Retinal layers thickness changes following epiretinal membrane surgery.

PurposeTo evaluate the time course of changes in the thickness of retinal layers after epiretinal membrane (ERM) removal surgery.MethodsA retrospective cohort study of patients following surgery for idiopathic ERM. We used new specialized image analysis software to create a thickness map of each retinal layer and analyzed changes during one year follow-up. Healthy fellow eyes were used as negative controls and the retina prior to surgery as positive control.ResultsTwenty-one patients were included with a mean age of 68±13 years. Central macular thickness decreased steadily until 6 months after surgery (25% decrease, 516±76 to 386±73 µm, P<0.001) with no further decrease between 6 and 12 months (386±73 to 390±73 µm, P=0.291). The retinal nerve fiber layer (RNFL), and the ganglion cell and inner plexiform layer (GCIPL) were most affected (57%, P<0.001 and 27%, P=0.010, respectively). The thickest region showed a more abrupt decrease of 21% at first follow-up (504±61 to 399±58 µm, P=0.001) with subsequent decrements of about 3%. Prior to surgery all retinal layers were thicker in study eyes compared with healthy control eyes (6-63%, all P<0.05).ConclusionsFollowing ERM surgery, in the course of 6 months, the macula gradually becomes thinner after which a stable state is reached. All layers appear to be affected, with the RNFL and GCIPL impacted the most. Our results provide a unique view on how the thickness of different retinal layers changes following ERM surgery.

Intraocular pressure measurement after DSAEK by iCare, Goldmann applanation and dynamic contour tonometry: A comparative study.

PURPOSE: Corneal thickness inevitably increases following Descemet's stripping automated endothelial keratoplasty (DSAEK), owing to the addition of a donor graft. The current study compares different devices in assessing post-DSAEK intraocular pressure (IOP). METHODS: We compared IOP values measured by the Goldmann tonometry (GAT), iCare rebound tonometry (iCare) and Pascal dynamic contour tonometry (PDCT) in eyes following DSAEK. Agreement between measurements was calculated with correlation analysis and Bland-Altman plots. Effects of keratometry, central, thickness (CCT), endothelial cell density (ECD) and axial length on IOP measurements were assessed with Pearson's correlation. RESULTS: Twenty eyes of 20 patients (mean age 74.3±14.4, 14 females) post-DSAEK were included in this study. There was a high concordance between the IOP readings obtained by the three devices: a strong and significant correlation was found between GAT and PDCT (r=0.94, P<0.001) GAT and iCare (r=0.86, P<0.001) and iCare with PDCT (r=0.81, P<0.001). However, the iCare measurements were significantly and consistently lower than that obtained with GAT (ΔIOP=1.68±2.0, P=0.002, 95% CI: 0.7-2.6) and with PDCT (ΔIOP=1.61±2.5, P=0.01, 95% CI: 0.4-2.8). CCT, ECD, CCT, AXL, corneal curvature or astigmatism did not influence IOP measurement by any instrument. CONCLUSIONS: IOP measurement with three different techniques (applanation, rebound and dynamic contour) showed good correlations, despite an increased corneal thickness following DSAEK. However, the iCare, which is based on a rebound tonometry showed significant lower IOP then the two other methods. This should be taken into account when evaluating patients post DSAEK.