Purpose:
Epiretinal membrane (ERM) may induce mild to severe visual disturbance. Chan et al. determined by optical coherence tomography (OCT) the outer retina complex (ORC; outer nuclear layer and inner and outer photoreceptor segments) as 91.1 + 7.9 υm, and the total retinal thickness (TRT) as 258.9 + 10.1 υm in normal eyes. The goal of this study was to analyse the ORC and TRT in different stages of ERM.
Methods:
OCT-scans of 64 eyes with ERM were grouped according to the visual symptoms in group A (visual acuity VA 20/16 - 20/25), group B (VA 20/32 - 20/50) and group C (VA 20/63 or worse). The ORC and TRT as well as the depth of the surface wrinkling (inner retinal folding, IRF) and outer retinal folding (ORF) of the ORC were digitally analyzed.
Results:
Surface wrinkling retinopathy (group A) is associated with normal ORC and TRT, while the mild IRF has no to minimal effect in the VA. Group B is associated with moderate increase in TRT but significant ORC reducing the VA by 3 lines. In group C there is a severe thickening of the ORC and TRT associated with severe folding of the inner and outer retinal structures. With decreasing VA we observed an increased TRT especially of the ORC.
Conclusions:
It may be difficult to define by funduscopy the impact of an ERM on the VA. Digital analysis of the tomographic architecture of the retinal can clearly differ superficial, from inner and full thickness folding of the retina. Increased thickness of the photoreceptors seems to have the highest impact on the VA.
Keywords: retinal adhesion • edema • imaging/image analysis: clinical