gms | German Medical Science

The idiopathic epiretinal membrane is often interpreted as a complication of a posterior hyaloid detachment. But it is also seen in patients with attached vitreous. This present study examines the characteristic OCT-findings in patients with an idiopathic epiretinal membrane in order to evaluate possible reasons for these changes.

In 20 patients (10 patients with a macular edema in the FLA, 10 patients without a macular edema) with an idiopathic epiretinal membrane the typical OCT-findings have been analyzed and compared with 10 normal findings: 1. hyperreflektive band at the inner retinal surface: visuability, separation, traction; 2. retinal morphology: foveal and extrafoveal thickness, visuability of the foveola, edematous changes of the outer retinal surface.

While a hyperreflective band at the inner retinal surface is not seen in normal patients, the band was partially detached or attached in all patients with an idiopathic epiretinal membrane. Patients with an associated macular edema showed also a separation of this band combined with a focal traction. The retinal thickness is in the fovea and extrafoveal significant different: normal findings foveal 186μm / extrafoveal 295μm, idiopathic epiretinal membrane without macular edemafoveal 329μm / extrafoveal 351μm, idiopathic epiretinal membrane with macular edema foveal 443μm / extrafoveal 348μm. The foveal dip wasn´t seen in patients with idiopathic epiretinal membrane with macular edema and the retinal structure seemed to be loosened or cystic. The clinical visuable folds of the inner retinal layers which were observed in all patients were seen in the OCT only in some cases.

The OCT-findings in patients with an idiopathic epiretinal membrane showed a thickening of the whole retina in combination with a hyperreflective band at the inner retinal surface. The thickening of the retina seemed to be independent from the presence of a macular edema or from having a retinal folding or separation of the epiretinal membrane. An additional retinal reason - for example an abnormal function of the gliocytes would be possible. An increasing separation of the epiretinal membrane with a focal traction seems to be responsible for causing a macular edema.