Novel Optical Coherence Tomography Parameters as Prognostic Factors for Stage 3 Epiretinal Membranes

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.

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.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.