Microincisional Cataract Surgery
BY ROBERT M. KERSHNER, MD, FACS
Techniques for optimizing refractive results are within our grasp.
Bigger is not always better, at least not where cataract surgery is concerned. The popularity of refractive procedures to eliminate or reduce the need for glasses has led patients to expect—even demand—faster and smaller incisions, quicker recovery, and better visual outcomes from their cataract procedure. With the explosion of new technologies and techniques, microincisions and high-tech IOLs provide the simplest and most reproducible route to full visual correction with cataract surgery. This approach also holds promise for the correction of presbyopia.
Because today's cataract procedure uses small (less than 2.5-mm) incisions, it is more safe, consistent, and more predictable than ever. Due to the development of laser phaco, phakonit, and other advanced technologies, the size of cataract incisions is rapidly approaching 1 mm or smaller. These microincisions are positioned on the clear cornea, which precludes the need for conjunctival dissection, cautery, sutures, the injection of anesthetics, bandaging, and the postoperative restriction of patients’ activities. In addition, microincisional cataract surgery has all but eliminated the complications of wound leak, uveal prolapse, and surgically induced astigmatism.
These advances have paved the way for faster, more efficient surgery with less instrumentation, less intervention, and better uncorrected visual recovery for the patient. In turn, the superior visual results patients have achieved through IOL correction of their preexisting myopia, hyperopia, and astigmatism (with or without arcuate keratotomy incisions) has translated into fewer complications and less worry for the surgeon.
I have developed and adhered to a single-incision, single-instrument approach to cataract surgery that involves: (1) the smallest possible clear corneal microincision; (2) the simultaneous correction of spherical and astigmatic errors with refractive keratotomy and toric IOLs; (3) in-the-bag phacoemulsification with a mini-phaco-flip maneuver; and (4) the injection of the IOL through the unenlarged microincision. Patients’ visual results and immediate, unrestricted recovery have been made possible by improved tools for incision construction, newer high-tech viscoelastics, and advanced-technology IOLs that reduce spherical aberration, improve UCVA, and can be implanted through increasingly smaller incisions. The refractive outcomes achieved by following these techniques are the best we have ever achieved, and, with incision sizes approaching 1 mm, this technology holds promise for even greater advances in the near future.
All my cataract surgery patients undergo a comprehensive, preoperative ophthalmic evaluation. When devising a surgical plan, I take into consideration the patient’s cycloplegic refraction, combined with corneal topography and ultrasonic biometry, in order to select the best surgical approach and the ideal IOL for complete refractive correction.
I use topical anesthesia with self-fixation to stabilize the eye as I place the incision. I position the Kershner Reversible Eyelid Speculum (Rhein Medical, Tampa, FL) under the eyelid margins, away from the incision site. I then locate the steep meridian and make the incision with the Becton Dickinson Clear Cornea Incision System (BD Ophthalmic Surgery, Waltham, Mass) using an accurate depth blade or 600 microns and a 2.5-mm keratome. It is important to keep the cornea dry when creating the incisions. Rather than irrigate with BSS, I apply a single drop of 2.5% hydroxypropylmethylcellulose to the corneal surface after creating the incisions to protect the cornea, keep it clear and moist, and provide 1.5 X magnification.
Capsulorrhexis, Hydrodissection, and Phacoemulsification of the Lens
I inject a hyaluronate viscoelastic (Healon and Healon 5; Pharmacia, Peapack, NJ) into the anterior chamber to flatten the capsule and reduce zonular stress during capsulorrhexis.
The Kershner One-Step Micro Capsulorrhexis Forceps (Rhein Medical) creates a 5-mm, round, central capsulotomy through a 125 micron incision. I perform hydrodissection with a Binkhorst cannula and BSS irrigation (Alcon Laboratories, Ft. Worth, TX) to loosen the subincisional cortex prior to phacoemulsification. I execute in-the-bag, three-step, single-incision, single-instrument phacoemulsification with a 30º tip, phaco power at 20%, maximum vacuum at 500 mm Hg, and an aspiration rate of 25cc/min. Before rotating the lens, I perform central sculpting deeply and widely.
Next, I press the phaco tip on the superior pole of the nucleus, flipping it inside the capsular bag while I remove the remainder of the lens. I remove residual cortex with the Kershner Clear Corneal I/A Tip (Rhein Medical, Tampa, FL) and irrigate all lens epithelial remnants out of the capsular bag. I then inflate the capsular bag with Healon to open the capsular rim without overinflating the anterior chamber of the eye. I place a single bolus of Healon5 at the center of the capsule to facilitate unloading of the lens.
Injecting the IOL
I prefer the three-piece, silicone CeeOn Edge 911A lens (Pharmacia, Peapack, NJ), the aspheric Tecnis Z 9000 IOL (Pharmacia), or the silicone Toric IOL (STAAR Surgical, Monrovia, CA) for full refractive correction. I load the IOL into the injector shuttle, pass the lens through the incision into the capsular bag at the proper meridian, and insert the IOL without additional manipulation.
Surgeons have within their grasp the techniques for optimizing the refractive results of their cataract procedure. Today, we can fully correct refractive error with cataract removal and IOL implantation, and do so with minimal intervention and virtually no interruption in the patient’s normal routine. Microincisional cataract surgery has made the procedure faster, with quicker recovery and better UCVA than previously possible. Patients are seeing that smaller is better and expect nothing less from their surgeons.
Robert M. Kershner, MD, FACS, is Director of the Eye Laser Center, Suite 303, 1925 West Orange Grove Road in Tucson, Arizona. Dr. Kershner holds no financial or proprietary interest in any of the techniques or instruments mentioned herein. He may be reached at (520) 797-2020; firstname.lastname@example.org.
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Figure 1. The disposable Becton Dickinson Clear Cornea Incision System (BD Ophthalmic Surgery) may be used to create the proper corneal incisions for cataract surgery.
(See CD-ROM QuickTime Movie: 1KershnerIncision.mov)
Figure 2. The author facilitates creation of the capsulorhexis with Healon5 (Pharmacia) and the Kershner One-Step Micro Capsulorrhexis Forceps (Rhein Medical). (See CD-ROM QuickTime Movie: 2KershnerInjectH5.mov and 3KershnerCapsulorhexis.mov)
Figure 3. The author performs phacoemulsification with a single-incision, single instrument approach.
(See CD-ROM QuickTime Movie: 4KershnerHydrodissection.mov, 5KershnerPhaco.mov)
Figure 4. The IOL is aligned with the steep meridian and injected into the capsular bag.
(See CD-ROM QuickTime Movie: 6KershnerFillBag.mov, 7IOLInjection.mov)
Figure 5. The remaining viscoelastic is removed with I/A.
(See CD-ROM QuickTime Movie: 8KershnerIA.mov)