I have embraced the concept of toric IOL implantation since these lenses became available in Europe in 2006. Today, more than 50% of the IOLs I implant in Greece are aspheric torics (AcrySof IQ Toric; Alcon Laboratories, Inc.). Results have been extremely rewarding, even in the presence of 1.00 D of astigmatism; however, there is still potential for a clear corneal incision to induce astigmatic changes that can affect the quality of vision after cataract surgery. One way to minimize these topographic changes is to introduce laser-assisted cataract surgery in conjunction with toric IOL implantation.
CONSISTENT INCISIONS
One advantage of using a femtosecond laser for cataract surgery is that corneal incisions and capsulotomies are always of consistent size and shape. In my practice, the LenSx Laser System (Alcon Laboratories, Inc.) is used to create a 2.8-mm incision, a 5.0-mm capsulorrhexis, and a lens fragmentation circle 4.8 mm in diameter. In the technique we have developed, the anterior capsule is removed after capsulorrhexis, and then an ophthalmic viscosurgical device (OVD) is used to open the four-meridian nuclear dissection created by the LenSx laser. After the four nuclear pieces are separated, some OVD is burped out of the eye, and hydrodissection is performed. In many cases, one quadrant pops into the anterior chamber during the hydrodissection, increasing the efficacy and safety of lens evacuation.
At the conclusion of surgery, a toric IOL is implanted on the chosen axis, aligned to marks that were previously placed, guided by one mark placed at the 6-o’clock position at the slit lamp. If astigmatic keratometry is to be performed, this mark can also be used as a reference when placing the patient interface of the LenSx laser, as well as to place the two access markers for the toric lens.
PHACO ENERGY NO LONGER REQUIRED
The latest enhancement to my procedure is the Cetus Nd:YAG laser (A.R.C. Laser), which creates a plasma resulting in a shockwave that emulsifies the lens. This addition has allowed me to complete several cases with no phaco energy. A video demonstration of emulsification with the laser can be viewed at eyetube.net/?v=dodiq. The probe does not need to be cooled, and there is adequate direct suction at the tip opening. Additionally, the 0.9-mm stylus of the probe provides tremendous grasp and followability of the nuclear pieces.
A contralateral eye study is being conducted to compare surgical results using the LenSx Laser System and the Infiniti Vision System (Alcon Laboratories, Inc.) in one eye with the LenSx Laser System and the Cetus laser in the other. Thus far, with the latter combination, the average ultrasound energy is 6 J with the laserphaco combination and fewer than 3 J with the laser-laser combination. This could potentially reduce endothelial cell loss and corneal wound damage associated with ultrasound energy.
CONCLUSION
In one line, the take-home message is that the best way to address astigmatism is with all-laser, bladeless cataract surgery and implantation of a toric aspheric IOL.
A. John Kanellopoulos, MD, is the Director of the LaserVision.gr Eye Institute in Athens, Greece, and is a Clinical Professor of Ophthalmology at New York University School of Medicine. He is an Associate Chief Medical Editor of CRST Europe and states that he has no financial interest in the products or companies mentioned. He may be reached at tel: +30 21 07 47 27 77; e-mail: ajkmd@mac.com.
