Fundus angiography using Fourier-domain optical coherence tomography (FD-OCT) visualizes three-dimensional fundus microvasculature without fluorescence dyes. This method employs blood flow-induced change in the FD-OCT signal, to distinguish vessels from static tissues. Several methods for detecting blood flow using FD-OCT are reviewed; features of angiography by OCT and the current status of its development are also explained. Examples of fundus microvasculature imaging results are shown, and clinical application trials in ophthalmology are introduced.
Purpose: To evaluate changes in ciliary sulcus-to-sulcus diameter and crystalline lens measurements during accommodation, using ultrasound biomicroscopy (UBM).
Methods: Enrolled in this study were 11 eyes of 11 subjects, age 22 to 33 (27.7 ± 3.1) years, who had no history of ocular disease, except for refractive error. The patient’s left eye was corrected to emmetropia with a soft contact lens. UBM examination was performed in the supine position with fixation target placed on the ceiling, 1.9m above. Accommodation was stimulated with the addition of minus lens on the left eye; changes in the anterior segment of the right eye were recorded by the UBM with wide scanning field (VU-MAX-II).
Results: We confirmed significant changes in all parameters before and after accommodative stimulation. Mean change with −6D lens addition was −0.17 ± 0.12mm (sulcus-to-sulcus), 0.27 ± 0.1mm (lens thickness), −0.17 ± 0.06mm (anterior chamber depth), 2.28 ± 0.98mm (anterior curvature of crystalline lens) and −1.23 ± 0.66mm (posterior curvature of crystalline lens).
Conclusions: Changes in anterior segment and crystalline lens during accommodation were successfully measured by UBM with wide scanning field.
Purpose: To investigate the influence of glare light in peripheral visual field upon contrast sensitivity (CS) in healthy subjects.
Methods: The subjects were 13 healthy volunteers who accepted CS measurement. Measurement was performed using the contrast glare tester CGT-2000 (TAKAGI SEIKO), under photopic (background luminance: 100 cd/m2) and mesopic vision (background luminance: 10 cd/m2). Glare light was irradiated from a visual angle 12 degrees; its intensities were glare M (luminance: 40,000 cd/m2) or glare H (luminance: 100,000 cd/m2). Binocular CS without glare light was compared with glare M and glare H.
Results: Compared with binocular CS without glare light, there was no change between CS with glare light under photopic vision. On the other hand, CS significantly decreased with glare H under mesopic vision (ANOVA, Scheffé, p < 0.05).
Conclusions: We suggest that binocular CS decreases in the case of the highest intensity of glare light in the peripheral visual field under mesopic vision.
In this study, we evaluated the change in visual perception for specular reflections using binocular stereoscopic display. In our experiment, subjective evaluation was performed using both 2D and 3D images comprising a combination of both diffuse and specular reflection. Furthermore, the disparity angle between diffuse and specular reflection in the 3D images was changed in the depth-perceptible range. When the depth was hardly observed, the scores of visual perception for specular reflections were almost the same for both 2D and 3D images. On the other hand, when the depth was obviously perceived, the score of 3D images for specular reflections was stronger than the score of 2D images. This difference was observed even if the contrast between diffuse and specular reflection was changed. We confirmed that visual perception for specular reflection rose in the case of 3D representation when the disparity angle between diffuse and specular reflection was in the depth-perceptible range.