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Centers of reference develop strategic lines for keratoconus management
Protocols for diagnosis and treatment are being developed.
 Joseph Colin |
Within the framework of the National Plan for Rare Diseases, a comprehensive program involving rare disease experts, health professionals, patient organization representatives, and the ministries for health and research, a number of designated keratoconus specialists in France are developing strategic lines for the diagnosis and care of keratoconus patients.
Two centers of reference, Bordeaux and Toulouse, have been designated and are in the process of coordinating their action with the seven centers of competence in Amiens, Brest, Clermont-Ferrand, Nantes, Nice, Paris and Rouen.
“The national plan is aimed at reinforcing the quality of patient care, developing research on rare diseases, and enlarging Europe as an international cooperation to share expertise, experience and resources,” Joseph Colin, MD, OSN Europe Edition Board Member, said at the meeting of the French Society of Ophthalmology in Paris.
Centers of reference
The main task of the centers of reference is to provide the centers of competence with protocols for diagnosis and treatment and to implement a common approach to each of the rare diseases. National platforms are also developing a decision tree for every disease.
“Mission No. 1 is to determine keratoconus stage, graded 0 to 4 based on keratometry, pachymetry, associated ametropia and corneal transparency,” Dr. Colin said. “Visual acuity with spectacles, tolerance of contact lenses and disease progression are other key factors influencing treatment decision-making.”
Contact lens use
Based on these factors, there are currently several therapeutic options for keratoconus. Contact lenses are still first-line treatment, used by 90% of patients.
“Contact lenses are the first treatment proposed to patients when they don’t need surgery. They are also widely used after surgery, whether this is intracorneal rings, cross-linking (CXL) or corneal transplantation,” Dr. Colin said.
A network of contact lens specialists who specifically deal with keratoconus has recently been organized.
“The idea is to allow patients to find an ophthalmologist who is a keratoconus specialist and also a CXL specialist. About 100 ophthalmologists have already joined in this network, which will eventually cover all regions of France,” Dr. Colin said.
Cross-linking use
Corneal transparency is the main parameter for therapeutic choice. If the cornea is transparent, there are several options; if it is not, transplantation is the only option.
The second essential parameter is progression of keratoconus. There is the chance to stop progression by corneal cross-linking, either with conventional techniques or with the new flash technique, in which the use of a customized photoactive cross-linking agent shortens light exposure time to only 3 minutes.
Dr. Colin said it is important to understand that cross-linking is not a refractive procedure; instead, it is a method to stop progression that has shown efficacy in 97% of patients over 5 years of follow-up.
“The remaining 3% are mostly young patients. In consideration of this, a group of keratoconus experts has reached the common conclusion that keratoconus in pediatric age must be treated immediately with CXL when there is visual loss, without waiting for the disease to start progressing. Keratoconus in very young patients must be considered as an emergency,” Dr. Colin said.
Experience has also shown that cross-linking re-treatment is possible and that patients older than 35 years should be excluded.
“Past this age, there are more complications than benefits. In addition, keratoconus spontaneously stops progressing at around this age, and there is no point in cross-linking a cornea that is quiescent,” Dr. Colin said.
Decision tree
The decision tree for keratoconus starts from the evaluation of corneal transparency.
“If the cornea is not transparent, we don’t have many options. Lamellar keratoplasty is the procedure of choice, unless there are complications such as hydrops, which may require penetrating keratoplasty. In cases of high ametropia, phakic or aphakic toric implants might be added,” Dr. Colin said.
If the cornea is transparent, there are a variety of options.
The first step is to evaluate progression. If keratoconus is stable, contact lenses are prescribed to patients who can tolerate them. If patients cannot tolerate contact lenses, intracorneal rings, such as Intacs (Addition Technology) or Ferrara rings (Ferrara Ophthalmics), can be implanted with reasonable results.
In cases of progressive keratoconus, cross-linking and intracorneal ring implantation should be performed in the same surgical session, according to Dr. Colin. If contact lenses are tolerated, cross-linking can be combined with contact lenses for refractive adjustment. – by Michela Cimberle
For more information:
Joseph Colin, MD, can be reached at Hôpital Pellegrin, Place Amélie Raba-Lèon, 33076 Bordeaux, France. +33-5-56795608; fax: +33-5-56795909; email: joseph.colin@chu-bordeaux.fr.
Disclosure: Dr. Colin is a consultant for Addition Technology and has had research funded by Horus Pharma.