Biomedical Engineering Reference
In-Depth Information
as soon as experimental tests are able to prove preservation of capsular me-
chanical functions and clarity of refilled lens. Moreover, it would be important
for the feasibility of this technique, to demonstrate that a biocompatible valve
on the anterior lens capsule tissue could be set up to facilitate lens-refilling
operations.
To improve cataract surgery, thus providing a surgical solution to presby-
opia, some of us proposed a solution for performing a flap valve with the use
of a patch of capsular tissue obtained from a donor lens, to be laser-welded
onto the recipient capsule. The procedure may also be used to repair acciden-
tal traumas, such as capsular breaks or perforations during intraocular lenses
implantation [70]. Because of its particular fragility and elasticity, it is quite
impossible to suture capsular tissue using standard techniques; however, at
present there are no alternative methods. Laser welding could be used to ac-
complish this goal. The study is in progress, and preliminary evidence of the
feasibility of this technique has recently been obtained [55, 70].
Experimental tests were carried out ex vivo, on freshly-enucleated porcine
eyes (Fig. 15.7). Closure tests were performed by means of patches of donor
capsulae (mean diameter: 3 mm). The inner side of the patch was stained with
an ICG-saturated solution in sterile water (7% weight/weight). The staining
solution was left in place for 5 min. The sample was then washed with abun-
dant water, to remove any excess of ICG. The stained patch was then applied
to the anterior lens capsule, through a previously performed corneal incision.
Fig. 15.7.
An ICG-stained capsular patch was welded onto the anterior lens capsule
of a pig eye. Laser spots are clearly evident at the periphery of the patch
