Posters

Epiretinal membrane leads to a mismeasurement of the peripapillary retinal nerve fiber layer (RNFL) in spectral domain optical coherence tomography (SD-OCT)

Poster Details

First Author: F.Ruefer GERMANY

Co Author(s):    J. Bartsch   C. Erb   A. Riehl   D. Uthoff   P. Franko Zeitz  

Abstract Details

Purpose:

Measuring the peripapillary RNFL is an important part of glaucoma routine diagnostics and enables high resolution images. This study examined whether an epiretinal membrane leads to mismeasurements of the peripapillary RNFL.

Setting:

Augenklinik Bellevue in Kiel/Germany

Methods:

119 eyes of 119 patients (46 m., 73 f.) were enrolled in the study. All patients underwent SD-OCT (Topcon 3D OCT 2000) with scans of the fovea and ring scans of the optic nerve head. Group 1 consisted of 67 patients with an epiretinal membrane (mean age 73.0 ± 7.35 years). Group 2 served as a control and included 52 patients (mean age 67.4 ± 11.5 years) without retinal or optic nerve head pathologies. The mean cup disc ratio (CDR) was 0.43 ± 0.24 in group 1 and 0.47 ± 0.24 in group 2 (p=0.39). No patient had glaucoma. Systemic diseases were distributed similarly between both groups. In group 1, 25 patients (37.3 %) had stage 0, 19 (28.4%) stage 1, and 21 (31.3%) stage 2 epiretinal membranes (Gass). 2 patients (3.0%) had vitreomacular traction. Differences between retinal thickness, RNFL, and measurement errors of different retinal layers were proven statistically significance by nonparametric tests.

Results:

The mean central retinal thickness was 347± 99 µm in group 1 and 230 ± 43 µm in group 2 (p<0.001). The mean RNFL in group 1 was 110 ± 20 µm in the superior, 86 ± 22 µm in the temporal, 119 ± 22 µm in the inferior, and 83 ± 20 µm in the nasal quadrant. In group 2, it was 113 ± 14 µm in the superior, 72 ± 11 µm in the temporal, 112 ± 20 µm in the inferior, and 89 ± 20 µm in the nasal quadrant. The differences were statistically significant temporally (p<0.001) and inferiorly (p=0.05). Errors in RNFL measurement occurred in group 1 in 24 of 67 eyes (35.8%), in group 2 in 1 of 52 eyes (1.9%). This difference was highly significant (p<0.001). Further, errors in RNFL measurement occurred in group 1 in 8 of 25 eyes (32.0 %) with stage 0, in 5 of 19 eyes (26.3%) with stage 1, and in 11 of 21 eyes (52.4%) with stage 2 epiretinal membrane.

Conclusions:

Eyes with an epiretinal membrane have invisible parapapillary changes. An epiretinal membrane leads to an overestimation of the RNFL in the temporal and inferior quadrants of the optic nerve head, which is caused by a mismeasurement of the RNFL in about one third of examined eyes. These findings could interfere with glaucoma diagnostics in eyes with both an epiretinal membrane and glaucoma. FINANCIAL INTEREST: NONE