High-resolution OCT of ILM hyperconvolution associated with epiretinal membrane.

Macular oedema is a common complication and vision-limiting factor in uveitis. The aim of this study was to compare retinal thickness as measured by optical coherence tomography and photoreceptor function as measured by fundus-related microperimetry with respect to their correlation with visual acuity. Prospective observational monocentre study. Thirty-one patients (53 eyes) with endogenous uveitis and fluorescein angiographically confirmed macular oedema were evaluated. Foveal thickness was analysed using spectral-domain (Spectralis(TM) ; Heidelberg Engineering, Heidelberg, Germany) OCT and retinal sensitivity was assessed using fundus-related microperimetry (MP1; Nidek Technologies, Padova, Italy). All findings were correlated with best-corrected visual acuity (BCVA). Foveal thickness was correlated with BCVA [p = 0.005, r = 0.38, 95% confidence interval (CI) 0.12-0.59]. For microperimetry measurements, a negative correlation with logMAR visual acuity was found. Fixation abnormalities were not associated with poor visual acuity, increased foveal thickness or retinal sensitivity. In eyes with cystoid changes in the outer plexiform and inner nuclear layer, foveal thickness was increased (p < 0.0001). Epiretinal membrane formation was present in 70%. In these eyes, foveal thickness was significantly increased (p = 0.003) and visual acuity was worse (p = 0.08). Foveal thickness and fundus-related microperimetry were correlated with visual acuity. Cystoid changes in the outer plexiform and inner nuclear layer and the presence of epiretinal membrane were associated with poor visual acuity. Fixation abnormalities were not associated with poor visual acuity.

Assessment of the Vitreomacular Interface Using High-Resolution OCT in a Population-Based Cohort Study of Older Adults

To investigate the changes of the vitreomacular interface during a 1-year follow-up after idiopathic epiretinal membrane (iERM) surgery. Six patients affected by fovea-attached iERM were recruited in this pilot study. Pars plana vitrectomy associated with epiretinal membrane peeling was performed uneventfully in all cases. In four cases, the inner limiting membrane was removed using Brilliant blue G. En face high-resolution adaptive optics and cross-sectional spectral domain optical coherence tomography retinal imaging were performed before and at 1, 3, 6, and 12 months after surgery. The microstructures of vitreomacular interface in high-resolution adaptive optics images were correlated to the cross-sectional spectral domain optical coherence tomography data. Preoperatively, adaptive optics images showed multiple abnormalities of the vitreomacular interface, such as macrofolds, microfolds, and hyperreflective microstructures. We identified two subtypes of iERM according to the distribution of microfolds over the foveal area, which included the radial-type and the grid-type iERM. After surgery, the morphology of the vitreomacular interface changed compared with the preoperative state. The number of both macrofolds and microfolds was reduced in all cases. The hyperreflective structures were still resolvable in all cases, however presenting different shape and morphology than preoperatively. In addition, they showed marked differences between eyes that had internal limiting membrane removal and eyes that did not. Adaptive optics imaging gives new insight into the changes of vitreomacular interface after iERM surgery. Enhanced multimodal imaging of the vitreomacular interface and retinal structures can be valuable to monitor treatment outcome of iERM.

Aim:To describe vitreoretinal imaging of eyes with vitreomacular abnormalities using high-resolution coronal-plane optical coherence tomography (OCT) scanning combined with simultaneous scanning laser ophthalmoscope (SLO) imaging.Methods:A SLO–OCT (OTI, Canada) was used...

We assessed the value of preoperative optical coherence tomography (OCT) for predicting the visual outcome for patients undergoing macular surgery for epiretinal membranes (ERMs). In a retrospective trial, we analyzed the medical charts of patients who had received surgery for ERMs between January and August 2011. The best-corrected pre- and postoperative logMAR visual acuity was assessed. We pre- and postoperatively measured the central foveal thickness with high-resolution spectral-domain OCT and analyzed the structure of the outer retinal layers (retinal pigment epithelium, photoreceptors, and external limiting membrane) before and after surgery. The study included 49 patients (23 male, 27 female) with an average age of 69 years (SD 6.7) who had received macular surgery during the above-mentioned period. For phakic eyes (n = 34), treatment had also included phacoemulsification and intraocular lens implantation. Postoperative follow-up examinations and OCT controls had been conducted after an average of 9 weeks (SD 5). The mean improvement in visual acuity was 2.4 lines (SD 2.3; p < 0.001). For patients with phakic eyes, the combination of vitrectomy and cataract surgery resulted in a slightly better, but insignificant increase in visual acuity than for patients with primary pseudophakia (Δ = 0.05, p = 0.46). On average, central foveal thickness regressed by 94 μm (SD 129 μm). Linear regression showed a significant linear relationship between the reduction of central foveal thickness and improvement of visual acuity (R (2) = 0.16, B = 0.71, p = 0.004). A decrease in foveal thickness by 100 μm resulted in an increase in visual acuity by 0.71 lines. Visual improvement did not significantly differ between the group of patients with intact outer retinal layers before surgery and the group of patients with preoperative defects of the retina (p = 0.085). We found a significant linear relationship between the reduction of central foveal thickness and improvement of visual acuity for patients undergoing surgery for ERM. However, the preoperative OCT status (intact vs. broken) of the outer retinal layers did not correlate with the change in visual acuity.

The diagnosis of epiretinal membranes is clinical following a thorough history and fundus assessment. This lecture focuses however on additional imaging modalities currently available to facilitate the diagnostic and postoperative evaluation. Multicolour fundus imaging or confocal infrared imaging have provided superior ERM detection in comparison to fundus photography in mild cases. Diagnostic evaluation with OCT allows the estimation of retinal deformity due to the membrane, determines the involvement of the fovea and, with en‐face OCT, allows for the estimation of the membrane extent and dynamic development. High resolution OCT allows for the classification of epiretinal membranes to conventional or atypical. Specific retinal features have been identified in symptomatic eyes (macropsia). OCT imaging has allowed the determination of the ERM profile for specific categories of patients as patients with uveitis or concurrent diabetic macular oedema. Imaging following ERM peeling allows the estimation of anatomic and functional outcomes. OCT allows the qualitative and quantitative assessment of central macular thickness or individual retinal layers. Additional retinal features, some of which could have prognostic implications such as features of retrograde maculopathy, can be identified. Pre‐ and postoperative macular vascular circulation can be evaluated with the use of OCT‐A and evaluation of retinal oxygen saturation can be evaluated with the use of retinal oximeter. The features of the FAZ postoperatively have been investigated and have been associated with the degree of visual recovery. The impact of artefacts in this modality need to be taken into account.

Intraoperative optical coherence tomography (iOCT) represents another milestone in ocular imaging technologies. Now, for the first time, high resolution OCT images are available not only pre- or postoperatively, but also intraoperatively. In recent years, there have been significant advances in iOCT technology - from hand-held probes and mounted systems towards iOCT systems which are fully integrated into the surgical microscope and which provide seamless integration into the workflow. These systems offer high-resolution, intraoperative OCT scans in real-time and provide additional information on microstructures of the retina or the cornea. These findings may even lead to a modification of surgical strategies. Like any other new technology, iOCT technology still has some limitations, such as shadowing from instruments and the lack of eye tracking systems. Therefore, the current state of iOCT technology still requires some skill to track surgical maneuvers in real time. Further research and development will help to solve these limitations in the future. However, even if not required for all surgical procedures, iOCT imaging can already improve safety and control in many surgical procedures on the anterior and posterior segments. This has already been shown in several studies and case series. Particularly in the surgery of vitreomacular traction, peeling of epiretinal membranes (ERM peeling) and macular hole surgery, iOCT offers significant added value. It improves the visualisation of transparent structures and helps to avoid the usage of dyes. In addition the success of the surgical maneuvers can be investigated intraoperatively. In lamellar keratoplasty and glaucoma surgery too, iOCT improves precision and safety. Moreover, iOCT technology may help to achieve further insight into ocular pathologies and a better understanding of the impact of surgical maneuvers on visual rehabilitation. Further prospective studies are however required to evaluate the usefulness of iOCT in various surgical procedures on both, the anterior and posterior segments.