You are here: MEDICA Portal. Our Topics in 2009. Topic of the Month October: Laser Medicine. Interviews.
„The TÜV-Approved Lasik Is Not More Than A Kind Of Promotion“
Anyhow, this kind of intervention is not as harmless as promised by medics using Lasik – says Andreas Berke. The physiologist spoke to MEDICA.de about the laser adjustment being a modern lifestyle surgery and why it is somehow a game of chance.
MEDICA.de: Mr. Berke, meanwhile about 100,000 Germans receive treatment with the laser for adjusting their eye sight. Centres specialised in adjusting short- or longsightedness use slogans such as „painless, without blood and over in a sec“. Is the intervention really as harmless as implied?
Andreas Berke: Certainly not. The most commonly used surgery technique in these centers is the Lasik which does not hurt a lot but it is certainly not painless. And the intervention is not at all without risks – as is true for any surgery.
MEDICA.de: What exactly happens during a Lasik?
Berke: A flap, a thin corneal lamella, is cut with a micro-knife or a femtosecond laser and then lifted up exposing corneal tissue. This tissue is being ablated with laser to such a degree that lens and cornea project an image exactly to the retina. After that, the flap is being moved back into place. However, this flap does not perfectly adhere again, a fact that is not readily being communicated. That means that the flap is firmly attached at its edges but remains relatively loose across its surface.
MEDICA.de: Is it possible that the flap may detach later?
Berke: Yes, it is possible, but it does not happen very often, I presume. However, no serious long-term studies exist concerned with the effects of Lasik.
MEDICA.de: What potential long-term effects may occur?
Berke: Cases of keratectasia have been reported. This term describes a bulging of the cornea at the site of scar tissue, which is accompanied by a loss of sight since the cornea constantly thins out and becomes more irregular. This state can only be improved by corneal transplantation. However, a further problem has to do with the treatment of an eye cataract - with 500,000 to 600,000 interventions per year the most common surgery in Germany. Since the lens needs to be replaced, it is necessary to take an exact measure of the eyes on a geometrical as well as optical basis before beginning surgery. This is difficult when the cornea has been treated with a laser previously. Whether the new lens then works or not becomes a game of chance.
MEDICA.de: What are the immediate side-effects of Lasik?
Berke: The most common problem is dry eyes. Almost every second patient treated suffers from this condition immediately after surgery, nearly every third or fourth patient suffers permanently from it.
Berke: Corneal tissue is intertwined with many nerve fibres, which inform the brain about dry spots in order to stimulate the lacrimal gland to produce liquid. However, when cutting the flap, these nerves are being cut as well and the brain is missing any information about the state of eye moisture. These nerves do regenerate later, but not completely. A study observed that nerve fibre concentration decreases by about a third.
MEDICA.de: What other side-effects may occur?
Berke: Night vision may be affected in 20 to 30 per cent. Also opacitiy of the lens may cause glare because the cornea is being injured during Lasik which is followed by wound healing and scars that may disturb corneal transparency.
MEDICA.de: Those recommending Lasik state that these side-effects, if they occur at all, stay only temporarily and disappear again after a few weeks. Only one to two percent would be permanently affected.
Berke: Even if this was true, it would be disastrous since Lasik is a lifestyle surgery and not a medical necessity.
MEDICA.de: Proponents also state that laser technique has improved a lot over the last years resulting in lesser numbers of serious complications like 1 patient out of 10,000.
Berke: Well, it depends what one defines as a serious complication. Dry eyes as well as being sensitive to glare are conditions not regarded as a complication, they do not appear in any statistics. Maybe it is true that only one out of 10,000 is affected by keratectasia after surgery, but I think that around 3,000 could suffer from dry eyes and increased sensitivity to glare maybe even resulting in not being able to drive in the dark. Quality of laser techniques may continuously improve and become more and more precise, but our cornea differs from one individual to another. Each one reacts differently to Lasik. We obey blindly to a great belief in technology which lets us forget that physiological and biological reactions are hardly always predictable.
MEDICA.de: A German independent testing and assessment service called TÜV assign seals of quality, the Lasik-TÜV, to Lasik centers. This is to ensure quality of treatment in laser clinics. Can a patient trust this certificate and therefore assume to be in good hands in an approved clinic?
Berke: This Lasik-TÜV is overrated in its importance. It is not possible to rule out any correcting second surgeries or complications with an approved clinic. The TÜV-approved Lasik is not more than a kind of promotion, many centers offering Lasik intentionally do without this TÜV logo .
The interview was conducted by Sonja Endres