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Study shows Prelex and LASIK is effective in highly ametropic cases PRESBYOPIC refractive lens exchange (Prelex) combined with LASIK offers a safe, straightforward and reliable
He also advised performing YAG capsulotomy early if there was the slightest sign of posterior capsule opacification and said that such early intervention would lead to a dramatic improvement in the patient's visual acuity, especially in terms of near vision.Dr Knorz stressed that almost all Prelex patients have the capability to neuro-adapt to their new visual systems, which is an important process in achieving the best quality of vision after surgery. These patients experience simultaneous near and distance vision, and their brains need to learn how to ignore one image when focusing on the other, he said.Patient selection was also crucially important, said Dr Knorz, and it was essential to fully explain the pros and cons of the treatment to prospective patients. "It's vital that surgeons explain to patients that the procedure might involve some compromise as it involves adapting to a new quality of vision. This means that the patient has to learn to read again and to accommodate using simultaneous vision. They should also be warned in advance that the procedure might require a combination of Prelex and LASIK to get the optimum results," he said.Dr Knorz reiterated that lens exchange and multifocal IOL implantation, with or without additional laser treatment, provided a viable and safe option for the surgical treatment of presbyopia, and should grow in popularity as more surgeons become more familiar with the technique. "Appropriate patient screening, accurate biometry and lens power calculations, meticulous surgical technique and effective astigmatic control will allow surgeons to maximise their success with this procedure," he concluded. Prof. Michael C. Knorz, MD |
approach to correct myopia and hyperopia as well as presbyopia, according to German ophthalmologist Michael Knorz , MD. Presenting the results of his most recent clinical studies, Dr Knorz told delegates at the XXI Congress of the ESCRS that clear lens extraction followed by implantation of a multifocal IOL is becoming widely adopted as a treatment for presbyopia in many centres throughout Europe and could also be a valuable procedure for presbyopic ametropes. "Prelex has been available for many years and has considerable advantages, however it is still not being as widely used as it might be. Refractive surgeons have to look at ways to achieve consistently perfect results to help overcome some of the concerns that are perhaps preventing them from offering this procedure to their patients," he commented. Dr Knorz said that clinical studies of patients undergoing crystalline lens extraction and implantation of multifocal IOLs, showed consistently good results with most patients coming within 1.0 D of emmetropia.In his most recent study, 86 eyes of 43 patients with refractive errors ranging from –16.0 D to +8.0 D underwent Prelex and implantation of the AMO Array foldable multifocal IOL. If residual ametropia was present, LASIK was performed after three months. At three to six months, all eyes were within 0.5D of emmetropia and saw 20/25 or better without correction. Uncorrected near acuity was J3 or better in 95% of cases. Four eyes (5%) could not achieve useful near vision without correction because of small pupils. 
Prelex was particularly suitable for hyperopic patients over 40 years-of-age, followed by high myopes over 40 and then presbyopes. Patients with low myopia were generally not suitable for lens exchange, said Dr Knorz, as they were used to very good near vision, which might be affected by the procedure.Dr Knorz said that at his centre, Prelex is offered as an alternative to LASIK and phakic IOLs to presbyopic patients over 40 years with ametropia ranging from +8.0 D to –12.0 D. He noted that the surgical procedure for Prelex was relatively straightforward. He performed all procedures using intracameral lidocaine. He created a posterior limbal incision at the steepest meridian and performed relaxing incisions for any remaining astigmatism over 1.0 D. To maximise safety, he typically operated on the second eye after seven days, and then LASIK treatment after three months in those cases with residual ametropia.He stressed the importance of performing LASIK – usually after a three-month interval – if there is any residual ametropia present and said that this is one of the primary keys to achieving better refractive outcomes. Residual ametropia is far more critical in a multifocal IOL than it is with a standard lens. With the multifocal IOL the patient has two images reflected on the retina, which results in a slight blurring effect. This is worsened if residual ametropia is present and results in greatly diminished visual acuity and visual quality."