Prescription inserts approved for keratoconus treatment

September 1, 2004

Des Plaines, IL-Physicians treating advanced keratoconus may find a new standard of care now that the FDA has approved a Humanitarian Device Exemption (HDE) for micro-thin prescription inserts (Intacs).

Des Plaines, IL-Physicians treating advanced keratoconus may find a new standard of care now that the FDA has approved a Humanitarian Device Exemption (HDE) for micro-thin prescription inserts (Intacs).

The exemption, which was authorized Aug. 5, allows up to 4,000 patients per year within the United States to have the prescription inserts implanted. Manufactured by Addition Technology Inc., the inserts are used to reinforce and flatten the cone-shaped cornea to allow patients to achieve a better fit with rigid contact lenses or better vision with eyeglasses. Under the exemption, the prescription inserts will be implanted primarily in patients who are no longer able to wear contact lenses and for whom a corneal transplant may be the only remaining option. Coincidentally, about 4,000 corneal transplantations are performed each year to treat keratoconus.

The prescription inserts were approved in 1999 for the treatment of myopia; in September 2003, the company received Humanitarian Use Device status from the FDA as the first step toward achieving the exemption.

"Patients should be informed that Intacs do not cure their corneal condition and will not generally spare them the necessity for wearing a contact lens," noted Dr. Schanz-lin, who also is head of Addition Technology's scientific advisory board.

"Our experience has been an average of 3 lines of improvement of best spectacle- corrected visual acuity (BSCVA) and 5 lines of uncorrected visual acuity (UCVA)," Dr. Schanzlin said. "We see this marked improvement in spite of the fact that the keratometry is usually minimally changed. We believe that this improvement in UCVA and BSCVA is due to a significant decrease in the irregular astigmatism, caused by the Intacs."

Personal perspective Leslie A. Eisner, MD, a cataract surgeon in Stamford, CT, said having the prescription insert implanted in his left eye by Mark A. Swanson, MD, of Sonora, Mexico, has helped him avoid penetrating keratoplasty for his pellucid marginal degeneration.

"I had developed, over 3 or 4 years, an increasing amount of irregular astigmatism to the point where I could not wear contact lenses comfortably or with satisfactory vision. So, while my vision was functional, it was going downhill. I didn't know how bad it could get," said Dr. Eisner, who eventually had 10 D of astigmatism in his left eye.

At the American Academy of Ophthalmology meeting in 2003, he met with Dr. Swanson and discussed his work with the prescription inserts. Dr. Eisner, 52, underwent the procedure Feb. 13, and said it has lessened his astigmatism so that he can wear a soft contact lens in that eye with "reasonable comfort most of the day, and good vision."

He plans to repeat the procedure in his right eye in February 2005.