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

Visual Performance and Predictive OCT Biomarkers in Epiretinal Membrane Assessment: Beyond Distance Visual Acuity

Purpose

This study aimed to comprehensively assess visual performance in eyes with idiopathic epiretinal membrane (iERM). Additionally, it sought to explore the associations between optical coherence tomography (OCT) imaging biomarkers and visual performance in patients with iERM.

Methods

In this prospective, non-interventional study, 57 participants with treatment-naïve iERM from the University of Turin, between September 2023 and March 2024 were enrolled. Visual performance was measured using distance best-corrected visual acuity (BCVA), near BCVA, and maximum reading speed (MaxRS). Structural retinal imaging biomarkers were obtained from OCT, focusing on retinal layer thicknesses and epiretinal membrane characteristics. Statistical analyses, including linear regression and multivariate analysis, were used to determine relationships between visual function and imaging metrics.

Results

Monocular distance BCVA (0.37 ± 0.23 LogMAR), near BCVA (0.59 ± 0.18 LogMAR), and MaxRS (108.88 [68.38] words per minute [wpm]) in patients with iERM were significantly reduced compared with reference values. Both near BCVA and reading speed exhibited a greater percentage reduction than distance visual acuity. Patients with phakic showed worse visual acuity than patients with pseudophakia, although their reading performance was similar. Higher outer plexiform layers thickness and inner retinal thickness were associated with decreased distance and near visual acuity and reduced reading speed (beta, P value).

Conclusions

The iERM predominantly impacts near visual performance, with near visual acuity and reading speed being more affected than distance visual acuity. Structural OCT biomarkers, particularly retinal thickness in specific regions, correlate with worse functional impairments. This highlights the importance of near vision assessments and imaging biomarkers for a comprehensive evaluation of visual impairment in iERM.

A classification of idiopathic epiretinal membrane based on foveal avascular zone area using optical coherence tomography angiography

OBJECTIVE

To evaluate the characteristics and prognoses of idiopathic macular epiretinal membrane (iERM) using a classification based on the foveal avascular zone (FAZ) area.

METHOD

IERMs were classified into four stages based on the FAZ area. Baseline FAZ-related parameters, pre-and postoperative central macular thickness (CMT), and best corrected visual acuity (BCVA) were observed and compared between different stages. The correlations of structural parameters with pre-and postoperative logMAR BCVA were analyzed.

RESULTS

162 iERM eyes were enrolled, including 105 eyes followed up for 12 months after surgery. The preoperative BCVA was better at the early stage. Postoperative BCVA at Stages 2 and 3 were better compared to Stage 4. The early stage was associated with thinner CMT pre-and postoperatively. However, there was no significant difference in CMT between postoperative Stages 1 and 2 or Stages 3 and 4. Preoperative logMAR BCVA was negatively correlated with FAZ area, perimeter, and FD-300 and was positively correlated with CMT and acircularity index (AI). CMT correlated positively with BCVA for each stage, except Stage 4; FAZ area, perimeter, and FD-300 had a negative correlation at Stage 1. Baseline BCVA and CMT positively correlated with BCVA at the last follow-up, while FAZ area and FD-300 were negatively correlated. Baseline BCVA had a positive correlation for each stage, except Stage 1; FD-300 had a negative correlation at Stages 2 and 3; CMT had a positive correlation at Stage 3.

CONCLUSION

A classification based on the FAZ area was established innovatively. This classification can reflect the progression of iERM and is helpful to the postoperative prognosis.

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.

Retinal thickness profiles in patients with Behçet uveitis during remission

PURPOSE

The purpose of this study was to evaluate the intraretinal layer thickness in the macular region and its correlation with the duration of uveitis and visual acuity in patients with Behçet uveitis.

METHODS

In this cross-sectional study, we included 93 eyes of 57 patients with Behçet uveitis and 100 eyes of 50 healthy individuals admitted to a tertiary center from January to September 2017. We performed macular measurements in all subjects via spectral domain-optical coherence tomography (SD-OCT) and divided the retina into layers using automated segmentation software on the SD-OCT device. We then compared layer thicknesses between the patient and control groups and evaluated the correlation between OCT parameters and the duration of uveitis and visual acuity in the patient group.

RESULTS

Our records show a mean age of 37.9 ± 10.8 (18-64) years and 37.7 ± 12.2 (21-61) years in the patient and control groups (p=0.821), respectively. Meanwhile, data reveal a mean duration of uveitis of 6.9 ± 4.7 (1-20) years. We found a reduction in the total outer layer thickness in the patient group (p<0.001). However, we did not find a statistically significant difference in the inner retinal layers except in the inner nuclear layer. The duration of uveitis negatively correlated with the outer retinal layer's thickness (correlation coefficient = -0.250). On the other hand, visual acuity positively correlated with the central macular, the total inner layer, and the outer retinal layer thicknesses (correlation coefficients: 0.194, 0.154, and 0.364, respectively). However, the inner nuclear layer negatively correlated with visual acuity.

CONCLUSIONS

Using retinal segmentation via SD-OCT for follow-ups can help estimate visual loss in patients with Behçet uveitis, which can cause significant changes in intraretinal layers in the macular region.

Influence of Preoperative Foveal Layers’ Thickness on Visual Function and Macular Morphology by Phacovitrectomy for Epiretinal Membrane

Background. The aim of this retrospective study with short, differently dispersed follow-up is to record the relationships between the pathologies of the individual foveal layers, measured by spectral domain optical coherence tomography (SD-OCT), and to investigate their influence on pre- and postoperative best-corrected decimal far visual acuity (BCVA) by phacovitrectomy for epiretinal membrane (ERM) in comorbidity with cataract. Patients and Methods. 208 eyes of 173 patients with symptomatic idiopathic ERM and moderate cataract were included. Results. In all OCT morphological stages of ERM, as well as in their combination with macular lamellar hole (MLH) and vitreomacular traction (VMT), a significant difference in the thickness of the individual fovea layers was found. In addition, the entire fovea thickening led to the proportional thickening of the individual fovea layers ( $p<0.001$ ). The larger the central foveolar (CFT, R2 = −0.238, $p=0.002$ ), maximum foveal (MFT, R2 = −0.267, $p=0.001$ ), and ONL thickness (R2 = −0.16, $p=0.044$ ) were preoperatively, the worse the initial visual acuity was at all OCT stages of ERM. This was even more significant in the presence of a tractive component in the case of MLH or VMT ( $p<0.001$ ). In ERM without a traction component, only ONL thickening led to significant postoperative visual acuity reduction (R2 = −0.163, $p=0.047$ ). The foveolar retinal thickening (CFT and MFT) of the pure ERM is directly associated with distortion of the retinal layers (R2 = 0.292, $p<0.001$ and R2 = 0.287, $p<0.001$ ) as well as with separation of the ERM (R2 = 0.168, $p=0.034$ and R2 = 0.187, $p=0.018$ ). When ERM was combined with tractive component, CFT, ONL, and INL thickness correlated (positively) with the integrity of ellipsoid zone (R2 = 0.342, $p<0.05$ ) and external limiting membrane (R2 = 0.548, $p<0.001$ ). Conclusions. ONL thickening in ERM without a tractive component serves as a limited prognostic factor of postoperative visual acuity decrease. The preoperative BCVA in the groups of ERM with traction component showed significant correlation with CFT as well as with the thickness of individual foveal layers. VMT in ERM correlates with the disintegration of the ellipsoid zone.

DEEP LEARNING-BASED PREDICTION OF OUTCOMES FOLLOWING NONCOMPLICATED EPIRETINAL MEMBRANE SURGERY

PURPOSE

We used deep learning to predict the final central foveal thickness (CFT), changes in CFT, final best corrected visual acuity, and best corrected visual acuity changes following noncomplicated idiopathic epiretinal membrane surgery.

METHODS

Data of patients who underwent noncomplicated epiretinal membrane surgery at Severance Hospital from January 1, 2010, to December 31, 2018, were reviewed. Patient age, sex, hypertension and diabetes statuses, and preoperative optical coherence tomography scans were noted. For image analysis and model development, a pre-trained VGG16 was adopted. The mean absolute error and coefficient of determination (R 2 ) were used to evaluate the model performances. The study involved 688 eyes of 657 patients.

RESULTS

For final CFT, the mean absolute error was the lowest in the model that considered only clinical and demographic characteristics; the highest accuracy was achieved by the model that considered all clinical and surgical information. For CFT changes, models utilizing clinical and surgical information showed the best performance. However, our best model failed to predict the final best corrected visual acuity and best corrected visual acuity changes.

CONCLUSION

A deep learning model predicted the final CFT and CFT changes in patients 1 year after epiretinal membrane surgery. Central foveal thickness prediction showed the best results when demographic factors, comorbid diseases, and surgical techniques were considered.

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.

Incidence and risk factors of progressive nasal inner nuclear layer thickening after surgical peeling of epiretinal membrane

To assess incidence and risk factors of postoperative progressive nasal inner nuclear layer (INL) thickening after epiretinal membrane (ERM) surgery. Progressive nasal INL thickening was defined as 1.5-fold increase in thickness of nasal INL after ERM surgery compared to preoperative examination. Kaplan–Meier survival analysis was done to compare the cumulative risk ratio between groups stratified by presence of progressive nasal INL thickening. Logistic regression was performed to identify possible risk factors. Progressive nasal INL thickening occurred in 13.0% of ERM removal patients. Patients without progressive nasal INL thickening showed better visual acuity recovery compared to patients with nasal INL thickening (p = 0.029). Presence of cystoid space in inner retinal layer before surgery (odds ratio [OR] = 0.143, 95% confidence interval [CI] 0.028–0.736; p = 0.020), older age (OR = 0.896, 95% CI 0.817–0.982, p = 0.020), and thicker preoperative central macular thickness (OR = 0.994, 95% CI 0.988–1.000, p = 0.039) were correlated inversely with thickening of nasal INL. Correlation between nasal INL thickness and postoperative visual outcome was significant. Absence of cystoid space before ERM surgery, younger age, and thinner central macular thickness were risk factors for progressive postoperative nasal INL thickening. Progressive nasal INL thickening may serve as a new biomarker for worsened visual symptom after ERM surgery.

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.