Eye Health Headlines

A procedure called Lasik Xtra, which is designed to strengthen the cornea after LASIK, has received CE approval for marketing in the European Union. It was just approved in Canada as well.

Marketed by Avedro, Inc., Lasik Xtra is a corneal crosslinking procedure that applies the company’s VibeX riboflavin ophthalmic solution to the eye’s surface (cornea), and then uses Avedro’s KXL System to irradiate the cornea with UV-A rays. Lasik Xtra is an accelerated form of crosslinking — Avedro says it takes two minutes — which makes it more convenient to combine with LASIK.

Avedro said that in April it will report on studies that show the procedure has helped people who received hyperopic LASIK, which tends to regress more than myopic LASIK, to maintain the vision correction they had received from LASIK.

Although corneal crosslinking has not received FDA approval yet, Avedro’s VibeX solution has received orphan drug approvals from the agency. Orphan drug status is usually conferred on treatments for rare medical conditions (in this case, keratoconus, which is a gradual thinning of the cornea).

Smoking appears to be a risk factor for corneal haze in patients undergoing laser vision correction surgery to treat -5.0 diopters (D) or more of myopia, according to a recent study.

The research was headed by J. Richard Townley, MD, who was clinical director of ophthalmology services at Lackland Air Force Base (San Antonio, Texas) at the time of the study and is now affiliated with Massachusetts Eye & Ear Infirmary in Boston.

Dr. Townley and colleagues conducted a retrospective review of medical charts of more than 25,000 patients who underwent laser vision correction, with the objective of determining the percentage of these patients who developed corneal haze in association with smoking.

A total of 157 patients developed post-operative haze that was graded more than “mild.” Among them, 127 had been treated with PRK, 32 had undergone LASEK, and one patient had undergone LASIK.

The amount of treatment ranged from 3.9 D of farsightedness to -8.0 D of nearsightedness.

The researchers found that smokers undergoing laser vision surgery for the correction of -5.0 D of myopia or more were significantly more likely to develop corneal haze than non-smokers or smokers undergoing laser surgery to correct lesser amounts of refractive error.

Based on the results of the study, Dr. Townley recommended that refractive surgery candidates should be encouraged to stop smoking. Longer use of topical steroid medications after laser eye surgery also might lower the risk of corneal haze among smokers, he said.

Dr. Townley cautioned that because the rate of corneal haze in this study population was so low, a large multi-center prospective study would be helpful to reach definitive conclusions about the risk of corneal haze after refractive surgery associated with smoking.

LASIK is safe and effective for the correction of myopia in adults with amblyopia in one eye, according to a new study.

Researchers in Israel evaluated the effects of LASIK in adult patients with mild to moderate refractive amblyopia caused by significant inequality in the degree of myopia in their two eyes.

The retrospective study evaluated 30 nearsighted patients with unilateral amblyopia who underwent same-day bilateral LASIK. Prior to surgery, the corrected distance visual acuity (CDVA) in amblyopic eyes was approximately 20/35 or worse.

All LASIK procedures were performed using a Technolas 217z excimer laser (Bausch + Lomb), and patients ranged in age from 18 to 53 years (mean: 31 years).

Results of the study included:

• Myopia was significantly reduced in all treated eyes.
• Mean CDVA was slightly improved in both amblyopic and non-amblyopic eyes.
• Five of 30 eyes with mild to moderate amblyopia gained two to four lines of corrected distance visual acuity.

The study authors concluded laser eye surgery for the correction of nearsightedness was safe and effective in eyes with mild to moderate unilateral amblyopia.

SOURCE: LASIK correction of vision in adults with unilateral amblyopia. Journal of Refractive Surgery. January 2011.

It may be safe for some young people under the age of 21 to undergo LASIK surgery without significant risk of a recurrence of nearsightedness, according to a new study.

Researchers in Jordan recently conducted a large-scale study of the stability of refractive errors to determine which types of patients are most likely to have stable vision correction after refractive surgery and which are at greatest risk for refractive change.

The retrospective study evaluated the refractive errors of 46,384 consecutive patients seen at a single outpatient clinic in Amman, Jordan. Patients were distributed into four groups, based on refractive error:

• Emmetropia — Those with no nearsightedness, farsightedness or astigmatism.
• Low to moderate myopia — Those with up to -6.00 diopters (D) of nearsightedness.
• High myopia — Those with greater than -6.00 D of nearsightedness.
• Hyperopia — Those with any degree of farsightedness.

The age of the patients in the study ranged from 3 to 82 years.

Analysis of the study data revealed:

• Patients with less than -1.00 D of myopia at age 10 and less than -3.00 D of myopia at the time of LASIK surgery (after age 21) had no change in their nearsightedness after age 18.
• Among patients with high myopia, 7.4 percent demonstrated corneal changes that did not stabilize until age 30.
• Patients with hyperopia tended to experience a progression of their refractive error from age 30 to age 50.

Based on the results of the study, the researchers concluded that the minimum age of patients undergoing LASIK for the correction of less than -3.00 D of myopia can be safely lowered from 20 years to 18 years with little risk of progression of myopia after surgery.

The researchers also said that all patients seeking laser vision correction should be educated prior to surgery regarding the risk of progression of refractive error and other possible risks and LASIK complications, based on their required correction.

SOURCE: Age and refraction in 46,000 patients as a potential predictor of refractive stability after refractive surgery. Journal of Refractive Surgery. August 2009.

DUBLIN, Calif. — Carl Zeiss Meditec has released its new ReLEx vision correction method outside the United States. ReLEx uses only the VisuMax Femtosecond laser, as opposed to other LASIK methods that use a combination of a femtosecond laser or a microkeratome (blade) to create the flap and an excimer laser to correct the vision problem.

In the ReLEx version of LASIK, a flap is cut and a piece of tissue called a lenticule is created under the eye’s surface. The tissue is lifted out, and the flap is replaced on the eye.

In a release, Carl Zeiss Meditec CEO Ludwin Monz commented that the system would deliver “unprecedented workflow benefits” to refractive surgery practices.

The VisuMax Femtosecond laser can be used for vision correction procedures other than LASIK, such as the FLEx (femtosecond lamellar extraction) method and the SMILE (small incision lamellar extraction) method. ReLEx allows for small flap sizes, too. As of April 10, ReLEx procedures had been performed on more than 1,000 eyes outside the U.S.

ALICANTE, Spain — A retrospective study of 100 eyes showed that after cataract surgery with either monofocal or multifocal intraocular lens (IOL) implantation, LASIK was generally safe and effective in refining vision even further.

However, LASIK performed on the eyes that had received the monofocal IOLs provided a more accurate outcome than LASIK done on the eyes with multifocal IOLs.

Also, hyperopic LASIK for farsightedness provided a less predictable outcome in the multifocal IOL eyes.

The study appeared in the Journal of Refractive Surgery in August.