Abstract
Purpose :
Accommodating Intraocular Lenses (AIOLs) require a strong engagement of their haptics to the equatorial region of the emptied capsular bag in order to capture the forces from the ciliary muscle and change their surface shape and power. We recently demonstrated a photobonding method (Marcos et al. IOVS 2015) by which strips of capsular bag became strongly bonded to pHEMA polymer extraocularly. Here we present intraocular bonding of commercial IOL to capsular bag using Rose Bengal-Green light photobonding (RGP).
Methods :
Phacoemulsification (Laureate, Alcon) was performed in porcine cadaver eyes (<24 h post-mortem) through a 5-mm diameter anterior lens capsulorhexis. An Akreos IOL (B&L, pHEMA-MMA material) was inserted in the capsular bag, and kept in contact with the anterior capsular bag. Contact of the two surfaces was achieved by continuous air infusion into the anterior chamber of the eye, which provided sufficient pressure at the interface and oxygen, required in the photobonding chemical reaction. The capsular bag and the IOL were stained with 0.1 mL of a 0.1% solution of photosensitizer Rose Bengal in 0.01M phosphate buffered solution. A 1-mm diameter fiber-optic probe connected to a custom-made lamp provided with a diode-laser (532 nm) was inserted through a 1.5 -mm corneal incision and used to locally irradiate the capsular bag- IOL interface. The laser irradiance ranged from 10 -20 W/cm2 at the exit of the fiber probe and was applied during 2.5 - 7 minutes intraocularly, in different essays. After irradiation, the cornea was removed and the eye with the photobonded IOL was mounted in an uniaxial stretcher to assess the bonding breaking load.
Results :
We found that irradiance/time of 20/2.5 &10/7 W/cm2 /min were sufficient for the IOL-capsular bag intraocular photobonding to happen. In the stretcher, the breaking force was above 0.12N, higher than the accommodating forces of the ciliary muscle (net force of 0.08N around the entire equator). The zonulae broke before the IOL-capsular bag bonding, suggesting that the bond would eventually resist the stretching of the ciliary muscles.
Conclusions :
Photobonding (RGP) of the capsular bag and IOL polymer material can be achieved intraocularly, in a cataract surgery procedure, compliant with the natural ciliary muscle stretching mechanisms. This technique will enable function of AIOLs without relying on capsular bag integrity or natural haptic fibrosis.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.