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Emerging Refractive Technologies

Learn the latest in refractive lasers, procedures and products to retain your position as a refractive expert

JIMMY JACKSON, O.D., DENVER, COLO.

Although the optometric profession has evolved to include medical eye care, patients continue to view optometrists as the refractive experts. As a result, we must stay abreast of the latest advances in refractive surgery, so we can retain these patients post procedure.

Here, I discuss what is on the horizon, so you can maintain your reputation as an astute eyecare professional.

Topography-guided/multifocal ablations

Topography-guided ablations (utilizing either LASIK or PRK) are ideal for patients who have decreased BCVA or quality of vision due to irregular corneas from previous corneal surgery or injury. These ablations have been available outside the United States for several years now and are currently undergoing U.S. clinical trials. They work well, and I anticipate FDA approval in the next one to two years.

PresbyLASIK, also known as multifocal LASIK and bifocal LASIK, is designed for presbyopic patients who desire spectacle- and contact lens-free vision. Different ablation profiles have been tried outside the United States and are analogous to the different multifocal contact lens designs available in the United States. Also, similar to multifocal contact lenses, PresbyLASIK’s success depends on a combination of pupil size, lighting conditions and neuro-adaptation.

The procedure is currently undergoing U.S. clinical trials, but is several years away from reaching the U.S. market.

Corneal cross-linking

Corneal cross-linking (CXL) involves the application of UV light onto the cornea after pretreatment with riboflavin to strengthen a weakened cornea. The procedure, which can be performed with the epithelium intact or following removal of the epithelium, is designed for patients who have keratoconus, ectasia or an unstable radial keratotomy and, thus, require corneal support. CXL has been performed internationally for several years with encouraging results.

Sometimes, the procedure is used after the insertion of Intacs segments. These are small semicircular plastic rings of various thickness and lengths originally approved for the treatment of myopia. Specifically, the Intacs are inserted into the midperiphery of the cornea at a depth of 250µ to 300µ, which creates a central flattening. This provides additional corneal support for keratoconus and ectasia patients. Intacs may also be utilized in keratoconus patients without the subsequent CXL.

CXL is becoming more available in the United States under the auspices of numerous clinical trials as an off-label procedure.

Corneal inlays

These are tiny optical devices or lenses implanted underneath a flap or corneal pocket. Inlays are utilized to provide near vision similarly to monovision. They may be used in conjunction with LASIK in which the Excimer treatment is for the underlying refractive error and the inlay is for presbyopia correction. A huge selling point of all inlays is that they can be removed if the patient is dissatisfied.

The corneal inlays closest to FDA approval are the Kamra, from Accufocus, and the Raindrop, from ReVision Optics.

The Kamra received FDA panel approval (essentially one step from full approval) earlier this year. The Kamra functions as a pinhole device and is implanted in the non-dominant eye. It provides near vision via an extended depth of focus. Accurate centration is obviously critical.

The Raindrop is a hydrogel inlay that creates a more prolate cornea. The center area of the Raindrop provides near vision with a gradual transition toward the periphery. It is, likewise, implanted in the non-dominant eye.

Phakic IOLs also known as ICLs

The FDA has given preliminary approval to the toric model of the Visian ICL, from Staar Surgical, which has been available internationally for several years.

The currently available Visian ICL is a posterior chamber lens inserted behind the iris and in front of the natural lens (in the ciliary sulcus) to correct moderate to severe myopia. It is most commonly utilized in patients who have thinner corneas, which limits their candidacy for LASIK or PRK. It is made of a soft, foldable material that can be inserted through a 2.8mm corneal incision. (See “Refractive Cataract Surgery,” left.)

Confirmation

Patients present to their optometrist because they want to achieve the best vision possible. By being aware of what is forthcoming in refractive surgery, and sharing this information with patients, you confirm for them that you are, indeed, the best person to oversee their vision. OM

Dr. Jackson founded InSight Lasik in 2001. He provides evaluative, pre-operative and post-operative care. Also, he lectures extensively and has published numerous articles on the management of refractive surgery patients. E-mail him at jimmy@insightlasik.com, or send comments to optometricmanagement@gmail.com.