Spectral-domain optical coherence tomography for monitoring epiretinal membrane surgery

[Epiretinal membrane: diagnostics, indications and surgical treatment]

An epiretinal membrane (ERM) is a frequently occurring disease affecting the macula, which can be associated with visual impairment and metamorphopsia, depending on the severity and location. A distinction is made between an idiopathic form caused by age-related changes of the vitreous body and a secondary form associated with diseases of the posterior segment. The development of fibrocellular epiretinal membranes formed by dedifferentiation of intraretinal and extraretinal cells at the level of the vitreomacular interface plays a major role in the pathogenesis. The diagnostics and indications for surgical treatment of ERM are based on the visual acuity, evidence of metamorphopsia, ophthalmoscopic findings and optical coherence tomography (OCT) of the macula. In addition to the possibility of observation of the course where benign spontaneous courses are not uncommon, pars plana vitrectomy (PPV) with peeling of the ERM and internal limiting membrane (ILM) to prevent recurrences is the treatment of choice in symptomatic patients. The prognosis after surgical treatment is very good. In approximately two thirds of the cases, an improvement in visual acuity and/or a reduction of metamorphopsia can be achieved, with a number of predictive, primarily OCT-based factors enabling a prediction of the functional prognosis. Comprehensive patient education regarding the generally long duration of postoperative rehabilitation and the possibility of persistent symptoms or visual deterioration despite successful membrane removal is essential.

Correlation between retinal sensitivity assessed by microperimetry and structural abnormalities on optical coherence tomography after successful epiretinal membrane surgery

BACKGROUND

To verify the correlation between retinal sensitivity (RS) assessed by the microperimetry (MP) and optical coherence tomography (OCT) parameters measured in eyes submitted to pars-plana vitrectomy (PPV) for idiopathic epiretinal membrane (ERM) treatment.

METHODS

43 patients underwent PPV. Best-corrected visual acuity (BCVA) and OCT imaging were acquired preoperatively and 6 months after surgery. The RS values were recorded 6 months after the surgery. Total macular thickness (TMT) measurements and OCT-evaluated structural findings were also analyzed. The MP examination tested 44 points, with direct topographic correspondence with the OCT-ETDRS map. Correlations between BCVA, RS, and OCT parameters were assessed.

RESULTS

TMT measurements in patients were significantly thicker preoperatively and reduced after surgery. All patients demonstrated BCVA improvements after surgery. The RS parameters after surgery were significantly lower in patients. For OCT structural analyses, patients with lower RS at the fovea correlated with the preexisting disorganization of retinal inner layers (DRIL). In addition, lower RS values were associated with DRIL, outer retinal changes (ORC), and intraretinal microcysts after surgery.

CONCLUSIONS

The RS values after surgery were significantly lower when compared to controls. The DRIL presence before and after surgery, and microcysts and ORC after surgery were related to worse visual outcomes.

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.

Effect of internal limiting membrane peeling for idiopathic epiretinal membrane

Purpose

To further evaluate the necessity of internal limiting membrane (ILM) peeling for patients with idiopathic epiretinal membrane (iERM).

Method

We searched PubMed, Web of Science, Embase, Cochrane Library, and CNKI from their inception up to August 24, 2021. Eligible meta-analyses comparing iERM removal with and without ILM peeling were included. AMSTAR and GRADE classification was used to assess the methodological quality of each study and the quality for each outcome, respectively. The primary outcomes were best-corrected visual acuity (BCVA), central macular thickness (CMT), and recurrence.

Results

10 meta-analyses were included. 75.9% of studies revealed no statistically significant difference in BCVA between the groups, while only 10.3% showed better BCVA favorable to additional ILM peeling. 54.2% reported no significant difference in CMT between the groups, followed by 41.7% showing thicker CMT due to additional ILM peeling. Compared to iERM removal alone, additional ILM peeling provided a lower recurrence rate in 66.7% of studies.

Conclusion

ILM peeling could significantly reduce recurrence rate, but not significantly improve the recovery of visual outcome or decrease the thickness of central macula.

Functional and anatomic changes between early postoperative recovery and long-term follow-up after combined epiretinal and internal limiting membrane peeling

OBJECTIVE

To evaluate short- and long-term changes in best-corrected visual acuity (BCVA) and retinal layer thicknesses after combined epiretinal membrane (ERM) and internal limiting membrane (ILM) peeling for macular holes and symptomatic ERMs.

DESIGN

Retrospective observational case series.

PARTICIPANTS

Patients with ERMs or with macular holes and ERMs treated with combined ERM and ILM peeling.

METHODS

Study eyes (n = 36) and healthy fellow eyes (n = 17) were evaluated using the automated segmentation of retinal layers performed by SPECTRALIS software that automatically calculated the average central retinal thickness and the average thickness in each of the individual retinal layers. The analysis was performed at 6-18 months after surgery and after 60 months.

MAIN OUTCOME MEASURES

Changes in BCVA and retinal layer thicknesses determined by automated segmentation at the first and last follow-up visits.

RESULTS

BCVA improved from a baseline 0.48 ± 0.25 logMAR (20/60 Snellen) to 0.18 ± 0.18 logMAR (20/30 Snellen) at the short-term postoperative examination (p < 0.0001). Between first and last follow-up visit, 5 eyes (14%) were classified as better, 28 (78%) as stable, and 3 (8%) as worse. BCVA of the control fellow eyes remained stable during the follow-up. The thicknesses of retinal layers decreased significantly (p < 0.009). At the last follow-up, the ganglion cell layer was thinner and the inner nuclear layer was thicker in the operated eyes compared with the healthy fellow eyes.

CONCLUSION

Combined ERM and ILM peeling may improve BCVA in some patients. However, over a long follow-up period, it can be associated with progressive ganglion cell layer thinning that could affect BCVA stability.

Changes in the Hyperreflective Bands of Outer Retinal Layers after Idiopathic Epiretinal Membrane Surgical Removal

Purpose: The purpose of this study was to describe the relationship between the outer retinal hyperreflective bands and visual acuity recovery after idiopathic epiretinal macular membrane (ERM) surgical removal.Methods: A prospective longitudinal non-comparative study was conducted that included a total of 68 patients with idiopathic ERM, who underwent consecutive 23 G pars plana vitrectomy (PPV) at San Juan University Hospital (Alicante, Spain) from January 2019 to January 2021. All patients underwent a complete preoperative standard ophthalmic examination, including measurement of best corrected visual acuity (BCVA) and spectral-domain optical coherence tomography (SD-OCT) examination. This protocol was repeated at 1 and 3 months after surgery.Results: Mean preoperative decimal BCVA was 0.30 ± 0.13 and disruption of the first, second, third and fourth outer retinal hyperreflective bands was observed by SD-OCT in 9 (27.9%), 27 (39.7%), 33 (48.5%) and 17 patients (25%), respectively. BCVA improved after ERM peeling at 1 and 3 months in all patients, regardless of the presence of disruption in any hyperreflective band. Significantly larger improvement of BCVA was found at 3 months after surgery in patients not showing disruption of hyperreflective bands 1 and 4 (p = 0.048 and 0.001, respectively).Conclusions: The integrity of the outer retinal hyperreflective bands by SD-OCT in patients with idiopathic ERM is a valuable tool to determine the visual prognosis of the surgical treatment of this condition. A successful recovery of hyperreflective bands 1 and 4 with ERM surgery may be a potential biomarker of the visual improvement achieved due to their important anatomical relation with cone photoreceptors at the foveal level.

Correlations between Clinical and Histopathologic Characteristics in Idiopathic Epiretinal Membrane

PURPOSE

To investigate correlations between clinical and histopathologic characteristics of idiopathic epiretinal membrane (ERM).

DESIGN

Retrospective interventional case series.

PARTICIPANTS

In total, 87 eyes from 87 patients with idiopathic ERM who underwent pars plana vitrectomy with peeling of the ERM from 2019 to 2020 were included.

METHODS

The outcomes of clinical ophthalmic examination, including measurement of best-corrected visual acuity (BCVA) and spectral-domain OCT (SD-OCT), before and after surgery were reviewed. Surgical specimens were fixed in formalin and embedded in paraffin for histologic and immunohistochemical analysis.

MAIN OUTCOMES MEASURES

The association between morphological characteristics revealed on SD-OCT images and the cellular composition of the surgically excised ERM demonstrated with immunohistochemical staining were the main outcome measures. Changes in the BCVA and central macular thickness (CMT) were assessed through a comparison of preoperative and postoperative measurements.

RESULTS

Based on SD-OCT morphological characteristics in the foveal area, 15 cases were classified into group 1A (mainly outer retinal thickening), 39 into group 1B (more tenting of the outer retina and distorted inner retina), and 33 into group 1C (prominent inner retina thickening). Overall, postoperative final BCVA and CMT at 1 year improved in all groups. Patients who presented with a better initial BCVA exhibited a more favorable final BCVA. Epiretinal membranes in group 1C demonstrated the greatest decrease in CMT compared with those in groups 1B and 1A, but the final CMT did not differ among the groups. A negative correlation between the density of hyalocytes (P = 0.003) and myofibroblasts (P = 0.047) was noted between the 3 groups. Total cell density and glial cell density of the ERMs were strongly associated with poor final BCVA and BCVA improvement.

CONCLUSIONS

The present study provides new histopathologic information regarding the formation and progression of idiopathic ERM. Glial cell proliferation plays a predominant role in these processes. Epiretinal membranes with high cellularity and glial cell density may cause damage to the retina structure, resulting in poor postoperative visual outcomes. These findings provide additional evidence supporting early surgical intervention in patients with idiopathic ERM reported with visual disturbance.

Preoperative ocular coherence tomographic prognosticators of visual acuity after idiopathic epiretinal membrane surgery

PURPOSE

To provide a current review of the evidence for the utility of preoperative ocular coherence tomography (OCT) parameters in prognosticating postoperative visual acuity and visual improvement after idiopathic epiretinal membrane surgery. To determine which OCT bio-markers are most useful in this regard and where future studies may apply more emphasis.

METHODS

An extensive search of the PubMed database was performed for studies investigating this relationship. Key search terms included: idiopathic, epiretinal membrane, surgery, peel, vitrectomy, vision, outcomes, visual acuity, ocular coherence tomography, central foveal thickness, foveal contour, foveal morphology, ectopic inner foveal layers, inner retinal layers, inner retinal irregularity index, outer retinal layers, ellipsoid zone, interdigitation zone, photoreceptor outer segment length, central bouquet abnormality, staging, choroidoscleral irregularity, ganglion cell and nerve fibre layers, inner and outer plexiform layers, inner and outer nuclear layers. Forty-nine peer-reviewed articles were included in this review. These consisted of 28 retrospective studies [1-3,13,16-18,20,23-29,32-36,38,40,42-47], 17 prospective studies[6-12,14,19,21,22,30,31,37,41,48,49], 2 reviews [4,39] and 2 systematic reviews [5,15].

CONCLUSION

The weight of literary evidence seems to support photoreceptor integrity as the most consistent OCT marker of better postoperative visual acuity. This includes analysis of ellipsoid and interdigitation zones as well as photoreceptor outer segment length. However, the newer OCT staging system proposed by Govetto et al. (2017) fulfils a need for a clinically useful and evidence-based OCT classification. It may be the way forward in prognosticating ERM surgical outcomes by preoperative stratification. There is insufficient evidence to suggest the other discussed parameters in this review as useful prognosticators of postoperative visual acuity.

Vascular tortuosity analysis in eyes with epiretinal membrane imaged by optical coherence tomography angiography

Background

This study aimed to evaluate macular vessel tortuosity using optical coherence tomography angiography (OCTA) and its association with visual outcomes in eyes undergoing surgery for epiretinal membrane (ERM).

Methods

The study included 22 consecutive patients who underwent vitrectomy for ERM between May 2019 and July 2020 and OCTA at Osaka University Hospital. All patients underwent ophthalmologic examinations, including swept-source OCTA. Standard vitrectomy was performed, and the patients were followed up for 6 months postoperatively. Distortion of retinal vessels was calculated using two parameters: the actual vessel length in the vessel section (VL) and the direct vessel branching point distance (BD) in the three quadrants (nasal, temporal, and superior-inferior) of the macula. We analyzed the correlation between these parameters and visual outcomes.

Results

Significantly longer VL was found at 1, 3, and 6 months postoperatively (p = 0.006, 0.008, and 0.022, respectively) in the temporal quadrant compared to baseline temporal VL. Significantly shorter VL was found in nasal quadrants at 1 and 3 months (p = 0.046 and p = 0.018) in the comparison of nasal baseline VL. VL/BDs were correlated with the same postoperative best-corrected visual acuity (BCVA) at 1, 3, and 6 months (p = 0.035, 0.035, and 0.042, respectively) in the superior-inferior quadrant. A significant association of changes in VL and BCVA was found at 3 and 6 months postoperatively in the nasal quadrant (p = 0.018 and 0.0455, respectively).

Conclusions

Changes in vascular distortion after ERM surgery can be measured using OCTA. The change in vessels around the macula became more linear; this was associated with visual outcomes after surgery.

A prospective randomized clinical trial comparing nepafenac, intravitreal triamcinolone and no adjuvant therapy for epiretinal membrane

PURPOSE

To compare the efficacy of topical nepafenac 0.1% versus intravitreal triamcinolone acetonide (IVTA) at the conclusion of vitrectomy surgery versus no adjuvant therapy (NAT) in improving macular morphology post-operatively in patients undergoing vitrectomy for epiretinal membrane (ERM), as measured by optical coherence tomography (OCT) imaging and best-corrected visual acuity (BCVA).

METHODS

Design: Prospective randomized clinical trial Setting: Multi-centre 80 patients scheduled to undergo vitrectomy surgery for idiopathic ERM were randomized to receive either IVTA (4 mg/0.1 cc) at the end of surgery, topical nepafenac sodium 0.1% TID for 1 month post-operation or no adjuvant treatment (NAT). Optical coherence tomography (OCT) imaging, best-corrected visual acuity and intraocular pressure (IOP) were measured before surgery, and 1 and 2 months post-operation.

RESULTS

Although all three groups showed reduction in macular thickness post-operation, the NAT group showed the most improvement, with a reduction of 136.18 ± 29.84 μm at two months. There was no statistically significant difference in macular thickness between the groups at each time point, p = 0.158. The NAT group also had the best recovery in BCVA with an improvement of 0.207 logMAR (10.35 letters) at two months post-operation. There was no statistically significant difference in BCVA between the groups, p = 0.606. There was statistically significant difference in the IOP between the three groups, p = 0.04 only at 1-month visit. The IVTA group had the highest rise in average IOP at both 1 and 2 months post-operation (2.72 and 1.58 mmHg, respectively).

CONCLUSION

Our study data suggest there was no advantage in the use of topical nepafenac or IVTA for post-vitrectomy ERM surgery.

PREVALENCE AND RISK FACTORS OF ELLIPSOID ZONE DAMAGE AFTER PARS PLANA VITRECTOMY FOR IDIOPATHIC EPIRETINAL MEMBRANE

PURPOSE

To assess factors associated with external limiting membrane (ELM)/ellipsoid zone (EZ) damage after pars plana vitrectomy (PPV) for epiretinal membrane and evaluate ELM/EZ damage impact on functional and anatomical outcomes.

METHODS

Patients who underwent PPV with epiretinal membrane ± inner limiting membrane peeling were retrospectively analyzed. Best-corrected visual acuity and central macular thickness were longitudinally collected based on the available follow-up. Demographic data, clinical data, and surgical details were included in logistic regression models having ELM/EZ damage as a binary outcome.

RESULTS

Overall, 179 eyes (171 patients) were included; 93 had a 12-month follow-up. Thirty-four eyes (19%) had ELM/EZ damage after surgery; in nine eyes (5%), ELM/EZ damage persisted at 12 months. Phacoemulsification during PPV (odds ratio = 6.97; P = 0.007) and ELM/EZ damage before PPV (odds ratio = 6.91; P = 0.007) were risk factors for postoperative ELM/EZ disruption. Thicker outer nuclear layer (P = 0.002), thicker ectopic inner foveal layer (P < 0.001), and higher endoillumination power (P = 0.03) were associated with slower visual recovery. Inner limiting membrane peeling (P = 0.04) was associated with slower anatomical recovery.

CONCLUSION

Cataract extraction and outer retinal damage before PPV are associated with higher risk of photoreceptor damage postoperatively. The rate of visual improvement varies as a function of retinal layers' distortion before surgery; additional retinal manipulation slows restoration of the macular anatomy.

Ectopic inner foveal layer as a factor associated with metamorphopsia after vitrectomy for epiretinal membrane

PURPOSE

To analyse the relationship between the extent of metamorphopsia and optical coherence tomography (OCT) parameters including the ectopic inner foveal layer (EIFL) in patients with epiretinal membrane (ERM) who underwent pars plana vitrectomy (PPV).

METHODS

This study included 63 eyes of 62 patients who underwent PPV for ERM. Metamorphopsia was assessed by measuring the metamorphopsia score for vertical lines (MV) and metamorphopsia score for horizontal lines (MH) using M-CHARTS. Central retinal thickness (CRT), EIFL thickness and disruption of outer retinal layers were measured before and after surgery, and the relationship of these parameters with metamorphopsia scores at 3 months after vitrectomy was analysed.

RESULTS

Preoperative MV correlated with preoperative CRT and EIFL (p = 0.005 and 0.045 respectively). Postoperative MH correlated with preoperative CRT (p = 0.048), while postoperative MV correlated with preoperative CRT and EIFL (p = 0.002 and 0.0006 respectively). Postoperative MH correlated with postoperative CRT and EIFL (p = 0.001 and 0.002 respectively), and postoperative MV also correlated with postoperative CRT and EIFL (p = 0.0008 and < 0.0001 respectively). MH and MV did not correlate with outer retinal layer disruptions, both before and after vitrectomy. When multiple regression analysis was performed on preoperative and postoperative OCT parameters that correlated with postoperative metamorphopsia scores, only postoperative EIFL was identified as an independent factor associated with postoperative MV (p = 0.042).

CONCLUSION

When PPV was conducted for ERM, postoperative EIFL was found to be a significant factor associated with postoperative metamorphopsia score.

Predictive value of ectopic inner foveal layer without internal limiting membrane peeling for idiopathic epiretinal membrane surgery

PURPOSE

To investigate the clinical importance of ectopic inner foveal layer (EIFL) grading (mild to severe) in patients diagnosed with idiopathic epiretinal membrane (iERM) and had pars plana vitrectomy (PPV) with solely ERM peeling.

MATERIALS AND METHODS

Patients diagnosed with iERMs who had undergone PPV including only ERM peeling were enrolled in the study, and follow-up findings were recorded at baseline, and at 3, 6, 12 months and final examinations. EIFL was categorized into four grades, from mild to severe. Pre- and postoperative anatomical changes were measured using spectral domain optical coherence tomography (SD-OCT) imaging. The association between EIFL and other SD-OCT parameters with best-corrected visual acuity (BCVA) was assessed before and after PPV surgery.

RESULTS

One-hundred thirty-eight eyes of 106 patients with mild to severe EIFL were included in the study. Higher EIFL thickness was significantly correlated with lower baseline (r = 0.575, p = 0.020) and final BCVA (r = 0.748, p = 0.001). Although EIFLs continued in advanced-stage cases (stage 3 and 4) (64 eyes [82%]) at the final visit, it was observed in 8 eyes (23%) in the early stage (stage 2) of iERMs. A strong positive correlation was found between EIFL thickness and recurrence rate of ERM (r = 0.876, p < 0.001). Recurrence of ERM was detected in 27 eyes; 2 (7%) at stage 1, 3 (9%) at stage 2, 10 (23%) in stage 3, and 12 (33%) in stage 4 (p < 0.001).

CONCLUSION

A negative association was found between the severity of EIFL and postoperative anatomical and visual recovery. In terms of surgical timing, early stages (stages 1 and 2) may be preferred for providing good anatomical and visual recovery and a low recurrence rate following surgery.

Macular pigment optical density assessed by heterochromatic flicker photometry in eyes affected by primary epiretinal membrane

PURPOSE

To compare macular pigment optical density (MPOD) in healthy eyes vs eyes affected by primary epiretinal membrane (ERM) in different stages and to assess the relation between MPOD and optical coherence tomography findings.

METHODS

Prospective cross-sectional study of 62 eyes from 62 patients affected by unilateral primary ERM. Contralateral healthy eyes from the same patients were used as a control group. Main outcome measures were MPOD, ERM stage, central foveal thickness (CFT), outer nuclear layer thickness (ONLT), integrity of outer retinal bands (ORB) and presence of Central Bouquet (CB) abnormalities.

RESULTS

In the study group mean CFT was 444±75 µm and mean ONLT was 245±40 µm, while in the control group mean CFT was 230±21 µm and mean ONLT was 102±14 µm (p<0.001). Mean MPOD was 0.86±0.07 in eyes with ERM and 0.48±0.09 in contralateral healthy eyes (p<0.001). MPOD was associated with CFT (p=0.006) and ONLT (p<0.001) while no significant associations were observed between MPOD and ORB integrity (p=0.14) and CB abnormalities (p=0.08).

CONCLUSIONS

MPOD increased in eyes affected by primary ERM proportionally to CFT and, especially, ONLT. Probably, centripetal forces exerted by ERM contraction on the retinal surface lead to a progressive foveal packing of foveal Muller cells.

Influence of postoperative ectopic inner foveal layer on visual function after removal of idiopathic epiretinal membrane

Purpose

To investigate the functional and anatomical parameters and their postoperative changes according to the ectopic inner foveal layer (EIFL) staging scheme for idiopathic epiretinal membrane (ERM).

Methods

In this prospective study, patients with idiopathic ERM underwent pars plana vitrectomy and ERM removal, and were followed-up for 6 months. The associations of EIFL with pre- and postoperative functional and anatomical parameters were analyzed.

Results

A total of 84 eyes (84 patients) were included: 39 (46.4%), 33 (39.3%), and 12 (14.3%) as EIFL stages 2, 3, and 4, respectively. At 6 months after surgery, the mean best-corrected visual acuity (BCVA) significantly improved in all EIFL stages (P ≤ 0.003); however, metamorphopsia improved only in eyes with EIFL stage 2 (P = 0.039) and 3 (P = 0.011). The aniseikonia and foveal avascular zone (FAZ) area showed no significant postoperative changes in any of the EIFL stages. Both preoperatively and during 6 months after surgery, the EIFL stage showed a significant correlation with BCVA (P ≤ 0.033), metamorphopsia (P ≤ 0.008), central macular thickness (P < 0.001), and FAZ parameters (P ≤ 0.016) at each time point, but not with aniseikonia. Significant correlations of EIFL thickness with BCVA (P = 0.028) and metamorphopsia (P = 0.006) before surgery were not persistent after surgery.

Conclusion

Both pre- and postoperatively, the staging of EIFL, rather than its thickness, is a simple and adequate surrogate marker for visual acuity and metamorphopsia in eyes with idiopathic ERM.

Long-Term Follow-Up of Outer Retinal Layers in Patients with Epiretinal Membranes

PURPOSE

This study aimed to investigate the long-term effect of observed epiretinal membranes on the outer retinal layers and visual acuity.

METHODS

It is a retrospective observational study. Subjects with an epiretinal membrane and consecutive optical coherence tomography scans were followed for changes in visual acuity, central macular thickness, ellipsoid zone loss, and outer foveal thickness (OFT).

RESULTS

The study consisted of 24 eyes of 22 patients, with a mean follow-up of 5 ± 1.6 years. The mean visual acuity was slightly worse at the last follow-up (0.22 ± 0.36 LogMAR [20/33] vs. 0.27 ± 0.36 LogMAR [20/36], p = 0.05). Ellipsoid zone loss was found in 37.5% of eyes. Vision loss was associated with initial size of ellipsoid disruption (p = 0.048) and age (p = 0.027). A decrease in OFT was associated with an initially larger zone of ellipsoid disruption (p = 0.006) and an initially thicker OFT (p = 0.011). An epiretinal membrane associated with vitreomacular adhesion within 1,000 μm of the foveal center at baseline was associated with ellipsoid zone loss (p = 0.012) but not with a change in visual acuity.

CONCLUSIONS

Ellipsoid zone changes were common in this study and tended to enlarge over time. Epiretinal membranes associated with vitreomacular adhesion within 1,000 μm of the foveal center may be a risk factor for ellipsoid zone loss.

Artificial intelligence-based detection of epimacular membrane from color fundus photographs

Epiretinal membrane (ERM) is a common ophthalmological disorder of high prevalence. Its symptoms include metamorphopsia, blurred vision, and decreased visual acuity. Early diagnosis and timely treatment of ERM is crucial to preventing vision loss. Although optical coherence tomography (OCT) is regarded as a de facto standard for ERM diagnosis due to its intuitiveness and high sensitivity, ophthalmoscopic examination or fundus photographs still have the advantages of price and accessibility. Artificial intelligence (AI) has been widely applied in the health care industry for its robust and significant performance in detecting various diseases. In this study, we validated the use of a previously trained deep neural network based-AI model in ERM detection based on color fundus photographs. An independent test set of fundus photographs was labeled by a group of ophthalmologists according to their corresponding OCT images as the gold standard. Then the test set was interpreted by other ophthalmologists and AI model without knowing their OCT results. Compared with manual diagnosis based on fundus photographs alone, the AI model had comparable accuracy (AI model 77.08% vs. integrated manual diagnosis 75.69%, χ² = 0.038, P = 0.845, McNemar’s test), higher sensitivity (75.90% vs. 63.86%, χ² = 4.500, P = 0.034, McNemar’s test), under the cost of lower but reasonable specificity (78.69% vs. 91.80%, χ² = 6.125, P = 0.013, McNemar’s test). Thus our AI model can serve as a possible alternative for manual diagnosis in ERM screening.

Epidemiology of Pars Plana Vitrectomy in the Elderly: A Retrospective 10-Year Survey of 592 Cases

Purpose

To report the epidemiology of the surgical indications of pars plana vitrectomy in patients aged 75 years or older.

Patients and Methods

The medical records of patients who underwent vitrectomy surgery in a single center between 2008 and 2018 were evaluated retrospectively for demographics, medical background, and surgical indications. Data on patients aged 75–85 were compared to those of patients older than 85 years and those recorded between 2008–2013 and 2014–2018.

Results

A total of 592 patients were included, of whom 55% were males. The mean±standard deviation age of the cohort at presentation was 80.4±4.60 years, and the mean visual acuity was 1.3±0.93 logMAR. The main indications for surgery were retinal detachment (n=117, 19.7%), epiretinal-membrane/vitreomacular traction (n=140, 23.6%), dropped intraocular lens/retained lens (n=89, 15%), macular hole (n=64, 11%), submacular hemorrhage (n=40, 6.7%), diagnostic vitrectomy (n=37, 6.2%), non-diabetic vitreous hemorrhage (n=30, 5.1%), and diabetic vitreous hemorrhage and other diabetic complications (n=33, 5.6%). Patients aged 85 years and older had higher rates of urgent surgeries (65%), such as for submacular hemorrhage and trauma (p=0.0000039 and p=0.001, respectively), and lower rates of non-urgent surgeries, such as for epiretinal membrane and macular hole (p=0.000032 and p=0.02, respectively), compared to patients aged 75–84 years. Additionally, the surgical rate for submacular hemorrhage decreased during 2008–2014 compared to 2014–2018 (p=0.000014).

Conclusion

Understanding the unique distribution of indications for vitrectomy among elderly patients is essential for appropriate management and treatment. Urgent cases represent 65% of the surgeries performed in the older population.

Clinical Update on Metamorphopsia: Epidemiology, Diagnosis and Imaging

Purpose: To discuss the pathophysiology of metamorphopsia, its characterisation using retinal imaging and methods of assessment of patient symptoms and visual function.Methods: A literature search of electronic databases was performedResults: Metamorphopsia has commonly been associated with vitreomacular interface disorders (such as epiretinal membrane) and has also regularly been noted in diseases of the retina and choroid, particularly age-related macular degeneration and central serous chorioretinopathy. Developments in optical coherence tomography retinal imaging have enabled improved imaging of the foveal microstructure and have led to the localisation of the pathophysiology of metamorphopsia within the retinal layers of the macula. Alteration of alignment of inner and outer retinal layers at various retinal loci has been identified using multimodal imaging in patients with metamorphopsia in a range of conditions. Although the Amsler Grid assessment of metamorphopsia is a useful clinical indicator, new emerging methods of metamorphopsia assessment with psychophysical tests such as M-CHARTS and preferential hyperacuity perimetry, have been developed.Conclusions: It appears that there is a complex relationship between visual acuity and metamorphopsia symptoms that vary between retinal conditions. Although metamorphopsia has traditionally been challenging to measure in the clinic, advances in technology promise more robust, easy-to-use tests. It is possible that home assessment of metamorphopsia, particularly in conditions such as age-related macular degeneration, may help to guide the need for further clinic evaluation and consideration of treatment.

Development of a Fundus Image-Based Deep Learning Diagnostic Tool for Various Retinal Diseases

Artificial intelligence (AI)-based diagnostic tools have been accepted in ophthalmology. The use of retinal images, such as fundus photographs, is a promising approach for the development of AI-based diagnostic platforms. Retinal pathologies usually occur in a broad spectrum of eye diseases, including neovascular or dry age-related macular degeneration, epiretinal membrane, rhegmatogenous retinal detachment, retinitis pigmentosa, macular hole, retinal vein occlusions, and diabetic retinopathy. Here, we report a fundus image-based AI model for differential diagnosis of retinal diseases. We classified retinal images with three convolutional neural network models: ResNet50, VGG19, and Inception v3. Furthermore, the performance of several dense (fully connected) layers was compared. The prediction accuracy for diagnosis of nine classes of eight retinal diseases and normal control was 87.42% in the ResNet50 model, which added a dense layer with 128 nodes. Furthermore, our AI tool augments ophthalmologist's performance in the diagnosis of retinal disease. These results suggested that the fundus image-based AI tool is applicable for the medical diagnosis process of retinal diseases.

Epiretinal Membrane Surgery after Retinal Detachment Repair: Visual Acuity Outcomes and OCT Analysis

PURPOSE

To assess visual acuity (VA) outcomes of epiretinal membrane (ERM) surgery following primary rhegmatogenous retinal detachment (RD) repair and to identify OCT features predictive of visual outcomes.

DESIGN

Retrospective, consecutive case series.

SUBJECTS

Eyes undergoing pars plana vitrectomy (PPV) with membrane peel (MP) surgery for ERM following primary RD repair (PPV with or without scleral buckle (SB) and gas tamponade).

METHODS

Retrospective chart review from 2015 to 2018. A previously described ERM grading scale was utilized for OCT structural analysis.

MAIN OUTCOME MEASURES

Visual acuity (VA) and change in VA from pre- MP to 6 months and final follow-up. Secondary outcomes included RD and OCT features predictive of VA, as well as RD factors associated with need for subsequent MP surgery.

RESULTS

53 eyes of 53 patients underwent MP following RD repair. VA improved significantly from logMAR 1.00 ± 0.51 (Snellen 20/200) pre-MP to 0.45 ± 0.41 (20/56) at 6 months and 0.42 ± 0.41 (20/53) at final follow-up, (p<0.001) for each respectively. Macula on eyes had better 6 month [0.29 ± 0.18 (20/39) vs. 0.51 ± 0.46 (20/65), p=0.02] and final VA [0.29 ± 0.14 (20/39) vs. 0.46 ± 0.47 (20/58), p=0.04] after MP surgery. VA improved significantly from pre-MP to 6 months and final follow-up regardless of macula status. MP occurring ≤180 days from RD repair and IS/OS loss were associated with worse pre-MP VA [1.13 ± 0.09 (20/270) vs. 0.82 ± 0.07(20/132), p=0.01 and 1.21 ± 0.07 (20/324) vs. 0.74 ± 0.09 (20/110) p=0.0003, respectively]. IS/OS loss [adjusted means 0.54 ± 0.07 (20/69) vs. 0.25 ± 0.08 (20/36) at final visit, p=0.006] and RD repair with PPV/SB [0.53 ± 0.08 (20/68) vs. 0.31 ±0.07 (20/41) at final visit, p=0.03] were significantly associated with worse VA at both 6 months and final follow-up.

CONCLUSIONS

Eyes undergoing MP after RD repair have significant visual acuity gains independent of macula-status at time of RD repair. Pre-operative IS/OS disruption was the OCT feature best predictive of visual acuity.

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.

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.

Anatomical and Functional Recovery Kinetics After Epiretinal Membrane Removal

Purpose

To investigate the nature of anatomical and functional recovery kinetics after epiretinal membrane (ERM) removal.

Methods

The records of 42 patients (45 eyes) with idiopathic ERM treated with pars plana vitrectomy and surgical peeling of the ERM performed by a single surgeon at Massachusetts Eye and Ear between 2012 and 2017 were retrospectively reviewed. Outcome measures included spectral domain optical coherence tomography-measured central macular thickness (CMT) pre-operatively and at post-operative day 1, week 1, months 1, 3, 6, 12 and 24 as well as best-corrected visual acuity (BCVA). Correlations between baseline or early values and final anatomical and functional outcomes were investigated.

Results

Improvement in CMT was statistically significant after 1 week, 1, 3, 6, 12 and 24 months (p < 0.01). BCVA improvement was statistically significant after 1, 6, 12 and 24 months follow-up (p<0.01). The improvement of BCVA and CMT with time was found to be logarithmic (R² =0.96, R² =0.84) suggesting that early (<30 days) post-operative functional and anatomical changes may be predictive of long-term outcomes. Preoperative BCVA and CMT revealed a weak positive correlation with the respective BCVA and CMT at 24 months (R²=0.13 and R²=0.16). When plotted as a percentage of the fellow normal eye CMT, first week proportional improvement in CMT from pre-operative baseline was found to be correlated with final CMT proportional decrease (R²=0.72) suggesting that first week postoperative CMT could be predictive of final CMT.

Conclusion

There is a logarithmic improvement in CMT and BCVA after ERM peel with BCVA improvement following the CMT improvement. Early (less than 30 days) post-operative anatomical changes can be predictive of long-term anatomical outcomes.

Epiretinal membrane surgery outcome in eyes with abnormalities of the central bouquet

Background

Clinical studies have shown that epiretinal membranes (ERM) as well as abnormalities of the central foveal bouquet (CB) can be classified in different stages according to their morphological appearance. Furthermore, visual acuity correlates with the different stages of these features. The present study evaluated how these findings change after the surgical removal of the ERM and their impact on functional outcomes.

Methods

In this retrospective study eyes with ERM were evaluated by SD-OCT scans before and after pars plana vitrectomy (PPV) with macular ERM and internal limiting membrane (ILM) peeling. CB abnormalities were classified according to their morphological appearance from stage 0 (no abnormalities) to stage 3 (acquired vitelliform lesion). ERMs were classified ranging from stage 0 (absence of ERM) to stage 4 (ERM with significant anatomic disruption of macula). Changes in morphology were correlated with visual acuity before and after surgery.

Results

151 eyes were included into the study. Before surgery 27.2% (n = 41) of eyes showed CB abnormalities with stage 1 being the most common (11.9%, n = 18). Before surgery ERM was seen in all patients. The most common form was stage 1 (28.5%, n = 43), followed by stage 3 (27.8%, n = 42) and 2 (25.2%, n = 38). Only 18.5% (n = 28) presented with stage 4 ERM. The mean BCVA was 0.42 (logMAR) before and increased to 0.19 (logMAR) 8 weeks after vitrectomy (95% CI 0.20–0.28; p < 0.001). Patients who suffered from CB abnormalities had less increase in BCVA than patients who had no evidence of CB (0.28 vs. 0.14 logMAR; p < 0.001). Of all the patients with CB abnormalities at baseline, 68% had lower CB grading after the surgery (n = 28; 95% CI; p < 0.001). All patients showed an improvement of their ERM grading, with 98.7% reaching stage 0 (n = 151 vs. n = 149; 95% CI; p < 0.001).

Conclusions

The study indicates that the presence of CB abnormalities correlates with worse visual function. They are furthermore associated with worse visual outcomes after PPV with ERM and ILM peeling. These findings are valuable for deciding on PPV in patients with ERM.

Usefulness of the Components of Full-Field Electroretinography to Predict Postoperative Visual Outcomes in Patients With Epiretinal Membranes

Purpose

To confirm the predictors of postoperative visual outcomes by performing full-field electroretinography (ffERG) before surgery in patients with epiretinal membranes (ERMs).

Methods

Sixty-one eyes of patients with ERMs who underwent pars plana vitrectomy with membrane peeling were prospectively reviewed. Correlations between preoperative data (ffERG and optical coherence tomography) and postoperative best-corrected visual acuity (BCVA) were investigated. Receiver operating characteristic (ROC) curve analysis was performed to obtain cutoff values of the ffERG parameters predicting good visual outcome (final BCVA ≥ 20/30).

Results

Postoperative BCVA was significantly correlated with the implicit time and amplitude of the b-wave in light-adapted (LA) 3.0 electroretinography (ERG), with the amplitude difference between N1 and P1 in the LA 30-Hz flicker ERG, and with the sum of the amplitudes of OS1, OS2, and OS3 in dark-adapted (DA) oscillatory potential (OP) ERG (P < 0.01). The area under the ROC curve to predict good visual outcome was statistically significant for the four parameters (0.787, 0.815, 0.757, and 0.792, respectively).

Conclusions

The postoperative BCVA in patients with ERM was significantly correlated with the implicit time and amplitude of the b-wave in the LA 3.0 ERG, the amplitude difference between N1 and P1 in the LA 30-Hz flicker ERG, and the sum of the amplitudes of OS1, OS2, and OS3 in DA OP ERG of ffERG. It is thought that ffERG before surgery may help predict visual outcomes after surgery.

Translational Relevance

It was confirmed that the degree of retinal function in the ERM can predict BCVA after treatment.

Comprehensive review of surgical microscopes: technology development and medical applications

SIGNIFICANCE

Surgical microscopes provide adjustable magnification, bright illumination, and clear visualization of the surgical field and have been increasingly used in operating rooms. State-of-the-art surgical microscopes are integrated with various imaging modalities, such as optical coherence tomography (OCT), fluorescence imaging, and augmented reality (AR) for image-guided surgery.

AIM

This comprehensive review is based on the literature of over 500 papers that cover the technology development and applications of surgical microscopy over the past century. The aim of this review is threefold: (i) providing a comprehensive technical overview of surgical microscopes, (ii) providing critical references for microscope selection and system development, and (iii) providing an overview of various medical applications.

APPROACH

More than 500 references were collected and reviewed. A timeline of important milestones during the evolution of surgical microscope is provided in this study. An in-depth technical overview of the optical system, mechanical system, illumination, visualization, and integration with advanced imaging modalities is provided. Various medical applications of surgical microscopes in neurosurgery and spine surgery, ophthalmic surgery, ear-nose-throat (ENT) surgery, endodontics, and plastic and reconstructive surgery are described.

RESULTS

Surgical microscopy has been significantly advanced in the technical aspects of high-end optics, bright and shadow-free illumination, stable and flexible mechanical design, and versatile visualization. New imaging modalities, such as hyperspectral imaging, OCT, fluorescence imaging, photoacoustic microscopy, and laser speckle contrast imaging, are being integrated with surgical microscopes. Advanced visualization and AR are being added to surgical microscopes as new features that are changing clinical practices in the operating room.

CONCLUSIONS

The combination of new imaging technologies and surgical microscopy will enable surgeons to perform challenging procedures and improve surgical outcomes. With advanced visualization and improved ergonomics, the surgical microscope has become a powerful tool in neurosurgery, spinal, ENT, ophthalmic, plastic and reconstructive surgeries.

Optical coherence tomography biomarkers for visual acuity in patients with idiopathic epiretinal membrane

PURPOSE

To investigate the correlation between outer and inner retina optical coherence tomography (OCT) biomarkers and visual acuity in patients with idiopathic epiretinal membrane (iERM) and identify which of them may be predictive of visual function.

METHODS

A retrospective cross-sectional single-center study was conducted that included patients diagnosed with iERM. Spectral domain OCT images were obtained and assessed qualitatively and quantitatively. The association of OCT parameters with best corrected visual acuity was analyzed.

RESULTS

Charts of 97 eyes of 97 patients were reviewed. Central foveal thickness, maximal retinal thickness (MRT), photoreceptor outer segment length, outer foveal thickness, ganglion cell-inner plexiform layer complex thickening, inner retinal thickness and inner retinal layer irregularity index were among the major outcome measures. OCT scans were also assessed for the presence of cotton ball sign, ellipsoid zone disruption, ectopic inner foveal layer, disorganization of retinal inner layers (DRIL), intraretinal fluid, subretinal fluid (SRF) and epimacular membrane rip. Univariate analysis showed statistically significant association between all the aforementioned parameters with worse vision, except for cotton ball sign and SRF. Multivariate analysis found that MRT and severe DRIL were strongly correlated with worse vision (p < 0.001).

CONCLUSION

MRT and severe DRIL should be considered as negative prognostic factors for visual acuity.

Correlation between new OCT parameters and metamorphopsia in advanced stages of epiretinal membranes

PURPOSE

To correlate metamorphopsia provided by M-CHARTS and ectopic inner foveal layers (EIFL) or 'central bouquet' abnormality (CBA) in patients with advanced stages of epiretinal membrane (ERM) following the novel Optical Coherence Tomography (OCT)-based grading scheme.

METHODS

In 60 eyes of 57 patients affected by ERM (stages 3 and 4), the degree of metamorphopsia using the M-CHARTS was evaluated (M-SCORE) and correlated with EIFL, CBA and central foveal thickness (CFT) as measured on OCT scans.

RESULTS

A total of 37 and 23 eyes were diagnosed having ERM stages 3 and 4, respectively. Mean vertical and horizontal M-SCORE (M-V and M-H) were 0.64 ± 0.43 and 0.58 ± 0.37 standard deviations, respectively. Mean M-SCORE exhibited a statistically significant correlation with EIFL and CFT (both p < 0.0001), but not with CBA (p = 0.84). Analysing the direction of metamorphopsia separately, M-H and M-V were significantly correlated with EIFL (both p < 0.0001), but not with CBA thickness (p = 0.70 and 0.33 respectively). Ectopic inner foveal layers (EIFL) was significantly influenced by the presence of CBA (CBA present, 158.29 ± 63.53 micron; CBA absent, 107.05 ± 94.13 micron, p = 0.04). No significant differences were found for both M-V and M-H with respect to the presence of CBA.

CONCLUSIONS

Based on the novel OCT-based grading scheme for ERMs, our results demonstrate that EIFL, but not CBA, might be considered a good indicator for metamorphopsia in patients with advanced ERMs.

Relation of anatomy with function following the surgical treatment of idiopathic epiretinal membrane: a multicenter retrospective study

PURPOSE

To investigate the prognostic factors associated with functional and anatomical outcomes and to assess the longitudinal course of visual acuity and retinal morphology after vitreoretinal surgery for idiopathic epiretinal membrane (ERM).

METHODS

This multicenter, retrospective study included a total of 634 eyes who underwent surgery for idiopathic ERM in 22 academic centers nationwide in Turkey. Data on best-corrected visual acuity (BCVA) and optical coherence tomography features (central foveal thickness (CFT), ERM and foveal contour morphology, ellipsoid zone (EZ) integrity) were collected and compared at baseline, 6-month, 12-month, and 24-month follow-ups. Prognostic factors for functional (having ≥ 20/25 Snellen BCVA) and anatomical (having normal/shallow foveal contour) recoveries after surgery were investigated by means of multivariate regression analyses. A cutoff value of preoperative BCVA optimizing functional recovery was calculated using receiver operating characteristic curve analysis.

RESULTS

At a median follow-up of 24 months, 37.4% of the eyes achieved ≥ 20/25 BCVA and 54% regained normal or shallow foveal contour. Functional recovery was more likely in eyes with better baseline BCVA and intact EZ (R² = 0.356, p < 0.001). The cutoff baseline BCVA value for good visual prognosis was 0.35 logarithm of the minimum angle of resolution (Snellen 20/44) (sensitivity 60%, specificity 85%, p < 0.001). Anatomical recovery was negatively associated with advanced age, higher baseline CFT, foveal herniation-type ERM morphology, and internal limiting membrane (ILM) peeling (R² = 0.225, p < 0.001). The negative effect of ILM peeling on anatomical recovery was not significant after the first postoperative year (p = 0.05). Mean BCVA values and foveal morphology progressively improved at each visit. Cases with convex baseline foveal contour continued to change towards normal foveal depression over 24 months of follow-up, which took longer than the eyes with shallow/flat contoured cases. One-third of eyes with severe baseline EZ defects showed recovery at follow-up and achieved significantly greater visual acuity gains than the remaining eyes with persistent defects (p < 0.001).

CONCLUSIONS

Functional and anatomical restoration of the eyes appears to be a slow process after ERM surgery. This process may take much longer in eyes with worse foveal morphology at baseline. Although photoreceptor disruption may be reversible in some eyes, full functional recovery is unlikely when it persists.

Optical coherence tomography biomarkers as predictive factors for postoperative visual acuity in patients with epiretinal membrane treated with vitrectomy

BACKGROUND:

The purpose of this retrospective study was to evaluate potential predictive factors of postoperative visual outcome in patients with idiopathic epiretinal membrane (iERM), treated with pars plana vitrectomy (PPV).

METHODS:

Participants in the study were 46 patients diagnosed with iERM, who underwent PPV. Best-corrected visual acuity measurement and spectral domain-optical coherence tomography (OCT) were performed at baseline (preoperatively), and at months 6 and 12 postoperatively. Demographic characteristics and OCT parameters were assessed as potential predictive factors for postoperative visual outcome.

RESULTS:

Increasing age, retinal thickness, presence of disorganization of inner retinal layers, ellipsoid zone disruption, and presence of vitreomacular traction were found to be negatively associated with postoperative visual acuity. Gender, presence of subretinal fluid, cysts in the inner or outer nuclear layer, and hyperreflective foci were not found to affect visual acuity. There was statistically significant improvement in visual acuity and central retinal thickness between baseline and months 6 and 12 in the study sample.

CONCLUSIONS:

It is important to determine predictive factors for visual outcome, so as to inform patients about prognosis and help in the decision-making of patients' management.

A Review on Advances in Intra-operative Imaging for Surgery and Therapy: Imagining the Operating Room of the Future

With the advent of Minimally Invasive Surgery (MIS), intra-operative imaging has become crucial for surgery and therapy guidance, allowing to partially compensate for the lack of information typical of MIS. This paper reviews the advancements in both classical (i.e. ultrasounds, X-ray, optical coherence tomography and magnetic resonance imaging) and more recent (i.e. multispectral, photoacoustic and Raman imaging) intra-operative imaging modalities. Each imaging modality was analyzed, focusing on benefits and disadvantages in terms of compatibility with the operating room, costs, acquisition time and image characteristics. Tables are included to summarize this information. New generation of hybrid surgical room and algorithms for real time/in room image processing were also investigated. Each imaging modality has its own (site- and procedure-specific) peculiarities in terms of spatial and temporal resolution, field of view and contrasted tissues. Besides the benefits that each technique offers for guidance, considerations about operators and patient risk, costs, and extra time required for surgical procedures have to be considered. The current trend is to equip surgical rooms with multimodal imaging systems, so as to integrate multiple information for real-time data extraction and computer-assisted processing. The future of surgery is to enhance surgeons eye to minimize intra- and after-surgery adverse events and provide surgeons with all possible support to objectify and optimize the care-delivery process.

Baseline visual acuity and interdigitation zone as predictors in idiopathic epiretinal membranes: A retrospective cohort study

OBJECTIVE

Determine which functional and anatomical characteristics may be predictors of final visual acuity in patients with idiopathic ERM (iERM) submitted to pars plana vitrectomy (PPV) with ERM and internal and internal limiting membrane (ILM) peeling.

DESIGN

Retrospective cohort study.

SUBJECTS

Patients with iERM submitted to PPV between 2016 and 2017.

METHODS

Data regarding the best-corrected visual acuity (BCVA) and the characteristics of the retinal layers observed in SD-OCT were collected preoperatively and until 12 months postoperatively. Central macular thickness (CMT), disorganization of the retinal inner layers (DRIL), outer nuclear layer (ONL) thickness, integrity of subfoveal external limiting membrane (ELM), ellipsoid zone (EZ), and interdigitation zone (IZ) were evaluated.

RESULTS

A total of 128 eyes with iERM from 121 patients were included. BCVA improved significantly (p < 0.001). Significant improvement of BCVA, CMT, DRIL, ONL, ELM, and EZ were obtained. The final IZ was not different from baseline until the end of the study. A significant correlation was observed between the baseline BCVA, EZ, IZ, and the postoperative BCVA (p < 0.001). However, only the baseline BCVA and the integrity of the subfoveal baseline IZ were predictive factors for final BCVA (p < 0.005 and p < 0.001, respectively).

CONCLUSION

PPV provides a significant improvement of BCVA and retinal anatomy recovery in iERM eyes. Baseline IZ didn't change during the 12 months following surgery. Baseline BCVA and subfoveal IZ at baseline were prognostic factors for the final BCVA.

Surgery for Idiopathic Epimacular Membrane: Morpho-Functional Outcomes Based on the Preoperative Macular Integrity of the Photoreceptoral Junction. A Prospective Pilot Study

INTRODUCTION

This study aimed to evaluate whether the preoperative integrity of the inner segment (IS) and outer segment (OS) photoreceptoral junction may influence the postoperative visual acuity, the macular morphology [assessed by spectral domain optical coherence tomography (SD-OCT)], and macular function (evaluated by multifocal electroretinogram, mfERG) in patients with idiopathic epimacular membrane (EMM) followed up for 6 months.

METHODS

In this observational prospective study, 18 patients with EMM (mean age 72.5 ± 6.87 years) were enrolled. They were divided into two groups according to the preoperative integrity of the SD-OCT IS/OS junction: the EMM-I group with an intact IS/OS junction (11 patients, mean age 72.75 ± 3.49 years, providing 11 eyes) and the EMM-D group with a disrupted IS/OS junction (7 patients, mean age 70.86 ± 10.79 years, providing 7 eyes). For each enrolled patient, visual acuity (VA), mfERG, and SD-OCT were assessed at baseline (preoperative) and after 1, 3, and 6 months of follow-up after surgical treatment for EMM (pars plana vitrectomy with EMM removal and internal limiting membrane peeling).

RESULTS

During the whole follow-up, VA was significantly increased in EMM-I eyes and unmodified in EMM-D eyes. In both groups, mfERG responses were not significantly different and not related to VA differences. In EMM-I eyes a significant reduction of central retinal thickness (CRT) was observed; however, it was not correlated with VA changes. In EMM-D eyes CTR was not significantly reduced, whereas macular volume was significantly reduced. These changes were significantly related to the corresponding differences in VA.

CONCLUSIONS

Our results suggest that the preoperative evaluation of the integrity of the IS/OS junction is relevant for postoperative outcomes. The recovery in VA was higher in EMM-I eyes than in EMM-D eyes. Postoperative recovery was not associated with morphology of the outer retina (photoreceptor and outer nuclear layer) and the function of preganglionic elements.

The Clinical Course of Patients with Idiopathic Epiretinal Membranes and Good Visual Acuity Managed Without Surgery

Background/aims

To report the clinical course of patients with idiopathic epiretinal membranes (iERMs) and good baseline best-corrected visual acuity (BCVA) managed without surgical treatment.

Methods

Retrospective, observational case series of patients with iERMs and 20/50 or better BCVA who did not undergo surgery between January 2014 and December 2017 with a 1-year follow-up. Secondary epiretinal membranes were excluded. iERMs were stratified into two groups: Group I (BCVA 20/30 or better) and Group II (BCVA 20/40 to 20/50). The main outcome measures included baseline and final follow-up BCVA, central macular thickness (CMT) on OCT.

Results

The study included 174 eyes (145 patients): 139 eyes (79.8%) had typical iERMs and 35 eyes (18%) had LMH. For Group I typical iERMs, the logMAR baseline and final mean BCVA were 0.09 ± 0.1 (Snellen equivalent 20/25) and 0.10 ± 0.1 (20/25⁺) respectively (p = 0.22). In this group, the baseline and final mean CMT were 335 ± 73µm and 342 ± 78µm, respectively (p = 0.47). For Group II typical iERMs, the logMAR baseline and final mean BCVA were 0.3 ± 0.1 (20/44) and 0.4 ± 0.2 (20/45) respectively (p = 0.31). In this group, the baseline and final mean CMT were 386 ± 95µm and 391 ± 93µm, respectively (p = 0.84).

Conclusion

The clinical course of patients with iERM and good baseline BCVA is generally favorable without surgery and includes stable BCVA and OCT measurements after at least one year.

Effect of axial length and age on the visual outcome of patients with idiopathic epiretinal membrane after pars plana vitrectomy

We evaluated predictive factors for visual outcomes in patients with idiopathic epiretinal membrane (iERM) after pars plana vitrectomy (PPV). Clinical records for 114 eyes (114 patients, mean age: 70.6 years) with iERM treated by PPV between March 2012 and March 2018 were retrospectively reviewed. Overall, the mean postoperative best-corrected visual acuity (BCVA) and central retinal thickness measured by optical coherence tomography improved as early as 1 month after surgery, and further improved until 3 months (P < 0.01). Multiple linear regression analyses adjusted for the preoperative BCVA showed that older age (B, 0.010; 95% confidence interval, 0.003 to 0.016; P = 0.003) and a shorter axial length (AL; B, −0.059; 95% confidence interval, −0.099 to −0.019; P = 0.005) predicted worse postoperative BCVA. The Mann-Whitney U test showed that the postoperative BCVA was worse in eyes with AL < 23.6 mm than in eyes with AL ≥ 23.6 mm (P = 0.037), and in patients aged ≥69 years than in patients aged <69 years (P = 0.024). The findings may help in evaluating surgical indications for each patient to obtain satisfactory outcomes, irrespective of the preoperative BCVA.

Automatic Identification and Intuitive Map Representation of the Epiretinal Membrane Presence in 3D OCT Volumes

Optical Coherence Tomography (OCT) is a medical image modality providing high-resolution cross-sectional visualizations of the retinal tissues without any invasive procedure, commonly used in the analysis of retinal diseases such as diabetic retinopathy or retinal detachment. Early identification of the epiretinal membrane (ERM) facilitates ERM surgical removal operations. Moreover, presence of the ERM is linked to other retinal pathologies, such as macular edemas, being among the main causes of vision loss. In this work, we propose an automatic method for the characterization and visualization of the ERM's presence using 3D OCT volumes. A set of 452 features is refined using the Spatial Uniform ReliefF (SURF) selection strategy to identify the most relevant ones. Afterwards, a set of representative classifiers is trained, selecting the most proficient model, generating a 2D reconstruction of the ERM's presence. Finally, a post-processing stage using a set of morphological operators is performed to improve the quality of the generated maps. To verify the proposed methodology, we used 20 3D OCT volumes, both with and without the ERM's presence, totalling 2428 OCT images manually labeled by a specialist. The most optimal classifier in the training stage achieved a mean accuracy of 91 . 9 % . Regarding the post-processing stage, mean specificity values of 91 . 9 % and 99 . 0 % were obtained from volumes with and without the ERM's presence, respectively.

POSTOPERATIVE CHANGES AND PROGNOSTIC FACTORS OF VISUAL ACUITY, METAMORPHOPSIA, AND ANISEIKONIA AFTER VITRECTOMY FOR EPIRETINAL MEMBRANE

PURPOSE

To investigate postoperative changes and prognostic factors of visual impairment after vitrectomy for unilateral epiretinal membrane.

METHODS

A prospective observational study on 45 eyes from 45 patients with unilateral idiopathic epiretinal membrane who underwent vitrectomy. Visual parameters (best-corrected visual acuity, metamorphopsia using M-CHARTS, and aniseikonia using the New Aniseikonia Test) and spectral domain optical coherence tomography parameters (macular retinal layer thickness and microstructure of the outer retina) were measured preoperatively and 6 and 12 months postoperatively. Statistical analyses included linear mixed-effects models for the longitudinal changes and prognostic factors of visual parameters.

RESULTS

Best-corrected visual acuity and horizontal metamorphopsia improved significantly from 6 months after surgery (P < 0.001), whereas aniseikonia decreased significantly only at 12 months (P = 0.015). Vertical metamorphopsia remained unchanged. Preoperative inner nuclear layer thickness was significantly correlated with preoperative metamorphopsia. Besides baseline values, best-corrected visual acuity had no significant prognostic factors, but preoperative ellipsoid zone disruption had a negative direction of association with postoperative metamorphopsia (coefficients: -0.37 and -0.62, P = 0.015 and 0.006 for horizontal and vertical metamorphopsia, respectively), and preoperative horizontal metamorphopsia had a positive direction of association with postoperative aniseikonia (coefficient: 1.77, P = 0.002).

CONCLUSION

After vitrectomy, postoperative changes and prognostic factors for unilateral epiretinal membrane differed for best-corrected visual acuity, metamorphopsia, and aniseikonia.

Changes in Metamorphopsia, Visual Acuity, and Central Macular Thickness after Epiretinal Membrane Surgery in Four Preoperative Stages Classified with OCT B-Scan Images

Purpose

To observe the changes in metamorphopsia, visual acuity, and central macular thickness (CMT) in patients undergoing vitrectomy for idiopathic epiretinal membranes (iERM); all of which were preoperatively stratified into 4 stages according to the anatomical structure of the macula seen on the optical coherence tomography (OCT) b-scan images.

Methods

A total of 108 eyes of 106 patients were included. We evaluated and classified the severity of each preoperative ERM based on OCT. Changes in the best-corrected visual acuity (BCVA), metamorphopsia, and CMT were studied by comparing the pre- and postoperative measurements. The follow-up time was at least 6 months.

Results

There were 41 eyes at stage 2, 35 at stage 3, 32 at stage 4, and none at stage 1. BCVA and metamorphopsia significantly improved at the final visit in all patients (P < 0.01). However, comparing the pre- and postoperative measurements at each stage, only the BCVA and CMT improved significantly for all stages (P < 0.001). For stages 2 and 3 ERMs, the horizontal (MH) and vertical (MV) metamorphopsia scores decreased significantly after surgery (P < 0.05). No significant difference was found in either MH or MV for stage 4 ERMs (P both >0.05). The preoperative BCVA, MH, and CMT had significant difference among the three stages (P < 0.05). Similarly, the postoperative values in the three variables mentioned above also had significant difference among the three stages (P < 0.05). For stage 2 ERMs, the baseline MH and MV were positively correlated with the baseline CMT. The MH and MV at the final follow-up also presented a significant positive correlation with the baseline CMT. For stage 3 ERMs, only the baseline MV showed significant correlation with the CMT.

Conclusion

Categorization of the preoperative ERMs is a useful method to predict the postoperative improvement in metamorphopsia, which would aid in surgical decisions for patients with ERMs.

Idiopathic epiretinal membrane surgery: safety, efficacy and patient related outcomes

This review aims to give to the reader an overview selectively oriented on safety and efficacy of surgery, providing concise and direct answers about crucial questions of trainees and experts. Surgery for idiopathic epiretinal membrane (ERM) is a safe and effective procedure that can achieve long-term stable postoperative visual and anatomical improvement, with an overall low recurrence and complication rate. Young patients, with a short onset of symptoms and with better initial visual acuity achieve higher levels of visual outcome. The preoperative degree of metamorphopsia is the prognostic factor for their postoperative degree. Successful results may be obtained in eyes with specific optical coherence tomography criteria, such as thin ganglion cell layers, thin internal plexiform layer, longer photoreceptors outer segment, regular ellipsoid zone and cone outer segment tips line, and without ectopic inner foveal layer. Internal limiting membrane peeling demonstrates positive anatomical and functional outcomes, but final positions about its safety remain controversial.

Epiretinal membrane profile on spectral domain optical coherence tomography in patients with uveitis

Purpose:

To study the epiretinal membrane (ERM) profile on the spectral-domain optical coherence tomography (SDOCT) in eyes with uveitis.

Methods:

In this prospective observational study, macula of uveitic eyes were evaluated by SDOCT (Cirrus, model 5000) for ERM. ERM was quantified (in microns) and were followed up along with the best-corrected visual acuity (BCVA) and treatment profile for 1 year. ERM morphology (focal, global, or mixed) and characteristics (thickness at fovea, maximum thickness, and location of maximum thickness in relation to fovea) were documented. Changes in altered foveal contour, cystoid macular edema (CME), and central foveal thickness were also noted. BCVA was noted when the inflammation subsided and it was correlated to specific ERM characteristics. SDOCT characteristics were compared in three treatment groups (no oral steroids, oral steroids with, and without immunomodulators).

Results:

Thirty-four eyes of 25 patients were evaluated. Mean logMAR BCVA decreased from 0.25 to 0.35 (P = 0.005). Foveal involvement with ERM (P = 0.011), lost foveal contour (P = 0.043), and ellipsoid layer disruption (P = 0.017) were associated significantly with reduced BCVA. Focal attachment of ERM was more commonly associated with CME (P = 0.03). Median ERM thickness showed significant increase (P < 0.001). Significant ERM progression from parafoveal to foveal (P = 0.02), significant progression of the thickest area of ERM closer to fovea (P = 0.0006) indicated a strong tendency of foveal involvement and this was correlated with worse BCVA (P = 0.009, r = −0.44) Oral steroids/immunomodulators showed no significant benefit on ERM progression.

Conclusion:

ERM progression in uveitis has a tendency to involve the fovea and is associated with significant vision loss, particularly in foveal ERM, focal attachment, and IS-OS disruption. Oral steroids and immunomodulators have no role in halting progression.

Multifocal Electroretinography in Assessment of Macular Function after Internal Limiting Membrane Peeling in Macular Hole Surgery

Purpose

Internal limiting membrane (ILM) peeling is important for macular hole (MH) surgery but may have secondary effects visible on spectral domain optical coherence tomography (OCT) and multifocal electroretinography (mfERG). We relate integrity of inner and outer macular layers with functional results with mfERG.

Methods

Nonrandomized prospective study of 33 consecutive eyes of 33 patients with macular hole who underwent vitrectomy with ILM peeling. Best-corrected visual acuity was assessed, and integrity of external layers was measured using OCT. Each component of mfERG, N1 and P1 amplitude and latency, was also measured.

Results

All eyes showed macular hole closure. Visual acuity improved from 20/400 to 20/40 in the Snellen visual acuity chart (P < 0.001), and OCT external lines were intact in 19 eyes and disrupted in 14 eyes. Postoperatively, N1 and P1 amplitudes in ring 1 increased compared to preoperative values (P < 0.001 for both). Latency remained delayed for both N1 and P1 wave. In the group of 19 eyes with integrity of outer retinal layers, N1 amplitude in ring 1 was superior to the group of 14 patients with disrupted outer retinal layers (P=0.042).

Conclusions

In macular hole surgery, structure analysis in OCT is one of the important outcomes for the retinal surgeon. Functional results are parallel with anatomic results, but visual gain is limited. The limited recovery in mfERG suggests an alteration of retinal physiology that could explain limited vision recover.

Comparison of Individual Retinal Layer Thicknesses after Epiretinal Membrane Surgery with or without Internal Limiting Membrane Peeling

Purpose

To compare changes in the retinal layer thickness and visual outcomes in patients undergoing epiretinal membrane (ERM) surgery with or without internal limiting membrane (ILM) peeling.

Methods

Seventy-six eyes of 76 patients who underwent ERM surgery from January 2013 to March 2015 at the Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea, were analyzed. While ERM removal with ILM peeling was performed in ILM peeling (P) group (n=39), ILM peeling was not performed in non-ILM peeling (NP) group (n=37). Retinal layer segmentation was performed using optical coherence tomography images. Individual retinal layer thicknesses before and at 6 months after ERM surgery were compared. The postoperative best-corrected visual acuity (BCVA) was also compared.

Results

In the P group, the thicknesses of retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), and inner plexiform layer (IPL) were significantly reduced. In the NP group, significant decreases in the RNFL, GCL, IPL, inner nuclear layer, and outer plexiform layer were observed. The P group manifested a greater mean postoperative GCL (35.56 ± 1.53 µm vs 29.86 ± 2.16 µm; p=0.033) and less loss of GCL (−10.26 ± 1.91 µm vs −19.86 ± 2.74 µm; p=0.004) compared to the NP group. No statistically significant differences were observed when comparing the changes in BCVA.

Conclusions

This study demonstrates that ILM peeling for ERM surgery may result in better preservation of GCL compared to no ILM peeling.