Comparison of visual acuity, metamorphopsia, and aniseikonia in patients with an idiopathic epiretinal membrane

[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.

Title - Long term outcomes of vitrectomy and ERM peel: Can pre-operative metamorphopsia measured using the D-Chart help improve surgical candidate selection?

PURPOSE

To assess the predictive value of pre-operative metamorphopsia, measured using the D-Chart, in patients undergoing epiretinal membrane (ERM) surgery and how this relates to improvement in quality of life after surgery.

METHODS

17 patients from vitreo-retinal surgery clinics at a tertiary ophthalmology centre were recruited when listed for pars plana vitrectomy (PPV) with ERM peel between September 2019 - February 2020. Pre-operatively patients underwent visual acuity (VA), Visual-Function Index 14 (VF-14) and metamorphopsia (D-Chart-Thomson Software Solutions) assessment and answered a questionnaire regarding cardinal ERM symptoms. Post-operatively patients were re-assessed in the same domains.

RESULTS

13 patients completed the protocol (inclusion rate 76%) with a mean follow-up of 32.1 (± 3.1) months. Mean pre-operative VA of the affected eye was 0.42 logMAR (± 0.25). Mean pre-operative VF-14 score was 81.51 (± 12.8) and mean M-Score of the affected eye was 14.6 (± 12.7). Post-operatively, mean VA of the operated eye was 0.11 logMAR (± 0.11), mean VF-14 score was 97.4 (± 3.8) and mean M-Score was 1.31 (± 2.8). Mean improvement in VA was 0.31 logMAR (p < 0.001), in VF-14 15.9 (p = 0.002), and M-Score -13.3 (p = 0.003). There was a significant association between pre-operative D-Chart score and improvement in VA (r = -0.570, p = 0.042), visual functioning (r = 0.606 p = 0.028) and metamorphopsia (r = 0.916 p < 0.001), with those demonstrating poorer D-Chart scores showing greater improvements.

CONCLUSION

Pre- and post-operative visual distortion measured using the D-Chart, correlates with vision related quality of life in patients undergoing epiretinal membrane surgery. Patients with worse pre-operative distortion scores noticed the greatest improvements in distortion and vision related quality of life following surgery. With a mean follow-up time of 32.1 months, this long-term follow-up data further reinforces the efficacy of vitrectomy and ERM peel by demonstrating significant and sustained improvement in visual acuity, metamorphopsia and visual functioning. The authors suggest there is a role for D-Chart assessment pre-operatively to improve selection of patients in ERM surgery.

Idiopathic Epiretinal Membranes - Pathophysiology, Classifications and OCT-Biomarkers

Epiretinal membranes (ERMs) are a common finding in patients with increasing age. Diagnosis and treatment of ERMs have changed dramatically in recent years due to technological advances in ophthalmological care. In recent years, tomographic imaging has allowed for accurate visualization of ERMs and contributed to the growing understanding of the pathophysiology of this condition. The literature review conducted here summarizes recent innovations in diagnosis, classification, and treatment of idiopathic ERMs and specifically addresses novel optical coherence tomography (OCT) biomarkers that allow for the generation of prognoses regarding the clinical postoperative outcome.

A novel vector field analysis for quantitative structure changes after macular epiretinal membrane surgery

The aim of this study was to introduce novel vector field analysis for the quantitative measurement of retinal displacement after epiretinal membrane (ERM) removal. We developed a novel framework to measure retinal displacement from retinal fundus images as follows: (1) rigid registration of preoperative retinal fundus images in reference to postoperative retinal fundus images, (2) extraction of retinal vessel segmentation masks from these retinal fundus images, (3) non-rigid registration of preoperative vessel masks in reference to postoperative vessel masks, and (4) calculation of the transformation matrix required for non-rigid registration for each pixel. These pixel-wise vector field results were summarized according to predefined 24 sectors after standardization. We applied this framework to 20 patients who underwent ERM removal to obtain their retinal displacement vector fields between retinal fundus images taken preoperatively and at postoperative 1, 4, 10, and 22 months. The mean direction of displacement vectors was in the nasal direction. The mean standardized magnitudes of retinal displacement between preoperative and postoperative 1 month, postoperative 1 and 4, 4 and 10, and 10 and 22 months were 38.6, 14.9, 7.6, and 5.4, respectively. In conclusion, the proposed method provides a computerized, reproducible, and scalable way to analyze structural changes in the retina with a powerful visualization tool. Retinal structural changes were mostly concentrated in the early postoperative period and tended to move nasally.

Optical coherence tomography parameters as prognostic factors for stereopsis after vitrectomy for unilateral epiretinal membrane: a cohort study

This retrospective cohort study explored the relationship between monocular and interocular optical coherence tomography (OCT) parameters and stereopsis in 56 patients undergoing pars plana vitrectomy (PPV) for unilateral idiopathic epiretinal membrane (IERM). IERM impairs visual functions, with symptoms ranging from asymptomatic to severe impairment. Despite established surgical interventions, including PPV with membrane peeling, the impact on advanced three-dimensional visual functions such as stereopsis remains inadequately investigated. All subjects were assessed for stereopsis, visual acuity, and metamorphopsia, alongside spectral domain OCT parameters. These visual functions significantly improved 3-month postoperatively. Central retinal thickness at the fovea, parafovea, and perifovea (CFT, CRT-3 mm, and CRT-6 mm), ectopic inner foveal layer thickness, and retinal layer thickness notably decreased 1 week to 3 months after surgery. The interocular difference in OCT parameters between bilateral eyes was included as a parameter. Baseline CRT-3 mm difference and inner nuclear layer (INL) thickness were independently correlated with postoperative stereopsis on the Titmus Stereo Test, while baseline CRT-6 mm difference and INL thickness were independently related to stereopsis on the TNO stereotest. This study highlights the substantial enhancement in stereopsis post-IERM surgery, with both interocular and monocular OCT parameters independently influencing postoperative stereopsis. These findings underscore the importance of retinal microstructures in assessing and predicting stereopsis in IERM patients after vitrectomy.

Aniseikonia and retinal morphological changes in eyes undergoing macular hole surgery

Even after idiopathic macular hole (MH) surgery and with successful closure of MH, aniseikonia is a common postoperative symptom. We investigated the correlation of MH diameter, retinal displacement and retinal layer thicknesses with aniseikonia in 41 eyes of 41 patients undergoing MH surgery with internal limiting membrane peeling. Aniseikonia was measured with the New Aniseikonia Test. Retinal displacement (RD%) was defined as change of retinal distance between the temporal margin of the optic papilla and the intersection of the retinal vessels. Changes of thicknesses of the inner nuclear layer (INL%) and the outer retinal layer (OR%) were calculated. Aniseikonia improved postoperatively. Preoperative aniseikonia and their improvement at 6 months correlated with MH diameters (P = 0.004-0.046). Improvement of aniseikonia correlated with temporal RD% (P = 0.002-0.012). Improvement of vertical aniseikonia correlated with INL% at 2 weeks and with the nasal OR% at 1, 3, and 6 months (P = < 0.001-0.028). MH diameter and age were significant predictors for improvement of aniseikonia. The greater the temporal retina displacement, and the thinner the postoperative INL and OR, the greater the improvement of aniseikonia. MH diameter and age are strong predictors for improvement of aniseikonia after MH surgery.

Short-term-outcomes of idiopathic epiretinal membranes treated with pars-plana-vitrectomy - examination of visual function and OCT-morphology

BACKGROUND

Epiretinal membranes (ERM) represent one of the most common findings in retinal examination. Structural changes of the retinal layers in patients with ERM can be visualized and classified using OCT. The purpose of this study is to evaluate structural and functional changes related to surgical treatment of ERM.

METHODS

Monocentric retrospective analysis of 92 patients who underwent 23-gauge-pars plana vitrectomy (ppV) combined with cataract surgery for idiopathic ERM from 2015 to 2020. Visual acuity was determined directly preoperatively, at four weeks and three months postoperatively. Disease stage and tomographic biomarkers related to ERM were assessed in OCT imaging.

RESULTS

92 eyes of 92 patients were included. At the time of surgery, the mean patient age was 71 years. Visual acuity improved significantly by 2 lines postoperatively, on average from LogMar 0.4 to 0.2 (p < 0.001). Disease stage regressed from stage 3 to stage 2 postoperatively (p < 0.001). No patient had stage 4 postoperatively (n = 0). In the presence of preoperative intraretinal fluid, mean retinal thickness was 488 μm and decreased to 392 μm postoperatively (n = 32; p < 0.001). Preoperative presence of a Cotton Ball Sign (n = 30) was associated with better visual acuity (p = 0.009). This was also visible in patients with preoperative vitreomacular traction syndrome (p < 0.001). The presence of preoperative intraretinal fluid showed a tendency towards better disease staging after surgery (p = 0.080).

CONCLUSION

Surgery was able to achieve visual improvement and morphological regression of the preoperative OCT findings related to ERM. ppV led to a reduction in retinal thickness and disease stage. The presence of the Cotton Ball Sign and vitreomacular traction was associated with better visual acuity in the follow-up period. In our cohort the preoperative presence of intraretinal fluid showed a tendency for better postoperative disease staging.

Epiretinal Membrane Impairs the Inner Retinal Layer in a Traction Force-Dependent Manner

Purpose

To investigate the relationship between retinal traction force and impairment of the inner retinal layer in patients with epiretinal membrane (ERM).

Design

Nonrandomized, retrospective consecutive case series.

Participants

Two hundred nine eyes of 201 patients with idiopathic ERM who underwent vitrectomy for idiopathic ERM were enrolled.

Methods

Retinal folds caused by ERM were visualized using en face OCT, and the maximum depth of retinal folds within the parafovea (MDRF) was measured. Focal macular electroretinogram (ERG) was used to measure the amplitude and implicit time of each component for the ERM eyes and the normal fellow eyes. B-scan OCT images were used to measure the thicknesses of the inner nuclear layer (INL) and outer nuclear layer (ONL) + outer plexiform layer (OPL). Expression of α-smooth muscle actin (α-SMA) in surgically removed ERM specimens was quantified by reverse-transcription polymerase chain reaction.

Main Outcome Measures

We analyzed the relationship between MDRF and the relative amplitudes of focal macular ERG (affected eye/fellow eye), the relationships between MDRF and the mean INL thickness and ONL+OPL thickness, comparison of INL thickness and ONL+OPL thickness for each area when cases were classified according to MDRF localization in the ETDRS chart, and the relationship between MDRF and the relative expression of α-SMA in the ERM specimens.

Results

The MDRF significantly correlated with the relative amplitudes (affected eye/fellow eye) of b-waves and oscillatory potentials (r = -0.657, P = 0.015; r = -0.569, P = 0.042, respectively) and the mean INL thickness and ONL+OPL thickness (r = 0.604, P < 0.001; r = 0.210, P = 0.007, respectively). However, only the INL thickness progression rate was significantly correlated with the MDRF progression rate (r = 0.770, P < 0.001). On case stratification by localization of MDRF based on the ETDRS chart, in regions other than temporal regions, the INL thickness was significantly greater in regions with MDRF than in other regions. The MDRF significantly correlated with α-SMA expression in the ERM specimens (r = 0.555, P = 0.009).

Conclusions

The findings suggest that ERM impairs the inner retinal layer in a traction force-dependent manner.

Financial Disclosures

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Evaluation of the optical coherence tomography findings of patients with idiopathic epiretinal membrane

BACKGROUND

This study aimed to determine the relationship between basal visual acuity (VA) and basal optical coherence tomography (OCT) parameters of patients with idiopathic epiretinal membrane (iERM).

METHODS

The study included 200 eyes of 200 patients with iERM. In the evaluation of basal VAs, logMAR 0.3 (0.5 on Snellen chart) was accepted as the limit, and the patients were divided into two groups as Group 1 with VA values below logMAR 0.3 and Group 2 with those above logMAR 0.3. Using OCT, the ellipsoid zone (EZ), interdigitation zone (IZ), external limiting membrane (ELM) integrity, peaked appearance of EZ in the fovea, disorganization of the inner retinal layers (DRIL), central foveal thickness (CFT), maximum retinal thickness (MRT), total photoreceptor length (TPL), photoreceptor outer segment length (PROSL), photoreceptor deformity index (PDI), and inner retinal layer irregularity index (IRLII) were evaluated and compared between the groups.

RESULTS

There were an equal number of patients in Group 1 and Group 2. The preservation of ELM, EZ, and IZ integrity and the peaked appearance of EZ in the fovea were observed at higher rates in Group 1, whereas the rate of DRIL was higher in Group 2 (p < 0.05 for all). In the multiple regression analysis performed to evaluate categorical OCT parameters, only the presence of DRIL was found to be significantly associated with VA (p < 0.003). CFT*, MRT*, and IRLII** were significantly lower in Group 1 (*p < 0.001, **p = 0.001). TPU, PROSL, and FDI were similar between the two groups (p > 0.05 for all).

CONCLUSION

According to the multiple regression analysis, only the presence of DRIL was correlated with lower VA values. Among the OCT parameters, an increase in CFT and MRT, as well as the IRLII value moving away from 1 were related to lower VA values.

Idiopathic epiretinal membrane: progression and timing of surgery

Primary idiopathic epiretinal membrane (iERM) is a common finding, particularly so in the era of high street spectral-domain optical coherence tomography. Clinicians often face the dilemma of early versus delayed surgical intervention in the management of iERM with macular pucker, especially in those patients with good vision. The aim of this review is to assist clinicians in their understanding of the natural history of iERM to enable decision-making and optimally advising patients. We systematically searched the Medline and EMBASE databases for relevant publications from 2001 onwards using defined search terms with pre-planned inclusion and exclusion criteria. In this article, we review the epidemiology of iERM, classifications, their effect on visual function, the natural history and factors predicting progression and finally, factors which might predict the visual outcome with surgery.

Long-term functional outcomes and vision-related quality of life after vitrectomy for epiretinal membrane: a prospective cohort study

To investigate the long-term effect of unilateral idiopathic epiretinal membrane (uiERM) removal on monocular and binocular visual function, and on vision-related quality of life (VR-QoL). Prospective, single-center study. The following data were collected before and after surgery: distance monocular and binocular best-corrected visual acuity (BCVA), horizontal and vertical metamorphopsia, horizontal and vertical aniseikonia, stereoacuity and National Eye Institute Visual Function Questionnaire-25 item (NEI VFQ-25). Forty-two patients (mean age: 72.7 ± 7.4 years; 24 men) were included. At 6 months postoperatively, distance monocular BCVA (p < 0.001), horizontal metamorphopsia (p = 0.001) and the composite score of NEI VFQ-25 (p < 0.001) significantly improved, in comparison to baseline. At 2 years postoperatively, distance monocular (p < 0.001) and binocular (p = 0.01) BCVA, horizontal (p < 0.001) and vertical (p = 0.02) metamorphopsia, vertical aniseikonia (p = 0.01), stereoacuity (p < 0.001) and 3 subscales scores of the NEI VFQ-25 (p < 0.05) (“general vision”, “mental health”, “driving”) significantly improved in comparison to baseline. Removal of uiERM improves VR-QoL and achieves good visual outcomes on both monocular and binocular visual parameters over long-term. Visual symptoms induced by macular contraction have different improvement kinetics after surgery. Stereopsis, the highest level of binocular vision, can be improved in some cases.

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.

Aniseikonia following intravitreal ranibizumab treatment for branch retinal vein occlusion

PURPOSE

To quantify aniseikonia following intravitreal ranibizumab (IVR) in patients with branch retinal vein occlusion (BRVO) and assess the relationship between aniseikonia and retinal microstructure.

STUDY DESIGN

Prospective observational study.

METHODS

This study included 50 patients undergoing IVR treatment for unilateral BRVO. The degree of aniseikonia and best-corrected visual acuity (BCVA) was examined, and retinal microstructure was assessed with optical coherence tomography (OCT) before and 1, 2, 3, 4, 5, and 6 months after treatment. Based on OCT images, we assessed central retinal thickness (CRT), presence of the epiretinal membrane, and serous retinal detachment (SRD), as well as status of the external limiting membrane and ellipsoid zone.

RESULTS

At baseline, mean aniseikonia was - 1.0 ± 2.5%, ranging from - 11.0 to + 6.0%. Nine out of 50 patients had micropsia (18%), one had macropsia (2%), and 40 had no aniseikonia (80%). After 6 months of treatment, mean aniseikonia was - 0.7 ± 1.5%, ranging from - 4.5 to + 3.5%. BCVA significantly improved after treatment (P < 0.001), but aniseikonia did not change (P = 0.73). In patients with BRVO who had micropsia (≤ - 2.0%) at baseline, mean aniseikonia significantly improved from - 4.8 ± 3.3% to - 0.9 ± 1.4% (P < 0.05). Aniseikonia after treatment significantly correlated with BCVA (P < 0.05) and the presence of SRD at baseline (P < 0.05).

CONCLUSION

Majority of eyes with aniseikonia in BRVO had micropsia. The BCVA as well as the micropsia improved following treatment with IVR for BRVO. BCVA and the presence of SRD were predictors of post-treatment aniseikonia.

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.

Epiretinal membrane: A review

The prevalence of epiretinal membrane (ERM) is 7% to 11.8%, with increasing age being the most important risk factor. Although most ERM is idiopathic, common secondary causes include cataract surgery, retinal vascular disease, uveitis and retinal tears. The myofibroblastic pre-retinal cells are thought to transdifferentiate from glial and retinal pigment epithelial cells that reach the retinal surface via defects in the internal limiting membrane (ILM) or from the vitreous cavity. Grading schemes have evolved from clinical signs to ocular coherence tomography (OCT) based classification with associated features such as the cotton ball sign. Features predictive of better prognosis include absence of ectopic inner foveal layers, cystoid macular oedema, acquired vitelliform lesions and ellipsoid and cone outer segment termination defects. OCT-angiography shows reduced size of the foveal avascular zone. Vitrectomy with membrane peeling remains the mainstay of treatment for symptomatic ERMs. Additional ILM peeling reduces recurrence but is associated with anatomical changes including inner retinal dimpling.

Effect of internal limiting membrane peeling on visual field sensitivity in eyes with epiretinal membrane accompanied by glaucoma with hemifield defect and myopia

PURPOSE

To investigate the effects of internal limiting membrane (ILM) peeling on visual field sensitivities in eyes with epiretinal membrane (ERM) accompanied by glaucoma with hemifield defect and myopia.

STUDY DESIGN

Retrospective clinical study METHODS: We reviewed clinical records of patients with ERM who underwent vitrectomy and ERM/ILM peeling. We first collected clinical data of eyes with ERM and glaucoma with hemifield defect. We recorded visual field sensitivities at 52 points and analyzed differences between before and after surgery. We then compared the changes in visual field sensitivity between glaucomatous and normal hemifields. Next, we collected ERM eyes without glaucoma and stratified them into two groups based on axial length (threshold = 26.0 mm). In these eyes, we also recorded visual field sensitivities at 52 points and analyzed differences between before and after surgery.

RESULTS

The study included 18 eyes with ERM and glaucoma with hemifield defect (11 men; mean age, 68.3 ± 7.2 years). These eyes showed significant sensitivity reductions at 5/26 points, mainly in the nasal area of the glaucomatous hemifield, whereas only 1/26 points exhibited significant sensitivity reduction in the normal hemifield. In eyes with axial length <26.0 mm and axial length ≥26.0 mm, 29 peripheral and seven superior peripheral points showed significant improvements in visual field sensitivities, respectively.

CONCLUSION

Visual field sensitivity reduction occurred mainly in the nasal region of the glaucomatous hemifield. Differences in axial length alone were not a prominent risk factor for reduced visual field sensitivity after ILM peeling in eyes with ERM.

Influences of Central Bouquet Alterations on the Visual Outcome in Eyes Receiving Epiretinal Membrane Surgery

Background: Previous studies have shown that epiretinal membranes (ERMs) may be associated with abnormal outer retinal anatomy. However, long-term morphological and functional results of pars plana vitrectomy (PPV) with ERM and internal limiting membrane (ILM) peeling in eyes with central bouquet (CB) alterations have not yet been investigated. Methods: In a retrospective, consecutive study all patients underwent best corrected visual acuity (BCVA) testing and spectral domain optical coherence tomography (SD-OCT) before and after a mean of 20 months (range 3–70 months) postoperatively. CB abnormalities and ERMs were classified according to Govetto’s staging systems. Results: Of the 67 eyes, 22 (34%) showed CB abnormalities at baseline. The mean BCVA increased from 0.42 at baseline to 0.20 LogMAR at final follow-up (p < 0.001). Neither ERM stage (p = 0.06) nor CB stage (p = 0.939) at baseline were significant predictors of vision improvement following surgery. Conclusions: Our results show that baseline BCVA, but not classification of CB changes and ERM at baseline, seems to be a useful predictor for functional outcomes following PPV with ERM and ILM peeling in the long-term.

Correlation between tangential distortion of the outer retinal layer and metamorphopsia in patients with epiretinal membrane

PURPOSE

To evaluate tangential morphological changes in the outer retina and assess their correlation with the degree of metamorphopsia in patients with idiopathic epiretinal membrane (ERM).

METHODS

This retrospective study included patients with idiopathic ERM who underwent vitrectomy between January 2018 and December 2019. We evaluated the preoperative examination results. Using cross-sectional spectral-domain optical coherence tomography (OCT) images along the horizontal/vertical meridian through the fovea, we defined a new parameter, tangential displacement (TD), as the tangential component of the position vector of the distorted outer nuclear layer caused by ERM. Visual function measurements included M-CHARTS results (vertical/horizontal metamorphopsia score [MV/MH]) and best-corrected visual acuity (BCVA). The correlations among the OCT parameters including TD and central foveal thickness (CFT) with visual function measurements were determined.

RESULTS

Overall, 78 eyes of 76 patients (49 females; mean age, 67.9 [± standard deviation, 7.5 years]) were included. The mean horizontal TD was 24.0 ± 73.9 μm, which was significantly different from 0 (p = 0.005). The mean vertical TD was 6.0 ± 76.2 μm, which was not significantly different from 0. The absolute value of horizontal TD was significantly correlated with MV (r = 0.513, p < 0.01) and MH (r = 0.423, p < 0.01). The absolute value of vertical TD was also significantly correlated with MV (r = 0.274, p = 0.02) and MH (r = 0.413, p < 0.01). However, neither value was significantly correlated with BCVA. Multiple regression analysis showed that the horizontal absolute TD was an independent factor associated with both MV (β = 0.635, p < 0.001) and MH (β = 0.259, p = 0.048).

CONCLUSION

We found that ERM tended to distort the outer retinal layer toward the temporal side of the fovea. The tangential distortion of this layer was associated with the degree of metamorphopsia, suggesting that misalignment of parafoveal photoreceptors causes metamorphopsia in patients with ERM.

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.

Monocular and binocular end-points after epiretinal membrane surgery and their correlation to patient-reported outcomes

PURPOSE

This study evaluates current available endpoints for epiretinal membrane (ERM) surgery and examine their correlation to patient reported outcomes (PRO).

METHODS

Retrospective study including 38 eyes of 38 patients who underwent cataract extraction and subsequent vitrectomy for idiopathic ERM. The fellow eye was phakic with good visual acuity. The registered outcomes were monocular and binocular visual acuity, stereoacuity, M-chart metamorphopsia score, aniseikonia and aniseikonia tolerance range (ATR). Two questionnaires were completed: the convergence insufficiency symptom survey and Visual Function Questionnaire (VFQ-39).

RESULTS

Median total aniseikonia was 11% (range 0-35). There was a statistically significant correlation between the mean total M-chart score of the study eye and VFQ-Near (Spearman rho: VFQ-Near: -0.54, p < 0.01). There was no correlation between the best corrected visual acuity (BCVA) of the project eye, binocular BCVA, stereoacuity, ATR or mean total aniseikonia and PRO (Spearman p-values > 0.05). There was no correlation between mean total aniseikonia and mean total M-chart score (Spearman rho: 0.21 p = 0.26). There was a large variation between the mean total M-chart scores and questionnaire results.

CONCLUSION

The mean total M-chart score is currently the best end-points to predict PRO of ERM surgery; however, it is possible to have high M-chart values and have no visual complaints.

Changes in metamorphopsia after the treat-and-extend regimen of anti-VEGF therapy for macular edema associated with branch retinal vein occlusion

This study aims to investigate the changes in metamorphopsia after administering the treat-and-extend regimen of anti-vascular endothelial growth factor therapy for branch retinal vein occlusion-associated macular edema. We retrospectively examined 27 patients (27 eyes) with macula edema due to branch retinal vein occlusion who received intravitreal injections of anti-vascular endothelial growth factor agents using the treat-and-extend regimen for ≥18 months. We evaluated best-corrected visual acuity, central macular thickness, macular edema recurrence, and amount of metamorphopsia quantified by M-CHARTS. The best-corrected visual acuity (logarithm of minimum angle of resolution) and central macular thickness significantly improved at 18 months compared to baseline, the median value (interquartile range [IQR]), 0.30 (0.15–0.52) and 459 (373–542) μm at baseline, and 0 (-0.08–0.16) and 267 (232–306) μm at 18 months. The M-CHARTS score (the mean of vertical and horizontal scores) significantly decreased at 1, 6, and 12 months compared to baseline, but worsened at 18 month, the median value (IQR), 0.45 (0.250–0.925), 0.4 (0.15–0.70), 0.4 (0.150–0.625), 0.4 (0.225–0.550) and 0.45 (0.225–0.750) at baseline, 1 month, 6 months, 12 months and 18 months, respectively. The median cumulative number of macular edema recurrences was 2 (IQR, 0.5–3.0) at 18 months. Simple linear regression and multivariate analyses revealed that the change in the mean M-CHARTS score at 18 months was significantly correlated with the baseline score and the cumulative number of macular edema recurrences. Anti-vascular endothelial growth factor therapy using the treat-and-extend regimen improved metamorphopsia in branch retinal vein occlusion-related macular edema in the short to mid-term follow-up period, but not in the long term. Macular edema recurrence may be associated with persistent metamorphopsia.

Preoperative aniseikonia is a prognostic factor for postoperative stereopsis in patients with unilateral epiretinal membrane

PURPOSE

To investigate stereopsis and other visual functions in patients with unilateral epiretinal membrane (ERM) and to identify vision-related parameters affecting stereopsis.

METHODS

This prospective study included 63 consecutive patients who were scheduled to undergo vitrectomy for unilateral idiopathic ERM. We examined stereopsis (Titmus Stereo Test, TST; TNO stereotest, TNO), best-corrected visual acuity (BCVA), letter contrast sensitivity, severity of metamorphopsia, and degree of aniseikonia preoperatively and 6 months postoperatively.

RESULTS

Preoperatively, we observed significant correlation between TST scores and other vision-related parameters except severity of metamorphopsia and between TNO score and all the vision-related parameters. Multiple regression analysis showed that preoperative TST and TNO scores were significantly associated with the degree of aniseikonia (both P < 0.01). ERM surgery significantly improved stereopsis, BCVA, contrast sensitivity, and metamorphopsia, but not aniseikonia. Postoperatively, TST was significantly associated with BCVA, and TNO showed association with BCVA and aniseikonia. Postoperative TST and TNO scores showed significant correlation with preoperative aniseikonia (P < 0.005 and P < 0.001, respectively).

CONCLUSIONS

Impairment of stereopsis in patients with unilateral ERM was considered to be due to retinally induced aniseikonia. Aniseikonia did not improve by surgery, and preoperative aniseikonia can be a prognostic factor for postoperative stereopsis.