Early centripetal displacements of capillaries in macular region caused by internal limiting membrane peeling

[Effects of internal limiting membrane peeling in epiretinal membrane surgery on OCT-angiography]

PURPOSE

To assess macular microvascular parameters using OCT-angiography (OCT-A) in idiopathic epiretinal membrane surgery with or without internal limiting membrane peeling.

MATERIALS AND METHODS

We retrospectively studied 17 eyes of 17 patients who underwent vitrectomy surgery for idiopathic epiretinal membrane with (n=10) or without (n=7) internal limiting membrane peeling. Patients operated on between July 2020 and June 2022 at the Colmar Hospital (France) by a single surgeon were evaluated before and 1 month after surgery, using OCT-A (Spectralis OCT-A module, Heidelberg Engineering®, Germany). The parameters studied were the area, perimeter and acircularity index of the foveal avascular zone (FAZ), the foveolar (FVD) and parafoveolar (PRVD) perfusion density and the macular vessel density ratio (MVR) in the superficial vascular complex (SVC) and the deep vascular complex (DVC). These parameters were measured using ImageJ software (National Institutes of Health, Bethesda, Maryland, USA).

RESULTS

We found no statistically significant difference between the two groups postoperatively in either area, perimeter, or acircularity index of the FAZ, FVD, PRVD, or MVR in either the SVC or DVC.

CONCLUSION

Our results with regard to macular microvasculature demonstrate no difference related to peeling of the internal limiting membrane and thus do not argue against this practice during epiretinal membrane surgery.

[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.

Effects of physiological fluctuations on the estimation of vascular flow in eyes with idiopathic macular pucker

OBJECTIVES

To evaluate the macular vascular flow in eyes with idiopathic macular pucker (EyeiMP), pre and post pars plana vitrectomy with epiretinal and limiting membranes peeling, and to compare it with the vascular flow in the healthy fellow eyes (Eyefellow), taken as physiological reference value.

METHODS

40 eyes of 40 patients were recruited. Best-corrected visual acuity (BCVA) was evaluated. Spectral domain optical coherence tomography (SD-OCT) and OCT-angiography parameters were central foveal thickness (CFT), choroidal thickness (CT), foveal avascular zone (FAZ) area, vessel area density (VAD), vessel length fraction (VLF), vessel density index (VDI) of superficial capillary plexus (SCP) and deep vascular complex (DVC), choriocapillaris (CC) flow. Absolute and relative difference calculation was applied to evaluate macular vascular flow in EyeiMP adjusted for physiological changes detected in Eyefellow.

FOLLOW-UP

6 months.

RESULTS

BCVA improved (p = 0.003) in all cases following surgery. CFT reduced postoperatively (p = 0.0138). FAZ area was smaller in EyeiMP than Eyefellow (p = 0.0071) preoperatively and postoperatively it shrank further (p = 0.0027). After surgery, inverse correlation between FAZ area and BCVA was detected (r-0.683). VAD of SCP was pre- and post-operatively higher in EyeiMP than Eyefellow (baseline p = 0.0344, 6th month p = 0.0466). Relative difference of VDI of SCP (p = 0.0096) and CC flow (p = 0.0013) at 6 months reduced. DVC flow changed significantly only in Eyefellow. CT increased post-operatively in both EyeiMP (p = 0.0345) and Eyefellow (p = 0.00423), but relative difference did not change.

CONCLUSIONS

Vascular flow indices monitoring demonstrated significant changes in both eyes: EyeiMP and Eyefellow. Relative difference of vascular flow provided objective estimate of changes due to iMP surgery taking into account physiological changes in Eyefellow.

Foveal morphology of normal fellow eyes of patients with unilateral macular hole

PURPOSE

To determine the morphology of the fovea in the ophthalmoscopically and tomographically normal fellow eyes of patients with unilateral idiopathic macular hole (MH) and to determine the association between the foveal morphological parameters and the foveal outer nuclear layer (ONL) thickness.

DESIGN

Retrospective observational study.

PARTICIPANTS

Two hundred three normal fellow eyes of patients with unilateral MH and 216 normal eyes of 216 healthy subjects.

METHODS

All eyes were examined by swept source optical coherence tomography (OCT). The built-in software measured the average retinal and choroidal thickness in the center and in the inner four subfields defined in the Early Treatment Diabetic Retinopathy Study. The total retinal thickness and the three retinal layers at the fovea and parafovea (0.25- and 0.5-mm nasal and temporal from fovea) and foveal floor width (FFW) were measured in the image of a horizontal scan passing through the center of the fovea. We defined the thickness between the internal limiting membrane and outer plexiform layer as the inner retinal thickness, and the thickness between the external limiting membrane and retinal pigment epithelium as the outer retinal thickness. Multiple regression analyses were performed with the age, sex, axial length, and the presence of a posterior vitreous detachment as the dependent variables.

MAIN OUTCOME MEASURES

OCT measurements and correlations between the foveal parameters and foveal ONL thickness.

RESULTS

The fellow eyes had a thinner central retinal subfield, thinner fovea, thinner ONL at all points except 0.5 mm nasal, significantly thicker outer retina at all points, and a wider FFW (P=.040 to P<.0001). The foveal ONL thickness was significantly and positively correlated with the central subfield retinal thickness and foveal thickness and negatively with the FFW (all P< .0001).

CONCLUSIONS

The thinner and deeper fovea and the thinner ONL of the fellow eyes of patients with a unilateral MH makes these eyes more susceptible to forming MH.

Combination of Inverted ILM Flap Technique and Subretinal Fluid Application Technique for Treatment of Chronic, Persistent and Large Macular Holes

Introduction

The choice of surgical treatment for chronic, persistent and large full-thickness macular holes (FTMH) continues to be undefined and challenging, as some of these cases remain refractory to the treatment. We report the efficacy of combination of inverted internal limiting membrane flap technique (IILMFT) and subretinal application of the fluid (SR fluid application) technique for treatment of refractory FTMHs.

Methods

Nine patients (nine eyes) were enrolled into this retrospective non-randomized exploratory consecutive case series study. All patients were diagnosed with chronic, persistent or large FTMH and were treated with a combination of IILMFT and SR fluid application technique. The following outcome parameters were analysed during 1- and 6-month follow-up visits: anatomical FTMH closure rate on spectral domain optical coherence tomography (SD-OCT), best-corrected visual acuity (BCVA), degree of postoperative retinal displacement.

Results

The mean preoperative diameter of FTMH was 542.0 μm (range 154–1930 μm). Final closure of FTMH was achieved in nine of nine cases (100%). In one case a second operation was required because of postoperative rhegmatogenous retinal detachment. The mean BCVA after the FTMH closure increased from 1.0 logMAR (0.7–1.3) to 0.4 logMAR (0.2–0.8 logMAR) (W = 2.67; p = 0.008). A positive correlation was revealed between preoperative BCVA and axial length (ρ = 0.67, p = 0.048), between preoperative BCVA and duration of the symptoms (ρ = 0.818, p = 0.007), as well as between postoperative BCVA at 1-month follow-up and BCVA at 6-month follow-up (ρ = 0.821, p = 0.007).

Conclusion

Combination of IILMFT with SR fluid application technique for refractory FTMH surgery appears to be effective and safe. Improvement of anatomical and visual outcomes after the single surgery benefits from and is ensured by the advantages of both novel surgical approaches.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40123-021-00361-2.

The Role of OCT Angiography in the Assessment of Epiretinal Macular Membrane

Background

The aim of this observational study is to assess pre- and postoperative retinochoroidal vascular changes in patients undergoing epiretinal macular membrane (ERM) surgery by using optical coherence tomography angiography (OCTA).

Materials and Methods

23 eyes affected by ERM and those which underwent phacovitrectomy associated with ERM peeling were enrolled. They were evaluated using structural OCT and OCTA before surgery and at 1, 3, and 6 months postoperatively.

Results

We found a statistically significant (p < 0.05) increase in the superficial capillary plexus vessel density (VD) from baseline to the 6-month follow-up. We observed a large increase in both the perfusion density (PD) and the VD of the deep capillary plexus between baseline and the 6-month follow-up (p < 0.001). A significant decrease in the VD and PD of the choriocapillaris (CC) from baseline to the 1^st month and a significant increase in CC perfusion density at the 6-month follow-up compared to the preoperative value were revealed. The FAZ area and perimeter after surgery significantly increased during the follow-up (p < 0.001) at baseline retinal and choroidal plexi with a lower PD or VD correlated with worse visual acuity (p < 0.05 for all plexi). At baseline and at the 1-month follow-up, a significant correlation was found with the FAZ area and the FAZ perimeter: a smaller FAZ area or a smaller FAZ perimeter was correlated to a lower visual acuity. Before surgery, negative correlations (p < 0.05) were found between the Govetto ERM stages and perfusion density of the SCP and the DCP and between the Govetto stages and vessel density of the DCP.

Conclusions

In our study, OCTA detected vascular alterations induced by the presence of the ERM, allowing several correlations with functional data. In these patients, OCTA may be useful to add new potential surgical prognostic factors.

POSTOPERATIVE MOVEMENT OF THE FOVEA AFTER SUCCESSFUL SURGERY IN PATIENTS WITH IDIOPATHIC EPIRETINAL MEMBRANES

PURPOSE

To evaluate the change in the fovea's postoperative location after successful pars plana vitrectomy with combined epiretinal and internal limiting membrane peeling in patients with idiopathic epiretinal membranes (iERMs).

METHODS

In this prospective study 32 eyes of 32 patients with iERMs were followed from baseline before until 3 months after surgery. Study measures included 4-m Early Treatment Diabetic Retinopathy Study best-corrected visual acuity, enhanced-depth imaging-optical coherence tomography, and intraoperative fundus photographs. Foveal movement was assessed by measuring the change in the papillofoveal distance (∆PFD).

RESULTS

Mean ∆PFD in the study eye was -124 µm (±138) and -272 µm (±213) one day and 3 months after surgery, respectively. Mean ∆PFD after 3 months was greater in the study than in the fellow eye (P < 0.001). ∆PFD at Month 3 did not correlate with the internal limiting membrane area peeled (P = 0.78).

CONCLUSION

Foveal movement starts immediately after surgery and causes a statistically significant reduction in PFD after uneventful macular pucker surgery. ∆PFD correlates statistically significantly with baseline best-corrected visual acuity and baseline central retinal thickness. The internal limiting membrane peeling size had no significant effect on the amount of postoperative foveal dislocation.

OCT Angiography Findings in Macula-ON and Macula-OFF Rhegmatogenous Retinal Detachment: A Prospective Study

Background: The aim of the study was to evaluate pre-operative and post-operative retinal vasculature using optical coherence tomography angiography (OCTA) in patients who underwent rhegmatogenous retinal detachment (RRD) surgery repair. Materials and Methods: A total of 33 eyes were included in this prospective consecutive observational study: 15 affected by macula-ON and 18 by macula-OFF RRD. Superficial (SCP), deep capillary plexus (DCP), and foveal avascular zone (FAZ) area variations were evaluated by OCTA and correlated with visual acuity (VA) during a six-month follow-up. Results: In the macula-ON group, the preoperative vascular density (VD) of the whole SCP (wSCP) on affected eyes was lower than that of the fellow eyes (p < 0.05); this difference disappeared at 6 months after surgery (p = 0.88). The wSCP VD and the parafoveal SCP (pfSCP) VD increased during follow-up (p < 0.05); moreover, the higher the preoperative wSCP and pfSCP VD, the better the baseline VA (p < 0.05). In the macula-OFF group, at the first and sixth months after surgery, the larger the FAZ, the lower the VA (p < 0.05). Conclusions: Macula-ON SCP VD affected preoperative VA, and it was lower than the fellow eye, but recovered over time. In the macula-OFF group, a larger FAZ area was related to a worse VA, as is the case in diabetes and in retinal vein occlusion (RVO).

Intraretinal microvascular changes after ERM and ILM peeling using SSOCTA

BACKGROUND

To prospectively investigate retinal vascular changes in patients undergoing epiretinal membrane (ERM) and internal limiting membrane (ILM) peeling using swept source optical coherence tomography angiography (SSOCTA).

METHODS

Consecutive patients were grouped based on ERM severity and followed using SSOCTA up to month 3 after surgical intervention. Superficial and deep foveal avascular zone (s/dFAZ) as well as foveal and parafoveal vessel density (VD) were correlated with ERM severity and visual acuity. Differences between groups were evaluated.

RESULTS

Significant correlations were found between ERM severity and baseline sFAZ, dFAZ and best corrected visual acuity (BCVA), central retinal subfield thickness (CST) and ΔCST (r = -0.52, r = -0.43, r = -0.42, r = 0.58, r = 0.39; all p<0.05). Vascular flow parameters did not correlate with age, peeling size, pseudophakia or CST, but correlated with intraretinal cysts presence. No associations of BCVA with any of the OCTA parameters across time were found. Significant differences between ERM severity groups 1 and 2 were found for sFAZ at baseline (p = 0.005) and at the 3-month follow-up (p = 0.014), and for dFAZ at baseline (p = 0.017). Superficial foveal and parafoveal VD were not significantly different between groups (all p>0.05).

CONCLUSIONS

This study clearly shows that ERM severity based on ERM staging has to be taken into account when undertaking studies in patients with idiopathic ERM using SSOCTA. Further, specific changes in the superficial and deep retinal vasculature in eyes undergoing ERM and ILM peeling were found. However, the clinical usefulness and prognostic value for post-surgical treatment BCVA of the SSOCTA-derived variables (sFAZ and dFAZ area, as well as foveal and parafoveal VD) used remains questionable.

The effect of epiretinal membrane surgery on macular microvasculature: an optical coherence tomography angiography study

PURPOSE

To investigate both the possible effects of both idiopathic epiretinal membrane (IERM) itself and surgery on macular microvascular structure using optical coherence tomography angiography (OCT-A) and to determine the associations with structural and visual outcomes.

METHODS

Twenty-four eyes of 24 patients with IERM and 24 eyes of 12 healthy controls were included. Vascular parameters, including the superficial capillary plexus (SCP) and deep capillary plexus (DCP) were evaluated by OCT-A prior to and 6 months after ERM removal. The foveal avascular zone (FAZ, mm²) area, parafoveal vascular density (VD, %) and flow area (mm²) measurements were used to evaluate the macular vascular integrity.

RESULTS

The mean preoperative vascular density (VD) of both plexuses was lower in eyes with IERM than in healthy eyes (both p = 0.0001). The mean preoperative flow area of the DCP in eyes with IERM was significantly lower than that in the control eyes (p = 0.016). There was no significant difference in the VD or flow area in either superficial or deep capillary plexuses as a result of surgery (SCP; p = 0.957, p = 0.97, DCP; p = 0.861, p = 0.6, respectively). Both the parafoveal DCP-VD and flow area in DCP were negatively correlated with best-corrected visual acuity (logMAR) at 6 months postoperatively (r = -0.46, p = 0.03; r = -0.52, p = 0.01, respectively).

CONCLUSION

Epiretinal membranes may cause dynamic microvascular changes at the macula. However, the effect of surgery on microvasculature may be more limited than that on anatomical and visual recovery. OCT-A may serve as a useful tool in understanding the pathophysiological basis of diseases.

Association between displacement and thickness of macula after vitrectomy in eyes with epiretinal membrane

The purpose of this cross-sectional retrospective study was to determine the relationship between the retinal displacements and the retinal thickness in eyes with epiretinal membrane (ERM) after vitrectomy with internal limiting membrane (ILM) peeling. To accomplish this, we measured the retinal thickness using optical coherence tomography (OCT) and the retinal displacement using OCT angiography to obtain 3 mm × 3 mm en face images before, and 2, 4, and 8 weeks following the surgery from 20 eyes of 20 patients. The distance between the retinal vessel bifurcations and the fovea was significantly displaced centrifugally and asymmetrically in the 4 quadrants postoperatively (P < 0.001). The foveal avascular zone (FAZ) was significantly enlarged, and the central foveal thickness (CFT) and the inner nuclear layer (INL) thickness were significantly thinner postoperatively. The displacements were significantly correlated with the changes in the FAZ area (r = 0.717, P < 0.001), the CFT (r = − 0.702, P < 0.001), and the INL thickness (r = − 0.702, P < 0.001). In conclusion, the distance between the retinal bifurcations and the fovea was asymmetrically expanded after the surgery and was significantly correlated with the morphological changes. These results indicate that a horizontal macular contraction is correlated with vertical retinal contraction in the eyes with an ERM.

Stereopsis After Unilateral Macular Hole Surgery with Internal Limiting Membrane Peeling

Purpose

We have shown distinct morphological changes of the foveal retina such as horizontally asymmetrical retinal thicknesses and displacements of the fovea toward the optic disc after successful idiopathic macular hole (MH) closure by MH surgery with internal limiting membrane (ILM) peeling. The purpose of this study was to determine whether these morphological changes will alter the stereoacuity.

Setting

This was a non-randomized, retrospective study conducted on patients who underwent MH surgery at the Matsumoto Dental University Hospital, Nagano, Japan.

Methods

Forty patients (22 women, 18 men) who underwent MH surgery with ILM peeling for a unilateral MH were studied. At >6 months after the PPV, the stereoacuity was measured with the Titmus stereotest (TST) and the TNO stereotest (TNO). The relationship between the stereoacuity and the age, MH size, best-corrected visual acuity (BCVA), foveal retinal thickness, and amount of nasal shift of the retina was determined.

Results

The mean postoperative BCVA was −0.05 ± 0.11 logarithm of the minimum angle of resolution (logMAR) units. The percentage of cases with good stereoacuity of ≤100 sec of arc was 87.5% with the TST and ≤240” was 90% with the TNO test. A better stereoacuity was significantly correlated with a younger age (r = 0.36, P <0.05; with TNO), smaller MH (r = 0.51, P < 0.001, with TST), better postoperative BCVA (r = 0.43 P <0.01 with TST; r = 0.49, P <0.01 with TNO), but not with the parafoveal retinal thickness or degree of nasal shift.

Conclusion

The postoperative stereopsis is relatively good in patients with better postoperative BCVA after MH surgery with ILM peeling, even though foveal morphological changes had occurred.

Removal of foveal hard exudates by subretinal balanced salt solution injection using 38-gauge needle in diabetic patients

PURPOSE

To examine the anatomic and visual outcomes after removal of foveal hard exudates through a macular hole created by subretinal balanced salt solution (BSS) injection.

METHODS

This was a retrospective, consecutive, case series. Six patients (7 eyes) underwent vitrectomy with removal of foveal hard exudates. All patients were women and the mean age was 65 years (range from 55 to 71). All patients had a history of panretinal photocoagulation. Previous treatments included intravitreal anti-vascular endothelial growth factor injection in one eye and vitrectomy in both eyes of one patient. The geometric mean preoperative decimal visual acuity was 0.11 (range from 0.08 to 0.3). The mean postoperative follow-up period was 12 months (range from 6 to 19). The status of lens was two phakic and five pseudophakic. Surgical procedures included simultaneous cataract surgery if phakic, creation of posterior vitreous detachment if not present, internal limiting membrane (ILM) peeling and a gas or air tamponade. Manual subretinal BSS injection using 38-gauge needle was performed at ILM-peeled area. Removal of foveal hard exudates was conducted by the water flow through the macular hole created during subretinal BSS injection.

RESULTS

Foveal hard exudates decreased in all cases early after surgery. The geometric mean final decimal visual acuity was 0.31 (range from 0.1 to 0.9). Visual acuity improved more than 0.2 LogMAR units in six eyes and unchanged in one eye. There was no severe complication and recurrence of macular edema.

CONCLUSION

This procedure may be effective for foveal hard exudates in diabetic patients.

[Foveal avascular zone and OCT angiography. An overview of current knowledge]

BACKGROUND

The foveal avascular zone (FAZ) has often been analyzed under different aspects in the last decades, mainly by fluorescence angiography (FA); however, the novel technology of optical coherence tomography angiography (OCTA) enables a non-invasive examination, visualization and quantitative analysis of the FAZ, which has recently led to many new findings, especially in a multidisciplinary manner. This article provides an overview of the investigation of the FAZ using OCTA and the new findings that have been obtained using OCTA in recent years.

METHODS

This article is based on a comprehensive literature review.

RESULTS

In many studies a good reproducibility and repeatability of the FAZ measurements by OCTA could be proven, also by comparing different OCTA devices. In patients with ocular pathologies and systemic diseases, e. g. after retinal vein occlusion or retinal surgery and in patients with diabetes mellitus without diabetic retinopathy, differences to healthy control groups and correlations to visual function could be shown. Moreover, in patients with neurological diseases, such as Alzheimer's dementia, changes of the FAZ could be identified.

CONCLUSION

The OCTA is a non-invasive technology, which enables a reliable visualization and reproducible quantification of the FAZ. The size of the FAZ seems to be altered in different retinal and systemic diseases, which also may correlate with visual function; however, long-term studies evaluating the diagnostic value of these changes in the course of the disease are currently lacking.