Choroidal Circulation Research Articles

Are optic nerve head and choroidal circulation affected by eye movements?

Although it has been reported that the optic nerve can be mechanically affected by the eye's horizontal movements, studies examining horizontal movements with optical coherence tomography angiography (OCTA) have only recently begun to emerge. This study aimed to investigate whether there are changes in the OCTA data of healthy individuals in the primary gaze, abduction, and adduction. Thirty volunteers (15-73 years old) were included in this prospectively designed study. Radial peripapillary capillary density parameters (RPCD) taken with OCTA in cases of primary gaze, abduction, and adduction were examined. With the OCTA device Angio Disc QuickVue that was used in the study, 3 main vessel structures could be examined. In the patients' primary, abduction, and adduction positions, a difference was observed only in the superior hemifield area of the left eye (P = 0.032). The superior hemifield all vessels vessel densities (AV VD) were 60.1 ± 2.7 in the central gaze, 59.9 ± 2.6 in the adduction, and 60.8 ± 2.6 in the abduction positions, with a relative decrease observed in adduction. This was also related to age. No difference was detected in terms of the other RPCD parameters. In healthy individuals, short-term horizontal eye movements may not result in significant changes except for superior hemifield in OCTA data.

Safety of and chorioretinal circulation during repeated low-level red-light therapy for myopic children.

To evaluate the safety of repeated low-level red-light (RLRL) therapy in children, and the dynamic evolution of choroidal and retinal blood flow. This is a single-centre, randomised, single-blind, parallel-group clinical trial. Seventy myopic children were randomly assigned to either the intervention group [receiving RLRL therapy plus single-vision spectacle (SVS)] or the control group (wearing SVS). Participants underwent comprehensive ophthalmic examinations following their first irradiation, 9 months continuous RLRL therapy and stop of treatment. Quantitative analyses of choroidal and retinal microcirculation were analysed via optical coherence tomography angiography. Over 9 months of treatment, while the RLRL treatment demonstrated significantly less increases in refractive error and axial length compared with the SVS treatment (ps < 0.05), no abnormalities in fundus structure or visual function (mfERG, VEP and microperimetry) were detected (ps > 0.05). A single red-light exposure did not exert a significant influence on choroidal thickness (ps > 0.05). Upon continuous treatment, the RLRL group achieved peak values in these circulations at 9 months (ps < 0.05). Following cessation of exposure, all circulations exhibited a declining trend, reaching similar levels in both groups (ps > 0.05). As the frequency of red-light exposures intensified, there was a consistent surge in these circulations (ps < 0.05). Nine months of continuous RLRL exposure does not cause toxic side effects on retinal or optic nerve functions, and there is a time-dependent cumulative response in choroidal and retinal circulation.

Long-Term Impact of Carotid Endarterectomy on Choroidal and Choriocapillaris Perfusion: The INFLATE Study

PurposeWhen performed for clinically significant carotid artery stenosis (CAS), the long-term impact of carotid endarterectomy (CEA) on choroidal and choriocapillaris (CC) circulation was studied using swept-source optical coherence tomography angiography (SS-OCTA). DesignProspective observational study. ParticipantsPatients with clinically significant CAS undergoing unilateral CEA. MethodsSS-OCTA scans were performed on both eyes at baseline (before CEA), within one week post-CEA (short-term follow-up [FU]), and at least 30 days post-CEA (long-term FU). Using validated algorithms, we measured mean choroidal thickness (MCT), choroidal vascularity index (CVI), choroidal vessel volume (CVV), CC flow deficit percentage (CC FD%), and CC thickness within the 5mm circle centered on the fovea for both the eye ipsilateral to CEA (surgical side) and the contralateral eye (nonsurgical side). Multivariable regression analysis was conducted to evaluate the impact of baseline demographic and clinical factors on the changes in choroidal and CC parameters. Main Outcome MeasuresBoth the short- and long-term changes in MCT, CVI, CVV, CC FD%, and CC thickness. ResultsThe study included 58 eyes from 29 patients. Significant short-term improvements in MCT (P<0.001) and CC thickness (P=0.006) were observed post-CEA on the surgical side. Long-term FU showed sustained increases in MCT compared with baseline (P=0.02), while CC thickness was not significantly different from baseline (P=0.10). The CVI did not change significantly from baseline at either short-term (P=0.45) or long-term (P=0.22) FU on the surgical side. While CVV demonstrated a short-term rise immediately post-CEA (P<0.001), the difference was not statistically significant at the long-term evaluation (P=0.06). No significant improvement in CC FD% from baseline was observed at any visit post-CEA (short-term P=0.81, long-term P=0.91). The nonsurgical side only showed a significant reduction in CVI at the long-term FU visit compared with before CEA (P=0.01). Clinical variables such as age, degree of stenosis, diabetes, hypertension, and smoking status did not greatly impact the outcomes. ConclusionsUnilateral CEA demonstrated a sustained increase in MCT suggesting persistent improvements in choroidal perfusion in the ipsilateral eye.

The Effect of Repeated Low-Level Red-Light Therapy on Myopia Control and Choroid.

To investigate the long-term effects of repeated low-level red light (RLRL) therapy on the axial length (AL), spherical equivalent (SE), and choroidal parameters. Two hundred eight myopic eyes were recruited. The RLRL group included 100 eyes, whereas the control group included 108 eyes. Throughout the one-year follow-up period, changes in AL and SE were recorded for both groups. The RLRL group underwent additional choroidal imaging, and changes in choroidal thickness (CT), choroidal vascularity (CV), and choriocapillaris luminal area (CLA) were assessed before and after RLRL therapy. During the follow-up period, the changing trends in AL and SE differed significantly between the RLRL and control groups. In the RLRL group, AL decreased at three and six months (both P < 0.05) and returned to pretreatment values at 12months (P = 0.453). In contrast, AL increased significantly throughout the follow-up period (three, six, and 12months) in the control group (all P < 0.001). The SE increased significantly during the entire follow-up period in the RLRL group (all P < 0.001), whereas it decreased significantly in the control group (all P < 0.05). Regarding choroidal parameters, significant improvements were observed in CT, CV and CLA throughout the follow-up period (all P < 0.05), and changes in most choroidal parameters were significantly correlated with changes in AL and SE during the follow-up period (all P < 0.05). Furthermore, AL, SE, and most choroidal parameters showed significant correlations between changes at three and 12months (all P < 0.05). RLRL therapy significantly improved choroidal blood perfusion and circulation, which may explain the observed slowing or reversal of myopia progression in the RLRL group. Thus RLRL therapy may be a novel and effective method for controlling myopia. Furthermore, the short-term effect of photobiomodulation therapy (i.e., changes at three months) can be used to predict the long-term effects (i.e., changes at 12months). In this study, RLRL therapy showed a significant control effect on the development of axial length and spherical equivalent. RLRL therapy also promoted the choroidal blood perfusion and circulation. RLRL therapy could be a novel and effective method for myopia control.

Choroidal Alterations in Diabetic Macular Edema Treated with Intravitreal Dexamethasone: What Can Choroidal Vascularity Index Tell Us?

Diabetes mellitus (DM) significantly impacts ocular health, particularly the retina and choroid, leading to diabetic retinopathy (DR) and diabetic macular edema (DME). This study aimed to evaluate the effects of intravitreal dexamethasone (IVD) on the choroidal vascularity index (CVI) in order to evaluate its potential as a biomarker. This was a retrospective observational study in which 37 eyes with DME treated with IVD were included. Baseline and follow-up (2 and 4 months post-injection) comprehensive ophthalmological examinations and spectral domain optical coherence tomography (SD-OCT) were performed. The CVI, luminal area (LA), stromal area (SA), and total area (TA) were assessed. No statistically significant changes in CVI, LA, SA, and TA were observed in the overall patient sample from baseline to 2 and 4 months post-IVD injection. However, a significant CVI reduction was noted in responder patients at 4 months. Positive correlations were found between the CVI and central macular thickness (CMT) at 2 months, suggesting that higher CMT values are associated with higher CVI values. This study indicated that IVD influences choroidal circulation, as evidenced by CVI reduction in responder patients. The CVI could potentially serve as an objective biomarker for treatment response in DME. Larger, prospective studies are warranted to clarify these findings further.

The Evaluation of Change in Choroidal Circulation Time before and after Half-Dose Photodynamic Therapy in Central Serous Chorioretinopathy Using Wide-Field Indocyanine Green Angiography.

Background: Indocyanine green angiography (ICGA) is often used for diagnosis of, and as an indication to apply laser treatment for, central serous chorioretinopathy (CSC). Although photodynamic therapy (PDT) is effective against CSC, the details of the mechanism are unknown. To verify the effect of PDT, we compared the time of choroidal circulation before and after PDT in CSC patients, using ICGA. Methods: Seven eyes of seven patients (six male, one female) who were diagnosed with chronic CSC associated with serous retinal detachment (SRD) in the macular area and who underwent half-dose PDT were included. Wide-field ICGA images with an angle of 102° were taken and evaluated at the superior and inferior temporal quadrants. Choroidal circulation time (CCT) was defined as the time from the start of contrast filling in the choroidal artery to the first appearance of contrast filling in the temporal vortex vein ampulla. Results: The average CCT before and after PDT in the superior temporal vortex vein was 3.96 s and 5.41 s (p = 0.018), and 4.12 s and 5.02 s (p = 0.046) in the inferior temporal vortex vein, respectively. All SRD and choroidal vascular hyperpermeability areas dissolved after PDT. Conclusions: In this pilot study, half-dose PDT prolonged CCT in CSC patients, indicating the effect of selective vascular obstruction in the choriocapillaris.

OCULAR CYSTICERCOSIS: A CASE REPORT

Ocular cysticercosis, though rare, can be extraocular or intraocular. Ocular manifestations usually occur as a part of a systemic infection and can lead to partial or complete visual impairment over a 3-5 y period. The parasite reaches the posterior segment of the eye via the high-flow choroidal circulation through the short ciliary arteries. A 35 y old female patient presented to us with history of blurring of vision in right eye over one week. Fundus examination revealed an oval translucent cyst of about 4 mm in diameter. The patient underwent USG B scan, which revealed well-circumscribed cystic lesion in posterior vitreous.

Factors affecting choroidal circulation parameters in 4–14-year-old Chinese children measured by SS-OCT/OCTA

PurposeTo measure the choroidal circulatory parameters Han Chinese children aged 4–14 years from Southwest China, and to explore the relationships between these parameters and age, axial length (AL), and choroidal thickness (ChT). Methods284 eyes from 142 subjects were included in this cross-sectional study. All participants underwent cycloplegic refraction and IOLMaster500 examination. Swept-source optical coherence tomography (SS-OCT) was used to measure submacular choroidal thickness, choroidal vascular volume (CVV), choroidal stromal volume (CSV), choroidal vascularity index (CVI), and CVV/CSV ratio. ResultsIn this population, the mean CVV was 2.92 ± 0.55 mm3, CSV was 4.69 ± 0.68 mm3, CVI was 38.22 ± 2.46 %, and CVV/CSV ratio was 62.11 ± 6.44 %. Multivariable regression analyses showed that both CVV and CSV were negatively correlated with AL (both P < 0.001) and positively correlated with ChT (both P < 0.001), while age showed no significant correlation with them (both P > 0.05). However, the correlations between CVI and age were not uniform rectilinear. Among participants aged ≤8 years, CVI showed no correlation with age (P > 0.05), while among those aged >8 years, it was positively correlated with age (P < 0.01). CVV/CSV ratio was positively correlated with ChT and age (both P < 0.01). ConclusionAfter the age of 8, age was positively correlated with CVI. ChT was well correlated with CVI. Longer AL and thinner ChT were associated with reduced CVV and CSV, with CVV decreasing more rapidly than CSV.

Ultra-wide field indocyanine green angiography in central serous chorioretinopathy.

To study ultra-widefield indocyanine green angiography (ICGA) patterns in central serous chorioretinopathy (CSC). A cross-sectional observational study was undertaken on 30 patients aged 20 to 60 years with CSC at the retina clinic of a tertiary care center. Of them, 43 eyes were affected by CSC, whereas 17 eyes were unaffected as the bilateral disease was observed in 13 patients. All patients were evaluated for best-corrected visual acuity, intraocular pressure, detailed slit-lamp bio-microscopy, indirect ophthalmoscopy, ultra-widefield imaging for pseudo color photograph, fundus autofluorescence (FAF), fundus fluorescein angiography (FFA), and ICGA, and macular swept-source optical coherence tomography (SSOCT) characteristics. The mean age of patients was 41.43 ± 8.81 years (range: 25-59 years). The median log MAR visual acuity in CSC eyes was 0.30 (range: 0.17-1.0), whereas it was 0 in non-CSC fellow eyes ( P < 0.001). Pachy-vessels and late hyperpermeability on ultra-widefield ICGA were observed in all eyes. Vortex vein anastomosis was present in 93% of the affected eyes versus 88.2% in unaffected fellow eyes ( P = 0.61). Disc and posterior poles were the sites of the maximum number of anastomoses in both affected and unaffected eyes ( P = 0.77). Asymmetry in vortex vein drainage of the macula was present in 88.4% of affected eyes and 88.2% of unaffected eyes. Studying the ICGA findings in CSC patients emphasized the role of choroidal circulation in pathogenesis as Pachy vessels were observed in all eyes affected with CSC and even fellow eyes of patients. Vortex vein anastomosis around the disc or posterior pole and asymmetric drainage from the macula were noted and could be contributing to CSC pathology.

Acute spontaneous vortex vein occlusion: clinical features, multimodal imaging and natural course

AimsTo describe the clinical features, multimodal imaging, treatments and natural course of acute spontaneous vortex vein occlusion.MethodsClinical data were collected on nine patients with acute vortex vein occlusion. The symptoms...

OCTA characteristics in non-arteritic central retinal artery occlusion and correlation with visual acuity.

To observe the retinal and choroidal circulations in patients with non-arteritic permanent central retinal artery occlusion (NA-CRAO) via optical coherence tomography angiography (OCTA) and analyze their correlation with visual acuity. Sixty-two eyes with clinically confirmed acute NA-CRAO were included in the study and divided into: A type (mild n=29), B type (moderate n=27) and C type (severe n=6) based on the degree of visual loss, retinal edema, and arterial blood flow delay in fundus fluorescence angiography (FFA). Contralateral healthy eyes were used as the control group. Best-corrected visual acuity (BCVA), slit lamp microscopy, indirect ophthalmoscopy, fundus color photography, OCTA, and FFA were performed. Spearman's correlation analysis was used to determine the correlations between retinal and choroidal vessels and visual acuity. There were no statistically significant differences in age, gender, and intraocular pressure among the three types and the control group (P>0.05). Vessel density in deep capillary plexus (VD-DCP) significantly decreased (P<0.05) in all three types of NA-CRAO patients compared to the control group. Vessel density in superficial vascular plexus (VD-SVP) significantly decreased (P<0.05) in type A patients and choriocapillaris flow area significantly decreased (P<0.05) in type B and type C patients compared to the control group; while outer retinal flow areas significantly increased in the type A (P<0.05) and decreased in type C patients (P<0.05). The retinal thickness significantly increased in type C group (P<0.05). The VD-SVP at fovea in the type A was significantly lower than both of type B and C. The VD-SVP at nasal parafovea in type A and B was significantly lower than type C (P<0.05). The logMAR BCVA of type A was significantly better than that of type B and C groups (P<0.05). Spearman's correlation analysis showed that the logMAR BCVA was positively correlated with VD-SVP at fovea (r=0.679, P=0.031) and nasal parafovea (r=0.826, P=0.013). OCTA is valuable for assessing retinal ischemia, and evaluating visual impairment. Deep retinal vasculature is commonly affected in all NA-CRAO types. VD-SVPs at fovea and nasal parafovea can serve as reliable markers of visual impairment in NA-CRAO.

Correlation between choroidal vascularity and retrobulbar ocular blood flow changes and thyroid-associated ophthalmopathy activity: a cross-sectional study

ObjectiveTo evaluate the alterations in retrobulbar color Doppler imaging (CDI) parameters and retinal/choroidal optical coherence tomography angiography (OCTA) parameters and their association with the clinical activity and severity in thyroid-associated orbitopathy (TAO) patients.MethodsIn this study, the retrobulbar flow parameters including resistance index (RI), Pulsatile Index(PI), peak systolic velocity (PSV) and end diastolic velocity (EDV) in posterior ciliary artery (PCA), central retinal artery (CRA) and ophthalmic artery (OA) were determined by CDI. Moreover, the retina and choroidal vascularity including the superficial vessel density (SVD), deep vessel density (DVD), choroidal thickness (ChT) and choroidal vascularity, including total choroidal area (TCA), luminal area (LA), stromal area (SA) and Choroidal Vascularity Index (CVI), were determined by OCTA. All patients grouped as active TAO and inactive TAO based on Clinical activity score (CAS). We picked the severe eye among the subjects and compared all parameters between two groups. We analyzed the correlations among those parameters.ResultsThere was a significant difference in CAS score, proptosis value, ChT, LA, CVI between patients with active TAO and inactive TAO. In the active group, PSV and EDV of PCA were significantly higher than the inactive group. On logistic regression analysis, CAS was closely associated with PSV-PCA. On multiple linear regression, proptosis value was closely associated with ChT, LA, SA and CVI.ConclusionChoroidal vascularization and retrobulbar blood flow were concurrently higher in active TAO patients and several variables in choroid circulation was closely related to TAO clinical features.

GLAUCOMA SECONDARY TO NONSPECIFIC ORBITAL INFLAMMATION: A DIAGNOSIS NOT TO OVERLOOK

Introduction : Nonspecific Orbital Inflammation (NSOI) is an inflammatory condition of unknown etiology manifesting as pain, ocular motility disturbances, eyelid edema, chemosis, and increased intraocular pressure (IOP). We illustrate a case of glaucoma secondary to NSOI and the importance of understanding the cause-effect relationship between the two conditions.&#x0D; Case Illustration : An eighteen-year-old girl presented with severe pain, ptosis, chemosis, ophthalmoplegia, and increased IOP (38 mmHg) despite a leaking trabeculectomy bleb, on the left eye. She was referredwith the diagnosis of primary angle-closure glaucoma (PACG) and a history of twice trabeculectomy surgeries done elsewhere two months before she came to our hospital. She could not move her lefteye nasally five months before the first surgery and felt joint pains for a year. After thorough diagnostics, she was assessed with left eye NSOI and secondary glaucoma with spondyloarthropathy. Oral prednisone 30 mg/day was given to manage the inflammation and the resultant glaucoma. One week follow-up showed an improved condition with decreased IOP (16 mmHg) despite the same anti-glaucoma therapy regimen.&#x0D; Discussion : NSOI can mimic various diseases, making diagnosis challenging. The raised IOP in NSOI is often caused by extraocular muscles and orbital tissue swelling, which compresses the superior and inferior ophthalmic veins, resulting in choroidal circulation problems. The IOP was quickly reduced once the inflammation was managed. This is a case of secondary glaucoma caused by an overlooked NSOI, aggravated by the immunological process in the orbit after trabeculectomy surgeries.&#x0D; Conclusion : Secondary glaucoma should be considered as a differential diagnosis of PACG in patients with NSOI.

APOB100 transgenic mice exemplify how the systemic circulation content may affect the retina without altering retinal cholesterol input.

Apolipoprotein B (APOB) is a constituent of unique lipoprotein particles (LPPs) produced in the retinal pigment epithelium (RPE), which separates the neural retina from Bruch's membrane (BrM) and choroidal circulation. These LPPs accumulate with age in BrM and contribute to the development of age-related macular degeneration, a major blinding disease. The APOB100 transgenic expression in mice, which unlike humans lack the full-length APOB100, leads to lipid deposits in BrM. Herein, we further characterized APOB100 transgenic mice. We imaged mouse retina in vivo and assessed chorioretinal lipid distribution, retinal sterol levels, retinal cholesterol input, and serum content as well as tracked indocyanine green-bound LPPs in mouse plasma and retina after an intraperitoneal injection. Retinal function and differentially expressed proteins were also investigated. APOB100 transgenic mice had increased serum LDL content and an additional higher density HDL subpopulation; their retinal cholesterol levels (initially decreased) became normal with age. The LPP cycling between the RPE and choroidal circulation was increased. Yet, LPP trafficking from the RPE to the neural retina was limited, and total retinal cholesterol input did not change. There were lipid deposits in the RPE and BrM, and retinal function was impaired. Retinal proteomics provided mechanistic insights. Collectively, our data suggested that the serum LDL/HDL ratio may not affect retinal pathways of cholesterol input as serum LPP load is mainly handled by the RPE, which offloads LPP excess to the choroidal circulation rather than neural retina. Different HDL subpopulations should be considered in studies linking serum LPPs and age-related macular degeneration.

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

The aim of this study was to evaluate the choroidal thickness and choroidal vascular index in normotensive individuals with dipping and nondipping patterns. Patients who applied to the cardiology clinic for routine checkups and underwent 24-h blood pressure monitoring were included in our study. They were divided into two groups based on their dipper status. The patients in whom systolic blood pressure decreased during the nocturnal time by 10% or more of the daily blood pressure were defined as dippers. On the contrary, patients whose nocturnal systolic blood pressure decreased by less than 10% were defined as nondippers. Choroidal thickness and choroidal vascular index were measured by spectral-domain optical coherence tomography. Central macular thickness, retinal nerve fiber layer, and ganglion cell layer (GCL) analyses were also recorded. In total, 35 patients with dipper pattern and 34 patients with nondipper pattern were recruited. The mean subfoveal choroidal thickness was 349.72±90 μm in the dipper group and 358.54±132.5 μm in the nondipper group. The groups had no significant difference in choroidal thickness, central macular thickness, retinal nerve fiber layer, and ganglion cell layer analyses. However, the choroidal vascular index was statistically significantly lower in the nondipper group when compared to the dipper group (0.61±0.02 vs. 0.64±0.02; p<0.001). Also, the choroidal vascular index was negatively correlated with subfoveal choroidal thickness in the nondipper group (Spearman; r=-0.419; p=0.033). Our study showed that the choroidal vascular index was significantly lower in nondippers than in dippers. Nondipper individuals may be affected by vascular dysregulation, leading to alterations in the choroidal circulation.

The effects of physical exercise on ocular blood flow

Vascular resistance is physiologically regulated by changing the local diameter of the arterioles to keep the local blood flow constant. It is well known that physical activity has profound impacts on the vasculature in humans. Short‐term exercise induces immediate changes in artery function, whereas long‐term exercise induces chronic functional adaptation and structural arterial remodelling which leads to a lower risk of risk for cardiovascular disease. These changes depended on the characteristics of the training load and are modulated by other factors such as exercise‐induced inflammation and oxidative stress.The ocular circulation consists of the retinal and choroidal circulations. The retina is the tissue with the most active metabolism in the human body, resulting in a high rate of oxygen consumption. Therefore, ocular blood flow is particularly susceptible to physical exercise. With the arrival of imaging technologies numerous studies have explored the effects of exercise on the ocular blood flow. Most of these studies are focused on the transient impact of acute exercise on ocular blood flow. The objective of this talk is to discuss the scientific literature available about the effects of physical exercise on ocular blood flow, and to highlight its impact on ocular health.

Comparison of retinochoroidal and optic nerve head microvascular circulation between HIV-positive patients and healthy subjects using optical coherence tomography angiography

To evaluate the retinal, choroidal, and optic disc head microvascular circulation in human immunodeficiency virus (HIV)-infected individuals without retinopathy receiving highly active antiretroviral therapy (HAART) using swept-source optical coherence tomography angiography (SS-OCTA). This cross-sectional study included 100eyes of 100patients with HIV infection but no HIV-related ocular disease and 108 eyes of 108 age- and sex-matched healthy subjects as the control group. SS-OCTA was used to assess foveal avascular zone (FAZ) area, retinal nerve fiber layer thickness (RNFL), choriocapillaris (CC) flow area, outer retinal (OR) thickness, radial peripapillary capillary (RPC) vessel density (VD), ONH VD, and choroidal thickness. No statistically significant difference was found between the two groups except in the foveal VD of the deep capillary plexus (DCP). The foveal VD of the DCP was lower in the HIV-positive group (P=0.011). The mean FAZ area (mm2), perimeter (mm), and CC flow area (mm) values were higher in the HIV-positive group at statistically significant levels (P=0.021, P=0.02, and P=0.039, respectively). However, no statistically significant differences were found between the two groups concerning the OR flow area, subfoveal choroidal thickness, or the VDs of the RPC or ONH. This is the first study in the literature to evaluate the microvascular circulation of the ONH in HIV-positive patients. Although retinal and choroidal microvascular circulation decreased in HIV-positive patients receiving HAART treatment, we found no effect on the microvascular circulation of the ONH or RPC microvascular circulation. Our findings suggest that retinochoroidal microvascular circulation is affected in HIV-positive patients over time.

Hyperbaric Oxygen Therapy in Ophthalmology: A Narrative Review.

Hyperbaric oxygen therapy (HBOT) has been used for the past 50 years for conditions such as decompression disease and wound healing. It has promising effects in the treatment of vision-threatening diseases, such as retinal artery occlusion, retinal vein occlusion, diabetic macular edema, and acute optic neuropathy; however, HBOT has not been approved for use in these conditions by regulatory authorities. This paper provides an overview of the theoretical effectiveness and most recent indications for HBOT in ophthalmology. The fundamental aspects of the physiology of choroidal circulation and metabolism are provided together with the clinical aspects that should be accounted for when selecting patients for this therapy. The paper also presents case reports of when HBOT was successfully implemented. The goals of this review were to explore the indications and benefits of HBOT and to evaluate the effectiveness of HBOT as an intervention in treating ophthalmology disorders. Lastly, the paper details the side-effects and discusses the safety issues of HBOT.

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.

Investigation of the effects of gestational diabetes and hypertension on retinal and choroidal microvascular circulation using swept-source optical coherence tomography angiography

PurposeThe aim of this study was to investigate the microvascular changes in the retina and choroid in gestational diabetes mellitus (GDM) and pregnancy-induced hypertension (PIH) and to compare the results with those of healthy pregnant subjects. MethodsTwenty-nine pregnant subjects with coexisting GDM and PIH (group 1) and 36 healthy pregnant subjects (group 2) were enrolled in the study. All subjects were examined by optical coherence tomography (OCT) and angiography (OCTA). The retina, retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), choroidal thickness (CT), superficial capillary plexus (SCP), deep capillary plexus (DCP), choriocapillaris (CC) vascular density (VD), and foveal avascular zone (FAZ) were measured. ResultsWe observed that the values of CT and VD were lower in group 1 than in group 2. No significant difference was found between groups in RT, FAZ area and CC VD. SCP and DCP VD values were higher in group 2 in all quadrants. We observed a significant increase in FAZ area and CC VD with increasing systolic blood pressure. No correlation was observed between diastolic blood pressure and FBS with other parameters. In group 1, FAZ area was significantly higher in the diet-treated group than in the insulin-treated group. ConclusionMonitoring and treatment of pregnant women with PIH and GDM is important because of the risks that may occur during pregnancy. We believe that changes in microvascular circulation can be detected noninvasively with OCTA, even in the absence of clinical or retinal findings.