Outflow facility in isolated porcine eyes after creation of an intrascleral canal by injection of stabilized hyaluronic acid
Nikolaos Mavrakanas 1*
and
Tarek Shaarawy 1
1 Ophthalmology Department, Geneva University Hospitals, Glaucoma Surgery Research Laboratory, Geneva, Switzerland
* To whom correspondence should be addressed. E-mail: nikolaos.mavrakanas{at}hcuge.ch.
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Abstract |
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Purpose: To investigate outflow facility in isolated porcine eyes after creation of an intrascleral canal by injection of stabilized, non-animal, hyaluronic acid gel (NASHA).
Methods: Outflow facility of 60 porcine eyes was measured after creation of an intrascleral canal into the anterior chamber by injection of NASHA gel using 6 different combinations of needle size (21,23,27G) and canal length (4,6 mm). 10 eyes were tested in each of the 6 subgroups and an additional 10 eyes were controls. After cannulation of the anterior chamber and adjustment of the inflow rate to achieve a stable pressure of 10 mmHg, an intrascleral channel was created by injection of NASHA gel. The inflow rate was then increased to achieve a stable pressure of 20mmHg, and then again adjusted to maintain a stable pressure of 30 mmHg.
Results: A significant increase in outflow facility was found between the control group and the NASHA gel injected group (60 eyes) for both 10-20 mmHg and 20-30 mmHg pressure change (p<0.001). Increase in outflow facility was independent of the canal lengths and the needle sizes used for both 10-20 mmHg (p=0.82) and 20-30 mmHg (p=0.99) pressure change.
Conclusion: A single ab externo intrascleral canal created by injection of NASHA gel increases the outflow facility in isolated porcine eyes. This appears to be a potentially promising new technique for lowering intraocular pressure. It remains to be seen if these positive results can be reproduced for significant periods of time in humans.
Key Words:
aqueous flow, glaucoma surgery, hyaluronic acid
