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Up Front | Nov 2002

Treating High Hyperopic Astigmatism

A clear lensectomy with piggyback lenses offers a patient-friendly solution.

The refractive combination of high hyperopia with high keratometric astigmatism is difficult to treat. In addition, there are not many suitable options to offer such patients presenting with this condition. I am uncomfortable performing LASIK on patients who have greater than 4.0 D of hyperopia, and I find myself treating more and more of these patients with PRELEX. Last year, I developed a procedure of piggybacking the STAAR toric IOL (STAAR Surgical Company, Monrovia, CA) in the bag with an Array multifocal lens (Advanced Medical Optics, Inc., Santa Ana, CA) in the sulcus, and I have been extremely pleased with the results so far. The 3.5-D STAAR lens corrects about 2.2 D of astigmatism. I have also added limbal relaxing incisions at the time of the initial surgery if needed.

Initially, my colleagues and I collected information on seven consecutive patients (14 eyes) who underwent the surgery beginning July to November of 2001. Subsequently, I have treated approximately seven additional patients and I am looking for more. To date, we have had no major complications, and therefore I find no reason not to perform this procedure.

There have been minimal complications using this dual lens technique both with or without relaxing incisions in our group of 14 patients. We have had two toric lens rotations, which we easily fixed by returning the patient to the OR and rotating the lens into the proper position with a Lester hook (Katena Products, Inc., Denville, NJ) through a sideport incision under topical anesthesia. A somewhat unexpected complication involved two patients who had decentered Array lenses. We observed these at the slit lamp the first postoperative day. The amount of the decentrations was between 0.5 mm and 1.0 mm. Although both patients had fairly good vision, they also had significant glare and visual distortion. We easily fixed these problems by taking the patients back to the OR and simply rotating the lens with a Lester hook through a sideport incision approximately 45º to 90º. I theorize that this decentration occurred because the haptic loops became caught in the zonules, or perhaps the ciliary sulcus is not perfectly round. Therefore, it is imperative when placing the Array lens in the sulcus not to assume that it will automatically center once the trailing haptic is placed in position. I always make sure to rotate the lens in the sulcus before finishing the case.

Preoperative assessment of the pupil is important. Many patients' pupils, due to near reflex and bright lighting conditions, are too small to permit reading under most conditions in daily life. The surgeon must identify these patients preoperatively and advise them that they will certainly need reading glasses at least some of the time. Presently, I ask patients to literally focus on my nose while I stand in front of them under bright lighting conditions and personally measure their pupil size. If their pupils measure 3.0 mm or less, I perform approximately seven tiny sphincterotomies to enlarge their pupil (see sidebar). To date, performing sphincterotomies has proven quite successful when utilized on high hyperopic astigmatism patients and PRELEX patients. In addition, the surgeon must preoperatively advise the patient of the risk of a halo effect, although I find that most hyperopic patients are fairly tolerant of halos because they have experienced them with glasses and contact lenses. It is also important to tell patients that there is a 5% chance that the STAAR toric lens will rotate and may have to be repositioned. Additionally, I tell my patients that because they are so severely hyperopic, there is approximately a 10% chance we may have to perform a lens exchange if we insert the wrong power. So far, our piggyback procedures have been amazingly accurate, but I am not yet ready to reduce this 10% prediction for the patient.


Selecting the Lens Power
First, I use the Holladay formula to determine the overall lens power needed in the patient's eye. In surgery, I will implant the STAAR toric lens in the bag first, using 10.0 to 11.0 D. I then place the remainder of the power in the sulcus with the Array lens. Locat-ing the Array in the sulcus in-creases the lens' effective power, which has worked quite well up to about 30.0 D. Above 30.0 D, I may add another 1.0 D to the Array if, for example, the Holladay formula calls for a +34 or +36 lens. If the patient's keratometric astigmatism is greater than 2.2 D, I will place limbal relaxing incisions in the steep meridian at a depth of 0.6 mm. If you must replace the Array lens because of a power error, it is easy to retrieve from the sulcus.

Using a Peribulbar Block
I prefer to give patients peribulbar blocks when performing this procedure. I have performed it under topical anesthesia, but the procedure is lengthened somewhat and I have had a couple of severely photophobic patients who persuaded me to abandon topical. Before administering the block, a technician marks the limbus at the 6-o'clock meridian. I prefer to tape the lids and avoid speculums that can cause positive pressure. If I plan to create relaxing incisions, I will mark the proper axis using a Mendez ring and make those incisions. Temporally, I will create a 2.8-mm near limbal incision with a sideport incision to the right (because I am a left-handed surgeon). If the relaxing incisions were in the horizontal meridian, of course I will enter through them. The sideport incision must be made large enough to hold a chamber maintainer, which I will discuss later. Next, I inject OcuCoat viscoelastic (Bausch & Lomb Surgical, San Dimas, CA) into the eye and also layer it over the cornea to improve visibility and hide corneal striae.

Lensectomy and Lens Insertion
I remove the lens in the usual manner: by performing a capsulorhexis followed by hydrodissection, phaco-emulsification, and I/A. Following the lensectomy, I immediately and easily insert the STAAR Toric IOL (3.5 D) in the bag without viscoelastic (STAAR has a lower-powered lens, 2.2 D, but I never use it. I feel that if the patient requires only that amount of power, I should perform relaxing incisions.). Next, I rotate the lens to the proper meridian and then insert the chamber maintainer in the sideport incision. With the chamber maintainer opened wide, I insert the Array multifocal lens into the ciliary sulcus and then remove any excess viscoelastic that seeped in through the inserter. As mentioned above, I rotate the lens 45º and check its centration. To finish, after ensuring that the Toric lens is where I left it, I inject BSS (Alcon Laboratories, Fort Worth, TX) through the sideport incision to help close the no-stitch incision.

With this procedure, I am trying to help some of the most difficult ophthalmic patients and severely farsighted individuals with high keratometric astigmatism. So far, this piggyback technique has hit a home run with almost all of the cases I have treated on the first attempt. I enjoy being able to help these patients because many of them have had to wear severe-looking glasses as a result of their condition. These patients' postsurgical results are almost immediate and they are very happy with their outcomes.

To view the sidebar "Reducing Postoperative Chairtime With Intraoperative Sphincterotomies" related to this article, please refer to the print version of our November/December issue, page 48.
Maurice E. John, MD, is Founder and Medical Director at the John-Kenyon Eye Center, which is based in Jeffersonville, Indiana, and Louisville, Kentucky. He does not hold a financial interest in any product or technology mentioned herein. Dr. John may be reached at (812) 288-9011; mjohn@johnkenyon.net.
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