current nomenclature and lesion components for PCV, and proposed an updated consensus nomenclature that reflects our latest understanding based on imaging and histologic reports. The workgroup evaluated a set of diagnostic features based on OCT images and color fundus photographs for PCV that may distinguish it from typical nAMD and assessed the performance of individual and combinations of these non-ICGA features, aiming to propose a new set of diagnostic criteria that does not require the use of ICGA. The final recommendation was validated in 80 eyes from 2 additional cohorts.

MAIN OUTCOME MEASURES

Consensus nomenclature system for PCV lesion components and non-ICGA-based criteria to differentiate PCV from typical nAMD.

RESULTS

The workgroup recommended the terms polypoidal lesion and branching neovascular network for the 2 key lesion components in PCV. For the diagnosis of PCV, the combination of 3 OCT-based major criteria (sub-retinal pigment epithelium [RPE] ring-like lesion, en face OCT complex RPE elevation, and sharp-peaked PED) achieved an area under the receiver operating characteristic curve of 0.90. Validation of this new scheme in a separate subset 80 eyes achieved an accuracy of 82%.

CONCLUSIONS

We propose updated terminology for PCV lesion components that better reflects the nature of these lesions and is based on international consensus. A set of practical diagnostic criteria applied easily to spectral-domain OCT results can be used for diagnosing PCV with high accuracy in clinical settings in which ICGA is not performed routinely.

Analysis of choroidal morphology and comparison of imaging findings of subtypes of polypoidal choroidal vasculopathy: a new classification system

AIM

To classify polypoidal choroidal vasculopathy (PCV) into 2 subtypes based on the subfoveal choroidal thickness (SFCT) and to further evaluate their multimodal image features.

METHODS

A retrospective observational case series study. Sixty-four eyes of 64 patients with PCV were enrolled and classified into 2 groups based on SFCT (thick-choroid group/thin-choroid group). Then further analyze the spectrum domain optical coherence tomography (SD-OCT) and indocyanine green angiography (ICGA) differences of the two subtypes. Imaging analysis included measurement of SFCT, maximum vascular diameter ratio (MVDR), choroidal vascularity index (CVI), central macular thickness (CMT), and the presence of pigment epithelial detachment (PED) on SD-OCT. Polypoidal lesions (polyps) number, branching vascular network (BVN) area, greatest linear dimension (GLD), and the choroidal vascular hyperpermeability (CVH) were analyzed by ICGA.

RESULTS

The distribution of SFCT was bimodal with two peaks at 195 and 285 µm, and a trough at 225 µm. The 225 µm was taken as the cutoff point for the following classification of thick/thin choroid groups. The PCV eyes in the thick-choroid group presented with greater MVDR, CVI within 3 and 6 mm of the fovea, but lower CMT, less PED, small PED diameters on SD-OCT scans, and fewer polyps, smaller BVN and GLD, but more frequency of CVH on ICGA.

CONCLUSION

The SFCT at 225 µm can be used as a readily available indicator for the classification of PCV subtypes. The thick-choroid group presents much apparent enlargement of the choroidal layer and vasculature expansion, which indicates different pathogenesis of the two subtypes.

Microglia Contribution to the Regulation of the Retinal and Choroidal Vasculature in Age-Related Macular Degeneration

The retina is a highly metabolically active tissue with high-level consumption of nutrients and oxygen. This high metabolic demand requires a properly developed and maintained vascular system. The retina is nourished by two systems: the central retinal artery that supplies the inner retina and the choriocapillaris that supplies the outer retina and retinal pigment epithelium (RPE). Pathological neovascularization, characterized by endothelial cell proliferation and new vessel formation, is a common hallmark in several retinal degenerative diseases, including age-related macular degeneration (AMD). A limited number of studies have suggested that microglia, the resident immune cells of the retina, have an important role not only in the pathology but also in the formation and physiology of the retinal vascular system. Here, we review the current knowledge on microglial interaction with the retinal vascular system under physiological and pathological conditions. To do so, we first highlight the role of microglial cells in the formation and maintenance of the retinal vasculature system. Thereafter, we discuss the molecular signaling mechanisms through which microglial cells contribute to the alterations in retinal and choroidal vasculatures and to the neovascularization in AMD.

Comparison of choriocapillary flow density between fellow eyes of polypoidal choroidal vasculopathy and neovascular age-related macular degeneration

Background

To compare the choriocapillary flow density (CFD) among the fellow eyes of polypoidal choroidal vasculopathy (PCV), neovascular age-related macular degeneration (nAMD), and healthy controls using spectral-domain optical coherence angiography tomography (SD-OCTA).

Methods

This is a cross-sectional study that includes the fellow eyes of 38 patients with unilateral PCV, 36 patients with unilateral nAMD, and 36 eyes from 36 healthy volunteers. The PCV group was further classified into polypoidal CNV (P-CNV) and typical PCV (T-PCV) for subgroup analysis. The age, subfoveal choroidal thickness (SFCT), Age-Related Eye Disease Study (AREDS) classification, and fellow eye diagnosis were acquired. All subjects underwent SD-OCTA with a 6.0-mm scan pattern. Circles with radius of 1.00, 1.50, and 3.00 mm were manually selected in the choriocapillaris (CC) slab, and the CFD was calculated as the percentage of the flow area to the whole selected area as CFD-1.00, 1.50, and 3.00, respectively. Univariate and multivariate analysis were performed to study the correlation between the aforementioned factors with CFD.

Results

The mean CFD-1.00, 1.50, and 3.00 of the nAMD group were 61.51, 63.18, and 66.20, respectively; these were significantly lower than those of the PCV group (65.90, 66.89, and 67.94; P < 0.001, P < 0.001, and P = 0.010; respectively) and control group (66.28, 66.96, and 68.42; P < 0.001, P < 0.001, and P = 0.001, respectively), and no difference was detected between the PCV and control group or between PCV subtypes. The AREDS classification and fellow eye diagnosis were correlated with CFD in univariate analysis; however, only the fellow eye diagnosis showed a significant correlation after multiple linear regression.

Conclusions

The CFD of nAMD fellow eyes was significantly lower than that of PCV and control eyes, and no difference was detected between PCV and control group, indicating that CC loss plays a different role in the early pathogenesis of nAMD and PCV.

Analysis of Choroidal Thickness in Children with Congenital Aniridia

Purpose: To evaluate the choroidal thickness (CT) in children with congenital aniridia in comparison with age-matched controls. Methods: This was a cross-sectional, observational study that included 64 eyes of 32 children with congenital aniridia (aged 5-12 years) and 80 eyes of 40 healthy subjects who were age-matched. In all subjects, subfoveal choroidal thickness (SFCT) was assessed at 750-μm intervals from the fovea to 1.5 mm in the temporal and nasal directions with spectral-domain optical coherence tomography (SD-OCT). Results: The mean SFCT was 207.67 ± 30.99 µm in the aniridic eyes. This SFCT was significantly thinner than that in control eyes (288.55 ± 30.06 µm) (P < .001). The SFCTs at 1.5 mm and 0.75 mm intervals in the temporal and nasal directions from the fovea were also significantly thinner in eyes with aniridia than control eyes (P < .001).There was a significant negative correlation between the SFCT and axial length in eyes with aniridia (B = -10.60, 95%CI = -19.31~-1.89, P = .017). Conclusions: The subfoveal and parafoveal CTs were significantly thinner in eyes with congenital aniridia than in control eyes. These choroidal changes could open up a new way for the research related to the pathophysiology of congenital aniridia.

Choroidal Vascularity Index: An In-Depth Analysis of This Novel Optical Coherence Tomography Parameter

Remarkable improvements in optical coherence tomography (OCT) technology have resulted in highly sophisticated, noninvasive machines allowing detailed and advanced morphological evaluation of all retinal and choroidal layers. Postproduction semiautomated imaging analysis with dedicated public-domain software allows precise quantitative analysis of binarized OCT images. In this regard, the choroidal vascularity index (CVI) is emerging as a new imaging tool for the measurement and analysis of the choroidal vascular system by quantifying both luminal and stromal choroidal components. Numerous reports have been published so far regarding CVI and its potential applications in healthy eyes as well as in the evaluation and management of several chorioretinal diseases. Current literature suggests that CVI has a lesser variability and is influenced by fewer physiologic factors as compared to choroidal thickness. It can be considered a relatively stable parameter for evaluating the changes in the choroidal vasculature. In this review, the principles and the applications of this advanced imaging modality for studying and understanding the contributing role of choroid in retinal and optic nerve diseases are discussed. Potential advances that may allow the widespread adoption of this tool in the routine clinical practice are also presented.

Comparison of OCT and OCTA manifestations among untreated PCV, neovascular AMD, and CSC in Chinese population

AIM

To compare the qualitative and quantitative features among untreated polypoidal choroidal vasculopathy (PCV), neovascular age-related macular degeneration (nv-AMD) and central serous chorioretinopathy (CSC) using optical coherence tomography (OCT) and OCT angiography (OCTA).

METHODS

This retrospective study included 16 eyes with thin-choroid PCV, 18 eyes with thick-choroid PCV, 16 eyes with nv-AMD and 17 eyes with CSC, respectively. The indicators were obtained by OCT and OCTA.

RESULTS

Sub-foveal choroidal thickness (SFCT) in CSC was thicker compared to other groups (all P<0.05). SFCT in nv-AMD was thicker compared to thin-choroid PCV, but thinner compared with thick-choroid PCV (both P<0.05). As the ratio of thickness of Haller's layer to thickness of SFCT, which of thin-choroid PCV was significantly higher than CSC (P<0.001). Likewise, thick-choroid PCV had significantly higher ratio than nv-AMD (P=0.016) or CSC (P<0.001). There were differences among them in pigment epithelium detachment (PED). The whole-superficial retinal vessel density (RVD), deep RVD and choroidal capillary vessel density (CCVD) in CSC were significantly higher compared to other three groups, respectively (all P<0.05). The whole CCVD in nv-AMD was higher compared to thick-choroid PCV (P=0.032). Cross-sectional local angiographic form was 87.50%, 83.33%, 0 and 35.29% in thin-choroid PCV, thick-choroid PCV, nv-AMD and CSC, respectively. Cross-sectional diffuse angiographic form was 12.50%, 16.67%, 100% and 5.88% in thin-choroid PCV, thick-choroid PCV, nv-AMD and CSC, respectively.

CONCLUSION

Combination of OCT and OCTA can effectively observe the significant alterations existed in PCV, CSC and nv-AMD, and there are distinctive differences among them. The pathogenesis is not exactly the same between PCV and nv-AMD, or PCV and CSC.

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.

Short-term effect on the ocular circulation induced by unilateral intravitreal injection of aflibercept in age-related maculopathy

Purpose

Intravitreal injection of anti‐vascular endothelial growth factor (anti‐VEGF) is the standard treatment for neovascular age‐related macular degeneration (AMD). As VEGF is a physiological key player for regulating retinal vascular tone, questions have been raised whether the application of anti‐VEGF could induce alterations in ocular perfusion.

Methods

The study included 20 eyes from 20 Caucasian patients with unilateral neovascular AMD and 20 fellow eyes. All eyes were treated with standard intravitreal injection of aflibercept (IVA). Measurements of blood flow at the optic nerve head (ONH) and the choroid were performed with laser speckle flowgraphy (LSFG). The intraocular pressure (IOP), systolic and diastolic blood pressure, heart rate, mean arterial pressure (MAP) and ocular perfusion pressure (OPP) were analysed. Measurements were performed at baseline and repeated immediately after the injection and 30 and 45 min later.

Results

Mean time between injection of aflibercept and first follow‐up was 8:56 ± 4:25 min. The injection led to significant rise in IOP. In the injected eyes, mean blur rate (MBR, i.e. a relative measure of perfusion and the main outcome parameter of LSFG) within the major vessels of the ONH as well as at the entire ONH region decreased significantly (p < 0.001). No change in MBR was observed in the fellow eye. Choroidal blood flow was maintained stable in both eyes.

Conclusion

Intravitreal injection of aflibercept (IVA) led to a short‐term reduction in perfusion only in the treated eye. This was independent from IOP, indicating a direct pharmacological effect. No changes in choroidal perfusion were observed during the first 45 min after the injection.

Choroidal binarization analysis: clinical application

INTRODUCTION

Image processing of optical coherence tomography scans through binarization techniques represent a non-invasive way to separately asses and measure choroidal components, in vivo. In this review, we systematically search the scientific literature regarding binarization studies published so far.

METHODS

A systematic research was conducted at PubMed database, including English literature articles for all of the following terms in various combinations: binarization, choroid/al, enhanced depth spectral domain/swept source optic coherence tomography, and latest publications up to November 2018 were reviewed.

RESULTS

Thirty-seven articles were included and analyzed regarding studied disease, binarization method, studied variables, and outcomes. Most of the studies have focused on the more common retinal pathologies, such as age-related macular degeneration, central serous chorioretinopathy and diabetic retinopathy but binarization techniques have also been applied to the study of choroidal characteristics in ocular inflammatory diseases, corneal dystrophies and in postsurgical follow-up. Advantages and disadvantages of binarization techniques are also discussed.

CONCLUSION

Binarization of choroidal images seems to represent a promising approach to study choroid subcomponents in an increasingly detailed manner.

Effects of three intravitreal injections of aflibercept on the ocular circulation in eyes with age-related maculopathy

AIMS

To investigate changes in ocular perfusion following three consecutive intravitreal injections with aflibercept for treatment of neovascular age-related macular degeneration (nAMD).

METHODS

The study included 20 eyes from 20 Caucasian patients with unilateral nAMD and 20 fellow eyes. All nAMD eyes were treated with standard intravitreal injection of aflibercept (IVA; 2 mg). Measurements of ocular perfusion at the optic nerve head (ONH) and the choroid were performed with laser speckle flowgraphy (LSFG). Measurements were conducted at baseline, 1 week after the first injection, at the time point of the second and third injection as well as 1 month after the third injection.

RESULTS

In treated eyes, mean blur rate (the main output parameter of LSFG) in the ONH microvasculature and in the choroid was significantly reduced 1 week after the first IVA treatment. The effect persisted throughout the entire follow-up period (p<0.001). No change in ocular perfusion was observed in fellow eyes.

CONCLUSIONS

IVA for treatment of nAMD leads to a reduction in perfusion of the ONH and the choroid in the treated eye with no apparent effect on the fellow eye.

The Utility of Frame Averaging for Automated Algorithms in Analyzing Retinal Vascular Biomarkers in AngioVue OCTA

Purpose

This study proposes an optical coherence tomography angiography (OCTA) frame-averaging method and investigates the effects of the number of frames acquired and averaged on metrics quantifying the foveal avascular zone (FAZ), vessel morphology, and parafoveal intercapillary area (PICA).

Methods

Ten OCTA frames were acquired for each of the 19 subjects without known retinal disease using the AngioVue OCTA system. For each subject, acquired frames were ranked by an image quality metric. A subset of frames was then registered and averaged. The effects of the number of frames acquired and averaged on FAZ segmentation and metrics of FAZ geometry, vessel morphology, and PICA were analyzed.

Results

Frame averaging increased the accuracy of the automatically segmented FAZ region; for example, the absolute error in FAZ area decreased from 0.026 mm² (1 frame) to 0.005 mm² (5 frames). Averaging multiple frames exponentially decreased the estimated number of vessel endpoints and increased the average vessel length with a 32% decrease in number of endpoints and 14% increase in average vessel length when averaging five frames compared with one. Frame averaging also improved the precision of PICA estimates.

Conclusions

Averaging multiple OCTA frames using the Optovue AngioVue system reduced error in FAZ segmentation and improved the robustness of OCTA vessel morphology and perfusion metrics. The study demonstrated limited benefit in acquiring and averaging more than five frames.

Translational Relevance

Averaging multiple OCTA frames improved the robustness of OCTA foveal biomarkers with limited benefit when averaging more than five frames.

Pachychoroid disease

Pachychoroid is a relatively novel concept describing a phenotype characterized by attenuation of the choriocapillaris overlying dilated choroidal veins, and associated with progressive retinal pigment epithelium dysfunction and neovascularization. The emphasis in defining pachychoroid-related disorders has shifted away from simply an abnormally thick choroid (pachychoroid) toward a detailed morphological definition of a pathologic state (pachychoroid disease) with functional implications, which will be discussed in this review. Several clinical manifestations have been described to reside within the pachychoroid disease spectrum, including central serous chorioretinopathy, pachychoroid pigment epitheliopathy, pachychoroid neovasculopathy, polypoidal choroidal vasculopathy/aneurysmal type 1 neovascularization, focal choroidal excavation, peripapillary pachychoroid syndrome. These conditions all exhibit the characteristic choroidal alterations and are believed to represent different manifestations of a common pathogenic process. This review is based on both the current literature and the clinical experience of our individual authors, with an emphasis on the clinical and imaging features, management considerations, as well as current understanding of pathogenesis of these disorders within the context of the recent findings related to pachychoroid disease.

Polypoidal choroidal vasculopathy: An update on current management and review of literature

Polypoidal choroidal vasculopathy (PCV) is a subtype of neovascular age-related macular degeneration (nAMD), commonly seen in the Asian population. It is dissimilar in epidemiology, genetic heterogeneity, pathogenesis, natural history, and response to treatment in comparison to nAMD. Confocal scanning laser ophthalmoscopy-based simultaneous fluorescein angiography and indocyanine green angiography, spectral-domain optical coherence tomography (OCT) with enhanced depth imaging, swept-source OCT, and OCT angiography have improved the ability to detect PCV, understand its pathology, and monitor treatment response. A plethora of literature has discussed the efficacy of photodynamic therapy, anti-vascular endothelial growth factor (VEGF) monotherapy, and combination of both, but only a few studies with higher level of evidence and limited follow-up duration are available. This review discusses the understanding of PCV with respect to epidemiology, pathogenesis, clinical features, natural history, imaging techniques, and various treatment options. Recent clinical trials (EVEREST-II and PLANET study) have emphasized that either anti-VEGF monotherapy or combination treatment is equally capable to strike a balance between polyp regression and stabilization of visual acuity. The recurrent nature of the disease, the development of macular atrophy, and the long-term poor visual prognosis despite treatment are concerns that open avenues for further research.

Choroidal Remodeling in Age-related Macular Degeneration and Polypoidal Choroidal Vasculopathy: A 12-month Prospective Study

Choroid thinning occurs in age-related macular degeneration (AMD). However, it remains unclear whether the reduction is due to reduction in choroidal vessels or shrinkage of choroidal stroma, or both. The purpose of this study was to evaluate the changes of the choroidal vascular and stromal area in 118 patients with typical AMD (t-AMD) and polypoidal choroidal vasculopathy (PCV) over a 12-month period. We used spectral-domain optical coherence tomography (SD-OCT) with enhanced depth imaging (EDI) mode to measure the subfoveal choroidal thickness (CT), central retinal thickness (CRT) and choroidal vascularity index (CVI - ratio of luminal area to total choroidal area). At baseline, PCV eyes had higher CRT (471.6 µm vs 439.1 µm, p = 0.02), but comparable subfoveal CT and CVI, compared to t-AMD. Eyes with high CVI at baseline showed marked reduction in stromal area compared with eyes with average or low CVI. Over 12 months, CRT and subfoveal CT significantly decreased (p < 0.001) in both subtypes. Eyes with high baseline CVI showed significant CVI reduction from baseline to month 12 (p < 0.001), whereas eyes with average to low baseline CVI showed increase in CVI. These differences in choroidal vascularity may reflect different predominant pathogenic processes and remodeling in AMD eyes with varying spectrum.

Characterization of Choroidal Morphologic and Vascular Features in Young Men With High Myopia Using Spectral-Domain Optical Coherence Tomography

PURPOSE

To describe detailed morphologic and vascular features of the choroid in eyes with high myopia.

DESIGN

Cross-sectional study.

METHODS

A total of 515 eyes of young men (mean age 21.59 ± 1.15 years) with high myopia (defined as -6.0 diopter [D] or worse, mean spherical equivalent -8.66 ± 2.00 D) and 88 controls with emmetropia in both eyes underwent choroidal imaging using spectral-domain optical coherence tomography with enhanced depth imaging (EDI-OCT). Raw OCT images were loaded on a custom-written application on MATLAB that enabled delineation for detailed morphologic and vascular analyses, including the distance of thickest point from the foveal center, choroidal thickness, choroidal volume, choroidal vascular and stromal areas within the macular (6 mm) and foveal (1.5 mm) regions, and choroidal vascularity, which was determined by dividing vascular area by total choroidal area.

RESULTS

The choroid in high myopic eyes was thickest temporally compared to subfoveal location in emmetropic subjects (thickest point distance from fovea: -1.51 ± 1.42 mm vs -0.53 ± 1.06 mm, P < .001). In eyes with high myopia, after adjusting for age, choroidal vascular and stromal areas were significantly lower (vascular area: β = -0.306, stromal area: β = -0.377, both P < .001) than control eyes with emmetropia at the macular region. Compared to control eyes with emmetropia, choroidal vascularity was greater in eyes with high myopia (β = 0.032, P < .001). Similar results were observed for the subfoveal region.

CONCLUSION

Our study suggests that choroidal thinning in eyes with high myopia is associated with the reduction in both its stromal and vascular components.