Femtosecond lasers can optimize the critical steps of cataract surgery (cataract incision, capsulotomy, and nucleus disassembly).1,2 Since 2008, I have had the opportunity to use OptiMedica’s Catalys™ Precision Laser System to create accurate, reproducible, and customized corneal and lenticular incisions for cataract surgery. This facilitates the subsequent intraocular steps of cataract surgery, but some adjustments to surgical technique are necessary.
The Catalys™ Precision Laser System treatment consists of 4 components:
- Plan: template-driven screens enable efficient treatment planning and customization in advance of the procedure.
- Engage: the patient’s eye is docked to the system with the Liquid Optics™ Interface. This novel patient interface stabilizes the eye and provides a clear optical path for OCT imaging, real-time video, and precise laser delivery by creating a wide field of view and eliminating the formation of corneal folds. Furthermore, the IOP rise is only 8-12mm Hg so that patients do not experience any discomfort or amaurosis, and subconjunctival hemorrhage is minimized.
- Visualize/customize: this is accomplished with Integral Guidance™ (INTEGRated ALgorithms). The anterior segment structures are visualized with 3D OCT imaging, and then sophisticated algorithms process the image, automatically and accurately detect surfaces, and create safety zones to maintain adequate distance from the posterior capsule and iris. The treatment plan is customized according to the patient’s ocular anatomy and the orientation of the eye (i.e., the system compensates for any lens tilt or decentration from docking).
- Treat: the ultrafast femtosecond laser, which utilizes pattern-scanning technology for precise pulse delivery to the intended location, completes the laser incisions in less than one minute, and total dock time is typically 2½ minutes. The Catalys is configured with a variety of lens fragmentation patterns to segment and soften the lens into grids of adjustable dimensions within each quadrant.
Observations about and suggested modifications to some of the intraoperative steps are as follows:
- Capsulorhexis: the resected capsular disc is usually free-floating. This is more easily visualized during injection of viscoelastic, which partially or completely elevates the disc off the lens surface. If the disc is not free-floating, then it should be grasped with forceps and removed with a circular motion similar to manual capsulorhexis technique in case there are any micro-adhesions.
- Hydrodissection: prior to injecting fluid, it is prudent to gently rock the lens to release cavitation bubbles so that capsular block does not occur. Less hydrodissection is required because of the partial pneumodissection created by the gas bubbles.
- Phacoemulsification: the lens segmentation creates exact cleavage planes and the lens quadrants are easily separated with minimal manual manipulations and evacuated as small aspiratable cubes with reduced ultrasound energy. On postoperative day one, laser treated eyes are noticeably quieter and the corneas much clearer.
- Cortex removal: the laser capsulotomy actually penetrates into the cortex and produces a smooth circular edge of cortex that is easily grasped with the I/A tip directly under the capsulotomy rather than having to probe far in to the bag recess under the iris for cortical remnants. This significantly facilitates removal of subincisional cortex.
- Lens implantation: the precisely sized and shaped capsulotomy also aids in IOL insertion. The centered capsulotomy facilitates IOL positioning and guarantees capsule overlap of the entire IOL optic edge for 360 degrees. Also, the stronger laser capsulotomy (demonstrated in porcine eyes) may be more resistant to tearing during IOL manipulations.
- Corneal incisions: perfect self-sealing and watertight wounds should also improve the safety of cataract surgery. Morever, the fs laser creates arcuate incisions of precise length, depth and location for more accurate astigmatism correction than what can be achieved manually.
The ability to make ideal self-sealing corneal wounds, to design arcuate incisions for precise astigmatic control, to produce a perfect capsulotomy with less deviation in effective lens position (ELP) for any IOL design, and to pre-cut the crystalline lens into numerous segments to reduce ultrasound energy and intraocular manipulations is remarkable. It has improved the safety and refractive outcomes of cataract surgery. Femtosecond laser devices have already begun to change the way we perform cataract surgery, and some adjustments in surgical technique will enable us to take full advantage of this incredible technology.
REFERENCES:
- Palanker DV, Blumenkranz MS, Andersen D, et al. Femtosecond laser-assisted cataract surgery with integrated optical coherence tomography. Sci Transl Med. 2010 Nov 17;2(58):58ra85
- Friedman NJ, Palanker DV, Schuele G, et al. Femtosecond laser capsulotomy. J Cataract Refract Surg. 2011; 37:1189-1198.
Related Articles
Femtosecond laser technology has revolutionized eye surgery. This technology ...
read more