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        Medicals International SARL



        Refractive Surgeries;
        Novelties & Options
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        May 2002.



        Issue 5
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           Refractive Surgeries.
           Novelties & Options

INTRODUCTION

Refractive surgery has evolved over time and has truly come a long way from the
simple Radial Keratotomy (RK), Photo Refractive Keratotomy (PRK), Anterior
Phakic IOL implantation, Implantable Contact Lens ICL, Intrastromal Corneal Rings,
Laser In Situ Keratomileusis (LASIK, which is very famous now); all with well
proven results.
What comes next?
Today’s podiums are crowded with challenging trials presented on customized
ablation, Laser Epithelial Keratomileusis (LASEK) and Laser Thermal Keratoplasty
(LTK). Exciting! Yes, especially when reporting about it.
In this issue I will specifically highlight and detail four refractive surgery procedures;
LASEK, LTK, ICL and Phakic IOLs with the hope of bringing a good value to this
report.

What is LASEK?

Laser epithelial keratomileusis (LASEK) was described and developed by Massimo
Camellin, MD, in 1999; Via Fiume 8, 45100 Rovigo, Italy.
 In this procedure the epithelium of the cornea is detached from the underlying basal
membrane using a 20% alcohol solution and rolled back as a flap. After laser ablation
has been performed, the epithelium is placed back to cover the wound bed. Re-
epithelialization occurs in a few days, while the epithelial flap protects the surface,
preventing pain, infection and accelerating visual recovery.


           Description of the procedure
 The procedure is performed under topical anaesthesia. Using a special micro-trephine
and a calibrated blade, an epithelial flap of 8.5 mm diameter and 70-µm depth is
performed. The trephine is designed to leave a hinge of 80° at 12 o’ clock.
Then a special cone is placed on the eye (the cone is of the same diameter of the flap)
and pour inside it 0.1 cc of a 20% alcohol solution, leaving it there for 20 seconds.
Thereafter, the corneal surface is thoroughly washed with balanced salt solution
(BSS) to remove the alcohol. The epithelium is lifted and folded back at the 12
o’clock position with a modified micro-hook.

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At this point, the treatment proceeds as for traditional PRK. After the Laser ablation,
the surface is cleaned with BSS and the epithelium is repositioned again using the
modified micro-hoe. A soft contact lens is kept on the eye for 48 hours to hold the
epithelial flap in place. Postoperatively, topical antibiotic drops are instilled for 2
days, topical corticosteroids and artificial tears are administered for 4 weeks.


           LASEK vs. PRK and LASIK
Compared to PRK, the technique has no drawbacks and offers the following
advantages: according to Dr. Camellin:
       Absence of postoperative pain
       No risk of infection- the epithelial flap acts as an effective protective barrier.
       Faster functional recovery
In comparison with LASIK, the only disadvantage is the use of a soft contact lens for
the first 3 days postoperatively, (this is a precaution which may be unnecessary). But
the advantages over LASIK are as follow:
       All the risks associated with the use of Micro-keratomes are eliminated.
       Problem related to the repositioning of the corneal flap are avoided. The risks
       include: opacities and intrastromal microfolds.
       In the event of infection, it will be sub-epithelial only and not intrastromal,
       and therefore more and easily manageable.
       The anatomy of the orbit has no relevance to the operation; thinner corneas
       can be treated with larger dioptre correction.
       Lesser instruments needed and though the cost should be lower.

           Where is LASEK today?
Several studies were done and all are still in the trial stage and not accepted by the
majority of surgeons:
“We think LASEK is too risky, the technique is not really good yet. The materials
used for LASEK do not give us much comfort. We think it still needs to be tested,”
Dr. Juliano Buratto, MD, reported.


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“I have never performed LASEK because I do not think it offers any advantage with
respect to PRK and LASIK,” Dr. Lucio Burrato said.




         Comparison of symptoms on day 3 after PRK and LASEK
         randomised to each eye in the same patient (15 patients). Standard
         deviations demonstrate a lack of statistically significant difference
         between the two procedures.



We hope this technique will evolve and will enhance results.

What is LTK?

Another procedure used for refractive surgery and mainly
used for Hyperopic treatment is the LTK:
The procedure utilizes laser energy to gently reshape the
cornea without touching the eye. No scalpel incisions or
laser ablations are used to cut or remove a patient’s corneal
tissue. This procedure is mainly used for hyperopic
treatments.
A holmium:YAG laser, which uses a process for shrinking collagen, applies two
concentric rings of eight simultaneous spots of laser energy to the periphery of the
cornea to gently heat the corneal collagen and steepen its shape. This is performed to
improve the cornea’s refractive power. No tissue is cut and no instruments touch the
eye, thus, the possibility of intra-operative complications, postoperative infections, or
risk of healing abnormality that may have an effect on vision is reduced.
The system is designed for in-office use and does not require a sterile environment,
special wiring, expensive disposables or special gases.




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           Clinical evidence
During clinical trials utilizing the LTK procedure, patients usually had improved
vision immediately after the procedure, with most being able to return to work and
resume daily activities one day after treatment. Some patients are immediately
exhilarated by the changes in vision. In other patients, it takes 24 hours before any
changes are felt. It depends on how the patients’ cornea responds to drying. Patients
go through a 3-minute period where the cornea is let to dry naturally prior to applying
the laser.
Topical anaesthetic eye drops were used prior to the procedure and patient complaints
of postoperative pain or discomfort were usually minimal, lasting about 24 hours or
less. When necessary, over-the-counter analgesics were recommended, such as
ibuprofen or acetominophen, and were normally discontinued within 1 to 2 days.
Long-term risks of LTK for hyperopic treatment have not been determined yet. The
safety and effectiveness of retreatment procedures with the LTK system have not been
established.



Refractive Implants

Refractive surgical implants, from phakic IOLs to corneal inlays and inserts are
expanding the scope of options for a range of myopic and hyperopic patients. The
main difference between the two types of refractive surgical implant is that cataract
surgeons may feel more comfortable implanting phakic IOLs, while LASIK and
Corneal surgeons may be more inclined to offer corneal implants and inlays to their
patients.



           Refractive IOLs
Phakic IOLs are becoming increasingly popular for correction of refractive errors in
patients for whom corneal laser surgery is contraindicated.
Surgeons agreed refractive results are more predictable with anterior chamber lenses
than posterior chamber ones; ICL refractive results are less predictable than results
with anterior chamber lenses, as a higher number of Preop parameters are required.
Anterior chamber phakic IOL models may offer more predictable refractive results,
but posterior chamber models can be inserted through smaller incisions.
George O. Waring III, MD, professor of ophthalmology at Emory University School
of Medicine and founding surgeon at the Emory Vision Correction Center in Atlanta,
said there are at least five reasons why phakic IOLs will grow in popularity
throughout the coming years.
   1. First, IOL technology has been around for half a century and every cataract
      surgeon knows how to implant an IOL. “This is a comfortable approach for
      anterior segment surgeons, whereas with LASIK, surgeons have to learn how
      to use microkeratomes and lasers,” he said.

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   2. Second, he suggested, there is a practical imperative to incorporating phakic
      IOL technology into a practice. “It is a lot easier for a surgeon who does 10
      cataract surgeries in a day, and who wants to do refractive surgery, to stay in
      the same operating room with the same staff and the same set-up and implant
      five phakic IOLs than it is for that surgeon to go across town to a refractive
      surgery center and have to deal with a whole complex set of negotiations and
      then still have the stress and strain of dealing with new microkeratomes and
      new lasers,” he said.
   3. The third reason, according to Dr. Waring, is that the quality of vision is better
      with a phakic IOL in higher corrections (greater than –9 D and greater than +4
      D) than it is with LASIK. “The eye is put back in focus with LASIK, but
      optical aberrations increase because the shape of the cornea is changed. With
      phakic IOLs, the cornea is not changed, and its normal asphericity remains
      intact,” he explained.
   4. The fourth reason for phakic IOLs’ bright future is that they are removable,
      Dr. Waring said. “Many patients simply like the idea that the procedure can be
      ‘undone’ if they are not satisfied with their quality of vision,” he said.
   5. Finally, phakic IOLs are adjustable while in the eye. “They are adjustable in
      the sense that LASIK can be done over them. Bioptics is the ultimate
      combination because we are not thinning the cornea nearly as much as when
      we attempt the full correction with LASIK.
As an example of the Phakic IOLs we will mention the Phakic 6H heparin-coated
phakic IOL From Oii (Ophthalmic Innovation International, USA) With flexible
loops and a small optic edge, and angle-supported lens for the average hyperopic
anterior chamber.
According to Dr. Gould, professor of ophthalmology at the New York Medical
College, angle-supported phakic IOLs are the best alternative procedure to corneal
refractive treatment for correcting higher ametropias. Hyperopia in particular has very
little to gain from corneal approaches, he said. According to Dr. Gould, the insertion
method of the Phakic 6H is easily mastered by any cataract surgeon. The design of the
lens, with 6-mm optics and softer loops, makes the procedure even easier. Being a
rigid IOL, the incision size must be 6.5 mm, but this is no problem at all.

           Refractive Corneal Implants:
Addition Technology acquired the Intacs technology from KeraVision last year and is
planning to expand the application of this intra-corneal ring for different applications,
including Myopia, Keratoconus and for patients with progressive keratectasia.
Actually In the United States, David J. Schanzlin, MD, of San Diego, has used Intacs
inserts in several cases of corneal ectasia following LASIK. In Europe both Dr. Colin
and Carlo F. Lovisolo, MD, of Milan, Italy, have had positive results with Intacs for
this therapeutic application. Other researchers including Ioannis G. Pallikaris, MD,
PhD, and Charalambos Siganos, MD, have published preliminary results using Intacs
inserts to treat LASIK-induced corneal ectasia.
On the other hand, management of the Keratoconus disease typically begins with
glasses or contact lenses. However, if vision continues to deteriorate, lamellar or

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     penetrating keratoplasty is required. A transplant can provide good results, but of
     necessity it is a last resort option. Visual rehabilitation is slow, and complications can
     threaten the vision. Even after transplant, sometimes keratoconus recurs. The beauty
     of this technology is that it is removable. Patients like this concept because it’s not
     permanent, and doctors like it because if a complication begins to occur, the segment
     can be removed.
     This was also the same in Europe: Dr. Colin performed his first Intacs procedure for
     keratoconus in June 1997. In the past 5 years, he has performed 200 cases, including
     40 cases performed in the European trials. “In most cases, results have been very
     positive,” Dr. Colin said, “but in some cases we do not get the improvement that we
     are expecting.” Dr. Colin said that in 80% of cases there has been a significant
     improvement in patients’ vision. After surgery there has been “very good”
     stabilization of the topography of the cornea.



      Closing

     From the above list of methods for treating and correcting refractive error, the surgeon
     must choose the suitable one to treat the particular case, according to the suitability of
     the method to the treated case.
     I hope the above will give enough information about this subject, aiming to give more
     in the next issues.

     References

              Ocular Surgery news OSN supersite: www.osnsupersite.com

              Herbert Gould, MD, can be reached at 345 East 37th Street, New York, NY 10016;
              (212) 697-0827; fax: (212) 697-0823; e-mail: HLGould60@aol.com

              Joseph Colin, MD, can be reached at Service d’Ophthalmologie, CHU Pellegrin,
              Place Amelie Raba-Leon, 33000 Bordeaux, France; (33) 556 795 608; fax: (33) 556
              795 909; e-mail: joseph.colin@chu-bordeaux.fr.

              Addition Technology, manufacturer of Intacs prescription inserts, can be reached at
              48630 Milmont Drive, Fremont, CA 94538; (510) 353-3000; fax: (510) 353-3030.

              Siganos CS, Kymionis GD, Astyrakakis N, Pallikaris IG. Management of corneal
              ectasia after laser in situ keratomileusis with Intacs. J Refract Surg. 2002;18:43-46.

              Deepinder K. Dhaliwal, MD can be reached at the Eye and Ear Institute, University of
              Pittsburgh Medical Center, 203 Lothrop St., Pittsburgh, PA 15213; (412) 647-2200;
              fax: (412) 647-5119; e-mail: dhaliwal@vision.eei.upmc.edu.

              Massimo Camellin, MD; Via Fiume 8, 45100 Rovigo, Italy.



This Bulletin is researched and prepared by Michel Kleib                    Medicals International SAL




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