Perifoveal microcirculation in eyes with epiretinal membranes

[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.

Retinal vessel geometry in patients with idiopathic epiretinal membrane

We investigated the associations between retinal vascular geometric measurements and idiopathic epiretinal membrane (ERM). Whether changes in retinal vascular geometry are independent of systemic cardiovascular risk factors was also evaluated. This retrospective, cross sectional study included 98 patients with idiopathic ERM, and 99 healthy age-matched controls. Quantitative retinal vascular parameters were measured from digital retinal fundus photographs using a semi-automated computer-assisted program. Multivariate logistic regression analyses were performed to evaluate associations between retinal vascular geometric parameters and the presence of idiopathic ERM after adjusting for systemic cardiovascular risk factors. There was no significant difference in the baseline characteristics of the two groups, except that the ERM group had a higher proportion of females than the control group. In multivariate regression analyses, female sex (odds ratio [OR] 0.402; 95% CI 0.196-0.802; P = 0.011), wider retinal venular caliber (OR 16.852; 95% CI 5.384-58.997; P < 0.001) and decreased total fractal dimension (OR 0.156; 95% CI 0.052-0.440; P = 0.001) were associated with idiopathic ERM. Idiopathic ERM was associated with alterations in global retinal microvascular geometric parameters, wider retinal venules, and less complex vascular branching patterns, independent of cardiovascular risk factors.

Longitudinal Change of Choroidal Thickness after Pars Plana Vitrectomy for Idiopathic Epiretinal Membrane

This study aimed to investigate changes in choroidal thickness after pars plana vitrectomy (PPV) with and without air tamponade in patients with idiopathic epiretinal membrane (ERM). We retrospectively reviewed 61 patients with ERM who underwent a 25-gauge transconjunctival sutureless PPV. The patients were divided into two groups: the air tamponade group (30 eyes) and the nontamponade group (31 eyes). Subfoveal choroidal thickness (SFCT) was analyzed over 12 months. No significant differences were seen between the two groups at baseline. For all patients, the SFCT was significantly thicker at 1 month after surgery and significantly thinner at 6 and 12 months after surgery than preoperative values. In the subgroup analysis, there was no significant difference in SFCT 3 months after surgery compared with the preoperative values in both groups, but SFCT was significantly lower 6 months after surgery in both groups. In conclusion, our results showed that choroidal thickness temporarily increased after surgery and then gradually decreased until 12 months after the PPV for ERM.

Postoperative Changes in Vessel Density according to Macular Hole and Macular Pseudohole Subtypes

Purpose: To determine the postoperative changes in vessel density according to macular hole and macular pseudohole (MPH) subtypes and to investigate the differences in the mechanisms underlying their development. We also investigated whether changes in vessel density are correlated with changes in the multifocal electroretinogram (mfERG) and best corrected visual acuity (BCVA).Methods: We reviewed the medical records of patients with MPH or a macular hole who underwent pars plana vitrectomy. We included 15 eyes of 15 patients with a full thickness macular hole (FTMH), nine eyes of nine patients with a tractional lamellar macular hole (LMH), eight eyes of eight patients with a degenerative LMH, and nine eyes of eight patients with a MPH. The BCVA, foveal avascular zone (FAZ), foveal and parafoveal vessel density, and mfERG ring 1 and ring 2 P1 amplitudes were analyzed before and 1 and 6 months after surgery.Results: One month postoperatively, the foveal vessel density of patients with a MPH or tractional LMH increased (p = 0.011, p = 0.008). The parafoveal vessel density of patients with a MPH, tractional LMH, and FTMH increased (p = 0.007, p = 0.038, p = 0.031). There was no significant increase in foveal or parafoveal vessel density in patients with a degenerative LMH (p = 0.201, p = 0.171). There was a significant correlation between the change in parafoveal vessel density and that in BCVA 6 months postoperatively in patients with a FTMH (r = -0.543, p = 0.037).Conclusions: By assessing changes in vessel density after vitrectomy, it is possible to estimate the effect of traction according to the type of macular hole. There was a significant correlation between parafoveal vessel density and BCVA in patients with a FTMH. Restoration of the retinal structure and vessel density might improve visual acuity.

Two-year Changes in Postoperative Central Macular Thickness and Subfoveal Choroidal Thickness in Epiretinal Membrane Patients

Purpose: To evaluate changes in central macular thickness (CMT) and subfoveal choroidal thickness (SFCT) after phacovitrectomy over a 2-year period in idiopathic epiretinal membrane (ERM) patients.Methods: The records of 52 idiopathic ERM patients (52 eyes) who underwent phacovitrectomy, without recurrence of the condition over a 2-year follow-up period, were reviewed retrospectively. Changes in CMT and SFCT, as measured by optical coherence tomography, were analyzed and compared with those of a normal control group over a 2-year period.Results: The mean preoperative CMT and SFCT were 425.67 ± 84.67 and 257.56 ± 90.13 μm, respectively. Postoperative CMT was reduced significantly to 372.17 ± 45.26 μm at 1 year and 363.15 ± 47.35 μm at 2 years (p < 0.001). SFCT at 1 and 2 years postoperatively was significantly reduced to 238.85 ± 84.85 and 230.31 ± 87.95 μm, respectively (p < 0.001). In the control group, there was no significant change in CMT; however, the SFCT decreased by 11.09 ± 22.36 μm during the 2-year follow-up (p = 0.007). In contrast, in the patient group, CMT and SFCT decreased by 62.52 ± 71.45 and 27.25 ± 41.97 μm, respectively, showing a significant difference from the control group (p < 0.001 and p = 0.043, respectively). Both before surgery and at 1 year postoperatively, the thinner the CMT, the better the best-corrected visual acuity (BCVA) (p = 0.010 and p = 0.018, respectively). A better postoperative BCVA at 2 years was associated with a thinner CMT and better BCVA before surgery (p < 0.001 and p < 0.001, respectively).Conclusions: Following a phacovitrectomy procedure, ERM patients showed significant reductions in both the CMT and SFCT at the 2-year follow-up.

The Postoperative Course of Choroidal and Central Retinal Thickness in Epiretinal Membranes with Respect to Membrane Severity

INTRODUCTION

The aim of this study was to evaluate the relation between choroidal thickness (CT), central retinal thickness (CRT) and best-corrected visual acuity (BCVA) after surgery for idiopathic epiretinal membrane (iERM).

METHODS

Patients with 4 severity stages of iERM, who underwent vitrectomy with membrane- and internal limiting membrane peeling, were included in this prospective study. CRT, CT, and BCVA were assessed at baseline (BSL), 1 week, 1 and 3 months postoperatively.

RESULTS

Twenty-one eyes were phakic, 11 eyes pseudophakic at BSL, in 14 cases combined cataract surgery was performed. BCVA was highest in stage 1 and 2, lowest in stage 4 iERM (p < 0.001) and correlated with CRT. After surgery, CRT decreased and BCVA increased significantly (p < 0.05). CT did not show significant differences among stages (p = 0.23). BSL CRT did not differ between phakic and pseudophakic eyes, the least reduction after surgery was detected in patients who underwent combined cataract surgery and vitrectomy. BSL CT was greater in phakic than in pseudophakic eyes (p = 0.033). Postoperative CT decreased in pseudophakic and phakic eyes, but remained higher after combined surgery (p = 0.0048).

CONCLUSION

CT is not related to the severity of iERM. Choroidal changes did not influence the BCVA. Additional cataract surgery seems to cause longer recovery in CT and CRT.

The predictive value of ectopic inner retinal layer staging scheme for idiopathic epiretinal membrane: surgical results at 12 months

BACKGROUND/OBJECTIVES

To assess the effect of ectopic inner foveal layers (EIFL) based staging scheme, foveal avascular zone (FAZ) alterations and other microstructural optical coherence tomography (OCT) findings on visual function for patients undergoing idiopathic epiretinal membrane (iERM) surgery.

SUBJECTS/METHODS

In this retrospective study, patients who underwent 27 G pars plana vitrectomy (PPV) for idiopathic ERM with a minimum follow-up of 12 months were included. Preoperative and postoperative OCT scans, FAZ area measurements on en face OCT angiography images and mean retinal sensitivity (MRS) using microperimetry were recorded in all cases. The correlation of FAZ area, EIFL and other OCT parameters with preoperative and postoperative best-corrected visual acuity (BCVA) was analysed.

RESULTS

In all, 112 eyes of 112 patients were included. Visual acuity improvement was statistically significant in all four stages; however, differences between Stages 2, 3 and 4 ERMs remained significant (p < 0.05). The presence and thickness of the EIFL was associated with worse baseline (p = 0.013; p = 0.005, respectively) and final (p < 0.001 for both) BCVA. The presence of cystoid macular oedema was associated with worse BCVA at baseline (p = 0.027) and postoperative month-6 (p = 0.04). The mean FAZ area was significantly reduced in all stages of ERM compared with the fellow eyes (p < 0.05 for all). Postoperative retinal sensitivity improvement was statistically significant in Stage 1 and Stage 2.

CONCLUSION

The presence of EIFL is an independent predictor of worse postoperative BCVA. Accordingly, despite significant BCVA improvements in all stages of ERM, visual acuity gain remains limited in eyes with Stage 3 and Stage 4 ERM.

Correlation between Visual Acuity and Optical Coherence Tomography Angiography Parameters in Unilateral Idiopathic Epiretinal Membrane

Background: The tangential traction by idiopathic epiretinal membrane (iERM) may alter the hemodynamics of the macula. We investigated the correlation between visual acuity and the optical coherence tomography angiography (OCTA) parameters in unilateral iERM. Methods: We included 61 eyes of 61 consecutive patients with unilateral iERM between January 2018 and December 2018. The flow area of the retinal superficial capillary plexus (SCP), deep capillary plexus (DCP), and choroidal capillary plexus (CCP) were measured using OCTA. The normal fellow eyes were used for comparison. The iERM patients were divided into those with a presence of foveal concavity and those with a loss of foveal concavity. Results: When compared with fellow eyes, the flow areas showed a statistically significant decrease in the SCP and CCP of those with iERM (p = 0.037 and p = 0.011, respectively). In the DCP, no significant reduction in flow area was found in iERM (p = 0.054). The flow area of the CCP was the only factor significantly associated with best vision (p = 0.012). No significant differences in the flow areas of the SCP, DCP, and CCP were found between the presence and loss of foveal concavity. Conclusions: The flow area of the CCP is an important determinant of vision, emphasizing the crucial role of choroidal circulation in iERM. Moreover, mechanical stretch by iERM is not the only mechanism affecting the flow area.

Evaluation of retinal vascular structure after epiretinal membrane surgery by optical coherence tomography angiography

PURPOSE

To evaluate the retinal vascular structure before and after the epiretinal membrane (ERM) surgery by optical coherence tomography angiography (OCTA).

METHODS

Twenty-two eyes with ERM (study eyes) had been evaluated by OCTA for superficial capillary plexus (SCP) and deep capillary plexus (DCP) vessel density (VD) at foveal and parafoveal regions and foveal avascular zone (FAZ) before and after ERM removal surgery. Twenty-two fellow eyes were selected as control group.

RESULTS

Preoperative VD of SCP and DCP were significantly lower in ERM eyes than in controls in both foveal and parafoveal areas (p < 0.05, for all). The difference regressed in SCP (fovea: 18.04 ± 3.1 vs 19.98 ± 18 p = 0.002 and parafovea: 47.33 ± 3.54 vs 49.71 ± 28 p = 0.001), but persisted in DCP (fovea: 17.25 ± 3.52 vs 17.57 ± 4.01 p = 0.856 and parafovea: 50.12 ± 4.35 vs 50.93 ± 3.24 p = 0.791) in study eyes, postoperatively. Superficial and deep FAZ areas were significantly smaller in study eyes than controls. Postoperatively, superficial FAZ area enlarged (0.288 ± 0.10 vs 0.307 ± 0.08 p = 0.012), whereas deep FAZ area did not (0.324 ± 0.09 vs 0.338 ± 0.07 p = 0.435). FAZ area was correlated with the best-corrected visual acuity in ERM eyes.

CONCLUSION

Vascular damage in SCP and DCP was demonstrated by OCTA in eyes with ERM. ERM removal surgery mainly improves superficial changes caused by ERM. Changes in deep retinal flow may be associated with visual outcomes after ERM removal surgery.

Association of macular choroidal thickness with optical coherent tomography morphology in patients with idiopathic epiretinal membrane

PURPOSE

To compare macular choroidal thickness of idiopathic epiretinal membrane (ERM) and fellow eyes, and before and after vitrectomy in terms of the morphological features on spectral-domain optical coherent tomography (SD-OCT).

METHODS

Eighty-four patients with unilateral idiopathic ERM were involved. Patients were categorized into: Group 1, ERM without membrane contraction; Group 2, ERM with membrane contraction and retinal folding; and Group 3, ERM with membrane contraction and macular edema. Twenty-two patients received surgical removal of ERM. Choroidal thickness was compared between ERM and fellow eyes, and before and after treatment.

RESULTS

Mean choroidal thickness was significantly greater in ERM eyes than in fellow eyes (234.4 ± 22.5 vs 220.6 ± 20.8 μm; P<0.01). Group 1 (n = 20) showed no significant difference in choroidal thickness between ERM and fellow eyes. Eyes in Group 2 (n = 27) and Group 3 (n = 37) showed statistically significant differences in mean choroidal thickness between ERM and fellow eyes (229.6 ± 23.8 vs 220.8 ± 19.6 μm; 242.6 ± 27.8 vs 221.0 ± 21.8 μm, respectively; P<0.05). In Group 2 (n = 8) and Group 3 (n = 16), choroidal thickness in ERM eyes decreased significantly at 1 month and 6 months after surgery, compared with that before surgery (P<0.05 for all comparisons).

CONCLUSIONS

Membrane contraction contributed to the increase in choroidal thickness in idiopathic ERM patients. This finding may help to elucidate the pathophysiologic features of idiopathic ERM as well as the response to treatment in these patients.

Optical coherence tomography angiographic findings of lamellar macular hole: comparisons between tractional and degenerative subtypes

We investigated the microvascular changes in eyes with lamellar macular holes (LMHs) using optical coherence tomography angiography (OCTA), compare them between two subtypes of LMH. Tractional and degenerative LMH were differentiated based on the morphological characteristics of OCT. In OCTA images, foveal and parafoveal vessel density (VD) in the superficial and deep capillary plexus (SCP, DCP) and foveal avascular zone (FAZ) area were measured. Eyes that underwent vitrectomy for LMH were included in subgroup analysis. We analysed 63 LMH (42 tractional and 21 degenerative) eyes and 63 control eyes. Compared with degenerative LMH, tractional LMH had better BCVA (p = 0.010), smaller FAZ area (p = 0.001), and higher foveal VD in the SCP (p = 0.130) and DCP (p = 0.002). In degenerative LMH, better BCVA was associated with greater foveal VD in the SCP (p = 0.040) and DCP (p = 0.005), and parafoveal VD in the SCP (p = 0.006). In subgroup analysis, only the tractional LMH group showed significant increases in foveal and parafoveal VDs in the SCP after vitrectomy (p = 0.001 and p = 0.026, respectively). Significant differences in microvascular changes were noted between tractional and degenerative LMH, suggesting that two subtypes are distinct pathogenetic entities.

Association between individual retinal layer thickness and visual acuity in patients with epiretinal membrane: a pilot study

Purpose

We investigated the correlation between visual acuity (VA) and individual retinal layer thickness in the foveal, parafoveal, and perifoveal regions of patients with an idiopathic epiretinal membrane (ERM).

Methods

One hundred and five subjects presenting with unilateral idiopathic ERM were included in this study. We segmented each patient’s optical coherence tomography (OCT) image into seven layers and calculated the mean layer thickness in the foveal, parafoveal, and perifoveal regions using the Iowa Reference Algorithm. In 105 patients with ERM, we detected correlations between their macular regions’ individual retinal layer thickness and their best corrected VA. Thirty-one of the 105 patients with ERM underwent vitrectomy and completed six months of follow-up. We then compared the 31 surgical patients’ preoperative and postoperative individual retinal layer thickness in each macular region. Additionally, the association between preoperative individual retinal layer thickness in each macular region and VA six months post-surgery in patients with ≥ two Snellen lines of visual improvement was determined.

Results

Multiple linear regression analysis showed that the inner nuclear layer (INL) thickness in the foveal, parafoveal, and perifoveal region were all associated with VA in the 105 patients (R² = 0.344, P < 0.001; R² = 0.427, P < 0.001; and R² = 0.340, P < 0.001, respectively). Thirty-one surgical patients 6 months post-surgery showed significantly decreased thicknesses (P ≤ 0.012) of the foveal INL, inner plexiform layer (IPL), and outer nuclear layer (ONL); the parafoveal retina nerve fiber layer (RNFL), IPL, INL, and ONL; and the perifoveal RNFL, IPL, INL, ganglion cell layer (GCL), outer plexiform layer (OPL), and photoreceptor layer (PRL). We found a weak correlation between postoperative VA and preoperative foveal and perifoveal RNFL thickness (r = 0.404 and r = 0.359, respectively), and a moderate correlation between postoperative VA and preoperative foveal and parafoveal INL thickness (r = 0.529 and r = 0.583, respectively) in the 31 surgical patients (P ≤ 0.047). The preoperative INL thickness in the foveal, parafoveal, and perifoveal regions showed a moderate to strong correlation (r = 0.507, 0.644, and 0.548, respectively), with postoperative VA in patients with ≥ 2 lines of visual improvement (P ≤ 0.038).

Conclusion

We detected a correlation between retinal damage and VA in the parafoveal, perifoveal, and foveal regions. Our results suggest that INL thickness in all macular regions may be a prognostic factor for postoperative VA in ERM patients.

Association of retinal vessel density with retinal sensitivity in surgery for idiopathic epiretinal membrane

PURPOSE

The success of surgical treatment for idiopathic epiretinal membrane (ERM) is measured by postoperative best-corrected visual acuity (BCVA), metamorphopsia, and foveal retinal sensitivity (RS).This study searched for predictive biomarkers of surgical success by determining the association between foveal RS and various aspects of vessel density (VD) in the fovea of patients with ERM.

METHODS

The study examined 25 eyes of 25 patients with ERM who underwent 27-gauge microincision vitrectomy surgery (MIVS). RS was measured with microperimetry (MP-3; NIDEK) at four central points in the fovea with an interpoint distance of 2°. VD was measured with SD-OCT (RS 3000; NIDEK) within the 1-mm² square defined by the 4 RS points at various depths, including the superficial and deep retinal capillary plexus (SCP and DCP, respectively).

RESULTS

Though VD did not change throughout the follow-up period, BCVA and RS significantly improved 1 and 3 months after surgery, respectively (both P < 0.0017). Postoperative RS at 6 months was positively correlated with postoperative DCP VD at 1, 3, and 6 months (r = 0.62, P = 0.001; r = 0.40, P = 0.049; r = 0.53, P = 0.007, respectively), but not with SCP VD at any time point. Multiple regression analysis confirmed that postoperative RS at 6 months was associated with postoperative DCP VD at 1 month (P = 0.03).

CONCLUSION

Higher postoperative DCP VD at 1 month contributed to better postoperative foveal RS at 6 months. Early postoperative VD in the fovea might be a useful predictive biomarker of late postoperative RS in the fovea in ERM patients.

Perioperative intraretinal fluid observed using optical coherence tomography in the epiretinal membrane

Background

Postoperative intraretinal fluid (IRF) is reportedly associated with visual outcomes after epiretinal membrane (ERM) surgery. However, preoperative IRF is common, and persistent IRF would have different impact on visual function from postoperative newly developed IRF. Therefore, we aimed to investigate the incidence rate and clinical implications of perioperative IRF in ERM.

Methods

Medical records of patients who underwent vitrectomy for idiopathic ERM between January 2014 and January 2017 were reviewed retrospectively. The incidence of IRF was analyzed using optical coherence tomography preoperatively and 1, 3, and 6 months postoperatively. On the basis of the presence or absence and the time of detection of IRF, patients were divided into three groups, namely preoperative IRF group, New IRF group, and IRF(−) group. Correlations of various parameters including age, sex, baseline visual acuity (VA), central subfield macular thickness, lens status, and surgical factors with IRF, along with the effect of IRF on VA, were evaluated.

Results

This study included 155 eyes from 155 patients. Thirty-six (23.2%) and 49 (31.6%) eyes demonstrated preoperative and newly developed IRF, respectively. Seventy eyes (45.2%), which did not exhibit IRF during the study period, were assigned to the IRF(−) group. At baseline, the IRF(−) group showed a better VA than the other two groups. Postoperatively, VA improved significantly in all three groups. There was no difference in VA between the IRF(−) and new IRF groups at 6 months; however, the preoperative IRF group had significantly lower VA than the other two groups.

Conclusion

IRF associated with ERM was frequently observed preoperatively and postoperatively, but it did not prevent postoperative vision improvement. Preoperative IRF was related to lower postoperative vision improvement.

Early retinal flow changes after vitreoretinal surgery in idiopathic epiretinal membrane using swept source optical coherence tomography angiography

(1) Background: The aim of this observational cross-sectional work was to investigate early retinal vascular changes in patients undergoing idiopathic epiretinal membrane (iERM) surgery using swept source optical coherence tomography angiography (SS-OCTA); (2) Methods: 24 eyes of 24 patients who underwent vitrectomy with internal limiting membrane (ILM) peeling were evaluated pre- and postoperatively using SS-OCTA system (PLEX Elite 9000, Carl Zeiss Meditec Inc., Dublin, CA, USA). For each eye, five 6x6-mm OCTA volume scans were acquired by two observers independently. The en face images of superficial capillary plexus (SCP) were then exported to imageJ and a semi-automated algorithm was used for subsequent quantitative analysis. Perfusion density (PD), vessel length density (VLD), vessel diameter index (VDI) and vessel tortuosity (VT) of SCP were evaluated in both the parafoveal (2.5 mm diameter) and perifoveal areas (5.5 mm diameter); (3) Results: At OCTA analysis statistically significant differences were found between controls and diseased eyes for all parameters in parafoveal and perifoveal regions (p < 0.001; p < 0.05) except for perifoveal VLD. During 6-month follow up, both anatomical/perfusion and functional parameters showed a statistically significant improvement if compared to preoperative values. In detail, at one-month post vitrectomy, VLD and VT significantly changed in parafoveal region (p = 0.043; p = 0.045), while PD and VDI showed a trend of increase in both parafoveal and perifoveal region. At 6 months after surgery, PD, VLD and VT of parafoveal region significantly improved (p = 0.021, p = 0.018, p = 0.047 respectively). (4) Conclusions: SS-OCTA provides a quantitative and qualitative analysis of the superficial capillary plexus allowing for early vascular changes assessment after vitrectomy with iERM and ILM peeling.

Macular vascular circulation and retinal oxygen saturation changes for idiopathic macular epiretinal membrane after vitrectomy

PURPOSE

To investigate the postoperative changes in retinal-choroidal blood flow area and retinal vascular oxygen saturation among patients with idiopathic macular epiretinal membranes (iERMs).

METHODS

This study prospectively included 24 eyes of 24 consecutive patients who underwent vitrectomy for iERMs. The flow area of choriocapillary layer, retinal superficial capillary plexuses (SCPs) and retinal deep capillary plexuses (DCPs) were performed using optical coherence tomography angiography with angiovue prototype software, and retinal vascular oxygen saturation was measured using retinal oximeter with the built-in software. The flow area of choriocapillary layers and mean retinal vessel oxygen saturation before and after surgery were compared.

RESULTS

Three months after vitrectomy, the foveal flow area of choriocapillary layer increased clinically significantly from 1.5 ± 0.2 to 1.6 ± 0.2 mm² (p = 0.02). The retinal vascular changes of SCPs and DCPs were not statistically significant. The mean retinal arterial oxygen saturation was 89.9 ± 11.3% preoperatively and increased to 94.5 ± 9.7% postoperatively (p = 0.04). Foveal retinal thickness revealed a clinically significant decrease from 547.8 ± 88.2 μm to 403.0 ± 47.5 μm after surgery (p < 0.05). Postoperative best corrected visual acuity had no statistically significant correlation with foveal flow area of the choriocapillary layer and retinal vascular oxygen saturation.

CONCLUSIONS

There was a decrease of retinal thickness, an improved flow area of choriocapillary layer in macular region, and an increase of retinal arterial vascular oxygen among iERMs patients after vitrectomy.

Foveal microvasculature features of surgically closed macular hole using optical coherence tomography angiography

Background

To describe the features of foveal microvasculature using optical coherence tomography angiography (OCTA) and to determine the related clinical factors in eyes with surgically closed macular hole (MH).

Methods

A retrospective case series of 18 patients with unilateral MH was reviewed. The patients maintained complete hole closure after vitrectomy with inner limiting membrane (ILM) peeling for at least 12 months. The healthy fellow eyes were studied as controls. The foveal microvasculature of both eyes was examined by OCTA. The area of the foveal avascular zone (FAZ) and the vascular density (VD) ratio in the superficial and deep capillary plexuses (SCP and DCP) were determined after surgery. Several clinical factors including age, stage and dimensions of MH, papillofoveal distance, the extent of nasal displacement of the fovea after surgery, postoperative central foveal thickness, and outer-retina integrity were evaluated to determine any relationships with the OCTA parameters.

Results

The mean FAZ area in both the SCP and DCP (0.29 ± 0.11 mm² and 0.39 ± 0.14 mm²) was significantly smaller than those of the controls (0.45 ± 0.14 mm² and 0.62 ± 0.22 mm²) (p = 0.001 and <0.001, respectively). The mean VD ratio in the SCP (0.270 ± 0.349) was similar to that of the controls (0.321 ± 0.189) (p = 0.231); however, that in the DCP (0.321 ± 0.189) was significantly lower than that of the controls (0.331 ± 0.119) (p = 0.025). Only the extent of nasal displacement of the fovea was correlated with the DCP FAZ-area difference values between the study group and the controls (correlation coefficient = 0.577; p = 0.012).

Conclusions

After successful MH surgery, the FAZ area in both the SCP and DCP was smaller and the VD ratio of the DCP was lower, suggesting a possible DCP vulnerability to tractional stress. As the FAZ area of the DCP in closed-MH eyes became smaller than that in the controls, the fovea was less displaced toward the optic disc, possibly reflecting a lack of retinal redundancy caused by horizontal stretching accompanied by foveal displacement.

Electronic supplementary material

The online version of this article (10.1186/s12886-017-0607-z) contains supplementary material, which is available to authorized users.

Vascular Density of Retinal Capillary Plexuses in Different Subtypes of Macular Hole

BACKGROUND AND OBJECTIVE

To compare vessel density and the foveal avascular zone (FAZ) area among eyes with full-thickness macular hole (FTMH), lamellar macular hole (LMH), and macular pseudohole (MPH) using optical coherence tomography angiography (OCTA).

PATIENTS AND METHODS

Cross-sectional study involving 10 eyes with idiopathic FTMH, 10 eyes with LMH, 10 eyes with MPH, 17 unaffected fellow eyes, and 10 healthy controls. All patients underwent 3 mm × 3 mm OCTA centered on the macula. Vessel density and FAZ area were calculated.

RESULTS

In the deep capillary plexus, FTMHs disclosed the highest vessel density (82.7% ± 16.8%), superior to LMHs (63.7% ± 5.9%; P = .0092), MPHs (37.8% ± 2.5%; P = .0011), and controls (53.0% ± 12.2%; P < .0001). In the superficial capillary plexus (SCP), MPHs had the lowest vascular density. Fellow eyes had reduced vascular density at SCP compared to control eyes.

CONCLUSIONS

Microvascular changes are evident in different subtypes of macular holes. Unaffected fellow eyes exhibit early involvement of SCP. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:648-654.].

Focal Nonperfusion of Deep Retinal Capillary Plexus in Eyes With Epiretinal Membranes Revealed by Optical Coherence Tomography Angiography

BACKGROUND AND OBJECTIVE

To evaluate the leakage pattern in eyes with idiopathic epiretinal membranes (ERM) using fluorescein angiography (FA) and the structure of the retinal capillary plexus with optical coherence tomography angiography (OCTA).

PATIENTS AND METHODS

The authors enrolled patients with idiopathic macular ERM in the consecutive case series study. All patients were evaluated using FA at the central macula area and OCTA at the central 3 mm × 3 mm.

RESULTS

Six patients (seven eyes) with ERM completed this preliminary study. The authors examined five eyes that showed increased macular thickness without a lamellar hole and two eyes that showed combined ERM with a lamellar hole. In the five eyes with ERM alone, the irregular focal hypofluorescent areas in FA corresponded to the locations of absent or low flow signals within vasculatures in the deep retinal capillary plexus seen in OCTA, whereas most of the superficial retinal capillary plexus was not affected, except vascular tortuosity in OCTA. In the two eyes combined with lamellar hole, OCTA showed central cystic lesions without vasculatures, but no low flow signals within vasculatures in the deep retinal capillary plexus beyond the hole. These focal irregular, absent, or low flow signals within vasculatures in the deep retinal plexus improved 1 month after surgical removal of the ERM in one eye.

CONCLUSION

Mechanical stress exerted from the ERM might affect deep retinal capillary flow more profoundly than the superficial capillary flow, which would account for the fluorescence changes seen in FA. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:404-409.].

Retinal vascular changes after vitrectomy for idiopathic epiretinal membrane: a pilot study with dynamic vessel analysis

PURPOSE

To investigate, using the Dynamic Vessel Analyzer (DVA), the retinal vascular changes that may occur after vitrectomy for idiopathic epiretinal membrane (ERM).

METHODS

Twenty-six eyes of 13 patients affected by unilateral idiopathic ERM were prospectively analyzed. 13 fellow eyes were used as control. The static (central retinal artery and vein equivalents) and dynamic (after flicker light stimulus) DVA analysis was performed at baseline (1 day before surgery) and 6 months after vitrectomy.

RESULTS

The static DVA analysis did not highlight any significant change between investigational eyes and controls at baseline and 6 months after surgery. The DVA dynamic analysis showed similar arterial flicker response between cases and controls at baseline (p = 0.3396), but disclosed a significant reduction of the arterial flicker response after surgery in the study eyes compared to fellow eyes (p = 0.0024). No significant changes were appreciated in the venous flicker response after surgery between cases and controls, both at baseline (p = 0.3450) and at the follow-up examination (p = 0.4214).

CONCLUSIONS

The physiological flicker-induced vasoconstriction is reduced after vitrectomy in arteries. The oxygen saturation change occurring after vitrectomy might have a role in the vascular tone modification.

Macular microcirculation in patients with epiretinal membrane before and after surgery

BACKGROUND

To investigate blood flow velocity (BFV) in the perifoveal capillaries before and after vitreous surgery for patients with epiretinal membrane (ERM).

METHODS

Twenty-one eyes in patients with ERM and 16 eyes in healthy subjects were involved in this study. Fluorescein angiography was performed using a scanning laser ophthalmoscope and BFV was analyzed by the tracing method. Foveal thickness (FT) was measured by optical coherence tomography.

RESULTS

BFV was significantly slower in the ERM patients (1.04 ± 0.10 mm/s) than in the healthy subjects (1.49 ± 0.11 mm/s ) (p = 0.0010). BFV in the ERM patients 6 months after vitreous surgery (6 M) (1.21 ± 0.02 mm/s) significantly increased compared with BFV before surgery (0 M) (1.04 ± 0.10 mm/s) (p = 0.0061). BFV 1 year after vitreous surgery (1 Y) significantly increased (1.38 ± 0.02 mm/s) compared with BFV(6 M) (1.21 ± 0.02 mm/s) (p = 0.0235). FT was significantly greater in the ERM patients (351.7 ± 87.1 μm) than in the healthy subjects (158.9 ± 16.9 μm) (p = 0.0011). FT (6 M) significantly decreased (285.3 ± 36.9 μm) compared with FT before surgery (0 M) (351.7 ± 87.1 μm) (p = 0.0212). FT did not show significant differences between (6 M) and (1 Y). No significant correlation was found between BFV and FT before surgery.

CONCLUSIONS

Perifoveal capillary BFV in patients with ERM was slower than that in the healthy subjects, and significantly improved after vitreous surgery as time progressed. It can be said that perifoveal capillary BFV is related to the development and improvement of ERM in the long term.

Correlation between thickening of the inner and outer retina and visual acuity in patients with epiretinal membrane

PURPOSE

The purpose of this study was to examine the relationship between thickening of the inner and outer retinal layers and visual acuity in patients with idiopathic epiretinal membrane.

METHODS

We examined 30 eyes of 30 patients and 25 eyes of 25 healthy volunteers as age-matched normal control subjects. The inner (between the vitreoretinal interface and the outer border of inner plexiform layer), outer, and full retinal thickness at the fovea, parafovea, and perifovea were measured using spectral-domain optical coherence tomography.

RESULTS

Thickening ratios of both the inner and outer retina were greater in the fovea than in the other macular regions (P < 0.0001). Inner foveal retinal thickening was significantly greater than outer foveal retinal thickening (P < 0.0001). However, outer retinal thickening in the fovea (r = 0.644, P < 0.001), parafovea (r = 0.616, P < 0.001), and perifovea (r = 0.410, P = 0.025) was significantly correlated with visual acuity; inner retinal thickening was not. Visual acuity tended to be worse, although not significantly so, in eyes with photoreceptor disruption.

CONCLUSION

Epiretinal membrane-induced retinal damage associated with visual acuity seems to be located within the outer retina external to the inner plexiform layer.

Morphologically functional correlations of macular pathology connected with epiretinal membrane formation in spectral optical coherence tomography (SOCT)

BACKGROUND

Preretinal membrane formation is a frequently diagnosed disease in ophthalmology. Its pathogenesis is unclear. Optical coherence tomography is an important diagnostic tool in patients with epiretinal membranes. In our study we use high-speed and high-resolution spectral OCT. Our goal was to present different forms of ERM and to analyze the influence of some morphological changes on visual acuity.

METHODS

We evaluated 44 cases of preretinal fibrosis. Patients were divided into two groups depending on macula morphology. High-resolution and 3D SOCT scans were acquired from all patients and analyzed. Maximum retinal thickness and retinal thickness in the fovea were measured. Type of ERM, presence of retinal cysts and photoreceptor defects were recorded. We analyzed the influence of those data on visual acuity.

RESULTS

Globally adherent membranes were the most frequent membrane architecture type in each group. The mean visual acuity in both groups did not significantly differ. Presence of retinal cystic formation had no influence on visual acuity. A statistically significant correlation was observed between central retinal thickness and VA in Group 2 (A = -0.488; p = 0.006). Photoreceptor defect was observed in 4 patients in group 1 and 11 in group 2. Patients with photoreceptor defect had significantly lower visual acuity (P = 0.04 for Group 1 and P = 0.002 for Group 2).

CONCLUSIONS

SOCT pictures of eyes with ERM are diverse. Thanks to high-resolution and 3D scanning protocols, more information can be gathered. Morphological changes in the retina, such as oedema with cystic spaces, lamellar macular holes, macular pseudoholes and photoreceptor defects, were present in patients with ERM. Estimation of those changes may be an important prognostic factor in cases of epiretinal membranes.

Perifoveal microcirculation before and after vitrectomy for diabetic cystoid macular edema

PURPOSE

To quantify the perifoveal microcirculation in diabetic eyes before and after successful vitreous surgery for cystoid macular edema without posterior vitreous detachment, and to determine whether improvement in perifoveal microcirculation is associated with improvement in postoperative visual acuity.

METHODS

In a prospective study, vitreous surgery was performed on 11 eyes of nine consecutive diabetic patients with cystoid macular edema, and their mean perifoveal capillary blood flow velocity was measured by fluorescein angiography with a scanning laser ophthalmoscope. Visual acuity was measured preoperatively and postoperatively, and the results were converted to the logarithm of the minimum angle of resolution (logMAR). The correlation between changes in logMAR visual acuity and capillary blood flow velocity was evaluated.

RESULTS

In all nine eyes of seven patients with successful vitreous surgery, the cystoid macular edema resolved within 6 months after surgery, and the mean capillary blood flow velocity was significantly increased compared with that before surgery (2.19 mm per second versus 2.68 mm per second, P =.021); the changes in capillary blood flow velocity were significantly correlated with the changes in the logMAR visual acuity (P =.024).

CONCLUSIONS

Vitreous surgery may improve perifoveal microcirculation in the eyes of diabetic patients with cystoid macular edema and resolve the macular edema. Improvement of perifoveal microcirculation may be an important factor affecting visual outcome.