Untersuchung vitreomakulärer Traktionen vor und nach Membranpeeling mittels hochauflösendem Raster-OCT

Perifoveal Microvascular Changes following Internal Limiting Membrane Peeling Surgery for Epiretinal Membrane and Macular Hole

INTRODUCTION

The aim of the study was to evaluate perifoveal microvasculature changes following pars plana vitrectomy with internal limiting membrane peeling for the epiretinal membrane (ERM) and macular hole (MH).

METHODS

This retrospective study included 59 eyes from 59 patients. Subjects were divided into two groups: an ERM group (n = 43) and an MH group (n = 16) based on the initial diagnosis. Swept-source optical coherence tomography angiography (SS-OCTA) was performed in the macular area, pre- and postoperatively. Perifoveal microvascular changes were calculated using MATLAB from the 6 × 6 mm SS-OCTA images, excluding the foveal avascular zone. Pre- and postoperative perifoveal vessel densities (pfVDs) were separately analyzed in six sectors (superior, superotemporal, inferotemporal, inferior, inferonasal, and superonasal) in the superficial capillary plexus (SCP) and deep capillary plexus (DCP). The baseline characteristics and other clinical factors were compared between the ERM and MH groups.

RESULTS

The postoperative best-corrected visual acuity significantly improved in both groups (p < 0.05). One year after surgery, the pfVD in the SCP of the ERM group significantly decreased in the inferotemporal sector (p = 0.049). The postoperative pfVD in the DCP of the MH group significantly decreased in temporal sectors (p < 0.05). The postoperative mean pfVD in the SCP in the MH group was significantly lower than that in the ERM group (p = 0.003). The presence of a dissociated optic nerve fiber layer (DONFL) was 75% in the MH group and 22% in the ERM group (p = 0.018). The correlation between the pfVD and DONFL was not statistically significant.

CONCLUSION

Postoperative pfVD reduction in the temporal sector, a corresponding area in which DONFL is present after MH surgery, was significantly observed. After vitreoretinal surgery in MH patients, OCTA may serve as a useful tool for monitoring perifoveal microvascular changes, especially in temporal sectors.

The influence of retinal oxygen saturation and choroidal volume on postoperative outcomes in patients with epiretinal membrane

Purpose

To investigate the effects of vitrectomy (Vy) with or without same time cataract surgery and membrane plus internal limiting membrane peeling (MP+ILMP) on retinal oxygenation and choroidal volume and their role on postoperative outcome.

Methods

Thirty‐two eyes were included in this prospective clinical study. All patients received 23 gauge Vy+MP+ILMP without endotamponade. Additional cataract surgery was performed in 14 patients. Follow‐up visits were scheduled at day 1, week 1, month 1 and month 3. At each visit, best corrected visual acuity (BCVA) using ETDRS charts (except at day 1), oxygenation of retinal vessels using the Oxymap T1, and optical coherence tomography (OCT, Heidelberg Spectralis) was performed.

Results

Mean BCVA increased significantly from 73 ± 11 letters to 77 ± 7 letters at month 3 (p = 0.02). Mean central retinal thickness (CRT) decreased from 456 ± 84 µm at baseline to 418±58µm (p = 0.01 baseline versus month 3). In the cataract surgery group, CRT was higher at month 3 than in the group without (400 ± 58 µm versus 441 ± 51 µm; p = 0.007). There was no statistically significant difference in choroidal volume or oxygenation of retinal vessels between groups (additional cataract surgery versus vitrectomy alone). Oxygenation of retinal arteries tended to decrease at day 1 followed by an increase, but the changes did not reach the level of significance (p = 0.29 baseline versus month 3). Oxygenation of retinal veins increased significantly (p = 0.02 baseline versus month 1; p = 0.04 baseline versus month 3, accordingly). There was a significant negative correlation (Spearman correlation coefficient rs = −0.35, p = 0.047) between visual acuity and oxygenation of retinal veins at month 3. No statistically significant correlation was found between CRT and oxygenation of neither retinal arteries nor veins. Choroidal volume (CV) of the central mm did not change significantly during the study period (baseline: 0.203 ± 0.04 mm³, median: 0.206, month 3: 0.205 ± 0.04 mm³, p = 0.54). There was no statistically significant effect of choroidal volume at baseline on postoperative clinical outcomes (change in BCVA estimate [95% CI]: 7 [−76; 90], p = 0.86; change in CRT: 147 [−577; 871], p = 0.68).

Conclusion

Oxygen saturation may affect the visual acuity outcome but not the CRT in patients after vitrectomy for epiretinal membrane. Choroidal thickness had no statistically significant influence on the study outcomes. Further studies are needed to evaluate if the measurement of retinal oxygenation may be helpful in the decision for surgery.

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.

[Intraoperative OCT in retinal detachment with macular involvement]

Hintergrund

Seit wenigen Jahren ermöglicht die intraoperative optische Kohärenztomographie (iOCT) die Darstellung retinaler Strukturen im Operationsmikroskop.

Ziel

Das Ziel dieser Studie ist die Analyse des Verhaltens der Netzhaut und die morphologische Befundung während Operationen bei Ablatio retinae mit Makulabeteiligung.

Methoden

Retrospektive Analyse von 41 konsekutiven Augen mit Makula-off-Ablatio, welche mittels Pars-plana-Vitrektomie (ppV) unter Verwendung von iOCT behandelt wurden, durch qualitative Beurteilung der Netzhautmorphologie zu definierten Zeitpunkten im OP-Ablauf.

Ergebnisse

In 63 % der Fälle gelang die iOCT-Darstellung der abgehobenen Makula, in den anderen Fällen überstieg die Netzhautabhebung die maximale Scantiefe der iOCT. Unter Perfluorodecalin zeigten 53,7 % der Augen noch subretinale Flüssigkeit, und 22 % der Augen zeigten eine Falte der äußeren Netzhautschichten. In 61 % der Augen konnte persistierende subretinale Flüssigkeit unter der endgültigen Tamponade festgestellt werden. Die subretinale Flüssigkeit konnte intraoperativ in dieser Menge mit bloßem Auge nicht festgestellt werden. In einem Fall konnte intraoperativ ein Makulaformen neu erkannt werden, in 3 Fällen zeigte sich zum Operationszeitpunkt eine wieder anliegende Makula.

Diskussion

Die Informationen der iOCT führen eher selten zu einer Änderung oder Erweiterung des Eingriffs. Sie liefert jedoch in Echtzeit neue Informationen über intra- und subretinale Flüssigkeitsverteilung, die nicht immer der klinischen Einschätzung entsprechen. Die Bedeutung von persistierender subretinaler Flüssigkeit und die Falten der äußeren Netzhautschichten am Ende der Operation sind noch unklar. Sie könnten möglicherweise als prognostischer Faktor für das postoperative Outcome dienen.

[Intraoperative real-time OCT in macular surgery]

BACKGROUND

Spectral domain optical coherence tomography (SD-OCT) has become a standard diagnostic tool in the surgical management of vitreomacular interface disorders. The high-resolution cross-sectional information obtained from SD-OCT is a perfect complement to vitreoretinal surgery. It provides detailed intraoperative anatomical views that are not possible with a microscope.

OBJECTIVE

To investigate the value of intraoperative real-time OCT with respect to improvement of surgical techniques in the management of vitreomacular disorders.

METHODS

A review of the current literature was conducted and an analysis of own systematically evaluated data was included to provide a comprehensive overview of potential applications for the clinical use of intraoperative real-time OCT in macular surgery.

RESULTS

Intraoperative real-time OCT can provide detailed visualization of epiretinal membranes and help to identify whether complete membrane removal has been achieved following surgery. In addition, it can provide qualitative and quantitative information that has previously not been available and assist in surgical decision-making. Intraoperative real-time OCT allows membrane peeling to be performed in selected cases without using retinal dyes, whereas it is not ideal for accurately guiding the surgeon while performing maneuvers.

CONCLUSION

Intraoperative real-time OCT provides high-resolution visualization of the effects of surgical maneuvers on the microarchitecture of the retina and surrounding tissues and will fill a gap in the understanding of the pathophysiology and prognostic factors of vitreomacular disorders; however, with currently available systems, accurate intraoperative real-time guidance of surgical maneuvers is hindered by several limiting factors.

The design and validation of an optical coherence tomography-based classification system for focal vitreomacular traction

PURPOSE

To develop and validate a classification system for focal vitreomacular traction (VMT) with and without macular hole based on spectral domain optical coherence tomography (SD-OCT), intended to aid in decision-making and prognostication.

METHODS

A panel of retinal specialists convened to develop this system. A literature review followed by discussion on a wide range of cases formed the basis for the proposed classification. Key features on OCT were identified and analysed for their utility in clinical practice. A final classification was devised based on two sequential, independent validation exercises to improve interobserver variability.

RESULTS

This classification tool pertains to idiopathic focal VMT assessed by a horizontal line scan using SD-OCT. The system uses width (W), interface features (I), foveal shape (S), retinal pigment epithelial changes (P), elevation of vitreous attachment (E), and inner and outer retinal changes (R) to give the acronym WISPERR. Each category is scored hierarchically. Results from the second independent validation exercise indicated a high level of agreement between graders: intraclass correlation ranged from 0.84 to 0.99 for continuous variables and Fleiss' kappa values ranged from 0.76 to 0.95 for categorical variables.

CONCLUSIONS

We present an OCT-based classification system for focal VMT that allows anatomical detail to be scrutinised and scored qualitatively and quantitatively using a simple, pragmatic algorithm, which may be of value in clinical practice as well as in future research studies.

Scanning laser 'en face' retinal imaging of epiretinal membranes

PURPOSE

Comparison of scanning laser ophthalmoscopy (SLO) based 'en face' imaging techniques of patients with epiretinal membranes (ERM) and evaluation of the accuracy of preoperative diagnostic imaging.

METHODS

A consecutive, prospective series of 53 study eyes of 46 patients with clinically diagnosed and in optical coherence tomography (OCT) confirmed symptomatic ERMs were included in this study. Spectral domain (SD-) OCT volume scans (20° × 20° with 49 horizontal sections, ART 15) including SLO en face and fundus autofluorescence (FAF) images of the macula were obtained with HRA2 (Heidelberg Retina Angiograph-Optical Coherence Tomography, Heidelberg Engineering, Heidelberg, Germany). In addition, wide-field SLO color and FAF images (Optomap 200Tx, Optos PLC, Dunfermline, UK) were performed also covering the macular area. En face images of both devices were graded for each included study eye based on SD-OCT cross sectional scans.

RESULTS

Grading of SD-OCT (HRA2) based SLO en face green-blue enhanced multi-color, green reflectance, blue reflectance and standard multi-color visualization revealed a better detectability of ERM than SD-OCT-based en face infrared or FAF images or wide-field SLO (Optomap) based pseudo-color, red laser separation, green laser separation, or FAF images. Both FAF visualizations, HRA2 and Optomap based, achieved low mean scores. SD-OCT based en face thickness map visualization revealed good visualization but poor demarcation of epiretinal membranes.

CONCLUSIONS

In summary, en face regular or enhanced multicolor SLO images acquired with HRA2 allow a better visualization of epiretinal membranes for preoperative evaluation compared to SD-OCT based en face thickness map or pseudo-color images acquired with Optomap while infrared or FAF images are least suitable to depict epiretinal membranes.

Parallelism as a novel marker for structural integrity of retinal layers in optical coherence tomographic images in eyes with epiretinal membrane

PURPOSE

To propose a new parameter, "Parallelism," to evaluate retinal layer integrity on spectral-domain optical coherence tomography (SDOCT), and to investigate the association between parallelism and visual function in eyes with idiopathic epiretinal membrane (ERM).

DESIGN

Retrospective, observational evaluation of a diagnostic test.

METHODS

We evaluated a consecutive series of 57 eyes of 57 patients with ERM and 30 healthy eyes of 30 volunteers for whom M-CHARTS testing and SDOCT were performed on the same day. OCT images were skeletonized, and the orientation of segmented lines in the image was termed "Parallelism" and was expressed as a value ranging from 0-1 and increasing as the retinal layers ran more parallel with each other. The relationships between parallelism and visual acuity and between parallelism and metamorphopsia score were evaluated.

RESULTS

In normal eyes, parallelism was nearly homogeneous and varied slightly with the location. Parallelism in eyes with ERM was significantly lower than that in normal eyes. In the horizontal and vertical scans, parallelism was significantly correlated with visual acuity, horizontal metamorphopsia score, and vertical metamorphopsia score. Parallelism of the center (1 mm) in the horizontal scan was strongly correlated with horizontal metamorphopsia score (R = -0.632; P < .0001). Significant negative correlation was found between parallelism and retinal thickness both in horizontal and vertical scans.

CONCLUSIONS

Parallelism was significantly lower in eyes with ERM than in normal eyes, and correlated strongly with metamorphopsia and visual acuity in eyes with ERM.

Retinal adherence and fibrillary surface changes correlate with surgical difficulty of epiretinal membrane removal

PURPOSE

To correlate surgical difficulty of epiretinal membrane (ERM) removal with characteristics of ERM adherence seen by spectral-domain optical coherence tomography (SD-OCT).

DESIGN

Prospective observational case series.

METHODS

Surgical difficulty was correlated with extent of ERM adherence by SD-OCT using masked observers in consecutive eyes undergoing ERM removal (N=31). Surgical videos were analyzed and difficulty of ERM removal (grade 1-3) was determined in 4 quadrants as well as the fovea by consensus of observers masked to SD-OCT findings. Extent of ERM adhesion was categorized (focal, broad, or complete) by masked observers using SD-OCT. The presence of fibrillary changes between the ERM and retinal nerve fiber layer (RNFL) was also evaluated. Surgical difficulty of ERM removal for each quadrant and fovea was compared to extent of ERM adherence and presence of fibrillary changes.

RESULTS

Assessment of ERM adherence using SD-OCT between masked observers was highly concordant (kappa=0.9178). Surgical difficulty of ERM removal was strongly associated with more extensive ERM adherence to the retina observed by SD-OCT. Complete ERM adherence correlated with an 8.6-fold increased surgical difficulty of ERM removal compared to focal adherence (P<.0001). The presence of fibrillary changes between the ERM and RNFL also correlated with a 25.5-fold increased difficulty of surgical removal compared to the absence of fibrillary changes (P<.0001).

CONCLUSION

Extent of ERM-retinal adhesion and presence of fibrillary changes determined by SD-OCT provide reliable preoperative assessment of surgical difficulty. Furthermore, SD-OCT analysis may help localize surgically advantageous coordinates to initiate ERM removal.

The role of the optical coherence tomography in identifying shape and size of idiopathic epiretinal membranes

AIM

Currently, the border of idiopathic epiretinal membranes (iERM) is outlined intraoperatively using vital dyes. Therefore, the authors set out to investigate the role of the preoperative retinal thickness map (RTM) of the optical coherence tomography (OCT) in identifying the shape and the size of the iERMs.

Methods

15 eyes of 15 patients with iERM who underwent vitrectomy with indocyanine green-assisted membrane peeling were included in this study. The authors analysed the intraoperative fundus images and preoperative Cirrus HD-OCT to detect the shape and the size of the iERM as well as the shape and the size of each thickness-indicating colour (white, red, orange and yellow) on the RTM, respectively. The correlation of areas and morphologic characteristics between both groups was explored.

Results

Analysis of iERM morphologic characteristics (shape) showed a similarity between the iERM contour and the corresponding RTM in 13 cases (86.6%). Furthermore, retinal folds were found in six iERMs and in their corresponding RTMs. Analysis of iERM size (area) revealed a positive correlation between the iERM area and each studied coloured area in RTM. The most significant correlation was between iERM and the red area (440–480 μm; r=0.87, p<0.0001).

Conclusion

The iERM-related retinal folds are clearly distinguishable on the HD-OCT. The red area in RTM representing the 440–480 μm retinal thickness can be a reliable predictor of the extent and the shape of the iERM.

Long-term evaluation of vitreomacular traction disorder in spectral-domain optical coherence tomography

PURPOSE

The aim of this article was to estimate the natural course of vitreomacular traction (VMT) disorder using high-resolution spectral-domain optical coherence tomography.

METHODS

Nineteen eyes of 19 patients with idiopathic symptomatic VMT and who underwent spectral-domain optical coherence tomographic follow-up examinations were included in the retrospective observational study. The average observation period of all patients who underwent the examination was 8 months (±4.4 months). We observed microstructural changes in the macula and the position, length, and vector forces of the attached vitreous in the macular surface.

RESULTS

Mean best-corrected visual acuity in the first examination was logarithm of the minimum angle of resolution 0.40 ± 0.37, and the final best-corrected visual acuity was logarithm of the minimum angle of resolution 0.30 ± 0.32 (P > 0.05, t-test). The vitreous was totally detached in the macular region (posterior vitreous detachment) in 9 of 19 eyes in the last examination. Complete disappearance of intraretinal cystoid spaces occurred in 6 of 19 eyes, and in all these eyes, posterior vitreous detachment was present. In two eyes with outer lamellar macular hole, posterior vitreous detachment occurred and the outer lamellar macular hole closed. In one eye, a full-thickness macular hole developed, and in one eye, lamellar macular hole developed. In one eye with lamellar macular hole in the first examination, this spontaneously closed. In three eyes, macular morphology and vitreous adhesion did not change. Epiretinal membranes (ERMs) were recorded in six eyes, and in one of these eyes, ERMs developed during the follow-up. In eyes in which totally detached vitreous in the macular region (posterior vitreous detachment) was noted in the follow-up(9 eyes), mean maximal horizontal vitreous surface adhesion was 180 ± 84 μm. These eyes were without ERM. In eyes with persistent VMT in the follow-up (10 eyes), mean maximal horizontal vitreous surface adhesion was 600 ± 385 μm. In 6 of these 10 eyes, we recorded ERM in the last examination (P < 0.05).

CONCLUSION

Vitreous surface adhesion and persistence of ERM may be the prognostic factors for the natural course of the VMT. We observed spontaneous resolution of VMT in eyes with less vitreous surface adhesion and without ERMs. In eyes with higher vitreous surface adhesion or coexisting ERM, pars plana vitrectomy with internal limiting membrane peeling should perhaps be performed.