May 28, 2003 — Corneal ring segments, marketed under the name Intacs (Addition Technology, Inc.), improve visual acuity in patients with keratoconus, according to the results of a nonrandomized, retrospective study published in the May issue of Ophthalmology.
"Patients with keratoconus are often fitted with rigid, gas-permeable contact lenses, which can cause corneal scarring. If they develop contact lens intolerance, they often proceed to corneal transplants," lead author Brian S. Boxer Wachler, MD, from the Boxer Wachler Vision Institute in Beverly Hills, California, says in a news release. "The use of Intacs seems to be an ideal solution, since it is a less invasive surgical intervention that changes the curvature of the cornea without removing tissue. It also provides good visual outcomes and helps patients avoid the risks of corneal transplantation."
This study evaluated 74 eyes in 50 patients, including 41 men and nine women, mean age of 35 years (range, 20-73 years). One eye was implanted with the corneal ring segments in 26 patients, and both eyes in 24 patients.
The corneal ring segments significantly improved uncorrected and best-corrected visual acuity, whether or not there was corneal scarring. Visual acuity improved by two or more eye-chart lines in corrected visual acuity in 33 eyes (45%) and by two or more lines in uncorrected visual acuity in 53 eyes (72%).
Mean best-corrected logMAR visual acuity was 0.41 ± 0.48 (20/50-1) preoperatively and 0.24 ± 0.31 (20/32-2) postoperatively, or two lines of improvement. Corresponding figures for uncorrected logMAR visual acuity were 1.05 ± 0.48 (20/200-2 1) and 0.61 ± 0.52 (20/80-), respectively, or four lines of improvement.
"This is a very promising study. There is great benefit to avoiding corneal transplants," said American Academy of Ophthalmology spokesperson Ernest Kornmehl, MD, from Kornmehl Laser Eye Associates. "However, because follow-up in this study ranges from one to 20 months, longer term follow-up will be needed to determine if the results are stable."
Reviewed by Gary D. Vogin, MD
Medscape Medical News © 2003
Cite this: Laurie Barclay. Corneal Ring Segments Effective in Keratoconus - Medscape - May 28, 2003.