Abstract
Purpose :
Feasibility study for targeting Schlemm’s canal (SC) and overlying trabecular meshwork from across the anterior chamber without a goniolens or contrast agent by using an infrared laser based fiberoptic PCI to enable goniolens free Excimer Laser Trabeculostomy (ELT) MIGS surgery.
Methods :
After determining the wavelength with the greatest transmission through the sclera of porcine eyes was determined by spectroscopy, an apparatus was built. This device uses a laser based time domain (TD)PCI-interferometer, driven by a linear motor (PI-type M-663) with a spatial resolution of 0.1 μm in the reference path and a GRIN fiber (GIF625-10, Ø62.5 µm Core,Ø125 µm Cladding, 0.275 NA,) in the measuring path, a SLD (1300nm) with a bandwidth of 85nm and a detector, all of which were linked via computer. A model was then created to simulate SC within sclera: a piece of fresh porcine sclera was split and a spread of oil was inserted within the split sclera. This sclera/oil /sclera sandwich was then evaluated from varying distances with the apparatus to determine whether the tissue borders could be identified. The system was optimized by a polarization controller in the measuring path and various means of focusing and collimating the laser light.
Results :
The wavelength with the greatest transmission through the sclera is +/- 1300 nm. The SNR was 68dB, the measuring depth averaged 18mm and the resolution was 9µm. All surfaces of scleral sandwich are clearly detectable.
Conclusions :
Schlemm’s canal location distal to the trabecular meshwork could be feasibly determined from within the eye by fiberoptic PCI. Improving the SNR will better enable such tissue recognition and localization in a human eye.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.