Abstract
Purpose :
Foveal avascular zone (FAZ) area has been measured by means of femtosecond mode-locked laser optical coherence tomography (OCT) that we developed. We measured FAZ area using en-face images obtained by this OCT in healthy eyes.
Methods :
In right eyes of 10 healthy subjects (8 males and 2 females with an average age of 35.6±7.8 y/o), a total of 300 macular single B-scans (3 mm x 3 mm) centered on the foveola were obtained in 10-μm steps using high resolution mode-locked laser OCT installing an ultra-broadband Kerr lens mode-locked Ti:Sapphire laser and a wideband spectrometer. The spectral bandwidth of the light source was 200 nm full-width at half maximum at a central wavelength of 840 nm. A high-speed CCD camera with 2048×300 pixels (Basler, Ahrensburg, Germany) was used as the detection system. The measurement speed was 50,000 depth-scans/s, and depth resolution was measured to be less than 2.0 μm into the tissue (Kuroda H, et al, Applied Physics Letters 2013). Three-dimensional images were rendered from these image sequences to obtain 2-μm thin slice en-face images of macular area. The nasal and temporal distances from foveola to the nearest vessels in the superficial ganglion cell layers were measured.
Results :
The FAZ areas in the superficial ganglion cell layer could be apparently observed in the en-face images thus obtained. The averaged distances from the foveola to the nearest nasal and temporal vessels were 242.0±48.9μm and 262.0±86.3μm (N=10), with no significant difference, respectively, and the mean horizontal FAZ diameter was 504.0±127.2μm. The current result was compatible with those reported using OCT angiographic technique, for example, 573±177μm in healthy eyes (Freiberg FJ, et al, Graefes Arch Clin Exp Ophthalmol 2015).
Conclusions :
En-face images need short aquisition time and exact 3-D images can be structured in the femtosecond mode-locked laser OCT that we developed. FAZ area can be measured by means of this OCT .
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.