Abstract
Purpose: :
Intermediate uveitis is often accompanied by morphologic changes in the central retina such as the formation of epiretinal membrane or macular edema (ME) that is used to evaluate the effectivity of treatment. Imaging techniques should provide fast, precise and reliable information. This study was conducted to investigate which device is the most suitable to detect retinal changes with respect to inter-observer reliabilty.
Methods: :
We selected a group of 17 patients from a randomized study comparing Interferon or Methotrexate for the treatment of ME secondary to intermediate uveitis. The 3 imaging methods (Stratus OCT / Zeiss, HRT Retina Module and Spectralis OCT / Heidelberg Engineering) were performed on the same day. Images were blinded and then evaluated by two independent, experienced observers in 5 separate steps. Furthermore, images of healthy controls were mixed in. The first 4 data sets presented only partial results. Only in the 5ths and last data set obtained with the 3 methods the complete imaging information of each subject was provided to the examiner.
Results: :
A total of 44 eyes were examined. The comparison of the 5 different data sets showed that the less information was given the more inter-observer variability occured. E.g. when only vertical and horizontal scans were shown, observer 1 detected pathologies in 87% of the Spectralis scans and 71% in the stratus whereas observer 2 in 50% with both techniques. Variability was highest when only the thickness maps were shown: pathologies detected in 26/71% with Spectralis, 41/59% with Stratus and 32/41% with the HRT. Variability decreased the more information was presented. When 6 scans of the retina map were shown: pathologies detected in 60/67% with the Spectralis and 40/41% with the Stratus. Especially epiretinal membranes were more frequently seen with the Spectralis.
Conclusions: :
Patients with intermediate uveitis present specific challenges to the currently used imaging techniques. In this study the results of OCT were less affected by intraocular opacities and eye movement and provided more precise and reliable information compared to the measurements by means of HRT. Evaluating all scans leads to enhanced detection of abnormalities and good inter-observer agreement. Especially thickness maps may be misleading if looked at alone. Pathologies, especially epiretinal membranes, were more frequently detected with Spectralis. Further statistical analysis will show the differences between Stratus and Spectralis OCT in this cohort.
Keywords: imaging/image analysis: clinical • macula/fovea • edema