Foveal configurations with disappearance of the foveal pit in eyes with macular pucker: Presumed role of Müller cells in the formation of foveal herniation

THREE-DIMENSIONAL RETINAL DISPLACEMENT BEFORE AND AFTER MACULAR PUCKER SURGERY

PURPOSE

To measure the coronal and sagittal retinal displacement before and after surgery for epiretinal membranes in InfraRed horizontal foveal sections and optical coherence tomography scans and describe displacement tridimensionality, vision loss, and metamorphopsia.

METHODS

Retrospective series with greater than 6-month average follow-up before and after surgery. The record included best-corrected visual acuity, optical coherence tomography, M-charts, and InfraRed retinography. Overall, pre- and postoperative coronal and sagittal retinal displacement across the entire field, concentric circles at 0.5-, 1.5-, and 4.5-mm radii, and the central horizontal and vertical meridian were calculated as the optical flow of consecutive images.

RESULTS

This study comprised 10 patients (4 men, 6 women), with 22.7 ± 25.2 months follow-up before surgery and 16.2 ± 7.3 months after. Best-corrected visual acuity reduced before surgery (0.15 ± 0.67 logarithm of minimum angle of resolution to 0.38 ± 0.85 logarithm of minimum angle of resolution; P < 0.05) and increased afterward (0.086 ± 0.61 logarithm of minimum angle of resolution; P = 0.003). Preoperative coronal displacement was 30.1 ± 29.1 µm versus 67.0 ± 23.4 µm after (P = 0.002). Sagittal retinal displacement was 140.9 ± 84.6 µm before surgery, 339.7 ± 172.5 µm after (P = 0.017), and 357.6 ± 320.8 µm across the entire follow-up. Preoperative best-corrected visual acuity decreases correlated with the foveal coronal displacement. Vertical metamorphopsia correlated with the average coronal displacement within a 4.5-mm radius. Pre- and postoperative sagittal displacement correlated with horizontal metamorphopsia (P = 0.006 and P = 0.026). Postoperative sagittal displacement correlated with postoperative best-corrected visual acuity (P = 0.026) and foveal thickness (P = 0.009).

CONCLUSION

This study confirms that postoperative displacement is greater than preoperative and that sagittal displacement is greater than coronal and correlates with best-corrected visual acuity and metamorphopsia changes.

Analysing early changes of photoreceptor layer thickness following surgery in eyes with epiretinal membranes

BACKGROUND/OBJECTIVES

To analyse short-term changes of mean photoreceptor thickness (PRT) on the ETDRS-grid after vitrectomy and membrane peeling in patients with epiretinal membrane (ERM).

SUBJECTS/METHODS

Forty-eight patients with idiopathic ERM were included in this prospective study. Study examinations comprised best-corrected visual acuity (BCVA) and optical coherence tomography (OCT) before surgery, 1 week (W1), 1 month (M1) and 3 months (M3) after surgery. Mean PRT was assessed using an automated algorithm and correlated with BCVA and central retinal thickness (CRT).

RESULTS

Regarding PRT changes of the study eye in comparison to baseline values, a significant decrease at W1 in the 1 mm, 3 mm and 6 mm area (all p-values < 0.001), at M1 (p = 0.009) and M3 (p = 0.019) in the central 1 mm area, a significant increase at M3 in the 6 mm area (p < 0.001), but no significant change at M1 in the 3 mm and 6 mm area and M3 in the 3 mm area (all p-values > 0.05) were observed. BCVA increased significantly from baseline to M3 (0.3LogMAR-0.15LogMAR, Snellen equivalent = 20/40-20/28 respectively; p < 0.001). There was no correlation between baseline PRT and BCVA at any visit after surgery, nor between PRT and BCVA at any visit (all p-values > 0.05). Decrease in PRT in the 1 mm (p < 0.001), 3 mm (p = 0.013) and 6 mm (p = 0.034) area after one week correlated with the increase in CRT (449.9 µm-462.2 µm).

CONCLUSIONS

Although the photoreceptor layer is morphologically affected by ERMs and after their surgical removal, it is not correlated to BCVA. Thus, patients with photoreceptor layer alterations due to ERM may still benefit from surgery and achieve good functional rehabilitation thereafter.

Müller Glial Cells in the Macula: Their Activation and Cell-Cell Interactions in Age-Related Macular Degeneration

Müller glia, the main glial cell of the retina, are critical for neuronal and vascular homeostasis in the retina. During age-related macular degeneration (AMD) pathogenesis, Müller glial activation, remodeling, and migrations are reported in the areas of retinal pigment epithelial (RPE) degeneration, photoreceptor loss, and choroidal neovascularization (CNV) lesions. Despite this evidence indicating glial activation localized to the regions of AMD pathogenesis, it is unclear whether these glial responses contribute to AMD pathology or occur merely as a bystander effect. In this review, we summarize how Müller glia are affected in AMD retinas and share a prospect on how Müller glial stress might directly contribute to the pathogenesis of AMD. The goal of this review is to highlight the need for future studies investigating the Müller cell's role in AMD. This may lead to a better understanding of AMD pathology, including the conversion from dry to wet AMD, which has no effective therapy currently and may shed light on drug intolerance and resistance to current treatments.

RETINAL TECTONICS AFTER MACULAR PUCKER SURGERY: Thickness Changes and En Face Displacement Recovery

PURPOSE

To study visual function, retinal layer thickness changes, and tangential displacement after pars plana vitrectomy for epiretinal membrane.

METHODS

Retrospective series of patients undergoing pars plana vitrectomy for epiretinal membrane, with 6-month follow-up including best-corrected visual acuity, optical coherence tomography, M-charts, epiretinal membrane grading, and infrared fundus photograph at time 0 (T0, preop) at months 1 (T1), 3 (T3), and 6 (T6) postop (±1 week). Retinal layer thickness and tangential ( en face ) retinal displacement between successive times for the entire retinal surface and the central horizontal and vertical meridian were also measured. En face displacement was calculated as optical flow of consecutive images.

RESULTS

Average best-corrected visual acuity improved from 0.28 ± 0.08 logarithm of Minimum Angle of Resolution at T0 to 0.16 ± 0.25 at T6 ( P = 0.05), best-corrected visual acuity improvement correlated with best corrected visual acuity (BCVA) at T0 ( P < 0.001). Vertical metamorphopsia decreased from 1.33° ± 0.70° at T0 to 0.82° ± 0.69° at T6 ( P < 0.05). Foveal thickness reduced from 453 ± 53 µ m at T0 to 359 ± 31 µ m at T6 ( P < 0.05) and reduction correlated with best-corrected visual acuity improvement ( P < 0.05). Foveal layers decreased ( P < 0.05) in all cases. The mean en face deformation was 155.82 ± 50.17 µ m and mostly occurred in the first month: T0-T1 displacement was 83.59 ± 30.28 µ m, T1-T3 was 36.28 ± 14.45 µ m, while T3-T6 was 39.11 ± 22.79 µ m ( P < 0.001) on average. Perifoveal and parafoveal deformation correlated with optical coherence tomography foveal thickness reduction at all time intervals (1, 3, and 6 months: P < 0.01).

CONCLUSION

Epiretinal membrane peeling affects all retinal layer thickness and results in new force balance across the entire retina and tangential displacement. Both en face and in-depth changes correlate with visual function.

Clinical features of idiopathic epiretinal membrane in children and the factors influencing postoperative visual acuity

PURPOSE

To describe the characteristics and surgical outcomes of idiopathic epiretinal membrane (iERM) in children and to determine the factors associated with postoperative visual acuity (VA).

METHODS

We retrospectively reviewed the medical records of 17 patients with iERM (age, < 18 years) who had undergone ERM surgery from 2009 to 2021. Spectral-domain optical coherence tomography features were documented. The eyes with iERMs involving the fovea were assigned to the localized and diffused groups depending on the morphological description of the membrane. Multiple linear regression analysis was used to explore the factors associated with the final VA.

RESULTS

The mean age was 9.2 ± 3.8 years. The mean follow-up period was 38.9 ± 45.4 months. After surgery, the central foveal thickness and the best-corrected VA (BCVA) improved significantly (all, P < 0.05). Fourteen eyes with iERMs showed involvement of the foveal area (localized group, six eyes; diffused group, eight eyes). There were no significant differences in the preoperative BCVA between the two groups (P = 0.064). However, the final BCVA was better in the diffused group than in the localized group (P = 0.043). Multiple regression analysis indicated that the localized membrane (P = 0.042) and lower preoperative BCVA (P = 0.043) were factors associated with a worse final VA in pediatric iERMs.

CONCLUSIONS

Surgical removal of ERM showed a high anatomical and functional success rate in children. In pediatric patients with iERMs involving the fovea, a good VA was more common when the membrane was diffused than when it was localized.

Multimodal Assessment of the Prognostic Role of Ectopic Inner Foveal Layers on Epiretinal Membrane Surgery

BACKGROUND

To perform a multimodal assessment of the ectopic inner foveal layers' (EIFL) prognostic role on idiopathic epiretinal membrane (ERM) surgery.

METHODS

We retrospectively followed-up for 12 months 27 patients who underwent ERM surgery and stratified them based on EIFL presence (group 1) or absence (group 2) at baseline. Central Retinal Thickness (CRT) and best-corrected visual acuity (BCVA) were compared pre- and post-operatively at 1, 4 and 12 months, whereas fixation stability (FS), macular sensitivity (MS) and multifocal electroretinogram (mfERG) responses were confronted at baseline and 12 months.

RESULTS

In group 1, BCVA improved at 4 and 12 months (MD = 0.14 (SE = 0.04); MD = 0.13 (SE = 0.05), respectively) as well as in group 2 (MD = 0.31 (SE = 0.07); MD = 0.41 (SE = 0.08), respectively). CRT did not change in group 1, whereas it decreased in group 2 at 4 and 12 months (MD = -73.13; SE = 23.56; MD = -76.20; SE = 23.56). MS showed no changes in both groups after surgery. FS did not change in group 1, whereas group 2 improved FS 2° (+8.91 ± 13.97) and FS 4° (+4.33 ± 3.84). MfERG P1 wave did not change in group 1, while in group 2 αP1-2, αP1-3 and αP1-4 improved postoperatively (27.97 ± 27.62; 12.51 ± 17.36; 10.49 ± 17.19, respectively).

CONCLUSIONS

Multimodal assessment confirmed that EIFL negatively affected ERM surgery outcomes.

Long-term Follow-up Results of Idiopathic Epiretinal Membrane Removal in the Eyes with Ectopic Inner Foveal Retinal Layers

PURPOSE

The purpose of this study was to evaluate pre- and perioperative factors related to time for the evolution of ectopic inner foveal layers (EIFL) following pars plana vitrectomy (PPV) for epiretinal membrane (ERM) peeling.

METHODS

This retrospective study included 81 consecutive eyes with idiopathic ERM that underwent vitrectomy surgery. Standard PPV + internal limiting membrane peeling was performed in all cases. A comprehensive ophthalmic examination was performed for all patients before and 1, 3, 6, and 12 months, and the last follow-up after surgery. We observed the postoperative improvement in EIFL severity in the short-term and longest follow-up and evaluated anatomical and functional improvement. Several parameters were assessed using the multivariate COX proportional hazard analysis.

RESULTS

Eighty patients (81 eyes) with a mean age of 70.33 ± 7.75 years were followed for a mean of 34.37 ± 23.61 months, and 55.5% of eyes (45 eyes) with EIFL ERM showed improvement of foveal contour to a better stage at the last follow-up. The median estimated time for evolving to a better stage was 29.73 months for stage 2, 49.68 months for stage 3, and 38.67 months for stage 4 (P = 0.001, log-rank test). The severity of EIFL was the only significant factor for time to evolution of EIFL ERM to a better stage, where the eyes with stage 4 EIFL ERM showed faster foveal contour improvement compared to those with stage 3 EIFL ERM (hazard ratio: 0.317, 95% confidence interval = 0.164-0.615, P = 0.001).

CONCLUSION

On assessing preoperative factors, the preoperative EIFL stage emerged as the sole significant factor for EIFL ERM improvement to a better disease stage. This study reports some of the longest follow-up durations for patients undergoing PPV for EIFL ERM, and both functional and anatomical improvements were observed across all stages of EIFL, including in the advanced stage 4 EIFL ERM.

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.

EPIRETINAL MEMBRANE WITH FOVEAL HERNIATION: Visual and Surgical Outcomes

PURPOSE

Foveal herniation occurs when neuroretinal tissue protrudes through and above the level of an epiretinal membrane. This study describes the visual symptoms and spectral domain optical coherence tomography findings associated with foveal herniation and evaluates the postoperative visual, anatomical, and surgical outcomes.

METHODS

A multicenter retrospective review of patients diagnosed with epiretinal membrane identified 59 patients with preoperative foveal herniation on spectral domain optical coherence tomography. Data regarding visual symptoms, preoperative and postoperative best-corrected visual acuity (BCVA), central retinal thickness, macular volume, and size of foveal herniation were collected, and statistical analysis was performed.

RESULTS

A total of 58 of the 59 patients with foveal herniation underwent surgical epiretinal membrane peeling, with foveal contour restored in 53.5% of patients after surgery. Average BCVA improved from 20/80 to 20/40 Snellen equivalent at most-recent postoperative visit (P < 0.0001). The average central retinal thickness decreased from 632 µm to 432 µm (P < 0.0001) and the average macular volume decreased from 11.3 mm3 to 9.5 mm3 (P < 0.0001) at 3 months postoperatively. Preoperatively, greater herniation height was associated with worse BCVA (P = 0.008), greater central retinal thickness (P = 0.01), retinoschisis, cystoid macular edema, foveolar detachment, ellipsoid zone abnormality, and external limiting membrane abnormalities (P < 0.05). Postoperatively, there was a decrease in retinoschisis, cystoid macular edema, foveolar detachment, ellipsoid zone, and external limiting membrane abnormality (P < 0.05) on spectral domain optical coherence tomography.

CONCLUSION

Patients with larger foveal herniation height had greater preoperative central retinal thickness, worse preoperative and postoperative BCVA, and more intraretinal abnormalities on spectral domain optical coherence tomography. Surgical epiretinal membrane peeling in patients with foveal herniation resulted in a significant improvement in patients' BCVA and microstructural abnormalities.

Tight adherent feature on optical coherence tomography predict postoperative visual outcome in epiretinal membrane eyes

Background

To identify the predictive parameter among preoperative measurements that best predicts postoperative visual outcome in the epiretinal membrane (ERM).

Methods

Thirty-three consecutive patients with idiopathic unilateral ERM patients between 2015 and 2018 were enrolled. Nineteen healthy normal eyes were selected as an independent age-matched group. Based on preoperative optical coherence tomography (OCT), we further divided the patients with ERM into two groups: type 1, loosely attached ERM, and type 2, tight adherent ERM. We documented the vision and thickness of various retinal layers: nerve fiber layer, ganglion cell layer, inner plexiform layer (GCL + IPL), inner nuclear layer (INL), outer retinal layer (ORL), and retinal pigment epithelium/Bruch complex layer before and after the surgery. The association between postoperative visual acuity and these variables was analyzed using multiple linear regression analysis.

Results

All retinal layers of ERM eyes were thicker than the normal eyes (P < 0.05). Among ERMs, we identified 11 eyes with type 1 adhesions and 22 eyes with type 2 adhesions. The preoperative GCL + IPL layers were significantly thicker in type 2 patients than in type 1 patients (93.67 ± 33.03 um vs 167.71 ± 13.77 um; P = 0.023). Greater GCL + IPL thickness was correlated with a worse postoperative visual acuity and multiple linear regression analysis showed that GCL + IPL thickness was an independent predictor of postoperative visual acuity (VA) (beta value = 0.689; P = 0.012). A greater thickness of GCL + IPL layers of type 2 patients had worse postoperative best-corrected visual acuity (BCVA) (P = 0.028). Ectopic inner foveal layers with disappearance of fovea pit were persistently presented in OCT profiles of both groups.

Conclusion

Idiopathic ERM demonstrated significantly thicker inner retinal layers (GCL + IPL and INL). However, the ORL thickness was similar between the normal eyes and ERM eyes. The preoperative GCL + IPL layers were significantly thicker in patients with type 2 ERM than that in patients with type 1 ERM. The increase in GCL + IPL thickness was significantly correlated with worse postoperative visual outcomes.

Effects of Ectopic Inner Foveal Layers on Foveal Configuration and Visual Function after idiopathic Epiretinal Membrane Surgery

PURPOSE

To investigate the effects of ectopic inner foveal layers (EIFLs) on foveal configuration recovery and visual acuity (VA) after idiopathic epiretinal membrane (iERM) removal and analyze the relationship of foveal configuration recovery between 1-month and long-term postoperatively.

METHODS

This retrospective study included 216 consecutive eyes with iERM that underwent vitrectomy surgery. A comprehensive ophthalmic examination was performed for all patients before and 1, 4,10, and 24 months after surgery. We observed the postoperative anatomical and functional recovery of eyes with and without EIFLs and analyzed the association between short-term and long-term anatomical recovery.

RESULTS

The presence of EIFL was associated with severe preoperative visual damage (P＜0.001) and was considered as a negative factor for postoperative foveal depression recovery (P＜0.001). No significant difference was found in postoperative BCVA between the eyes with and without EIFLs (P=0.442). For eyes with stage II ERMs, 17.6% developed EIFLs postoperatively, which did not affect the final BCVA. Overall, 24.5% of ERMs restored the foveal configurations at 1 month postoperatively, and 14.7% continued recovering during the follow-up. Foveal structure recovery in eyes with EIFLs was associated with earlier stage, fewer microcystic macular edema, complete IZ layer, and a thinner CFT (All P＜0.05) at 1-month postoperatively.

CONCLUSIONS

The EIFL is associated with severe preoperative visual damage and is a negative factor for postoperative anatomical recovery, but it is a minor factor for postoperative VA. We also found an association of foveal configuration recovery between 1-month and long-term after surgery.

Müller cells and astrocytes in tractional macular disorders

Tractional deformations of the fovea mainly arise from an anomalous posterior vitreous detachment and contraction of epiretinal membranes, and also occur in eyes with cystoid macular edema or high myopia. Traction to the fovea may cause partial- and full-thickness macular defects. Partial-thickness defects are foveal pseudocysts, macular pseudoholes, and tractional, degenerative, and outer lamellar holes. The morphology of the foveal defects can be partly explained by the shape of Müller cells and the location of tissue layer interfaces of low mechanical stability. Because Müller cells and astrocytes provide the structural scaffold of the fovea, they are active players in mediating tractional alterations of the fovea, in protecting the fovea from such alterations, and in the regeneration of the foveal structure. Tractional and degenerative lamellar holes are characterized by a disruption of the Müller cell cone in the foveola. After detachment or disruption of the cone, Müller cells of the foveal walls support the structural stability of the foveal center. After tractional elevation of the inner layers of the foveal walls, possibly resulting in foveoschisis, Müller cells transmit tractional forces from the inner to the outer retina leading to central photoreceptor layer defects and a detachment of the neuroretina from the retinal pigment epithelium. This mechanism plays a role in the widening of outer lameller and full-thickness macular holes, and contributes to visual impairment in eyes with macular disorders caused by conractile epiretinal membranes. Müller cells of the foveal walls may seal holes in the outer fovea and mediate the regeneration of the fovea after closure of full-thickness holes. The latter is mediated by the formation of temporary glial scars whereas persistent glial scars impede regular foveal regeneration. Further research is required to improve our understanding of the roles of glial cells in the pathogenesis and healing of tractional macular disorders.