COVER STORY Meeting Higher Patient Expectations With the ...€¦ · 15/08/2006  · IOL implantation each year. Our patients are increasing-ly sophisticated, internet-savvy, and

68 I CATARACT & REFRACTIVE SURGERY TODAY EUROPE I OCTOBER 2007

COVER STORY

Every successful refractive surgeon needs to deliv-er on three benchmarks: highly accurate results,high quality vision, and low complicationrates—and all must be approaching best prac-

tice levels. These axiomatic standards apply equally toexcimer laser treatments and cataract/lensectomy sur-geries. If unaided vision after lens surgery is augmentedby secondary procedures (eg, LASIK for astigmatism),then the rate of unplanned enhancements must be lowas well.

Approximately 12 to 15 million patients receive anIOL implantation each year. Our patients are increasing-ly sophisticated, internet-savvy, and more demanding ofhigher quality vision. Advances in surgical technique,better biometry, fourth-generation IOL calculation for-mulae, and latterly, advances in IOL design and manu-facture have enabled us to routinely achieve a highstandard of outcome. Ironically, these good results aresomething of a two-edged sword: The better webecome, the more our patients expect.

The largest recent thrust in IOL technologies hasbeen the advent of aspheric optics. These may be divid-ed into two broad groups. The first group employs anegative asphericity in an attempt to actively compen-sate for the typical positive corneal asphericity. The sec-ond group more modestly chooses to remain aspheri-cally neutral. Both groups seek to create less overallaberrations, increase contrast sensitivity, and providebetter image quality. Although a near-neutral asphericresult for every patient would be ideal, the negativeaspheric IOLs needed to achieve this are more sensitive

to the effects of decentration and tilt, and so some sur-geons elect to use the more forgiving neutral asphericlenses.

Before we engage in this debate, however, it is farmore salient to remember the need to correct sphereand cylinder before we have the luxury of chasing afterhigher orders of aberration. To achieve this, not onlydoes a refractive surgeon needs to employ the full suiteof advances available, but IOL manufacturers need toplay their part as well. The International Organization ofStandardization (ISO) has aided by setting standards for

Meeting HigherPatient ExpectationsWith the Softec HD

The major advantages of this lens are its 0.25 D increments and stated manufacturing tolerances.

BY PETER STEWART, MD, MBBS (QLD), FRACO

Figure 1. ISO benchmarks (center column) for IOL manufac-

turing tolerances are outdated and surprisingly lax.The

Softec standard (right column) is much lower than that of the

ISO.

OCTOBER 2007 I CATARACT & REFRACTIVE SURGERY TODAY EUROPE I 69

COVER STORY

IOL manufacturing tolerances. The ISO benchmarks,however, are outdated and surprisingly lax (Figure 1). Allmanufacturers claim to exceed these tolerances, butthey are reticent to go on the record with actual data.The difference with the Softec HD aspheric lens(Lenstec, Inc., St. Petersburg, Florida) (Figure 2) is thatits manufacturer actually publishes manufacturing tol-erances (Figure 1), thus creating the most accurateaspheric IOL advertised on today’s market.

The Softec HD is a one-piece hydrophilic acrylic lenssuitable for microincisional insertion. It is asphericallyneutral, has a square-edged optic, and utilizes a patent-ed equiconic aspheric design that splits the asphericityequally between the front and back surface of the lensto create crisper and sharper vision.

AVAIL ABLE IN SM ALLER INCRE MENTSAnother advantage of the Softec HD is that it is avail-

able in 0.25 D increments from 18.00 to 25.00 D. It isalso available in 0.50 D increments from 10.50 to 29.50D and 1.00 D increments from 5.00 to 36.00 D.

Since August 15, 2006, I have implanted 393 SoftecHD lenses. We use the IOLMaster (Carl Zeiss MeditecAG, Jena, Germany) for biometry and the ProfessionalEdition of the Holladay IOL Consultant (HolladayConsulting, Inc., Bellaire, Texas) for IOL calculations. Werefract our patients postoperatively on day 1 and at 1and 5 weeks. We were familiar with a very predictableand minor myopic shift seen from day 1 to week 1 withour previous IOL, the Tecnis Z9000 (Advanced MedicalOptics, Inc., Santa Ana, California). An early clinicalobservation with the Softec HD was that over the sameperiod, the refractive shift was more variable and could

be plus, minus, or absent. Initial concerns that this vari-ability would translate to poor dioptric accuracy provedto be unfounded, with the 5-week results being equiva-lent to our Tecnis Z9000 results (ie, ±0.50 D accuracy in90% of cases). A refractive surgeon needs to strive forthis level of accuracy to have parity with good LASIKsurgery accuracy. Both lenses offer similar predictabili-ties, and hence it might be considered that the actualrefractive results are the same. A predictable result,however, is not the same as a desired result. Because theSoftec HD is available in 0.25 D steps through the mostpopular range of powers, you can choose a lens powerto give a predicted result closer to the desired refrac-tion. The Softec HD offers less compromise of choiceand excellent results.

We found that employing entrapment to the capsu-lorrhexis offered additional benefit to the accuracy ofoutcomes. It is hard to achieve a 360º closure around anoptic, as the pupil center is not necessarily the same asthe center of the capsular bag. With this series of SoftecHD lenses, however, we achieved between 270º and 360ºclosure in all cases. This is probably one of the most sig-nificant surgical maneuvers to ensure dioptric accuracy.

SM ALL LO OPED DIA METERAnother advantage of the Softec HD is its looped

diameter, which is smaller than other acrylic lenses. If asmall tear in the posterior capsule occurs duringimplantation, it is still possible to place the lens in thebag without extending the tear. This is due to the rela-tively small amount of peripheral push of the haptics.Although not the classic textbook answer to handling aposterior capsule tear, this method allows the skilledsurgeon to still center the lens. In these cases, I contin-ue to place the leading haptic into the capsular bagwith the injector, but I do not attempt to follow withthe trailing haptic. Instead, I very gently use a manipu-lator to get the second haptic into the bag while it isstill opening. Overall, it is a low-damage and robustlens, providing that the haptics do not catch in theloading system.

The Softec HD is a safe option for those surgeonsjust learning to use aspheric IOLs, because it is not assensitive to tilt and decentration as other asphericmodels. I like this lens because aspheric IOLs that cor-rect for positive spherical aberration on the cornea,such as the Tecnis range and the AcrySof IQ (AlconLaboratories, Inc., Fort Worth, Texas), use a singleaspheric value based on population averages and donot always accurately correct the total aberration foran individual. Corneal Q-values sourced from placido-based topography are not helpful indictors of corneal

Figure 2.The Softec HD is a one-piece hydrophilic acrylic lens

suitable for microincisional insertion.

asphericity. Using the Softec HD allows me to besure—without doing a routine aspheric examination ofthe cornea—that the correction will provide qualityvision to the patient.

FUTURE PRODUCTSMany aspheric IOL models are available in Europe, and all

offer similar spherical aberration corrections. Companiesincluding Bausch & Lomb (Rochester, New York) andAdvanced Medical Optics, Inc. intend to either produce afamily of aspheric-powered IOLs that will depend on cornealasphericity or customize aspheric lenses to a patient’s pupiland corneal values. Until this industry moves more towardthat direction, I choose to implant the Softec HD because itis—to my knowledge—the only aspheric IOL that advertisesthe accuracy of its production, which is within ±0.125 D.Other companies have chosen to not disclose this informa-tion.

We are in an age where we strive to obtainemmetropia in our patients by attacking on manyfronts. We use gold standard biometry technology suchas the IOLMaster. We employ latest-generation IOLpower calculations with personalized constants. We

modify our surgical techniques according to our latestunderstanding. All of this would be pointless if we wereto use lenses that were manufactured to just meet theISO standards, which are too forgiving. I do not thinkthat it is sufficient for manufacturers to state that theirindividual lenses exceed the standard. I believe that sur-geons—and patients—deserve to know the sphericalmanufacturing tolerances of these increasingly expen-sive IOLs. Each company should be required to disclosethe lens’ tolerance on the box. The Softec HD asphericIOL has excellent manufacturing tolerances across theentire power range, gives very predictable results, andwith its range of 0.25 D lenses lets me walk up to adesired refraction. For these reasons, I choose toimplant it in any patient where a zero aberrationaspheric IOL is indicated. ■

Peter Stewart, MD, MBBS (QLD), FRACO, is Director ofLaser Surgery at Laser Sight Australia, in Spring Hill,Queensland, Australia. Dr. Stewart states that he has nofinancial interest in the products or companies mentioned.He may be reached at +61 7 5444 9000;[email protected].

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