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Today's Practice | Jun 2012

Recent Developments in Refractive Surgery

Several advances have enabled surgeons to offer a broader range of treatment options.

Currently there is a full range of refractive procedures with which surgeons can treat nearly all refractive errors. In some cases, combining surgical techniques using a bioptics approach can produce better visual results than performing a single procedure. Irrespective of the chosen method, today our results are excellent when we apply the right technique to the right patient at the right time.

A good refractive surgeon selects the appropriate refractive procedure based on patient characteristics including age; degree of ametropia; and the presence of myopia, hyperopia, or astigmatism as well as the patient’s individual needs and expectations. Too often refractive surgeons choose a procedure according to their infrastructure or their lack of skills and not according to a patient’s needs. Additionally, the surgeon should conduct thorough preoperative examinations to determine corneal stability and thickness, pupil diameter, axial length (in some circumstances), anterior chamber depth, and the patient’s overall ocular health. Extra chair time to fully inform the patient about what will and will not be obtained postoperatively will avoid a lot of headaches for the surgeon and will enhance patient satisfaction after surgery.

OFFER A MULTITUDE OF PROCEDURES

Unfortunately, however, not every refractive surgeon offers a multitude of refractive surgery procedures to treat the full range of refractive errors. For example, surgeons who are not equipped with the technology to perform laser treatments may more readily implant phakic IOLs and perform refractive lens exchange than a surgeon who offers laser vision correction. Likewise, surgeons who do not implant phakic IOLs may opt to apply a laser treatment beyond the reasonable range for high myopia treatments (-10.00 to -11.00 D); however, this results in too much corneal thinning and could jeopardize corneal integrity.

Refractive surgeons who perform only a limited number of techniques should consider expanding their armamentarium to treat a broader range of patients, as treatment recommendations should not be limited by the surgeon’s lack of available technologies or skills.

Below is a review of several advances in refractive surgery that, when offered within the same practice, as we do at Brussels Eye Doctors, allow surgeons to select the best surgical solution in each case.

LASER VISION CORRECTION

Compared with the mechanical microkeratome, the femtosecond laser increases safety of the LASIK procedure by eliminating possible intraoperative complications (eg, small flaps, incomplete flaps, buttonholes) and can produce thinner, more reproducible flaps. Because of this advance, we can treat patients with higher degrees of myopia than previously possible and spare enough tissue to guarantee long-term corneal stability.

Another aspect of laser vision correction that has changed in the recent past is the quality of treatment profiles: Wavefront-optimized and aberration-free profiles allow surgeons to minimize induced spherical aberration and thus night vision problems (eg, halos, glare), even in the presence of large pupils. Therefore, pupil diameter is now less of a hassle than it was previously. In cases of specific aberrations or asymmetric corneas, customized treatment profiles can be used as well.

MULTIFOCAL IOLs IN RLE

A variety of multifocal IOLs that are suitable for refractive lens exchange (RLE) procedures are available today. Although the breadth of lens designs is outside the scope of this article, the IOL that gives me the greatest satisfaction in 2012 is the FineVision (PhysIOL). This trifocal lens combines two diffractive profiles, one for distance and near and one for distance and intermediate, to split light into three useful orders—one for distance, one for intermediate, and one for near.

Because it is a trifocal lens, the FineVision IOL offers good reading vision and satisfactory intermediate vision.1 In hyperopic patients older than 45 years, I was previously offering laser vision correction with monovision, targeting slight shortsightedness in the nondominant eye. This monovision is simulated during the preoperative examination and possibly tested with a contact lens trial before surgery. My rate of spectacle independence for far and near vision is much higher when performing RLE with the FineVision implant than with other multifocal IOLs. In my practice, I have also started using the lens in myopic presbyopic patients and have achieved high patient satisfaction. A slight drawback of the FineVision IOL is that it is necessary to perform secondary laser vision fine-tuning in approximately 5% of these patients for residual ametropia and/or astigmatism. Once again, the cataract or lens surgeon needs a laser infrastructure to cope with the possibly imperfect refractive outcome in some patients.

TECHNIQUES FOR IMPROVED READING ABILITIES

Several emerging techniques have the potential to offer patients presbyopia correction. One option is the Kamra corneal inlay (AcuFocus, Inc.), which uses smallaperture optics to increase the eye’s depth of focus by allowing only focused light rays to enter the eye. The inlay is implanted within a pocket in the patient’s nondominant eye at a depth of 200 μm. These pockets can be created with a femtosecond laser. Additionally, implantation can be combined with femtosecond LASIK to correct hyperopia or myopia, but flap thickness must be 200 μm.

Another option for the treatment of presbyopia is Intracor. With this technique, the Technolas Femtosecond Workstation (Technolas Perfect Vision GmbH) is used to create intrastromal concentric rings within the cornea. These rings weaken the peripheral cornea, thus steepening the central zone.

The resultant multifocal cornea maintains a patient’s distance visual acuity and improves near and intermediate visual acuity. The advantage of this procedure is that it takes less than 20 seconds, according to the company. The possible disadvantage of the technique, however, is that we have no guarantee that the results will remain stable.

CONCLUSION

As a modern-day surgeon, it is imperative to be aware of all available techniques and, ideally, strive to be able to perform them. Most notably, surgeons should have access to a laser platform and should be able to offer RLE or phakic IOLs to their patients.

Using the range of methods described above, we can provide patients with refractive correction based on their individual characteristics, wants, and needs. Staying informed of the technologies that can provoke a change in refractive surgery indications is a key to being a leader in your field.

Jérôme C. Vryghem, MD, practices at Brussels Eye Doctors, in Brussels, Belgium. Dr. Vryghem states that he has no financial interest in the products or companies mentioned. He is a member of the CRST Europe Editorial Board. Dr. Vryghem may be reached at tel: +32 2 741 6999; e-mail: info@vryghem.be.

  1. Vryghem JC. MICS with implantation of a trifocal diffractive IOL. Cataract & Refractive Surgery Today Europe. 2011;6(5):45-49.

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