Nearsighted people who can’t have laser-assisted eye surgery may benefit from implantable lenses made of a collagen-like substance, say Japanese researchers.They noted that LASIK “has gained widespread popularity as a safe and effective surgical method for correction of myopia, but patients with high [severe] myopia or thin corneas face some restrictions in avoiding the risk of developing keratectasia [a weakening of the cornea].”

Earlier reports found that implantable lenses made of a collagen copolymer were effective in correcting moderate to severe vision problems. The implantation is reversible and the lenses are interchangeable. However, concerns were raised that the lenses cause complications such as cataracts, loss of cells lining the eye and glaucoma.

In this study, the researchers at the University of Kitasato School of Medicine in Kanagawa evaluated 56 eyes of 34 patients with the implantable lenses. The patients were assessed at regular intervals for four years after implantation.

After four years, 44 of the eyes (79 percent) were within 0.5 diopter (unit of measuring lens power) of the targeted correction and 52 eyes (93 percent) were within one diopter, the study found.

The researchers wrote that “results were good in all measures of safety, efficacy, predictability and stability for the correction of high myopia throughout the four-year follow-up.” They found no vision-threatening complications during the follow-up perod, they said.

They concluded that these lens implants “may be a good alternative for the treatment of moderate to high myopia. More prolonged careful observation for longer than four years is necessary to assess late-onset complications of this surgical technique.”

The study appears in the July issue of the Archives of Ophthalmology.