Abstract
Purpose :
To present the feasability and quantify the diameter and the collateral damage of sclerostomy using a new laser fibre and different pulse energies of the picosecond infrared laser system
Methods :
Freshly enucleated porcine globes were obtained from a local slaughter and refrigerated (4° Celsius) until the operation in the afternoon. The sclerostomies presented here are a result of laser ablations with a sapphire optical fibre coupled to the picosecond infrared laser system PIRL-HP2-1064 OPA-3000 (Attodyne Inc., Canada). The PIRL output was defined for a wavelength of 3000 ± 90 nm and a pulse duration of 300 ps.
Immediately after the intervention, eyes were fixed in phosphate-buffered 3.5% formaldehyde. For subsequent histological analysis the eyes were cut into 4μm thick sections, and stained with hematoxylin and eosin (H.E., Merck, Darmstadt, Germany). Stained samples were then scanned using MIRAX SCAN (Carl Zeiss Microimaging GmbH, Jena, Germany).
Furthermore we made electronmicroscopic images of the channel using the Environmental scanning electron microscopy (ESEM).
Results :
We used different pulse energies 150 μJ (N= 4), 175 μJ (N=6), 200 μJ (N=7) and 250 μJ (N=6).
The area of PIRL- FAST depending on the different pulse energies vary from 19591,81 ± 5028,18 μm2 (150 μJ) to 28444,16 ± 8294,81 μm2 (250 μJ). The area of PIRL- FAST was significant larger using the highest pulse energy (250 μJ) than using the smaller pulse energies.
The collateral damage zone (CDZ) was defined as atypical surrounding tissue. Those sclerostomies, being treated with 250 μJ presented significant more collateral damage zone depending on the created FAST than the other groups.
ESEM results reveal circular smooth sclerostomy wall with only minimal change of tissue ultrastructure.
Conclusions :
PIRL-FAST using sapphire fibre is a new tool to provide robust microinvasive stenting from the anterior chamber to the subconjunctival space. Since the PIRL has proven to work efficiently in several tissues with minimal scar formation these first proof of principle experiments might pave the way for a new minimal-invasive glaucoma surgery strategy. We have already initiated experiments to analyse the wound healing and scar formation in vivo.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.