[Optical coherence tomography biomarkers in epimacular membranes and vitreomacular traction syndrome]

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.

[Disorders of the visual system following vitreoretinal and macular surgery]

The visual system is highly complex. Monocular or binocular disorders can develop, for example during tractive alterations of the macula, such as in epimacular membranes, and result in symptoms, such as double vision, aniseikonia or metamorphopsia. These symptoms are also observed following vitreomacular or vitreoretinal surgery, especially after treatment of large retinal detachment involving the macular area using pars plana vitrectomy or scleral buckle surgery but also as a result of vitreomacular interventions, such as membrane peeling in epimacular gliosis. Some patients have preoperatively existing latent conditions, which are not explicitly addressed during routine preoperative diagnostics. For patients and surgeons it is worth noting that these troublesome symptoms are often manifested in patients with good restoration of best corrected visual acuity following vitreomacular surgery. In such cases, patients tend to be dissatisfied with the surgical result despite good visual acuity. Treatment of postoperative metamorphopsia, aniseikonia and double vision is often difficult. In clinical studies, the maximum depth of tractive retinal folds has been described as a reliable morphological biomarker for the occurrence of metamorphopsia in epimacular gliosis. As metamorphopsia tends to postoperatively resolve slowly and even persist in ca. 30% of cases, this biomarker can have an impact on preoperative consulting and postoperative monitoring. Persistent binocular discomfort is often treatable by exact refraction correction and by applying a vertical and, if necessary, a horizontal prism. This often requires patience on the part of both the patient and the physician but is mostly successful due to fusion and adaptability.

Prevalence and Associations of Vitreomacular Traction: The Beijing Eye Study

Purpose

To explore the prevalence and associations of vitreous macular traction (VMT) in Chinese population.

Methods

A population-based cross-sectional study with 3468 individuals (mean age of 64.6 ± 9.8 years) based on Beijing Eye Study 2011. Participants underwent detailed ophthalmic examinations, including spectral domain optical coherence tomography (SD-OCT). VMT was defined as abnormal posterior vitreous detachment with anatomical deformation of the fovea, which may include pseudocyst, macular schisis, cystoid macular edema, and subretinal fluid.

Main Outcome Measure

Prevalence of VMT.

Results

A VMT was detected in 151 (2.3%) eyes (prevalence rate (mean ± SE): 2.3± 0.2%; 95% CI: 1.9%, 2.7%) of 80 (2.4%) subjects (prevalence rate: 2.4± 0.3%; 95% CI: 1.9%, 2.9%). Mean age of all subjects with VMT was 70.1± 8.7 years (median, 70.0 years; range, 50–90 years), mean refractive error was −0.22 ± 2.38D (median, 0.25 D; range, −15.00 to 5.25D). In multivariate analysis, prevalence of VMT was associated with elder age (P=0.001, OR 1.06), female gender (P = 0.036, OR 1.77), subfoveal retinal thickness (P = 0.005, OR 1.01), and subfoveal choroidal thickness (P = 0.026, OR 0.10).

Conclusion

In adult Chinese in Greater Beijing, the prevalence of VMT was 2.3% for eyes or 2.4% for subjects. While it was associated with elder age, female gender, thicker subfoveal retinal thickness and thinner subfoveal choroidal thickness.