gms | German Medical Science

Purpose: Intermediate uveitis is often accompanied by morphologic changes in the central retina. Chronic ME threatens visual acuity and is used as a common indicator to evaluate the efficacy of treatment. Fluorescein angiography has widely been replaced by non-invasive and faster imaging methods. In general imaging techniques should provide fast, precise and reliable information. This study was conducted to investigate which device is the most suitable to detect macular pathologies in clinical practice with respect to inter-observer-variability.

Methods: We chose 17 patients with intermediate uveitis who at a point had suffered or were still suffering from uveitic macular edema and other retinal morphologic changes. They were examined on the same day with all three methods: Stratus OCT (Zeiss), HRT Retina Modul and Spectralis OCT (both Heidelberg Engineering). For further evaluation 5 healthy controls were mixed in. Images were blinded and then evaluated by two independant observers in 5 separate steps, in the first 4 only showing partial results, eg a single horizonatl scan or the 9 zones thickness maps only. In the 5th and last complete data obtained with the three methods of each subject was shown. Kappa Values for inter-observer variability were calculated.

Results: A total number of 44 eyes were examined. The comparison of the five different data sets showed that the images containing only partial information like a single horizontal scan or thickness maps were associated with a higher inter-observer variability. Regarding the correct recognition of healthy volunteers inter-observer agreement was excellent for both types of OCTs in steps 2, 3 and 5 and inter-observer agreement was still good for the HRT Retina Module in step 4. Inter-observer-agreement was generally higher detecting macular edema compared to epiretinal membrane. For both the pathologies the Spectralis OCT proved the best values for inter-observer-agreement.

Conclusion: Looking at detailed pathologies both OCT machines gave better inter-observer agreement, with the highest agreement in the Spectralis. OCT was shown to be superior to HRT, but laser scanning technology is a good screening tool detecting pathologic from normal. Evaluating all scans leads to better detection of abnormalities and inter-observer agreement. Especially thickness maps may be misleading if looked at alone.