Abstract
Purpose: :
To demonstrate ability of high resolution, high speed OCT for visualization and analysis of serous fluid accumulated under neurosensory retina of patients with confluent drusen.
Methods: :
Tomographic images were obtained by the prototype high-resolution SOCT system developed and constructed at Nicolaus Copernicus University, Poland. The instrument provides three-dimensional images with 4.5 µm axial and 15 µm transverse resolution, and acquisition speed of 25 000 axial lines per second. The reconstruction of the outer retina structure was performed with the use of custom-designed automated segmentation software enabling flattening of SOCT cross-sectional images and creating contour maps of RPE-IS/OS thickness, RPE topography and IS/OS topography. Additional modeling and visualization was performed with the aid of Amira 4.1 (Mercury Computer System, Inc). The 3-D OCT reconstruction of the outer retina along with contour maps were compared with FA, ICGA and fundus-related microperimetry. Seventy four eyes of 57 patients with soft confluent drusen were included in the study. Examination took place at Department of Ophthalmology, Nicolaus Copernicus University.
Results: :
The hyporeflective dark space beneath the neurosensory retina consistent with fluid collection overlying drusen was found in cross-sectional OCT images of 11 patients from the group of 57 patients. FA and ICGA did not show any signs of CNV in these subjects. Microperimetry displayed a decrease in retinal light sensitivity at the site of coalescent drusen. 9 patients who were followed up were found to have nothing but confluent drusen during the entire observational period. Five patterns of changes in fluid quantity overlying drusen were observed over time. The amount of fluid either remained unaltered, increased or decreased. There were also cases where focal change with fluid appeared or completely disappeared. Selected representative cases of all five patterns will be presented.
Conclusions: :
This study has demonstrated that soft confluent drusen can be accompanied by fluid accumulation under the sensory retina. This fluid is hypothetically not due to continous exudation from new blood vessels and can be visualized as structural rather than functional change. Therefore, we believe that it possible to visualize this fluid only by high resolution, 3-D OCT imaging.
Keywords: age-related macular degeneration • drusen • imaging/image analysis: clinical