Refractive surgery can sometimes be an option in keratoconus patients

With careful patient selection and close monitoring, phototherapeutic keratectomy, PRK and LASIK can be viable options in specific cases.

PARIS — Keratoconus is classically considered a contraindication for laser refractive surgery, and refractive surgery itself, especially LASIK, is known to be a potential cause of ectasia. However, laser refractive surgery can be, in specific cases, a valuable and safe way of improving vision in keratoconus patients, according to Joseph Colin, MD.

Joseph Colin

“[Phototherapeutic keratectomy] can be used to remove superficial opacities and subepithelial scars in patients intolerant to contact lenses. We have had cases where this procedure has allowed a new adaptation to contact lenses,” Dr. Colin said at the meeting of the French Society of Ophthalmology here.

“In some cases, PRK can be a good option to improve vision, particularly now that new procedures, like intracorneal ring segments and cross-linking, are able to create a more stable corneal substrate,” he said. “The negative effects of PRK on keratoconus have not been sufficiently proven, anyway. There are cases in which PRK seems to have inhibited rather than triggered the progression of the disease.”

Even LASIK can be used to treat myopic astigmatism in some keratoconus patients after corneal transplantation.

Laser can be an option, provided that a careful patient selection based on the stage and progression of the disease, as well as on the evaluation of specific preoperative parameters using the most updated technology, is carried out. Also, a close monitoring of keratoconus patients who underwent laser refractive procedures is mandatory, Dr. Colin said.

The best option for specific cases

In cases of suspected keratoconus, a wait-and-see approach is best. If the evaluation of potential candidates for refractive surgery shows an abnormal, asymmetric topography and a corneal thickness of less than 480 µm, a cautious approach should be adopted, Dr. Colin said.

“Refractive surgery is not an urgent procedure and can be postponed at least 3 months to re-evaluate these parameters. Prevention is, of course, the best treatment,” he said.

Currently, the Ocular Response Analyzer (Reichert) is able to provide new predictive indexes, such as corneal hysteresis and corneal rigidity factor, which have been proven to be significantly lower in keratoconus compared with normal corneas.

Forme fruste keratoconus and moderate keratoconus can now benefit from new corneoplastic treatment options, in case the patient is intolerant to contact lenses, Dr. Colin said.

Intracorneal ring segments have a fairly long follow-up, and a direct biomechanical, stretching action on the ectasia has shown to produce and maintain a stable flattening of the cornea, which improves refraction and visual acuity. — by Michela Cimberle

• Joseph Colin, MD, can be reached at Hôpital Pellegrin, Place Amélie Raba-Lèon, 33076 Bordeaux, France; +33-5-56795608; fax: +33-5-56795909; e-mail: joseph.colin@chu-bordeaux.fr.

A precise assessment of keratoconus stage, visual function and vision specific health status in keratoconus patients is crucial in order to choose the best treatment option. While in some specific cases, “wait and see” is the best solution, all of these methods can improve visual acuity when the cone has progressed to more advanced stages. We can combine some of them, such as cross-linking and intracorneal ring segments or intraocular toric lenses for best results. Further studies will help us to better define indications.

– Aylin Kýlýò, MD
Head of Kudret Eye Hospital, Ankara, Turkey