The Choroid and Optical Coherence Tomography

Short-term Effect of Strabismus Surgery on Choroidal Vasculature

PURPOSE

To investigate the effect of strabismus surgery on choroidal structure using the binarization method.

METHODS

Forty-two eyes of 27 patients who had surgery for horizontal strabismus were included in the study. Optical coherence tomography (OCT) images of the patients before the operation and at 1 day and 1 week after the operation were binarized. Total choroidal area (TCA), stromal area (SA), luminal area (LA), and choroidal vascularity index (CVI) were calculated and compared.

RESULTS

The mean age of the patients was 16.7 ± 13.5 years; 12 were female, and 15 were male. The mean spherical equivalent was 0.125 ± 0.50 diopters (D). The mean axial length value was 23.3 ± 1.3 mm. Preoperative TCA was 599686 ± 113451, LA was 394259 ± 67259, SA was 209180 ± 47723, and CVI was 0.66 ± 0.02. At 1 day postoperatively, TCA was 615575 ± 103686, LA was 395364 ± 60314, SA was 218418 ± 45620, and CVI was 0.65 ± 0.02. At 1 week postoperatively, TCA was 610997 ± 110578, LA was 394002 ± 65186, SA was 214995 ± 46481, and CVI was 0.66 ± 0.04. A statistically significant decrease in CVI and increase in TCA and SA were observed on the first postoperative day; these changes were observed as returning to preoperative values at 1 week postoperatively.

CONCLUSIONS

Strabismus surgery temporarily decreases the CVI by increasing the SA of the choroidal layer, possibly due to hemodynamic changes and/or inflammatory causes in the early period. [J Pediatr Ophthalmol Strabismus. 2024;61(2):114-119.].

The Haemodialysis Session Effect on the Choroidal Thickness and Retinal and Choroidal Microcirculation-A Literature Review

Haemodialysis (HD) is currently the most commonly used method of renal replacement therapy. The process of dialysis involves numerous changes that affect many systems, including the eye. The changes occurring in the course of HD may affect the ocular parameters, such as intraocular pressure, central corneal thickness, retinal thickness, retinal nerve fibre layer thickness, and choroidal thickness (CT). The choroid, being one of the most vascularized tissues, is characterized by the highest ratio of blood flow to tissue volume in the entire body, may be particularly susceptible to changes occurring during HD, and at the same time reflect the microcirculatory status and its response to HD. Patients with end-stage renal disease subjected to dialysis are highly susceptible to systemic microvascular dysfunction. Moreover, it is considered that the process of HD itself contributes to vascular dysfunction. Nowadays, thanks to the development of imaging techniques, the widely available optical coherence tomography (OCT) tests allow for the assessment of CT, while OCT-angiography allows for a quick, non-invasive, and repeatable assessment of the condition of retinal and choroidal microcirculation, which significantly expands our knowledge regarding the reaction of ocular microcirculation due to HD. The assessment of both retinal and choroidal circulation is even more attractive because retinal circulation is autoregulated, while choroidal circulation is mainly controlled by extrinsic autonomic innervation. Thus, assessment of the choroidal response to an HD session may provide the possibility to indirectly evaluate the functions of the autonomic system in patients subjected to HD. At a time when the importance of microcirculation in systemic and renal diseases is becoming increasingly evident, the assessment of ocular microcirculation appears to be a potential biomarker for assessing the condition of systemic microcirculation. In this work, we present a review of the literature on the effect of the HD session on CT and the retinal and choroidal microcirculation.

Retinal astrocytic hamartoma complicated by branch retinal vein occlusion in a patient with tuberous sclerosis complex

Purpose

To report a case with branch retinal vein occlusion secondary to a retinal astrocytic hamartoma in a patient with tuberous sclerosis complex.

Observations

A fourteen-year-old boy, a known case of tuberous sclerosis complex, with multiple bilateral retinal astrocytic hamartomas was followed by 6 months intervals. In his last follow-up, 6 months after initial presentation, the patient developed angiographic signs of branch retinal vein occlusion (BRVO) in the superotemporal arcade of the right eye distal to one of the retinal astrocytic hamartomas. He underwent targeted retinal laser photocoagulation. No secondary complication related to BRVO was observed during the next six-month follow-up.

Conclusion

And Importance: Although the co-occurrence of branch retinal vein occlusion and astrocytic hamartoma may represent an incidental finding, awareness of BRVO as a possible complication associated with retinal astrocytic hamartoma helps timely diagnosis and prompt treatment of this complication, improving the visual prognosis of these patients.

Evaluation of peripapillary choroidal vascularity index in young smokers

Purpose: This retrospective study aimed to compare the peripapillary choroidal vascularity index (CVI) between young smokers who smoked less than 5 packs/year and non-smokers.Methods: The study included 52 smokers and 67 non-smokers, and comprehensive eye examinations were performed on all participants. Axial lengths (AL) were measured, and peripapillary enhanced depth imaging optical coherence tomography (EDI-OCT) images were obtained and evaluated using the Open Source ImageJ software. The CVI, total choroidal area (TCA), luminal area (LA), stromal area (SA), and retinal nerve fibre layer (RNFL) quadrants were compared between the two groups.Results: The mean age of the smokers was 23.76 ± 1.84 years, and for non-smokers, it was 23.98 ± 2.18 years. The mean peripapillary CVI for smokers was 0.65 ± 0.08, and for non-smokers, it was 0.67 ± 0.03. No statistically significant difference in CVI was observed between the two groups. However, statistically significant differences were found in the temporal inferior (TI), temporal superior (TS), nasal inferior (NI), and nasal superior (NS) quadrants of the RNFL between the two groups (p < 0.05). There was no correlation between the number of packs/year and CVI values in the smoking group (r = 0.031, p = 0.826).Conclusion: The study revealed no significant difference in CVI among young smokers who smoked less than 5 packs/year compared to non-smokers. However, there was a statistically significant decrease in the TI, TS, NI, and NS quadrants of the RNFL in early-age smokers.

Compare of optic coherence tomography parameters in recreational synthetic tetrahydrocannabinol use and healthy control

PURPOSE

To evaluate retinal thickness (RT), retinal nerve fiber layer thickness (RNFLT), and choroidal thickness (CT) changes in synthetic cannabinoid (SC) users.

METHODS

This prospective study evaluated the RT, RNFLT, and CT values of 56 SC users and 58 healthy controls. The individuals using SCs were referred to us by our hospital's forensic medicine department. Retinal and choroidal images were obtained using spectral-domain optical coherence tomography (OCT). Measurements (one subfoveal, three temporals, three nasal) were taken at 500 μm intervals up to 1500 μm using the caliper system. Only the right eye was used for subsequent analysis.

RESULTS

Mean ages were 27.7 ± 5.7 years in the SC-user group and 25.4 ± 6.7 in the control group. Subfoveal Global RNFLT was in the SCs group 102.3 ± 10.5 μm and 105.6 ± 20.2 μm in the control group (p = 0.271). Subfoveal CT was in the SC group mean of 316.1 ± 100.2 μm and in the control group mean 346.4 ± 81.8 μm (p = 0.065). RT, T500 (283.3 ± 36.7 μm, 296.6 ± 20.5 μm, p = 0.011) and N1500 (355.1 ± 14.3 μm, 349.3 ± 18.1 μm, p = 0.049) were significantly higher in the SC group than in the control group, respectively.

CONCLUSION

Analysis of OCT findings of individuals who had been using SC for more than one year revealed no statistically significant difference between RNFLT and CT, although N1500 was significantly higher in RT. Further studies in the field of OCT are important to explore the pathology of SC.

Choroidal Microvascular Alterations in COVID-19 Patients

OBJECTIVE

To evaluate alterations in the choroidal angioarchitecture of COVID-19 patients using optical Coherence Tomography (OCT) based surrogate markers.

METHODS

This prospective case-control study recruited 56 COVID-19 patients (111 eyes) and 61 healthy individuals (120 eyes). Choroidal thickness (CT) and Choroidal vascularity index (CVI) were derived from OCT images using a purpose-built automated software for choroidal image segmentation. A linear mixed model with age and gender as covariates was employed to compare CVI and CT between groups.

RESULTS

COVID-19 patients had significantly higher subfoveal (81.3um vs 86.8um, p = .02), temporal (78.8um vs 84.3um, p = .005), nasal (87.5um vs 95.1um, p = .001) and average CT (82.5um vs 88.7um, p = .001). COVID-19 patients had significantly lower subfoveal (64.0 vs 63.5, p = .02) and average CVI (63.5 vs 63.1, p = .02).

CONCLUSION

COVID-19 results in significantly thicker choroid with reduced relative vascularity. This may be attributable to increased vascular permeability secondary to inflammation, resulting in choroidal stromal edema.

Microvascular and structural analysis of the retina and choroid in heart failure patients with reduced ejection fraction

This cross-sectional study was designed to assess alterations of choroidal and retinal microvasculature in patients with Heart Failure with Reduced Ejection Fraction (HFrEF) and compare them with a normal age and sex-matched population. Fifty-two eyes of 26 patients with HFrEF (left ventricular ejection fraction [LVEF] < 40%) and 64 eyes of 32 healthy individuals were considered as the patient and the control groups, respectively. We found no statistically significant differences in age-adjusted mean central macular thickness (CMT), superficial or deep retinal capillary plexus vascular densities, and choriocapillaris flow (CC flow) density between the HFrEF group and the normal controls, with the exception of the parafoveal mean superficial capillary plexus vascular density (P = 0.023), which remained statistically significant after adjusting for age (P = 0.034). The patients with HFrEF had a significantly lower subfoveal choroidal thickness (SFCT) than the normal subjects (264 ± 82 vs 313 ± 72; P = 0.009), and the difference was still statistically significant after age adjustment (P = 0.026). Although choroidal vascularity index (CVI) was lower in the HFrEF group than in the control group, the difference was not statistically significant before and after age adjustment (73.45 ± 6.67 vs 75.77 ± 5.92; P = 0.118 and P = 0.096, respectively). In conclusion, in patients with HFrEF, we observed a reduction in parafoveal retinal VD in the superficial capillary plexus, as well as SFCT, but no significant change in CVI, CMT, or CC flow density.

Effect of Nasal Septum Deviation on the Choroidal Thickness

INTRODUCTION

Nasal cavity blood circulation and ocular blood circulation have common pathways for both arterial blood supply and venous drainage. Therefore, nasal pathologies can affect ocular blood circulation. This study aimed to evaluate the relationship between nasal obstruction and choroidal thickness.

METHODS

A prospective study was planned by forming a group of 144 patients diagnosed with nasal septum deviation at the otorhinolaryngology clinic and 100 healthy voluntary individuals. Of the total, 69 patients with nasal right septum deviation were evaluated as Group 1, 75 patients with nasal left septum deviation as Group 2, and 100 healthy volunteers as the control group. Detailed ophthalmological examinations of all the participants were performed, and choroidal thickness was measured using spectral domain optical coherence tomography. The relationship between choroidal thickness and ocular parameters was evaluated and compared between the patient groups with nasal septum deviation and the control group.

RESULTS

When the choroidal thickness measurements of the patients in Group 1 were examined, the choroidal thickness increased in all the regions in the eye contralateral to the deviation side (left), and intraocular pressure (IOP) was higher compared to the eye on the deviation side (right) and the control group at a statistically significant level. In Group 2, the choroidal thickness measurements increased in all the regions in the eye contralateral to the deviation side (right), and IOP was higher compared to the deviation side (left) and the control group.

CONCLUSIONS

We found that the patients with nasal septum deviation had higher choroidal thickness and IOP values in the eye contralateral to deviation.

Effect of inferior oblique muscle myomectomy on choroidal and macular thicknesses in strabismus

BACKGROUND

In this study, we aimed to determine postoperative changes in macular and choroidal thicknesses in patients who underwent inferior oblique myomectomy.

METHODS

The study included 54 eyes of 44 patients who underwent inferior oblique muscle myectomy between January 2018 and April 2022. Visual acuity and macular and choroidal thickness measurements were performed preoperatively and postoperatively (day 1, week 1, month 1, and month 3).

RESULTS

When the choroidal thickness measurements were examined, it was determined that choroidal thicknesses decreased especially in the nasal and subfoveal regions on the first day and at the first week after surgery (p < 0.05) but approached their preoperative values ​​at the first- and third-month evaluations (p > 0.05). The macular thickness measurements revealed an increase in all macular regions on the first day and at the end of the first week (p < 0.05) and approached their preoperative values ​​at the end of the first and third months (p > 0.05).

CONCLUSIONS

In this study, although choroidal thicknesses decreased in the early postoperative period in patients who had undergone inferior oblique myomectomy, there was an increase in macular thicknesses. However, at the third postoperative month, choroid and macular thicknesses were found to be similar to the preoperative values​.

The impact of obesity on ocular hemodynamics and choroidal thickness

Background

Obesity affects microvascular structures. The effect of obesity on the ocular vascular system can be evaluated by changes in the choroidal thickness (CT) and retrobulbar blood flow (RBF).

Objectives

To evaluate the CT and RBF parameters in obese patients with various body mass index (BMI) values and compare these parameters with normal weight, healthy subjects.

Design

A prospective study.

Methods

The study included 102 eyes of 102 female patients. Patients were divided into three groups according to BMI as group 1 with a BMI of 18.5-24.99 (n = 32), normal weight group; group 2 with a BMI of 30-34.99 (n = 35), as obese class I; and group 3 with a BMI of 35-39.99 (n = 35), as obese class II. The peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index, and pulsatility index values of the central retinal artery (CRA) and ophthalmic artery (OA) were evaluated with color Doppler ultrasonography. CT was measured at the subfoveal area and at 500-µm intervals nasal and temporal to the fovea up to a distance of 1500 µm by using the enhanced depth imaging technique of optical coherence tomography. Intraocular pressure (IOP) was measured with a Goldmann applanation tonometry.

Results

There was a significant difference in IOP values within the groups with the highest values in group 3 (17.6 ± 2.1 mmHg) and the lowest in group 1 (12.4 ± 1.7 mmHg). The CT in groups 2 and 3 was found to be statistically significantly lower than that in group 1 at all measurement points (p < 0.001). There was a statistically significant negative correlation between CT at all measurement points and BMI (p < 0.001). The mean CRA PSV, EDV, and OA EDV values were statistically significantly lower in each obese group than those values in group 1 (p < 0.001). The OA PSV values were significantly lower in group 3 (36.5 ± 5.9 cm/s) than those in group 2 (43.8 ± 4 cm/s) and group 1 (44.6 ± 5.2 cm/s) (p < 0.001). Also, significant associations were found between BMI and CRA PSV, CRA EDV, and OA PSV values (p < 0.001).

Conclusion

Obesity may predispose to eye pathologies by changing the ocular vascular circulation.

Evaluation of Choroidal Vascularity Index in Keratoconus Patients: Does Choroidal Vascularity Change in Keratoconus?

Purpose

To investigate the choroidal structure in keratoconic patients with different severity using the choroidal vascularity index (CVI) derived from image binarization on enhanced depth imaging optical coherence tomography scans (EDI-OCT).

Methods

Sixty-eight eyes from 34 keratoconus (KCN) patients and 72 eyes from 36 healthy subjects were recruited in this prospective, noninterventional, comparative cross-sectional study. EDI-OCT was employed to measure choroidal parameters, including choroidal thickness (CT), total choroidal area (TCA), luminal area, stromal area, and CVI.

Results

Subfoveal CT was 354.6 ± 66.8 μm in the control group and 371 ± 64.5 μm in the KCN group (P = 0.86). There was no significant difference between control and KCN groups in terms of TCA (0.66 ± 0.14 mm2 vs. 0.7 ± 0.12 mm2; P = 0.70), luminal area (0.49 ± 0.10 mm2 vs. 0.53 ± 0.08 mm2; P = 0.67), and stromal area (0.16 ± 0.05 mm2 vs. 0.17 ± 0.05 mm2; P = 0.84). CVI was also comparable in the control group (75.4% ±3.4%) and the KCN group (75.6% ±4.5%; P = 0.43). There was also no significant correlation between other choroidal parameters and KCN severity indices.

Conclusion

It seems that CVI as well as other choroidal biomarkers were not significantly different between patients with KCN and healthy subjects.

Synergistically segmenting choroidal layer and vessel using deep learning for choroid structure analysis

Objective. The choroid is the most vascularized structure in the human eye, whose layer structure and vessel distribution are both critical for the physiology of the retina, and disease pathogenesis of the eye. Although some works have used graph-based methods or convolutional neural networks to separate the choroid layer from the outer-choroid structure, few works focused on further distinguishing the inner-choroid structure, such as the choroid vessel and choroid stroma. Approach. Inspired by the multi-task learning strategy, in this paper, we propose a segmentation pipeline for choroid analysis which can separate the choroid layer from other structures and segment the choroid vessel synergistically. The key component of this pipeline is the proposed choroidal U-shape network (CUNet), which catches both correlation features and specific features between the choroid layer and the choroid vessel. Then pixel-wise classification is generated based on these two types of features to obtain choroid layer segmentation and vessel segmentation. Besides, the training process of CUNet is supervised by a proposed adaptive multi-task segmentation loss which adds a regularization term that is used to balance the performance of the two tasks. Main results. Experiments show the high performance (4% higher dice score) and less computational complexity (18.85 M lower size) of our proposed strategy. Significance. The high performance and generalization on both choroid layer and vessel segmentation indicate the clinical potential of our proposed pipeline.

The effect of branch retinal vein occlusion on the vascular structure of the choroid

OBJECTIVE

Our aim is to examine choroidal structural changes in eyes with branch retinal vein occlusion (BRVO).

MATERIAL AND METHOD

This retrospective, comparative study included 34 newly diagnosed unilateral BRVO patients and 40 healthy controls. Subfoveal choroidal thickness (SFCT) measurement was performed with enhanced depth imaging optical coherence tomography (EDI-OCT). The images were binarized using the ImageJ software program. Total choroidal area (TCA), stromal area (SA), and luminal area (LA) were calculated from the 1500 µm area. The choroidal vascular index (CVI) was determined as the LA/TCA ratio. All parameter values were compared between the BRVO eye and the fellow eye, and the control group eyes.

RESULTS

Eyes with BRVO had a greater SA compared to both fellow and control eyes; hence, the CVI was lower (p < 0.001). LA did not differ between eyes. TCA, although not statistically significant, was larger in eyes with BRVO than in both fellow and control eyes. SFCT was also greater in eyes with BRVO. No correlation was observed between CVI and SFCT and best-corrected visual acuity (BCVA).

CONCLUSION

BRVO affects the stromal part of the choroid rather than its vascular structure. SA increases due to choroidal exudation that occurs in response to retinal ischemia, and CVI decreases accordingly.

Choroidal vascularity index changes during the Valsalva manoeuvre in healthy volunteers

PURPOSE

To evaluate the effects of the Valsalva manoeuvre (VM) on the choroidal vascularity index (CVI) in healthy volunteers.

METHODS

This prospective, cross-sectional study included 60 eyes of 30 healthy volunteers. Enhanced depth imaging-optical coherence tomography scans of both eyes involving the fovea were taken, and a 1500 μm subfoveal choroidal area was selected for image binarization with open-access Fiji software. The binarized image was segmented into the stromal area (SA) and luminal area (LA), and CVI was calculated as the ratio (%) of LA to the total choroidal area (TCA). CVI, subfoveal choroidal thickness (SFCT), IOP, systolic and diastolic blood pressure were evaluated at rest and during the VM.

RESULTS

During the VM, a mean ± standard deviation increase in LA (0.02 ± 0.05 mm² , p < 0.001) and CVI (1.72 ± 2.83%, p < 0.001) was observed, whereas SA (-0.02 ± 0.05 mm² , p < 0.001) decreased. There was no significant change in TCA (0.00 ± 0.03 mm² , p = 0.55) or SFCT (1.05 ± 10.92 μm, p = 0.46). There was a moderate positive correlation between the spherical equivalent refractive error (SE) and SFCT both at rest and during VM (r₅₈  = 0.49, p < 0.0005 and r₅₈  = 0.49, p < 0.0005, respectively). However, there was no significant correlation between SE and CVI either at rest or during VM (p = 0.11 and 0.06, respectively). In a multiple linear regression analysis, CVI was only associated with SFCT; however, SFCT was also associated with SE, both at rest and during VM (p < 0.001).

CONCLUSION

Valsalva manoeuvre increases CVI by choroidal vascular dilation as demonstrated by an increase in LA and a decrease in SA. Researchers should be careful about unintentional VM during examinations.

Evaluation of the impact of COPD severity grading and oxygen saturation on the retinal nerve fiber layer thickness and subfoveal choroidal thickness in COPD patients

Background

Retinal and choroidal blood vessels are involved in many systemic diseases because they are complex vascular systems. Chronic obstructive pulmonary disease is considered as an inflammatory disease that affects many systems and coexists with several co-morbidities. Systemic inflammation and hypoxia affect the macula, choroid, retinal nerve fiber layer (RNFL), and blood vessels. Ocular co-morbidities have been detected in COPD patients. These can be quantitatively and qualitatively evaluated by Spectral Domain Optical Coherence Tomography (SD-OCT). Enhanced depth imaging OCT (EDI-OCT) is a quite new technique that utilizes light with an extended wavelength. An apparent relation has been found between chronic pulmonary disease and low corneal endothelial cell density preoperatively. So this work aimed to assess the impact of COPD severity grading and oxygen saturation on retinal nerve fiber layer thickness and subfoveal choroidal thickness.

Results

This was a case-control study, recruited 50 COPD patients and another 50 healthy volunteers as a control group. Measuring the thickness of the RNFL (superior, inferior, nasal, and temporal) in the four quadrants as well as the subfoveal choroidal thickness was done to both groups. The RNFL thickness in all quadrants and the SFCT in the COPD group were statistically significantly thinner in comparison to the control group. The RNFL thickness (mean) was 79.16 ± 10.49 μm compared to 96.30 ± 4.66 μm in the control group (p value 0.001). The SFCT (mean) was 213.12 ± 25.61 μm compared to 354.62 ± 53.82 μm in the control group (p value 0.001). The degree of thinning of the RNFL (superior, inferior, and temporal) and the SCFT was related to COPD (GOLD) stages severity (p value 0.001). Nasal RNFL was thinned out in all stages of COPD (GOLD) but with no statistical significance (p value 0.264).

Conclusion

The choroid and retina seem to be of the affected tissues during the progressive inflammatory course of COPD. Ocular pathologies should be evaluated in patients with systemic hypoxia. The eye examination for COPD patients can be carried out via a non-invasive procedure such as the OCT and the changes in the RNFL and SFCT thickness could be used as indicators for the severity of COPD.

Choroidal features in flat irregular pigment epithelial detachment associated with Chronic central serous chorioretinopathy: Avascular versus vascularized

PURPOSE

To investigate the differences in the choroidal biomarkers between two forms of flat irregular pigment epithelial detachment (FIPED): avascular (aFIPED) and vascularized (vFIPED) in eyes with chronic central serous chorioretinopathy (CSC).

MATERIALS AND METHODS

Enhanced depth imaging optical coherence tomography (EDI-OCT) was done in eyes with FIPED correlated to chronic CSC, fellow eyes, and also in healthy eyes from gender- and age-matched subjects. Eyes with FIPED were classified into two subgroups based on optical coherence tomography angiography (OCTA) findings: vFIPED and aFIPED. Different choroidal biomarkers such as subfoveal choroidal thickness (SFCT), total choroidal area (TCA), and choroidal vascular index (CVI) were compared between the groups.

RESULTS

Forty-four eyes from 42 patients with chronic CSC and FIPED along with 40 eyes from 20 healthy subjects were included. OCTA identified vascularization in 14 eyes in the FIPED group (31.8%). Mean SFCT was higher in the FIPED group compared to two other groups (p = 0.005). In comparison to patients with aFIPED, patients with vFIPED had lower SFCT (p = 0.003) and higher CVI (p = 0.020) based on multivariate analysis.

CONCLUSIONS

It seems that measurement of CVI along with SFCT may help to differentiate aFIPED from vFIPED in patients with CSC. Further longitudinal studies would be required to confirm the clinical significance of these findings.

Choroidal structural evaluation in celiac disease

This observational case–control study assessed the differences in choroidal structure between patients with celiac disease and healthy subjects utilizing the choroidal vascularity index (CVI). Seventy-four celiac patients and 67 healthy subjects underwent a complete ophthalmological evaluation, axial length (AL) measurements and spectral-domain optical coherence tomography with enhanced depth imaging mode (EDI SD-OCT) evaluation. These images were binarized and choroidal vasculature was analyzed. Choroidal total subfoveal area (TSA), luminal subfoveal area (LSA), stromal subfoveal area (SSA), CVI and subfoveal choroidal thickness (CT) were measured. Furthermore, subfoveal CT, TSA, LSA, SSA, and CVI were also correlated with AL. A statistically significant difference was found between the two groups for TSA, LSA, SSA and subfoveal CT, but not for CVI. In celiac patients, a significant correlation was found between AL and TSA, LSA and SSA, but not with CVI. Similar findings were also noticed in the healthy subjects. Thus, celiac patients have a thicker choroid than healthy subjects, regardless of the AL, due to a proportional increase in both the vascular and stromal components, which does not alter the CVI.

Impact of large choroidal vessels on choriocapillaris flow deficit analyses in optical coherence tomography angiography

PURPOSE

To investigate the impact of large choroidal vessels (LCV) on Choriocapillaris (CC) flow deficit (FD) analyses with swept-source optical coherence tomography angiography (SS-OCTA).

DESIGN

Prospective, cross-sectional study.

METHODS

Macular 6x6mm SS-OCTA scans were obtained from intermediate age-related macular degeneration (iAMD) and healthy eyes. Images were captured and processed according to most common standards and analyzed for percentage of flow-deficits (FD%) within four 1x1mm squares at the corners of each image. Choroidal thickness (CT), iris color and refraction error were considered as potential influential factors for LCV visibility. A linear mixed model and logistic regression models were calculated for statistical evaluation.

RESULTS

Sixty-nine iAMD and 49 age-matched healthy eyes were enrolled. LCV were visible in at least one sector in 52% of iAMD and 47% of healthy eyes. Within the iAMD group FD% were significantly lower in areas containing LCV (p = 0.0029). Increasing CT resulted in an odds ratio decrease of LCV (OR: 0.94, p<0.0001). Below a CT value of ≤118μm LCV could be expected with a sensitivity of 86% and a specificity of 85%.

CONCLUSIONS

LCV can significantly affect CC FD analyses of SS-OCTA images. Their visibility is negatively associated with CT. The impact of LCV should be taken into account when performing CC FD assessments, especially in patients where reduced CT is to be expected and inclusion of affected areas should be considered carefully.

Comparison of effects of tamsulosin and silodosin on subfoveal choroidal thickness and pupil size diameters in patients with prostatic hyperplasia

PURPOSE

To compare the effects of selective α-1 adrenoceptor antagonists on subfoveal choroidal thickness (SFCT) and pupil diameter size (PDS).

METHODS

This prospective study included 87 patients diagnosed with benign prostatic hyperplasia who were treated with tamsulosin hydrochloride (n = 41) or silodosin (n = 46). SFCT measurements were obtained using spectral domain optic coherence tomography (SD-OCT), and PDS measurements were obtained under mesopic, photopic and scotopic conditions using a photography-based topography system. SFCT and PDS were evaluated at baseline and 3-, 6- and 12-mo follow-ups.

RESULTS

The initial mean SFCT was 270.53 ± 21.48 µm in tamsulosin group and 271.95 ± 24. 73 in silodosin group (P = 0.078). There was no statistically significant change in SFCT at the 3-mo visit. At the 6-mo follow-up, the mean SFCT was 281.34 ± 22.09 µm in tamsulosin group and 272.5 ± 22.4 µm in silodosin group. At the 12th month, the mean SFCT in tamsulosin group was 290.80 ± 17.27 µm, and it was 270.80 ± 13.14 µm in silodosin group. There was statistically significant difference in at 6th and 12-mo visits (P = 0.014 and P = 0.00). During the follow-up, both drugs induced a similar significant decrease in PDS under all conditions.

CONCLUSIONS

Tamsulosin hydrochloride caused a significant increase in SFCT. In contrast, SFCT did not increase in silodosin group. The decreases in PDS achieved using both drugs were similar. This should be kept in mind when choroidal disease and its response to treatment are followed by CT imaging.

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.

CHOROIDAL CHANGES DUE TO LONG-TERM USE OF N95 FACE MASKS

PURPOSE

We aimed to examine the changes in choroidal stroma and vascular system due to long-term use of N95 mask in healthcare workers.

METHOD

The healthcare workers included in the study were between the ages of 18-50, with best corrected visual acuity (BCVA) 10/10, spherical and cylindrical refractive errors less than 3 diopters, intraocular pressures (IOP) within normal limits, and axial lengths (AL) less than 25 mm. The choroid was imaged with enhanced depth imaging (EDI) techniques using SD-OCT. The choroidal vascularity index (CVI), total choroidal area (TA), luminal area (LA), and stromal area (SA) were measured in the subfoveal 2 mm area. Measurements were first made after wearing the N95 mask for at least 2 hours without removing it and repeated 1hour after removing, while doing office working.

RESULTS

The study included 62 eyes from 62 participants (32 women [%51.61]; 30 men [%48.39]). The mean age of patients was 33.81± 8.88 years (20-50 years). The differences in subfoveal TA, LA, SA between 2 hours of N95 mask use and 1 hour after removal of the mask were statistically significant (p<0.05 for each). However, the difference in CVI between the mask use and removal of the mask was not statically significant (p=0.537) CONCLUSION: Due to CO2 retention and hemodynamıc changes, choroidal vascular flow, the choroidal vascular area, and the choroidal stromal area may be affected by prolonged use of masks.

Comparison of retinal nerve fiber layer, macular ganglion cell complex and choroidal thickness in patients with migraine with and without aura by using optical coherence tomography

BACKGROUND

We compared the choroidal thickness (CT), peripapillary retinal nerve fibre layer thickness (pRNFLT) and macular ganglion cell complex thickness (mGCCT) by using spectral domain optic coherence tomography (SD-OCT) in patients with migraine with aura (MWA), migraine without aura (MWoA), and healthy controls.

METHODS

Thirty-seven patients with MWA, 40 patients with MWoA, and age and sex-matched 50 healthy controls were included in this cross-sectional study. CTs at fovea, nasal to fovea and temporal to fovea, global pRNFLT, four quadrants of pRNFLTs, mGCCTs in superior and inferior hemisphere were measured by SD-OCT. The duration of migraine, monthly attack number and the migraine disability assessment (MIDAS) questionnaire scores were recorded.

RESULTS

The mean foveal CT, nasal CT, and temporal CT in patients with MWA were significantly thinner than those of patients with MWoA and control (p < 0.001) while CTs of patients with MWoA were similar with those of controls. Patients with MWA and MWoA had thinner global pRNFLT, superior and inferior pRNFLT compared to controls but there were no significant differences between two migraineurs groups. Only nasal quadrant of pRNFLT was significantly thinner in patients with MWA than other groups. The superior and inferior mGCCTs were significantly thinner in patients with MWA and MWoA than controls.

CONCLUSION

Our results suggested that dysregulation of blood flow in ocular tissues caused by impairment of autoregulation in migraine. Patients with MWA might have an additional risk of choroidal and retinal ischemia than patients with MWoA and healthy controls.

Relation between nocturnal decline in blood pressure and choroidal thickness: a comparative analysis in dipper vs. non-dipper hypertensive patients

PURPOSE

To compare choroidal thickness (ChT) and echocardiographical changes in patients with dipper and non-dipper systemic arterial hypertension (HT).

METHODS

Patients with HT were evaluated in two groups according to the 24-hour ambulatory BP monitoring. Compared to day-time values, those whose night-time SBP decreased ≥10% were defined as dippers, and those whose SBP decreased <10% were defined as non-dippers. Transthoracic echocardiography was conducted in all patients. ChT and central macular thickness were measured with spectral-domain optical coherence tomography. ChT was obtained at the subfoveal, 1500 µm nasal and temporal to the fovea.

RESULTS

Thirty non-dipper (18 females and 12 males) and 23 dipper (16 females and seven males) hypertensive patients were recruited. Sex distribution and the mean age were similar between the groups (P = 0.472; P = 0.12). Disease duration was longer in the non-dipper group (8 ± 3.39 vs. 4.96 ± 1.19 years, P = 0.001). The non-dipper group had lower ChT in subfoveal and temporal locations (P = 0.02 and 0.03, respectively) and higher left atrial volume index (LAVI) and pulmonary valve maximum flow (PV-max; P < 0.001). The night-time SBP was negatively correlated with ChT (P = 0.048) and positive correlated with LAVI and PV-max (P < 0.05). However those correlations were not significant when were controlled by the possible confounding factors as disease duration, age and gender.

CONCLUSION

Non-dipper HT patients may have thinner choroid than dippers due to longer duration of HT and higher ambulatory BP levels.

Comparison of choroidal thicknesses in patients with coronary artery disease and patients at risk of coronary artery disease

PURPOSE

The study aimed to compare choroidal thicknesses (CTh) in patients with coronary artery disease (CAD) and patients at risk of coronary artery disease and investigate whether thinning of the choroid can be used as a biomarker for development of coronary artery disease in patients at risk.

MATERIALS AND METHODS

The study group was composed of 103 eyes of 53 patients with coronary artery disease, and the control group was composed of 62 eyes of 32 patients with diabetes mellitus, hypertension and/or hyperlipidemia without coronary artery disease. CAD was diagnosed in patients with one of the following: myocardial infarction with/without ST segment elevation, clinically proven history of cardiac catheterization testifying greater than 50% obstruction in at least one coronary artery, revascularization operations. The control group consisted of clinically proven patients with normal coronary arteries. The choroidal thickness was measured with enhanced depth imaging optical coherence tomography under the fovea and at six other points, located at 500 micron, 1000 micron and 1500 micron nasal to the fovea and 500 micron, 1000 micron, 1500 micron temporal to the fovea.

RESULTS

The subfoveal choroidal thickness was significantly thinner in the coronary artery disease group compared to the control group (244 µm vs. 289 µm; p < 0,001). In all other measured regions (nasal 500, nasal 1000, nasal 1500, temporal 500, temporal 1000, and temporal 1500 micron), CTh was statistically significant thinner in the CAD group. A negative significant linear relationship (low level) between CAD duration and choroidal thickness in the subfoveal, nasal 1000, nasal 1500, temporal 500, temporal 1000 micron regions was detected.

CONCLUSION

Patients with CAD have a decreased choroidal thickness compared to patients at risk of CAD. Detection of CTh thinning in a patient with diseases, such as diabetes, hypertension and/or hypercholesterolemia, which pose a risk for CAD may be a predictor of development of coronary artery disease. Clinical Trials Registration Kocaeli Derince Training and Research Hospital ethics committee-protocol number: 2020-106.

Orthokeratology and Low-Intensity Laser Therapy for Slowing the Progression of Myopia in Children

Orthokeratology (OK) is widely used to slow the progression of myopia. Low-level laser therapy (LLLT) provides sufficient low energy to change the cellular function. This research is aimed at verifying the hypothesis that LLLT treatment could control myopia progression and comparing the abilities of OK lenses and LLLT to control the refractive error of myopia. Eighty-one children (81 eyes) who wore OK lenses, 74 children (74 eyes) who underwent LLLT treatment, and 74 children (74 eyes) who wore single-vision distance spectacles for 6 months were included. Changes in axial length (AL) were 0.23 ± 0.06 mm for children wearing spectacles, 0.06 ± 0.15 mm for children wearing OK lens, and -0.06 ± 0.15 mm for children treated with LLLT for 6 months. Changes in subfoveal choroidal thickness (SFChT) observed at the 6-month examination were -16.84 ± 7.85 μm, 14.98 ± 22.50 μm, and 35.30 ± 31.75 μm for the control group, OK group, and LLLT group, respectively. Increases in AL at 1 month and 6 months were significantly associated with age at LLLT treatment. Changes in AL were significantly correlated with the baseline spherical equivalent refraction (SER) and baseline AL in the OK and LLLT groups. Increases in SFChT at 1 month and 6 months were positively associated with age at enrolment for children wearing OK lens. At 6 months, axial elongation had decelerated in OK lens-wearers and LLLT-treated children. Slightly better myopia control was observed with LLLT treatment than with overnight OK lens-wearing. Evaluations of age, SER, and AL can enhance screening for high-risk myopia, improve the myopia prognosis, and help determine suitable control methods yielding the most benefits.

Choroid Segmentation of Retinal OCT Images Based on CNN Classifier and l 2-l q Fitter

Optical coherence tomography (OCT) is a noninvasive cross-sectional imaging technology used to examine the retinal structure and pathology of the eye. Evaluating the thickness of the choroid using OCT images is of great interests for clinicians and researchers to monitor the choroidal thickness in many ocular diseases for diagnosis and management. However, manual segmentation and thickness profiling of choroid are time-consuming which lead to low efficiency in analyzing a large quantity of OCT images for swift treatment of patients. In this paper, an automatic segmentation approach based on convolutional neural network (CNN) classifier and l ₂-l _q (0 < q < 1) fitter is presented to identify boundaries of the choroid and to generate thickness profile of the choroid from retinal OCT images. The method of detecting inner choroidal surface is motivated by its biological characteristics after light reflection, while the outer chorioscleral interface segmentation is transferred into a classification and fitting problem. The proposed method is tested in a data set of clinically obtained retinal OCT images with ground-truth marked by clinicians. Our numerical results demonstrate the effectiveness of the proposed approach to achieve stable and clinically accurate autosegmentation of the choroid.

Comparison Between Central Choroidal Thickness in Pregnant Diabetic Females and Pregnant Non-Diabetic Females

Objective

To compare choroidal thickness in pregnant women with and without diabetes mellitus (DM).

Methods

Sixty pregnant females (60 eyes) were enrolled in this cross-sectional controlled study. They were divided into two groups: Group A (30 patients; 30 eyes) were pregestational diabetic pregnant females, while Group B (30 patients; 30 eyes) were non-diabetic pregnant females. Exclusion criteria were high-risk pregnancy, diabetic retinopathy in Group A subjects, systemic or ophthalmological pathology, drug intake other than vitamin supplements and diabetic medications, and large errors of refraction. All patients underwent full ophthalmological examination and enhanced depth imaging optical coherence tomography (EDI-OCT) to measure the choroidal thickness in the nine zones of the Early Treatment Diabetic Retinopathy Study (ETDRS) map.

Results

Our results show that Group A eyes (of pregnant diabetic females) had a highly significant greater choroidal thickness than Group B eyes (of pregnant non-diabetic females) in all nine zones of the ETDRS map (p-value <0.01). Moreover, we found a positive linear correlation between the duration of DM and the degree of choroidal thickening.

Conclusion

Pregnant diabetic females have a thicker choroid than that of pregnant non-diabetic females.

Effects of different mydriatics on the choroidal vascularity in healthy subjects

PURPOSE

To evaluate choroidal vasculature changes after the instillation of mydriatic parasympatholytic and sympathomimetic agents in healthy subjects.

METHODS

A total of 95 healthy subjects were enrolled in this prospective, randomized comparative study. Study participants were divided into three different groups depending on the drug to be administered: tropicamide (1%) group (n = 31), tropicamide (0.5%) + phenylephrine (10%) group (n = 30) and control group receiving artificial tears (n = 34). All participants underwent a complete ophthalmological examination including best corrected visual acuity, refractive status and axial length. Subfoveal choroidal thickness (CT), total choroidal area (TCA), luminal and stromal choroidal area (LCA and SCA) and choroidal vascularity index (CVI) were measured before and after eye drops instillation.

RESULTS

All the baseline characteristics were matched between the three groups (all P > 0.05). Before the mydriatic instillation, there were no significant differences of CT, TCA, LA, SCA, and CVI among the three groups (all P > 0.05). After drug administration, CT, TCA, LCA, SCA, and CVI did not show any significant change as well (respectively, P = 0.265; P = 0.483; 0.573; P = 0.405 and P = 0.708).

CONCLUSIONS

Instillation of mydriatic eye drops did not induce significant changes of the choroidal vasculature, suggesting that their use do not alter CT and CVI evaluation.

Subfoveal Choroidal Thickness in Myopia: An OCT-Based Study in Young Chinese Patients

Myopia is a common cause of visual impairment worldwide. Choroidal thickness (ChT) reflects the characteristic changes in myopic children and may be used as an important index of myopia. The purpose of this study was to investigate ChT and its distribution across the posterior pole in young myopic Chinese patients using enhanced depth imaging optical coherence tomography (EDI-OCT) and to explore the factors associated with it. A total of 402 myopic Chinese patients aged 6–16 years who underwent complete ophthalmic examinations, including those for axial length, cycloplegic refraction, and intraocular pressure, were examined with EDI-OCT. The mean subfoveal ChT was 303.08 ± 76.87 μm and displayed large variations at different positions (p < 0.05). The thickest sector was located 3 mm temporally from the fovea. Multivariate regression analysis showed a significant negative correlation of the subfoveal ChT values with axial length (AL), whereas the ChT was moderately influenced by the patient's sex. AL accounted for 7.9% of the ChT variance, whereas sex explained 9.6% of the ChT variance. In the population aged 11 years and older, AL accounted for 13.1% of the ChT variance. However, in those younger than 11 years, age was the only significant explanatory factor accounting for 5.2% of the ChT variance. In conclusion, we found a significant decrease in ChT with age in myopic children younger than 11 years. The negative association between age and ChT in children aged 11 years and older may be offset by the choroidal thickening mediated by pubertal growth spurts. The positive correlation between ChT and spherical equivalent in myopic adolescents aged 11 years and older suggests that the protective effect of lens thinning against rapid axial elongation disappears with age. Axial elongation becomes the dominant determinant of ChT in this age group.

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.

Increased Choroidal Thickness in Keratoconus Patients: Perspectives in the Disease Pathophysiology

Purpose

To analyze and compare choroidal thickness between keratoconus (KC) patients and age-matched non-KC subjects.

Methods

A cross-sectional, case-control study. One hundred and thirty-four keratoconic eyes and 78 control eyes, from individuals aged from 12 to 30 years old, were studied. Patients with KC followed in Corneal Department of Centro Hospitalar São João, Porto, Portugal, were identified and consecutively included between December 2017 and February 2018. A spectral-domain optical coherence tomography (OCT) using depth enhanced imaging was performed, and choroidal thickness in the center of the fovea and at 500 μm intervals along a horizontal section was measured and compared.

Results

The statistical analysis showed that keratoconic eyes present a thicker choroid in every measured location (p < 0.05). Mean subfoveal choroidal thickness (SFCT) values obtained were 375.86 ± 89.29 and 322.91 ± 85.14 in keratoconus and control groups, respectively (p < 0.001). In a multivariate analysis, SFCT was significantly associated with spherical equivalent (p=0.004) and the presence of keratoconus (p < 0.001), but not with age (p=0.167), gender (p=0.579), or best-corrected visual acuity (p=0.178). In a "fixed model," keratoconus patients were found to have a 67.55 μm (95% CI 36.61-98.49) thicker subfoveal choroid compared to controls.

Conclusion

Keratoconus patients seem to have a thicker choroid than healthy individuals. The exact pathophysiological mechanism resulting in a thicker choroid in KC patients is not known, but it could possibly be associated with inflammatory choroidal mechanisms.

The effect of strabismus surgery on choroidal thickness

Purpose:

To determine the effects of strabismus surgery on choroidal thickness.

Methods:

This was a prospective randomized study. The measurements of subfoveal and macular choroidal thickness of patients who underwent strabismus surgery were obtained by enhanced depth imaging optic coherence tomography. The patients were grouped as patients who had 1 horizontal muscle surgery (group 1), 1 oblique muscle surgery (group 2), 2 horizontal muscle surgeries (group 3), or 1 horizontal and 1 oblique muscle surgery (group 4). Choroidal thickness of the patients was measured preoperatively and on the postoperative first day, second week, first month, and third month. Choroidal thickness was measured at subfoveal area (S) and at the nasal (N1, N2) and temporal (T1, T2) fovea with 500-μm intervals.

Results:

The average age of the 37 patients was 15.59 ± 13.84 years. In preoperative and postoperative first day comparison, a decrease in choroidal thickness was found in all areas in group 1. In group 2, a significant decrease was found in N2, N1, and S values. In group 3, a significant decrease was found in N2, N1, and T2 values. In group 4, a significant decrease was found in N1 value. The second week comparison of all groups showed significant postoperative decrease in choroidal thickness in all areas. On the postoperative first month, a significant decrease in choroidal thickness was found only in the subfoveal area of group 1 and the N1 area of group 2. At the postoperative third month, there was no change in any group.

Conclusions:

Strabismus surgery causes a decrease in choroidal thickness in the early postoperative period.