Ever since I started performing eye surgery in 1993, I have focused on incorporating technologies and techniques that I feel have the greatest potential to improve patient outcomes. To achieve this, I continually evaluate the potential gains of a given technique against its potential effect on patient comfort during and after surgery. The largest factor in my decision is the probability that this new technique or technology will improve my patients’ quality of vision.
If patients do not fare better after surgery and outcomes are similar to those of other techniques, then I do not regard the change as beneficial enough to incorporate into my surgical skill set. For instance, I chose not to introduce phaco-chop maneuvers or bimanual microincision cataract surgery (MICS) techniques because I did not find them superior to divide-and-conquer techniques with coaxial MICS in terms of quality of vision for my patients.
One technology that I have recently evaluated and chosen to integrate into my practice is the ability to correct astigmatism with an IOL. Toric lenses have triggered a major shift in patient care because they achieve better outcomes in terms of visual quality and astigmatism correction. A case presentation of my coaxial MICS technique followed by toric IOL implantation can be viewed at http://eyetube.net/?v=kinot.
A 64-year-old woman presented with a grade 3 cataract and 3.20 D of existing astigmatism in her right eye. The decision was made to implant a one-piece AcrySof Toric IOL (Alcon Laboratories, Inc., Fort Worth, Texas) to reduce residual postoperative corneal astigmatism. After locating and marking the 0° and 180° corneal meridians with the Nuijts-Lane Pre-op Toric Reference Marker (AE-2791BL; ASICO, Westmont, Illinois), the patient was prepped for surgery. The eye was washed with betadine, and tetracaine preservative-free minims anesthesia was applied together with preservative-free lidocaine 2% gel. At the beginning of surgery, the appropriate axis for IOL alignment was marked with a surgical marker using the Mendez ring.
We performed standard microcoaxial phacoemulsification through a 2.2-mm incision. Incisions of this size produce a negligible amount of surgically induced astigmatism. In my hands, a 2.2-mm incision induces 0.38 D of corneal flattening on the incision axis. The AcrySof Toric IOL calculator takes the surgeon’s personal surgically induced astigmatism into account when calculating the desired toric component and alignment axis.
The IOL is implanted with the Monarch D cartridge (Alcon Laboratories, Inc.) if the total toric and spherical dioptric power is less than 28.00 D. For higher powers, a Monarch C cartridge can be used. The three hash marks located at the haptic-optic junction are positioned a few degrees counterclockwise from the intended axis. I wait until the haptics are deployed completely before removing the viscoelastic material from the anterior chamber and also from behind the IOL.
The IOL is then rotated clockwise with the I/A cannula until it is positioned in the right axis. The IOL should never be rotated counterclockwise if it is past the desired axis; it is better to continue the rotation clockwise 180°. Turning counterclockwise will trap the haptic in the capsule, and rotation will occur postoperatively when the haptic and capsule relax.
Once the IOL is in position, the I/A handpiece is retracted and the wounds are hydrated. As a last maneuver, if the hashmarks match the axis of astigmatism, I tuck the IOL against the posterior capsule to ensure exact alignment and avoid postoperative rotation. At the end of surgery, cefuroxime is delivered through the sideport incision. Lastly, I carefully check for any wound leakage and complete final hydration of the main incision and sideport wounds.
Postoperatively, this patient’s refraction was 9/10 (Snellen) without correction. She was happy with the result, and she decided to have the AcrySof Toric implanted in her other eye.
New techniques and technologies should always be evaluated before integrating them into your practice. I have found that the combination of coaxial MICS and toric IOL implantation provides appropriately selected patients with the best visual quality after surgery, and therefore it is my current treatment plan for any cataract patient who has astigmatism.
Johan Blanckaert, MD, is the Director of the Eye and Refractive Centre, Brussels, Belgium. Dr. Blanckaert states that he has no financial interest in the products or companies mentioned; however, he is a member of the speaker platform for Alcon Laboratories, Inc., and has conducted research for Novartis, Pfizer, and PhysIOL in the past 12 months. He may be reached at tel: +32 57 202300; e-mail: firstname.lastname@example.org.
- Do not remove the viscoelastic material from the anterior chamber or from behind the IOL until the haptics of the toric IOL are deployed completely.
- If the toric IOL is past the desired axis, it is better to continue rotation clockwise 180º rather than rotate it counter clockwise.
- Tuck the IOL against the posterior capsule if the hashmarks match the axis of astigmatism to ensure exact alignment and avoid postoperative rotation