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Evolving care

Safety in refractive surgery requires good surgical training and a strong evidence base for procedures used

Roibeard O’hEineachain

Posted: Friday, September 1, 2017


José Güell MD

Complications of refractive surgery are rare but can be severe. Care taken in patient selection, treatment choice and surgical technique helps reduce their incidence to a minimum, according to José Güell MD, Autonomous University of Barcelona, Barcelona, Spain.

“I think that it is important to point out that this is an elective versus a therapeutic surgery. Therefore, the main concern of a refractive surgeon should be to consider only the safest surgical approaches and also to improve the efficacy and predictability of the procedures, as well as the patient’s optical quality,” Dr Güell told the 21st ESCRS Winter Meeting in Maastricht, The Netherlands.

The three most common types of refractive procedures – corneal refractive surgery, phakic intraocular lenses (IOLs) and refractive lensectomy – have very low rates of visually significant complications. A literature search taking only Cochrane reviews or very large studies showed that nearly all of the complications that occur have an incidence below 1% and most of them are below .01%.

Dr Güell recommended a four-point strategy to reduce the incidence of complications still further. The first point is to avoid newer, less well tested technology with only short follow-up. The second point is careful patient and treatment selection, based on past experience and treatment guidelines. 
The third point is to have an experienced and properly trained surgeon. The 
fourth point is to have an adequate follow-up with peer-reviewed 
objective research.

He noted that newer refractive technologies, to be avoided by the regular surgeon and not being included in a closed study group, were specifically those that operated on a new untried principle and with little follow-up, such as femtosecond laser crystalline lens shape change induction or transepithelial corneal remodelling thorough corneal crosslinking (CXL). He added that, ideally, there should be rescue 
options to help return the eye to its preoperative state.

The length of follow-up before the procedure can be considered safe is debatable – 20 years is a good definition but it is impractical, because by the time there is sufficient follow-up new techniques have evolved. On the other hand, less than five years is probably not enough.

Regarding patient and technique selection, consideration is required not only of the visual outcome desired by the patient, but also the patient’s specific orbital anatomy and their likelihood of experiencing complications based on their ethnic profile, for example.

Preoperative examinations for refractive surgery should include topographic measurements, slit-lamp meticulous evaluation, endothelial cell count, optical coherence tomography etc. That will help to achieve the targeted refractive outcome and also detect whether the patient might be prone to ectasia in the case of laser refractive surgery, or corneal endothelial cell loss or cataract in the case of phakic IOLs.

In the case of multifocal IOLs, another measure that can help prevent an undesired visual outcome is to provide patients with preoperative simulation of the vision they are likely to achieve in proposed intervention, whether through contact lenses or adaptive optics.

CONTINUE TO EVOLVE
Patients also need to understand the temporary nature of refractive corrections, Dr Güell said. For example, corrections of myopia are unlikely to remain stable forever, since the underlying condition will continue to evolve and some myopic error will likely return over the years.

In addition, the anterior segment changes throughout life. Therefore, the distance between the crystalline lens and a phakic IOL will shrink over time. Similarly, the angle narrows with age, which could have implications for patients with phakic lenses both in the anterior and the posterior chamber.

He added that having an experienced and properly trained surgeon is probably more important in refractive surgery than in therapeutic surgeries, because of the higher expectations and the generally healthier eyes of patients requesting the treatment. Therefore, surgeons should have specific training for each type of refractive procedure.

Finally, the determination of the safety of refractive procedures requires peer-reviewed long-term controlled studies, both independent and industry-driven with follow-up lasting decades, providing professional, objective, realistic and independent information, Dr Güell said.

José Güell: guell@imo.es