Ocular Blood Flow Changes Impact Visual Acuity Gain after Surgical Treatment for Idiopathic Epiretinal Membrane

Evaluation of retinal and choroidal thickness changes in overweight and obese adults without ocular symptoms by swept-source optical coherence tomography

AIM

To evaluate the relationship of overweight and obesity with retinal and choroidal thickness in adults without ocular symptoms by swept-source optical coherence tomography (SS-OCT).

METHODS

According to the body mass index (BMI) results, the adults enrolled in the cross-sectional study were divided into the normal group (18.50≤BMI<25.00 kg/m2), the overweight group (25.00≤BMI<30.00 kg/m2), and the obesity group (BMI≥30.00 kg/m2). The one-way ANOVA and the Chi-square test were used for comparisons. Pearson's correlation analysis was used to evaluate the relationships between the measured variables.

RESULTS

This research covered the left eyes of 3 groups of 434 age- and sex-matched subjects each: normal, overweight, and obesity. The mean BMI was 22.20±1.67, 26.82±1.38, and 32.21±2.35 kg/m2 in normal, overweight and obesity groups, respectively. The choroid was significantly thinner in both the overweight and obesity groups compared to the normal group (P<0.05 for all), while the retinal thickness of the three groups did not differ significantly. Pearson's correlation analysis showed that BMI was significantly negatively correlated with choroidal thickness, but no significant correlation was observed between BMI and retinal thickness.

CONCLUSION

Choroidal thickness is decreased in people with overweight or obesity. Research on changes in choroidal thickness contributes to the understanding of the mechanisms of certain ocular disorders in overweight and obese adults.

[Clinical and pathophysiological contribution of OCT-angiography to epiretinal membranes]

Epiretinal membranes may lead to centripetal contraction forces on the retina and its vessels. OCT-Angiography (OCT-A) is a recent tool which permits a non-invasive understanding of these vascular changes. This review focuses on the OCT-A findings in idiopathic epiretinal membranes, before and after surgery, and the role of internal limiting membrane peeling. It appears that contraction of the epiretinal membrane is associated with both a reduction in the area and perimeter of the foveal avascular zone and alterations in the superficial and deep capillary plexuses. These changes mainly reflect a vascular shift from the perifoveal to the foveal region, increasing with retinal deformation, but also probable dynamic changes in vascular flow. Membrane peeling allows at least partial improvement of these microvascular parameters. Nevertheless, some limitations of OCT-A, such as segmentation errors on a retina with highly modified architecture, can lead to a selection bias in the studies and should call for caution in the interpretation of the results. Finally, internal limiting membrane peeling contributes to changes in the retinal architecture after surgery, in particular by causing a centripetal movement of the macular capillaries and a displacement of the fovea toward the optic nerve head. This role should be clarified in future studies.

A controllable perfusion microfluidic chip for facilitating the development of retinal ganglion cells in human retinal organoids

Retinal organoids (ROs) derived from human pluripotent stem cells (hPSCs) have become a promising model in vitro to recapitulate human retinal development, which can be further employed to explore the mechanisms of retinal diseases. However, the current culture systems for ROs lack physiologically relevant microenvironments, such as controllable mechano-physiological cues and dynamic feedback between cells and the extracellular matrix (ECM), which limits the accurate control of RO development. Therefore, we designed a controllable perfusion microfluidic chip (CPMC) with the advantages of precisely controlling fluidic shear stress (FSS) and oxygen concentration distribution in a human embryonic stem cell (hESC)-derived RO culture system. We found that ROs cultured under this system allow for expanding the retinal progenitor cell (RPC) pool, orchestrating the retinal ganglion cell (RGC) specification, and axon growth without disturbing the spatial and temporal patterning events at the early stage of RO development. Furthermore, RNA sequencing data revealed that the activation of voltage-gated ion channels and the increased expression of ECM components synergistically improve the growth of ROs and facilitate the differentiation of RGCs. This study elaborates on the advantages of the designed CPMC to promote RO growth and provide a controllable and reliable platform for the efficient maturity of RGCs in the ROs, promising applications in modeling RGC-related disorders, drug screening, and cell transplantation.

Choroidal structural changes following vitrectomy performed with phacoemulsification in unilateral idiopathic epiretinal membrane

BACKGROUND

This study aims to determine the influence of vitrectomy combined with macular epiretinal membrane dissection and internal limiting membrane (ILM) peeling and phacoemulsification on choroidal vasculature in patients with unilateral idiopathic epiretinal membrane (IERM) and concurrent cataract using optical coherence tomography (OCT).

METHODS

This retrospective study included 26 eyes of 26 patients (8 males and 18 females) with unilateral IERM without vitreomacular traction (VMT) (group 1) and the patients' fellow eyes (n = 26, group 2). Three-port 25-G pars plana vitrectomy (PPV) combined with macular epiretinal membrane dissection and ILM peeling and phacoemulsification was performed on all patients. The comprehensive ophthalmologic examinations of all patients involved OCT measurements at every visit before and after surgery, and the choroidal thickness (CT), central macular thickness (CMT) and choroidal vascularity index (CVI) were calculated.

RESULTS

The mean age of the IERM patients was 66.58 ± 7.06 years. Postoperatively, best corrected visual acuity (BCVA) was significantly greater than baseline (P = 0.023). The CVI of the IERM eyes was significantly lower (P < 0.01) than that of the fellow eyes at baseline. The subfoveal CT in the IERM eyes was lower than that in the fellow eyes (P = 0.023), but there was, no significant difference in the average CT between the two groups at baseline (P = 0.071). In eyes with IERM, the CVI significantly increased at 1 week, 1 month (P < 0.001), and 3 months (P = 0.049) postoperatively, the subfoveal CT was markedly thickened 1 month after surgery (P = 0.001), the temporal 3 mm and nasal CT significantly increased at 1 week and 1 month postoperatively (P = 0.041, P = 0.022 for temporal 3 mm; P < 0.001, P = 0.047 for nasal 1.5 mm; P = 0.01, P = 0.001 for nasal 3 mm), and only the temporal 3 mm CT increased significantly at 3 months postoperatively (P = 0.017). The baseline CMT of the IERM eyes was significantly thicker than that of the fellow eyes (P < 0.001). CMT significantly decreased at 3 months postoperatively in IERM eyes(P = 0.033).

CONCLUSIONS

The increase in the CVI in the IERM eyes without VMT after combined PPV with ILM peeling and phacoemulsification persists for at least 3 months.

Choroidal morphologic and vascular features in patients with unilateral idiopathic epiretinal membranes: An optical coherence tomography analysis integrated with assessment of retinal layers

Introduction

Integrated analysis of retinal and choroidal morphologic and vascular features is urgently needed to examine whether and how these two elements interact with each other, thus contributing to visual impairment in patients with idiopathic epiretinal membranes (iERMs).

Methods

An observational retrospective study consisting of 181 patients diagnosed with unilateral iERM between August 2019 and July 2022 was carried out at Peking University Third Hospital. All patients underwent a standardized set of ophthalmologic examinations, including EDI-OCT and OCTA scanning, and were subsequently categorized into four stages according to current classification schemes based on their OCT findings. Altogether, 15 qualitative and quantitative parameters of both the retina (full-layer, inner and outer layers) and choroid were identified.

Results

The results revealed variations in the choroidal vascularity index (CVI) among different stages of iERMs (p < 0.001) for the first time. Distributions of retinal parameters across four stages of iERMs were validated. Correlation analysis between choroidal and retinal parameters showed that the CVI was associated with both inner and outer retinal morphologic biomarkers. Functional damage to retinal integrity was determined to be a strong contributor to visual acuity reduction in iERMs.

Discussion

This study complemented our present understanding of posterior segment structural and vascular alterations in iERMs.

Insights into the underlying choroid in different stages of idiopathic epiretinal membranes after Viteromacular surgery

PURPOSE

The purpose of the study was to longitudinally investigate the correlation between choroidal morphologic and vascular parameters and postoperative visual outcome in different stages of idiopathic epiretinal membranes (iERMs).

METHODS

A prospective, observational, institutional case series of 102 consecutive patients diagnosed with unilateral iERMs were recruited at Peking University Third Hospital and were followed up for 12 months after surgical treatment with vitrectomy. Participants were classified into four stages according to current staging scheme. All eligible subjects underwent standardized imaging evaluation of choroidal parameters including subfoveal choroidal thickness (SFCT), choroidal vascularity index (CVI), and choroidal capillary perfusion (CCP) at baseline and each follow-up by enhanced depth optical coherence tomography (EDI-OCT) and OCT angiography (OCTA). Longitudinal follow-up of choroidal parameters over 12 months was analysed, and their correlations with best-corrected visual acuity (BCVA) were also assessed for predictive prognostic value.

RESULTS

CVI and CCP were significantly correlated with BCVA at each follow-up examination (all p < 0.05). However, SFCT exhibited no variation among different stages of iERMs at baseline (p = 0.981) or during follow-up (p = 0.520). The preoperative CVI correlated with 12-month postoperative BCVA (p < 0.001) and its predictive prognostic effect on BCVA was validated in multiple regression analysis (p = 0.006).

CONCLUSION

CVI varied among different stages of iERM and was significantly correlated with visual outcomes after the surgery. CVI could serve as a predictive prognostic marker in iERMs, which further indicates the underlying choroid should be taken into consideration in clinical evaluation of iERMs.

Evaluating Retinal and Choroidal Perfusion Changes after Isometric and Dynamic Activity Using Optical Coherence Tomography Angiography

Optical coherence tomography angiography (OCTA) is a non-invasive tool for imaging and quantifying the retinal and choroidal perfusion state in vivo. This study aimed to evaluate the acute effects of isometric and dynamic exercise on retinal and choroidal sublayer perfusion using OCTA. A pilot study was conducted on young, healthy participants, each of whom performed a specific isometric exercise on the first day and a dynamic exercise the day after. At baseline and immediately after the exercise, heart rate (HR), mean arterial pressure (MAP), superficial capillary plexus perfusion (SCPP), deep capillary plexus perfusion (DCPP), choriocapillaris perfusion (CCP), Sattlers’s layer perfusion (SLP), and Haller’s layer perfusion (HLP) were recorded. A total of 34 eyes of 34 subjects with a mean age of 32.35 ± 7.87 years were included. HR as well as MAP increased significantly after both types of exercise. Both SCPP and DCPP did not show any significant alteration due to isometric or dynamic exercise. After performing dynamic exercise, CCP, SLP, as well as HLP significantly increased. Changes in MAP correlated significantly with changes in HLP after the dynamic activity. OCTA-based analysis in healthy adults following physical activity demonstrated a constant retinal perfusion, supporting the theory of autoregulatory mechanisms. Dynamic exercise, as opposed to isometric activity, significantly changed choroidal perfusion. OCTA imaging may represent a novel and sensitive tool to expand the diagnostic spectrum in the field of sports medicine.

Preoperative Vision, Gender, and Operation Time Predict Visual Improvement After Epiretinal Membrane Vitrectomy: A Retrospective Study

Background

To evaluate the efficacy of micro-incision vitrectomy surgery using a non-contact wide-angle viewing system for fovea-attached type epiretinal membrane, and to report the factors influencing the outcome.

Methods

A retrospective, comparative case series that included 50 patients with fovea-attached type epiretinal membrane who received micro-incision vitrectomy surgery using a non-contact wide-angle viewing system.

Results

All patients were followed-up for a minimum of 12 months. Seven cases were classified as group 1A (mainly outer retinal thickening), 17 were group 1B (more tenting of outer retina and distorted inner retina), and 26 were group 1C (prominent inner retina thickening and inward tenting of outer retina). Outcome measures included operation time, recurrent rate, postoperative BCVA, and CRT. The mean operative time was 26.2 minutes. The mean change of BCVA (LogMAR) was −0.43 (p< 0.001). The mean change of CRT was 135.3 μm (p< 0.001). The mean change of CRT was significantly higher in group 1C. Worse preoperative BCVA, male gender, and longer operative time can predict better postoperative BCVA found by multivariate logistic regression and multiple regression models.

Conclusion

Significant improvement in BCVA and CRT is noted after micro-incision vitrectomy surgery to operate fovea-attached type epiretinal membranes. Worse preoperative BCVA, male, and longer operation time could predict better improvement. These findings may assist surgeons in better evaluating the potential of this method to help their patients with epiretinal membranes.

Influences of Central Bouquet Alterations on the Visual Outcome in Eyes Receiving Epiretinal Membrane Surgery

Background: Previous studies have shown that epiretinal membranes (ERMs) may be associated with abnormal outer retinal anatomy. However, long-term morphological and functional results of pars plana vitrectomy (PPV) with ERM and internal limiting membrane (ILM) peeling in eyes with central bouquet (CB) alterations have not yet been investigated. Methods: In a retrospective, consecutive study all patients underwent best corrected visual acuity (BCVA) testing and spectral domain optical coherence tomography (SD-OCT) before and after a mean of 20 months (range 3–70 months) postoperatively. CB abnormalities and ERMs were classified according to Govetto’s staging systems. Results: Of the 67 eyes, 22 (34%) showed CB abnormalities at baseline. The mean BCVA increased from 0.42 at baseline to 0.20 LogMAR at final follow-up (p < 0.001). Neither ERM stage (p = 0.06) nor CB stage (p = 0.939) at baseline were significant predictors of vision improvement following surgery. Conclusions: Our results show that baseline BCVA, but not classification of CB changes and ERM at baseline, seems to be a useful predictor for functional outcomes following PPV with ERM and ILM peeling in the long-term.

Epiretinal Membrane Surgery: Structural Retinal Changes Correlate with the Improvement of Visual Function

Several parameters have been studied for identifying the visual outcomes after pars plana vitrectomy (PPV) for epiretinal membrane (ERM) peeling. This retrospective study aimed to analyze structural retinal changes with spectral domain-optical coherence tomography (SD-OCT) and their correlations with visual acuity improvement in patients with ERM undergoing PPV. Twenty-one pseudophakic eyes were enrolled in the study. Ophthalmic evaluations included best corrected visual acuity (BCVA) and retinal layer thickness measurements with SD-OCT. The segmentation of the retina was divided into four parts: the inner retinal layer (IRL), composed of an internal limiting membrane, retinal nerve fiber layer, ganglion cell layer, and inner plexiform layer; inner nuclear layer (INL); outer plexiform layer (OPL); and outer nuclear layer (ONL). Correlations between changes in retinal layer thicknesses and BCVA were explored over a 6 month follow-up period. The postoperative thickness decrease of the INL was significantly correlated with thickness changes in all other measured retinal layers (p < 0.001). Non-parametric linear regression showed that postoperative improvement in BCVA was associated with a postoperatively decreased thickness in the IRL (p = 0.021), INL (p = 0.039), and OPL (p = 0.021). In eyes undergoing PPV, postoperative thickness decreases of the IRL, INL, and OPL were correlated with visual acuity improvements. Re-compaction of these retinal layers after relieving ERM-induced traction may be an important factor in postoperative visual function improvement.

Evaluating Retinal and Choroidal Perfusion Changes After Ocular Massage of Healthy Eyes Using Optical Coherence Tomography Angiography

Background and objectives: Ocular massage (OM) is used as a treatment option for acute retinal artery occlusion, under the assumption that it induces vessel dilatation and enhances perfusion. Since evidence of ocular perfusion alteration due to OM is lacking, we investigate the impact of OM on the hemodynamics of the posterior pole in healthy eyes in a noninvasive fashion by using optical coherence tomography angiography (OCTA). Materials and Methods: A prospective study was conducted on healthy volunteers, each of whom underwent measurements of intraocular pressure (IOP), central macular thickness (CMT), subfoveal choroidal thickness (SFCT), radial peripapillary capillary perfusion (RPCP), superficial capillary plexus perfusion (SCPP), deep capillary plexus perfusion (DCPP), choriocapillaris perfusion (CCP), Sattler’s layer perfusion (SLP) and Haller’s layer perfusion (HLP) before and after OM. OM was performed for 2 min, consisting of 10-s turns of compression and decompression of the globe. Results: A total of 21 eyes from 21 participants (median age 29) were included. After OM, IOP significantly declined (p < 0.001), while SFCT (p < 0.005), SCPP (p < 0.001), DCPP (p = 0.004) and CCP (p = 0.008) significantly increased. CMT, RPCP, SLP and HLP did not show any significant alteration due to OM. Changes in SCPP correlated positively with changes in CCP and vice versa. Conclusions: OCTA-based analysis in healthy adults following OM demonstrated a significant increase of retinal perfusion values, assumed to be due to failure of autoregulatory mechanisms. These findings may indicate a positive effect of OM as a treatment option for patients with acute retinal artery occlusion.

Intraocular pressure might play a role in the surgical management of patients with epiretinal membrane

PURPOSE

To investigate the prognostic factors and visual outcomes for patients with epiretinal membrane after pars plana vitrectomy and possible interactions between multiple factors.

METHODS

A retrospective chart review of adult patients with epiretinal membrane treated with pars plana vitrectomy performed by a single surgeon between February 1, 2015, and January 31, 2017 was conducted. The surgical procedures included standard 25-gauge vitrectomy with peeling of the epiretinal membrane and internal limiting membrane (ILM). Factors including age, sex, vision, intraocular pressure (IOP), lens status, and baseline optical coherence tomography angiography were analyzed to determine any association with visual outcomes. IOP and lens status were evaluated at every visit point and were used for analysis.

RESULTS

Visual changes after pars plana vitrectomy in patients with epiretinal membrane were significantly associated with time, lens status, baseline ellipsoid zone integrity, baseline vision, baseline parafoveal vessel density of superficial capillary plexus (SPVD), and IOP. Further investigation using Johnson-Neyman analysis revealed that vision improved over time, especially in pseudophakic eyes. High IOP at baseline or during follow-up was identified as a significant factor associated with limited visual improvement.

CONCLUSION

Our study showed that vision improved over time after vitrectomy for patients with epiretinal membrane. The surgical outcomes are more stable in pseudophakic eyes, and vision improved after cataract extraction in phakic eyes. IOP should be managed and monitored closely to optimize surgical and visual outcomes in patients.