Abstract
Purpose :
Ellipsoid zone (EZ) thickness has been measured by means of optical coherence tomography (OCT) technique. We measured EZ thickness obtained by high resolution mode-locked laser OCT in healthy eyes.
Methods :
In 31 eyes of 16 healthy subjects (12 males and 4 females with an average age of 33.3±7.3 y/o), longitudinal reflectance profile (LRP) was produced by measurements of luminance at 5 points (foveola, 0.5mm, 1.0mm nasal, or temporal from the foveola) in A-scans. Full width at 75% maximum in LRP was defined as EZ thickness. We developed the OCT system using 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).
Results :
The averaged EZ thickness values at 1.0mm, 0.5mm temporal from foveola, foveola, 0.5mm, 1.0mm nasal from foveola were 15.6±6.2μm, 16.5±5.2μm, 14.1±5.4μm, 17.2±7.2μm, 17.4±7.0μm, respectively. This result was almost equal to the report by Matsui, et al, using ultrahigh resolution SD-OCT (16.8±1.8μm,16.7±2.3μm,16.5±2.7μm,15.9±2.4μm,16.7±2.8μm,respecitively. Japanese Retina & Vitreous Society, Japanese Society for Ocular Circulation Joint Meeting 2015).
Conclusions :
Ellipsoid zone thickness measurements by high resolution mode-locked laser OCT don’t coincide with measurements by conventional SD-OCT, but coincide with those by ultrahigh resolution SD-OCT.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.