Abstract
Abstract: :
Purpose: To evaluate a noninvasive technique to detect the leakage point of central serous chorioretinopathy (CSR), using a polarimetry method. Methods: We prospectively examined 21 eyes of 21 patients with CSR. Images of 256 x 256 pixels were digitized using a scanning laser polarimeter (GDx–N, Laser diagnostic technologies), with scanning polarized light at 780 nm. A depolarized light image was computed from the portion of the light that was unmodulated for each pixel, for the crossed detector. Birefringence images, parallel polarized light images, and average reflectance images were also computed. Image Grading: For better visualization, distribution of intensities in each image was adjusted: minimum to maximum intensities in the images were converted to a grayscale that ranged from 0 to 256 grayscale units. Objective evaluation: We calculated edge contrast without adjustment of intensities. We selected one leakage point per eye. The average intensity of a 4 × 4 pixel region of retina for the leakage point was calculated, and the average intensity of the same size region adjacent to the feature was also calculated. Michelson contrast was calculated using these intensities. Results: In all eyes, leakage points could be clearly visualized as bright spots in depolarized light images. Michelson contrasts of the leakage area were 0.61 ± 0.26 (depolarized light), 0.14 ± 0.23 (birefringence), 0.10 ± 0.11 (parallel polarized light), and 0.19 ± 0.12 (average reflectance). Michelson contrasts for the leakage point in depolarized light images were significantly higher than for the birefringence images, parallel polarized light images, and average reflectance images from the same raw data set (P < .0001, for all tests, paired t–test). Conclusions: Polarization – sensitive imaging could readily localize the leakage point in CSR. This may assist with a rapid, noninvasive assessment of CSR.
Keywords: imaging/image analysis: clinical • retina • laser