Changes in Iris Perfusion Following Scleral Buckle Surgery for Rhegmatogenous Retinal Detachment: An Anterior Segment Optical Coherence Tomography Angiography (AS-OCTA) Study

Comparison of Vessel Density and Retinal Sensitivity After Scleral Buckling and Phacovitrectomy in the Management of Macula-on Primary Rhegmatogenous Retinal Detachment

Purpose

The choice of surgical method for rhegmatogenous retinal detachment (RRD) may have a significant impact on the retina. In this study, we aimed to compare retinal function and structure after scleral buckling (SB) and phacovitrectomy (phaco-PPV) for macula-on RRD.

Patients and Methods

This cross-sectional study included patients who underwent anatomically successful repair of macula-on RRD managed with SB (n=35) and phaco-PPV (n=35) between 2019-2023. All participants were examined within 6-20 months of surgery to evaluate the retinal structure using spectral domain optical coherence tomography (SD-OCT) and vessel density (VD) by OCT angiography (OCTA). Best-corrected visual acuity (BCVA) and microperimetry (MP) tests were used to assess the retinal function.

Results

Analysis of the microvascular network with OCTA between eyes after surgery and healthy eyes showed a decrease in VD. Significant changes in the superficial vascular plexus (SVP) and deep vascular plexus (DVP) were observed only in eyes after SB surgery (p <0.001 and p=0.02, respectively). Analysis of retinal function assessed by MP showed a significant decrease (p<0.05) in retinal sensitivity after phaco-PPV (24.81±2.25 dB) and SB (24.18±2.14 dB) operations compared to the healthy control group (25.97 ± 1.51 dB), whereas postoperative BCVA showed no differences (p>0.05).

Conclusion

Changes in retinal sensitivity were accompanied by impairment of the microvascular network in the eyes after SB and phaco-PPV surgeries due to macula-on RRD. Disorders were more pronounced in eyes following SB surgery, possibly secondary to mechanical stress.

Immediate effect of anti-VEGF injections on optic nerve head: Correlation between intraocular pressure and anatomical peripapillary changes

PURPOSE

This study was designed to investigate retinal nerve fiber layer (RNFL) and radial peripapillary capillaries (RPC) changes on optical coherence tomography (OCT) angiography and OCT thickness alterations associated with acutely increased intraocular pressure after intravitreal injections.

METHODS

This observational clinical study was conducted on 35 eyes (35 patients) with treatment-naïve age-related macular degeneration (AMD) and type 1 or type 2 MNV were enrolled. All patients underwent anti-vascular endothelial grow factor (VEGF) intravitreal injections with 0.05-mL aflibercept (2 mg) between January 2022 and October 2022. Peripapillary OCT angiography perfusion density, retinal nerve fiber layer thickness, and intraocular pressure (IOP) were measured before and immediately after intravitreal injections. In particular, the analysis was performed at the following visits: (T0) 5 to 15 min before the injection of aflibercept; (T1) 2 to 5 min after the injection of aflibercept. Paired t-test was used to compare pre-injection and post-injection values.

RESULTS

The mean baseline IOP (T0) value was 17.26 ± 2.4 mmHg and the immediate post-injection IOP (T1) mean value was 34.7 ± 11.50 mmHg (P < 0.01). The mean global RNFL thickness before and immediately after the injection was 100.9 ± 18.8 m and 98.6 ± 17.4 m (P = 0.001). Furthermore, the topographical RNFL analysis showed significant thickness reduction of the nasal and inferior sectors after the procedure when compared to T0 (P = 0.046 and P = 0.001). On the contrary, the mean RCP density changes at T1 did not reach statistically significant (P = 0.636). Furthermore, we found a significant negative correlation between the retinal nerve fiber layer global thickness and the IOP changes (Pearson's correlation = -0.126; P = 0.031). In particular, the nasal RNFL region showed a significant negative correlations with IOP values (Pearson's correlation = -0.198, P = 0,046).

CONCLUSIONS

We reported acute IOP changes that are associated with reduced RNFL thickness in a group of patients undergoing intravitreal injections of anti-VEGF drugs for neovascular age-related macular degeneration. Moreover, topographical sub-analysis revealed that the nasal RNFL region is most prone to IOP fluctuations. This finding may explain the sudden visual acuity change in patients immediately after injection and may sustain injuries to optic nerve head structures producing glaucomatous damage.

The use of optical coherence tomography angiography to measure changes in iris vasculature after strabismus surgery

INTRODUCTION

Anterior segment ischemia (ASI) is a rare but potentially sight-threatening complication of strabismus surgery. Preoperative imaging of the iris vasculature may be appropriate in patients at high risk of ASI. In clinical practice, this is currently done through invasive fluoresceine or indocyanine green (ICG) angiography and in study context through laser speckle contrast imaging. The purpose of this study is to investigate the use of noninvasive optical coherence tomography angiography (OCTA) as a screening tool for ASI in strabismus surgery.

METHODS

A prospective interventional trial was conducted from September until November 2021 at the Leuven University Hospitals. Patients scheduled for strabismus surgery to one or more rectus muscles underwent OCTA preoperatively and at day two postoperatively. The vascular density was calculated for all images with sufficient quality. Information on risk factors for ASI was collected. A two-sided t-test was used for pairwise comparison pre- and postoperatively. Filling defects were qualitatively assessed.

RESULTS

Eighteen patients were included. In only seven muscles of five patients, images of sufficient quality on both image acquisition moments were suitable for statistical analysis. The mean age of these patients was 45.2 years and 40% were women. A mean vascular density of 53,099% preoperatively and a mean density of 50,782% postoperatively with a mean decrease of 2.316% (p = .318, 95% confidence interval [-2.886; 7.516]) was found. No filling defects were identified.

DISCUSSION

The small final number of images contributing to statistical analysis shows that current application of the OCTA technique is hampered by poor image quality and poor repeatability. We identified difficulties in the image acquisition process and variable pupil size due to iris muscle contractions as the two main reasons. We believe that adjustments in the OCTA software such as pupil tracking and tracking of iris vasculature can largely overcome these limitations. Furthermore, there is a need for a normative database to allow good quantitative comparison and risk stratification. We conclude that OCTA could be suitable for screening in prevention of ASI with both qualitative and quantitative analysis if adjustments are made.

Current clinical applications of anterior segment optical coherence tomography angiography: a review

Optical coherence tomography (OCT) is a revolutionary in vivo imaging technology that presents real-time information on ocular structures. Angiography based on OCT, known as optical coherence tomography angiography (OCTA), is a noninvasive and time-saving technique originally utilized for visualizing retinal vasculature. As devices and built-in systems have evolved, high-resolution images with depth-resolved analysis have assisted ophthalmologists in accurately localizing pathology and monitoring disease progression. With the aforementioned advantages, application of OCTA has extended from the posterior to anterior segment. This nascent adaptation showed good delineation of the vasculature in the cornea, conjunctiva, sclera, and iris. Thus, neovascularization of the avascular cornea and hyperemia or ischemic changes involving the conjunctiva, sclera, and iris has become prospective applications for AS-OCTA. Although traditional dye-based angiography is regarded as the gold standard in demonstrating vasculature in the anterior segment, AS-OCTA is expected to be a comparable but more patient-friendly alternative. In its initial stage, AS-OCTA has exhibited great potential in pathology diagnosis, therapeutic evaluation, presurgical planning, and prognosis assessments in anterior segment disorders. In this review of AS-OCTA, we aim to summarize scanning protocols, relevant parameters, and clinical applications as well as limitations and future directions. We are sanguine about its wide application in the future with the development of technology and refinement in built-in systems.

Investigation of OCTA Biomarkers in Fabry Disease: A Long Term Follow-Up of Macular Vessel Area Density and Foveal Avascular Zone Metrics

INTRODUCTION

Retinal microvasculature is known to be altered in patients with Fabry disease (FD). We aimed to investigate the long-term changes in macular microvasculature and explore a reliable retinal biomarker for treatment monitoring in FD.

METHODS

Prospective study of 26 eyes with FD followed up to 48 months (mean 24, range 8-48). OCT angiography (OCTA) images (2.9 × 2.9 mm) were obtained using Heidelberg Spectralis II at baseline and follow-up. Macular vessel area density (VAD, %) was measured in three layers: superficial vascular plexus (SVP), intermediate capillary plexus (ICP) and deep capillary plexus (DCP) in three peri-macular circular sectors (c1, c2, c3). Additionally, foveal avascular zone (FAZ) area (mm2) and horizontal and vertical diameters (µm) were assessed.

RESULTS

VAD decreased over time in SVP, ICP (in sectors c2 and c3) and DCP (all sectors) (p < 0.04). VAD reduction was predominantly seen in treated FD patients. FAZ and horizontal diameters increased at follow-up in FD patients compared to baseline (p ≤ 0.025). Correlation analysis showed a moderate to strong negative correlation between VAD of SVP and DCP in the innermost circle and FAZ in treated patients (r = - 0.6; p < 0.0001).

CONCLUSIONS

This is the first long-term follow-up OCTA study in FD to our knowledge. A decrease in VAD, pronounced in the peripheral circle and deeper layers, as well as an enlargement of the FAZ could be observed over time. These changes reflect the vascular remodelling during the course of the disease. Interestingly, the reduction of VAD was more pronounced in treated patients. This could be a result of enzyme replacement therapy and could be potentially used as a reliable biomarker for monitoring the treatment of the disease. A baseline examination of VAD and FAZ before treatment initiation is meaningful. Larger studies are needed to establish the use of VAD and FAZ as biomarkers for treatment monitoring.

Effects of diabetic retinopathy on longitudinal morphological changes in AMD-associated type 1 macular neovascularization

The purpose of this study was to investigate the effect of diabetic retinopathy (DR) on longitudinal morphological changes in AMD-associated type 1 macular neovascularization using optical coherence tomography angiography (OCTA). We enrolled fifty treatment-naïve eyes with a diagnosis of exudative AMD and type 1 MNV. Twenty of 50 eyes were affected by mild DR. En face OCT angiography were examined for the MNV lesion area (mm2), the MNV flow area (mm2), the central macular thickness (CMT) and the BCVA. The OCTA acquisition was performed at the following visits: (i) before the loading phase (LP) of intravitreal injection of aflibercept (T1), and (ii) 1 month after the last intravitreal injection of loading phase comprising 3 monthly injections (T2). All morpho-functional parameters showed a significantly change at T2 compared to T1 values in both groups. Furthermore, we found a greater MNV area reduction after LP in eyes without DR (P = 0.023). With regard to the remaining parameters, no significant changes were found between two groups (P > 0.05). Our analysis revealed a less MNV area reduction after loading dose of anti-VEGF therapy in eyes affected by diabetic retinopathy.

A pilot clinical study of complex rhegmatogenous retinal detachment treatment via foldable capsular buckle scleral buckling

BACKGROUND

To evaluate the feasibility of and identify problems in treating complex rhegmatogenous retinal detachment using foldable capsular buckle scleral buckling.

METHODS

This prospective clinical study enrolled five patients with complex rhegmatogenous retinal detachment treated with foldable capsular buckle scleral buckling at the 988th Hospital of People's Liberation Army Joint Logistic Force, China. During the 24-week follow-up period, the patients underwent measurements of their best-corrected visual acuity, slit-lamp examination, indirect ophthalmoscopy, and visual field testing. Additionally, B-ultrasound and fundus photography of the patients' retinal reattachments helped evaluate the treatment's post-surgery efficacy. We determined the safety of foldable capsular buckle scleral buckling based on infection, eye pain, diplopia, elevated intraocular pressure, and other postoperative severe complications.

RESULTS

All five patients' complex rhegmatogenous retinal detachments were successfully treated and evaluated via B-ultrasound and fundus photography after surgery. Visual acuity was enhanced in four patients 24 weeks after surgery, while the remaining patients developed diplopia after surgery. No other complications were observed.

CONCLUSION

This pilot study preliminarily determined that foldable capsular buckle scleral buckling is feasible for efficient and safe treatment of complex rhegmatogenous retinal detachment. These results support this surgery as a potential and novel alternative to current extraocular procedures for treating complex rhegmatogenous retinal detachment.

TRIAL REGISTRATION

The prospective observational clinical study protocol was approved by the Institutional Review Board and Ethics Committee and registered at the clinical research center in the 988th Hospital of People's Liberation Army Joint Logistic Force, China (9,882,019,000).

Advances in swept-source optical coherence tomography and optical coherence tomography angiography

Background

The fast development of swept-source optical coherence tomography (SS-OCT) and swept-source optical coherence tomography angiography (SS-OCTA) enables both anterior and posterior imaging of the eye. These techniques have evolved from a research tool to an essential clinical imaging modality.

Main text

The longer wavelength and faster speed of SS-OCT and SS-OCTA facilitate better visualization of structure and vasculature below pigmented tissue with a larger field of view of the posterior segment and 360-degree visualization of the anterior segment. In the past 10 years, algorithms dealing with OCT and OCTA data also vastly improved the image quality and enabled the automated quantification of OCT- and OCTA-derived metrics. This technology has enriched our current understanding of healthy and diseased eyes. Even though the high cost of the systems currently limited the widespread use of SS-OCT and SS-OCTA at the first beginning, the gap between research and clinic practice got obviously shortened in the past few years.

Conclusions

SS-OCT and SS-OCTA will continue to evolve rapidly, contributing to a paradigm shift toward more widespread adoption of new imaging technology in clinical practice.

Vascular density and macular sensitivity in eyes after scleral buckling surgery for macula-on rhegmatogenous retinal detachment

PURPOSE

To investigate the structure and function of the retina after scleral buckling (SB) surgery due to macula-on rhegmatogenous retinal detachment (RRD).

METHODS

Twenty eyes with repaired macula-on RRD and 20 fellow eyes were included. All patients within 6-12 months of the procedure, were examined to evaluate retinal structure using spectral domain optical coherence tomography (SD-OCT) and vessel density (VD) by OCT angiography (OCTA). Best corrected visual acuity (BCVA) and microperimetry (MP) tests were used to assess retinal function.

RESULTS

Analysis of the microvascular network using OCTA between the operated and healthy fellow eyes showed a significant reduction on VD in superficial vascular plexus (SVP), deep vascular plexus (DVP) and radial peripapillary capillaries (RPC) (p< 0.001, p = 0.019 and p = 0.008, respectively). Comparison of retinal structure in SD-OCT showed no significant differences on thickness in ganglion cell complex (GCC) and peripaillary retinal nerve fiber layer (pRNFL) (p> 0.05) between examined eyes. Retinal function analysis by MP examination showed a decrease of retinal sensitivity (p = 0.0013) whereas postoperative BCVA showed no differences (p = 0.62) in the operated eyes. Significant Pearson's correlations were observed between retinal sensitivity and VD in SVP, RPC (p< 0.05).

CONCLUSION

In the eyes after SB surgery due to macula-on RRD, changes in retinal sensitivity were accompanied by impairment of the microvascular network assessed by the OCTA.

Microvascular Changes after Scleral Buckling for Rhegmatogenous Retinal Detachment: An Optical Coherence Tomography Angiography Study

This retrospective study aimed to investigate macular microvascular alterations after successful scleral buckling (SB) for rhegmatogenous retinal detachment (RRD). Nineteen eyes with macula-on RRD and 18 eyes with macula-off RRD were included. In all cases, an encircling band was placed. Optical coherence tomography angiography (OCTA) was performed at baseline and postoperatively. Changes in the foveal avascular zone (FAZ) area and vessel density (VD) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) were the primary outcomes. Correlations between OCTA findings and clinical variables were considered secondary outcomes. In both the macula-on and macula-off groups, the FAZ area was comparable with controls. In the macula-on group, VD in the whole SCP was lower compared with controls at both baseline (p < 0.001) and 6 months (p = 0.03), but showed a significant increase after surgery (p = 0.004). In the macula-off group, postoperative VD in both whole SCP and whole DCP was lower compared with controls (p < 0.001). In the macula-on group, there was an inverse correlation between axial length increase and SCP VD change (r = −0.508; p = 0.03). These findings demonstrated microvascular alterations after SB for RRD. However, VD impairment seems to be mitigated after surgery. A greater increase in postoperative axial length was associated with a poorer VD outcome.

Surgical Success Rate of Scleral Buckling Surgery and Postoperative Incidence of Cystoid Macular Edema: 10 Years of Experience at a Single Academic Hospital

The purposes of this study were to report the surgical success rate of scleral buckling surgery (SB) for rhegmatogenous retinal detachment (RRD) in a single academic hospital, analyze the incidence of cystoid macular edema (CME) after SB using optical coherence tomography (OCT), and reveal the factors associated with the development of CME. This was a retrospective observational study of patients with RRD who underwent SB from 2010 to 2020 in a single academic hospital. The anatomical success was initially achieved in 267 of 288 eyes (92.7%), and finally achieved in 288 eyes (100%). After excluding 17 eyes that underwent vitrectomy for reoperations, a total of 271 eyes of 267 patients (173 men; age, 43.5 ± 16.9 years) were retrospectively analyzed to evaluate the incidence of postoperative CME. CME occurred in 6 of 271 eyes (2.2%) within 3 months after initial surgery. Pseudophakic and aphakic eyes appeared more likely to develop CME (chi-squared test: p = 0.0078). Five of the six cases with postoperative CME were able to be medically treated. Scleral buckling surgery showed a high success rate even in the era of small-gauge vitreous surgery, and the postoperative frequency of CME after SB was low (2.2%). Previous cataract surgery may be associated with the development of postoperative CME, which is mostly medically manageable.

Optical coherence tomography angiography in the management of diabetic retinopathy

The introduction of optical coherence tomography angiography (OCTA) has granted a significant improvement in the assessment of patients with diabetes. In this review, we will provide a description of the prominent OCTA findings in diabetes. In detail, this imaging technology proved that both the retinal and choroidal circulation is affected in diabetic subjects. The recent employment of widefield technology and a three-dimensional (3D) visualization in OCTA imaging are also discussed.

Optical Coherence Tomography Angiography in Diabetes

ABSTRACT

The introduction of optical coherence tomography angiography (OCTA) has significantly improved our knowledge on the ocular vascular alterations occurring in diabetes. In this article, we will provide a review of the prominent OCTA findings in diabetes. In details, OCTA demonstrated that both the retinal vessels and the choriocapillaris are affected in diabetic subjects. The recent employment of widefield technology and a 3-dimensional (3D) visualization in OCTA imaging are also discussed.