Paragon launches post RK, PRK, LASIK soft lens

Issue: October 1997

MESA, Ariz. — Even as radial keratotomy (RK), photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) procedures enjoy ever higher rates of success as well as popularity with consumers, those very same patients are demanding higher rates of postoperative acuity as part of their eye care package.

As a result, Paragon Vision Sciences, located here, has introduced the Harrison Post Refractive Surgery (PRS) soft lens for patients who continue to require vision correction or vision enhancement in one or both eyes following PRK, RK or LASIK.

Although other postoperative specialty soft lenses, rigid gas-permeable (RGP) and bandage contact lenses are available, Paragon representatives said the Harrison PRS lens is "unique in that it accommodates the flat area of the cornea, but centers extremely well by draping over the steeper periphery of the cornea."

Approved by FDA

The Harrison PRS lens, manufactured by Paragon’s Flexlens Products specialty soft lens facility in Englewood, Colo., is currently the only soft lens with marketing approval from the Food and Drug Administration (FDA) to correct vision following refractive surgery, the company said in a released statement. The FDA approved the lens for marketing for this indication in October 1996.

"Even after reasonably successful refractive surgery, where vision may be corrected to as good as 20/30, many doctors will find the Harrison PRS lens the perfect contact lens to enhance patients’ vision," said Dave Dougherty, vice president of Sales and Business Development for Flexlens Products.

Keith Harrison, CLSA, director of the Contact Lens Clinic at the Toronto Eye Hospital in Canada, is the designer of the new lens.

Mr. Harrison described the singular optical requirements of a post refractive surgery patient and what the Harrison PRS can offer in terms of acuity and comfort.

"In this case, necessity was truly the mother of invention," Mr. Harrison said, "and in working with these post refractive surgical corneas and feeling limited because an RGP will give you the vision — no question about it. But from all practical standpoints it’s difficult to fit such an atypical corneal topography with a rigid lens — even a rigid lens designed for a flat center and steep periphery, and you’ve got a patient who had refractive surgery in the first place so they wouldn’t have to wear contacts."

Mr. Harrison said the success or failure of a new lens depends heavily on its shape in relation to the postsurgical topography of a patient’s cornea.

"The dynamics of the lens when it goes on the eye is to have a flat central curve with a thick optical zone for when it rests on what used to be the apex of the cornea and now may be mildly invaginated," Mr. Harrison explained. "It will align and reduce the tear layer between the lens and the eye to a more normal thickness. On a cornea that has just had, for example, RK, because of the invaginated nature of the center of the cornea, you now have a central tear thickness sometimes approaching four to six times that of a normal tear layer.

"With the soft lens you have a better chance of reducing that tear layer and certainly increasing regularity in optics," he continued.

Lens construction is key

Teresa Holleman, marketing director of new products for Paragon, said the key element of the Harrison PRS lens that makes it singular lies in its construction.

"The lens is designed with a reverse geometry that allows the central optical zone to be flatter than the mid-periphery," Ms. Holleman said. "So it’s flatter in the area where the surgery has actually occurred. And then there is a very thin peripheral lens carrier like a thin flange, which allows the lens to drape over the steeper part of the cornea."

Ms. Holleman said, "Conventional soft lens designs do not readily align with the visual axis that exists following refractive surgery, nor do they supply sufficient masking of corneal astigmatism. Many post refractive surgery patients also prefer the potential of intermittent wear afforded by a soft lens to augment low levels of ametropia."

For Your Information:

Dave Dougherty can be reached at Flexlens Products, 3241 South Zuni St., Englewood, CO 80110; (800) 223-3539; fax: (303) 789-0647.

Keith Harrison, CLSA, can be reached at Toronto Hospital, West Division, Edith Cavell Wing, 7th Floor, Room 14, 399 Bathurst St., Toronto, M5T 2S8; (416) 603-5474; fax: (416) 603-5114

Teresa Holleman can be reached at 947 East Impala Avenue, Mesa, AZ 85204; (800) 340-5129, Ext. 7605; fax: (602) 926-7369.

The Harrison PRS soft lens is distributed by Paragon Vision Sciences and is manufactured by the company’s Flexlens Products specialty soft lens facility in Englewood, Colo. For more information, contact Paragon Vision Sciences at 947 East Impala Avenue, Mesa, AZ 85204; (800) 528-8279; fax (602) 926-7369.