Ectasia is a horrible, visually impairing problem for LASIK patients, but there are now more effective ways to prevent and treat it.
“You can’t paint too rosy a picture because obviously it’s a horrible situation for patients,” said William Trattler, M.D., cornea specialist, Center for Excellence in Eye Care, Miami. “Patients expect to see better following LASIK, but if they develop ectasia, they can end up seeing much worse than before surgery.”
Nonetheless, Dr. Trattler, who is slated to present the course “Ectasia: Risk Factors & Treatment Options” at next month’s ASCRS•ASOA Symposium & Congress, Washington, D.C., said there are a variety of steps to identify at-risk patients and to reduce the risk of ectasia from occurring. And for those patients that have developed ectasia, vision for many patients can be restored with a variety of methods, starting with advanced contact lens fitting from an experienced contact lens specialist.

Determining ectasia risk

In the late 1990s, ophthalmologists learned that pre-operative corneal conditions increased the risk for developing ectasia following LASIK, Dr. Trattler said. Form fruste keratoconus, keratoconus, and Pellucid marginal degeneration are all conditions detectable with corneal topography and/or Orbscan (Bausch & Lomb, Rochester, N.Y.) that should raise red flags about performing LASIK.

A patient that developed ectasia.
He received Intacs (Addition
Technology, Des Planes, Ill.)
to help with the condition.
Source: William Trattler, M.D.

Corneal flattening after
combined C3-R (corneal
collagen crosslinking with
riboflavin) and Intacs on same
day.
Source: Brian S. Boxer
Wachler, M.D.

“Intra-operative factors can also place patients at risk for ectasia,” Dr. Trattler said. For instance, if the residual stromal bed is left too thin, there is an increased risk of ectasia, he said.
Of course, these intra-op evative factors can be avoided, he said. For one, while manufacturers often note that their microkeratomes cut at a certain depth, it turns out that there can be quite a bit of variability in the actual flap depth, he said.
“If you use a 130-micron head you may get surprise with an overly thick 200-micron flap,” Dr. Trattler said.
As a result, it is important for LASIK surgeons to perform intra-op pachymetry. With this measurement, the surgeon can calculate the final residual bed thickness. If the flap is unexpectantly thick, the surgeon can abort the procedure prior to the ablation.
Of course — even with careful attention to screening and methodical measurements of the intra-operative pachymetry — it is still possible to get ectasia following LASIK in seemingly “normal” eyes.
“We have had two cases at our practice where that happened,” Dr. Trattler said. “In one, the patient had no pre-op risk factors, had a very thin flap created, the ablation was not deep, and yet he developed ectasia,” Dr. Trattler said.
Still, the odds are very low — perhaps one in 5,000 to 10,000 — of ectasia occurring in a LASIK candidate without topographic warning signs, even if his residual stromal bed is above the 250 micron level, he said.

Current ectasia treatment options

Patients that develop ectasia have a variety of options for visual rehabilitation. In particular, there are many new types of contact lenses for ecstatic corneas that provide better vision and are more comfortable than in the past.
Besides reverse-geometry RGP lenses, contact lens specialists can use the Boston scleral lens (invented by Perry Rosenthal, M.D., Boston Foundation for Sight, Needham, Mass.), which is a 15- to 18-mm diameter RGP lens that vaults over the cornea.
Since the apex of the lens does not touch the cornea, it is very effect in ectactic.

Another contact lens option is a soft contact lens called Eni-Eye (AccuLens, Denver). This is specifically designed for patients with ectactic corneas that have difficulty tolerating RGP lenses.
“The art of contact-lens fitting has evolved to such great degree that all of the ectasia patients I have worked with except for one (who had Intacs, Addition Technology, Des Planes, Ill.) are comfortably wearing contact lenses and doing very well,” Dr. Trattler said.
Dr. Trattler gives credit to the local contact lens expert, who has helped the vast majority of the ectasia patients reach 20/25 or better best corrected visual acuity with the help of the variety of contact lens choices.
If contacts do not help the situation, the next step is Intacs, Dr. Trattler said.
“Intacs have been shown to be very effective for ectasia,” Dr. Trattler said.
Essentially, Intacs reshapes the cornea, flattening the central cornea, he said. This counteracts the abnormal bulging forward of the thinned cornea.
Still another alternative, although experimental in the U.S., is to perform a collagen strengthening procedure. This is done by applying riboflavin to the cornea, and activating the riboflavin with ultraviolet (UV) light. The activated riboflavin induces cross-linking of the collagen fibers, which strengthens the cornea.
So the end result is that the ectasia-weakened corneas become stronger and flatter, he said. The procedure is new and is currently undergoing clinical trials, he said.
“Even with Intacs or collagen strengthening, ectasia patients may still need contacts to achieve their best visual acuity,” Dr. Trattler said.
Finally, lowering a patient’s IOP may help reduce problems associated with ectasia, Dr. Trattler said.
Brian S. Boxer Wachler, M.D., director, Boxer Wachler Vision Institute, Beverly Hills, Calif., has reported one case where ectasia was caught four months after LASIK, Dr. Trattler said. Subsequently, the patient was prescribed Timoptic (timodol maleate, Merck, whitehouse Station, N.J.) to lower the eye pressure. Within one month, ectasia was no longer visible on topography, Dr. Trattler said.
“After seven months of Timoptic, the corneal shape remained stable. The Timoptic was stopped, and within three months, the ectasia had recurred,” Dr. Trattler said. “The patient was restarted on timoptic, and the ectasia resolved again, demonstrating that early identification of ectasia followed by lowering the pressure can potentially help.”

Editors’ note: Dr. Trattler has no financial interests related to his comments.

Contact Information
Trattler: 305-598-2020, fax 305-274-0426, wtrattler@earthlink.net