Welcome to Eurotimes

By Ana Hidalgo Simón MD, PhD

BORDEAUX — Patients with keratoconus have more surgical options than ever before and Phakic IOLs, Intacs and refractive surgery may all have a role to play, according to French specialist Joseph Colin MD.

Keratoconus is a progressive, non-inflammatory disease of the cornea that causes varying amounts of vision loss due to irregular astigmatism. Conventional treatment is initially based on spectacles and contact lenses but progression of the disease eventually requires surgery. The surgical options traditionally used are lamellar or penetrating keratoplasty (PK).

Dr Colin of the Service Ophtalmologie Hopital Pellegrin, Bordeaux, France, says traditional surgical solutions provide good visual results in many cases.
But the procedures are flawed. Many patients become allergic after the operation; visual rehabilitation is often very slow; and there is a constant low endothelial cell count up to three or four years after grafting.

“In young patients that can be important. We know now that 15 to 20 years after the operation we will have recurrence of the keratoconus,” Dr Colin said.
He added that results of these traditional approaches appear good, but very frequently have only short follow-ups. In addition, as much as 47% of patients will still require contact lenses after surgery to correct astigmatism or other residual refractive errors.

New surgical options
“We have procedures which can reinforce the cornea, those which can weaken the cornea and those which do not change it. The last group includes the intraocular procedures," he explained.
Many keratoconus patients with poor contact lens tolerance or poor quality of vision are currently asking for refractive surgery. Dr Colin recommends a non-corneal surgical option in these cases.

Phakic IOLs are another possibility that can improve the vision of these patients. A small incision is preferred, and either foldable anterior chamber or posterior IOLs are suitable. Anterior chamber depth is generally deep enough in these patients. In the near future, Dr Colin believes the insertion of customised IOLs will be a way forward for these patients.

Ablative procedures are also on the cards. “We were using radial keratotomy and asymmetric keratotomy in the old days. Now some surgeons are performing PRK. PRK can improve both vision and the ability to wear contact lenses, but long-term results may not be good.

“We could see the progression of disease. I don’t recommend making a thin cornea thinner. Rather, we need to help reshape the cornea,” he said.

Some surgeons, particularly in the US, have tried to correct keratoconus with LASIK. But Dr Colin believes the results presented do not warrant the use of LASIK as primary treatment for these patients. PTK may also be useful to remove a superficial scar and this could help the patient be refitted with contact lenses.

Dr Colin considers additive procedures more interesting. Planar epikeratoplasty was performed for the first time a few years ago, producing acceptable results but with only a moderate quality of vision.

Intacs for reshaping the cornea
Intacs are another option to treat keratoconus. Intacs are intrastromal corneal rings of varying thickness placed through a single peripheral incision. They aim to change corneal curvature without invading the patient’s central axis vision. Among their advantages, they offer maintenance-free corrections and produce rapid and predictable results.

“We use Intacs mainly in thin soft corneas. We perform the incision on the horizontal meridian of the temporal side, not so close to the limbus and far from vessels. The procedure is relatively easy and gives good results,” Dr Colin explained.

Intacs are not indicated in patients with central corneal opacities, because vision will not improve much. The best candidates are patients with keratoconus with contact lens intolerance, no scars in the center, at least 20/50 best corrected visual acuity, and corneal thickness of 450 microns or more at the sides of the segments.

Dr Colin said that in his own experience, a series of keratoconus patients who received Intacs showed improvements of mean visual acuity between 0.5 D and 0.72 D at six months.
He is currently trying to refine the procedure, using different ring patterns according to the shape of each particular cornea.

Dr Colin notes that if anything goes wrong with the Intacs implant, it is relatively easy to remove the segments particularly in the absence of disease progression. His recommendation is to remove the implants and wait for three to six months before performing PK in such cases.
Looking at the future of surgery for keratoconus, Dr Colin predicted the combination of some of the procedures currently available —like LASIK following PK or phakic IOL implantation following PK — to treat residual myopia.

Intacs may be used in combination with customised laser ablations to correct residual errors. Another interesting combination might be to place Intacs in combination with IOL implantation when the cornea has been successfully reshaped but with high residual myopia still present.

Top