One-year results for the CAPSULaser, a thermal laser that fits under a surgical microscope, show the device can make a perfectly round, precise capsulotomy in about 1 second.
Though still in development, the device is touted as the next generation in laser cataract technology, as it is expected to be less expensive and more convenient than a femtosecond laser. This video presented by Dr. Pavel Stodulka at ESCRS 2016 demonstrates the advantages of the CAPSULaser over femtosecond lasers, as well as promising early clinical data from 50 eyes.
Dr. Richard Packard also presented data at ESCRS from more than 200 eyes showing no adverse effects from the CAPSULaser. All capsular buttons were free, there was no pupillary miosis after the laser was applied and no increase in anterior chamber inflammation postop. In 20 patients with more than 12 months of follow-up, all corneas were clear, endothelial count was normal, there was no contraction of the capsule and no IOL decentration. Dr. Packard added that the device was also used successfully in patients with intumescent cataract.
The CAPSULaser uses wavelengths in the red/orange part of the spectrum. Because the laser fires continuously, not in a pulsed mode like the femtosecond laser, and is scanned in a single circular pattern to create the continuous curvilinear capsulotomy, it creates a smoother capsulotomy.
In contrast to a femtosecond laser, which requires a separate room in most cases, the box containing the CAPSULaser simply bolts to the underside of the operating microscope and is used only for making a capsulotomy.
The technique begins with trypan blue to stain the anterior capsule and create a selective target for the laser. The laser beam is focused onto the capsule with a specially designed contact lens with fine ridges on its under surface to help stabilize the globe. The patient stares at a fixation light to help centralize the area to be irradiated on the visual axis and the laser is fired.
As the laser is scanned in a single circular pattern, the laser energy facilitates the molecular phase change of the capsular collagen from Type IV to elastic amorphous collagen, creating a capsulotomy with a rim that has a high degree of elasticity and tear strength associated with the amorphous collagen.
Because amorphous collagen is more elastic than normal capsular collagen, the known effect of trypan blue to decrease capsular elasticity is counteracted. Dr. Packard said the effects of this collagen conversion and its interaction with trypan blue have been shown in animal studies.
Dr. Packard also noted that new IOLs are being developed to take advantage of perfectly round, consistent and central capsulotomies, which may allow better centration, potentially reduce negative dysphotopsias and improve effective lens position predictability.