A Period of Macular Hyperemia and Subclinical Edema Caused by Phacoemulsification Surgery in Noninfectious Uveitis

PURPOSE

To identify the changes in macular microvasculature in uveitic patients following phacoemulsification.

METHODS

A prospective cohort study was conducted by enrolling uveitic patients who underwent phacoemulsification at the Eye Hospital. Macular vessel densities (VD) of superficial and deep capillary plexus (SCP and DCP) and retinal thickness (RT) were quantified by optical coherence tomographic angiography (OCTA).

RESULTS

Twenty-one eyes obtained satisfactory OCTA scans at all the follow-up visits. After surgery, an increasing trend in SCP VD was found (p = .037) and reached its maximum (+2.79 ± 4.86%) at post-3 months (M). RT increased synchronously. The increases in SCP VD at post-3 M were significantly correlated with the changes in anterior chamber cells (ACCs) at post-1 M and 2 M (r = 0.450, p = .041; r = 0.477, p = .029, respectively).

CONCLUSIONS

Inflammation generates a long-term effect on retina demonstrated as an increase in SCP VD and RT which are associated with synchronous ACCs changes after phacoemulsification.

Effect of silicone oil on retinal microcirculation after vitrectomy for rhegmatogenous retinal detachment evaluated by OCT angiography: a literature review

Silicone oil (SO) has been widely used as intravitreal tamponade agent for rhegmatogenous retinal detachment (RRD) and has been occasionally associated with incomplete retinal structural and functional recovery. The use of Optical Coherence Tomography Angiography (OCT-A) has recently attracted significant attention for detailed analysis of retinal capillary plexus and blood flow changes as predicting factors for postoperative outcomes. A detailed literature search was performed in PubMed database until October 2022. The following keywords were used: rhegmatogenous retinal detachment, silicone oil, optical coherence tomography angiography, macular microvasculature, peripapillary capillary plexus, vessel density, and foveal avascular zone. We identified and reviewed 19 studies referring to microcirculation alterations of the retinal capillary plexus as seen on OCT-A in eyes treated by vitrectomy with intravitreal SO for RRD. A comprehensive update revealed variability of microcirculation characteristics of the retinal capillary plexus including the macular and the peripapillary capillaries. Further studies are warranted to clarify the OCT-A values in an attempt to identify the potential effect of SO on retinal tissue in clinical practice. A review of the existing literature sheds light on the effect of SO on retinal capillary plexus and the potential impact on functional outcomes after vitrectomy for RRD. This article discusses important aspects of key publications on the topic, highlights the importance to identify distinct alterations of the microvasculature status, and proposes the need for further future research in this field.

Optical coherence tomography angiography in retinitis pigmentosa: A narrative review

Retinitis pigmentosa (RP) is a group of inherited retinal disorders characterized by progressive rod and cone photoreceptor degeneration. Changes in retinal vasculature have long been associated with RP. Optical coherence tomography angiography (OCTA) is a novel imaging technology that enables noninvasive visualization of the retinal and choroidal microvasculature. OCTA enables quantification of microvascular changes in the retinal capillary plexus and choriocapillaris, in addition to qualitative feature description. Therefore, OCTA has the potential to become an important tool for better understanding, early detection, progression, and treatment of RP. In this review, we focus on the applications of OCTA in clinical research on RP. We also discuss future improvements in the OCTA technology for RP management. We believe that the advancement of the OCTA technique will ultimately lead to a better understanding of RP and aid in the prevention of visual impairment.

Optical coherence tomography angiography in intermediate uveitis-related cystoid macular edema

Background

Cystoid macular edema (CME) is the leading cause of permanent visual impairment in patients with uveitis, particularly in patients with intermediate uveitis (IU). This study was aimed at comparing the changes in the macular microvasculature in patients with IU with uveitic non-responsive CME and without macular edema.

Methods

In this case-control study, 55 eyes of patients with IU were assessed for macular microvascular structures, including vascular density, foveal avascular zone (FAZ) measurement, and vascular morphological changes, using spectral-domain optical coherence tomography angiography (OCT-A) with the AngioVue OCT-A system. We divided patients into the following two groups: the case group, including 30 eyes with IU-related non-responsive CME, and the control group, including 25 eyes with IU without macular edema.

Results

Participants in the case and control groups had comparable age (P = 0.753) and sex (P = 0.124) distributions. Superficial capillary plexus vessel density in the case group was significantly decreased in the whole image (P = 0.027) and the parafoveal area (P = 0.001) compared to the control group. However, there were no statistically significant differences between the two groups in terms of foveal superficial vessel density, deep capillary plexus vessel density, FAZ area, FAZ perimeter, FAZ acircularity index, or foveal vessel density in a 300-µm-wide annulus around the FAZ (all P > 0.05). Vascular morphological changes, such as the capillary tuft, telangiectatic vessels, or micro-aneurism, were not different in the overview images of the OCT-A printout between the two groups.

Conclusions

The mean superficial capillary plexus vessel density was lower in eyes with IU-related nonresponsive CME than in those without macular edema. We observed more cystoid spaces in SCP than in DCP. Microcystic changes in the inner retina and ischemia may be the underlying cause in eyes with nonresponsive CME. Future prospective longitudinal studies with healthy, matched controls are warranted to confirm our findings.

Characteristics of macular microvasculature before and after idiopathic macular hole surgery

AIM

To evaluate the macular microvasculature before and after surgery for idiopathic macular hole (MH) and the association of preoperative vascular parameters with postoperative recovery of visual acuity and configuration.

METHODS

Twenty eyes from 20 patients with idiopathic MH were enrolled. Optical coherence tomography angiography (OCTA) images were obtained before, 2wk, 1, and 3mo after vitrectomy with internal limiting membrane peeling. Preoperative foveal avascular zone (FAZ) area and perimeter and regional vessel density (VD) in both layers were compared according to the 3-month best-corrected visual acuity (BCVA).

RESULTS

The BCVA improved from 0.98±0.59 (logMAR, Snellen 20/200) preoperatively to 0.30±0.25 (Snellen 20/40) at 3mo postoperatively. The preoperative deep VD was smaller and the FAZ perimeter was larger in the 3-month BCVA<20/32 group (all P<0.05). A significant reduction was observed in FAZ parameters and all VDs 2wk postoperatively. Except for deep perifoveal VD, all VDs recovered only to their preoperative values. The postoperative FAZ parameters were lower during follow-up. Decreases in preoperative deep VDs were correlated with worse postoperative BCVA (Pearson's r=-0.667 and -0.619, respectively). A larger FAZ perimeter (Spearman's r=-0.524) and a lower deep perifoveal VD preoperatively (Pearson's r=0.486) were associated with lower healing stage.

CONCLUSION

The status of the deep vasculature may be an indicator of visual acuity in patients with a closed MH. Except for the deep perifoveal region, VD recovers only to preoperative levels.

Assessment of the Macular Microvasculature in High Myopes With Swept Source Optical Coherence Tomographic Angiography

Background: The risk of pathologic myopia (PM) increases with worsening myopia and may be related to retinal microvasculature alterations. To evaluate this, we analyzed the macular microvasculature of myopes with swept source-optical coherence tomographic angiography (SS-OCTA) in adolescent and young adult Singaporeans.

Methods: This is a prevalent case-control study including 93 young Chinese from the Strabismus, Amblyopia and Refractive error in Singaporean children (STARS, N = 45) study and the Singapore Cohort Study of Risk Factors for Myopia (SCORM, N = 48) studies. Macular vessel density (VD) measurements were obtained from 3 × 3 mm SS-OCTA scans and independently assessed using ImageJ. These measurements were compared between individuals with non-high myopia [non-HM, N = 40; SE >-5.0 diopter (D)] and HM (SE ≤-5.0D, N = 53).

Results: The mean macular VD was 40.9 ± 0.6% and 38.2 ± 0.5% in the non-HM and HM, groups, respectively (p = 0.01 adjusted for age and gender). Mean FAZ area in the superficial layer was 0.22 ± 0.02 mm² in the HM group, which was smaller compared to non-HM group (0.32 ± 0.03 mm², p = 0.04). Mean deep FAZ area was similar between the two groups (0.45 ± 0.03 mm² and 0.48 ± 0.04 mm² in the HM and non-HM groups, respectively, p = 0.70).

Conclusions: VD was lower and superficial FAZ area was smaller, in adolescents and young adults with HM compared to non-HM. These findings require validation in prospective studies to assess their impact on the subsequent development of PM.

Quantification of Macular Microvascular Changes in Retinitis Pigmentosa Using Optical Coherence Tomography Angiography

Purpose

To investigate macular structural and microvascular changes in retinitis pigmentosa (RP) eyes compared to age-matched controls using spectral domain optical coherence tomography (SD-OCT) and OCT angiography (OCTA).

Methods

This was a cross-sectional study. The foveal and parafoveal thickness and extent of ellipsoid zone (EZ) disruption were measured on OCT. The foveal avascular zone (FAZ) area and retinal vessel density (VD) were automatically calculated for superficial (SCP) and deep capillary plexuses (DCP) and choriocapillaris using OCTA-integrated software. VD was assessed for the whole 6 × 6 mm image, foveal and parafoveal regions. Quantitative measures were compared between healthy and diseased eyes.

Results

The study included 30 eyes of 30 RP patients and 24 eyes of 24 controls. Mean age was 26.9±6.4 years for RP patients and 27.4±4.9 years for controls (p=0.76). Mean LogMAR visual acuity (VA) was 0.9±0.5 for RP patients and 0.05±0.05 for controls (p <0.001). Foveal and parafoveal thicknesses were significantly lower in RP cases as compared to the control group. EZ disruption was observed in RP cases only (869±211 µm). Mean FAZ area was significantly larger in RP eyes in both SCP and DCP. VD was significantly reduced in RP eyes at the level of SCP, DCP and choriocapillaris. VA, deep parafoveal VD, foveal, parafoveal and whole image choriocapillaris VD were negatively correlated with the extent of EZ disruption.

Conclusion

We report OCTA findings in a relatively young cohort of RP patients. We demonstrated a reduction of retinal microvascular density in all studied layers on OCTA. We believe studying retinal vasculature in these patients is important, as a healthy blood supply is a prerequisite for the success of new cell-based therapies under trial for RP.

Macular microvasculature alterations in patients with primary open-angle glaucoma: A cross-sectional study

To evaluate and compare macular microvasculature changes in eyes with primary open-angle glaucoma (POAG) to normal eyes, and to assess associations among the retinal microvasculature, neural structural damage, and visual field loss.Ninety-nine eyes (68 patients with POAG and 31 normal subjects) were enrolled in this study. Thirty-five eyes with early-stage glaucoma (EG), 33 eyes with advanced-stage glaucoma (AG), and 31 normal eyes were included. An optical coherence tomography system with a split-spectrum amplitude-decorrelation angiography algorithm was used to measure the macular capillary vessel area density and retinal thickness. Visual field testing (30-2 and 10-2 programs) was performed using a Humphrey field analyzer. Correlations between the capillary vessel area density, retinal thickness, and visual field parameters were analyzed.Compared to normal eyes, those with EG and AG had a lower macular capillary vessel area density and lesser retinal thickness (P < 0.001, all). Results of multivariate linear regression analyses showed that each standard deviation (SD) decrease in the vessel area density was associated with a 1.5% and 4.2% thinning of the full retinal thickness and inner retinal layer thickness, respectively. Each SD decrease in the vessel area density was also associated with a 12.9% decrease in the mean sensitivity and a 33.6% increase in the pattern standard deviation (P < 0.001, both). The Pearson partial regression analysis model showed that the vessel area density was most strongly associated with the inner retinal layer thickness and inferior hemimacular thickness. Furthermore, a lower vessel area density was strongly associated with a more severe hemimacular visual field defect and the corresponding hemimacular retinal thickness.The macular capillary vessel area density and retinal thickness were significantly lower in eyes with POAG than in normal eyes. A diminished macular microvasculature network is closely associated with visual field defects, which are dependent on structural damage due to POAG.