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Intrastromal corneal ring segment achieves corneal flattening in keratoconic eyes
J Cataract Refract Surg. 2009;35(9):1604-1608.
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Implantation of a new intrastromal corneal ring segment effectively treated keratoconus, a study showed.
"It improved visual acuity and reduced corneal steepening in selected patients," the study authors said.
The retrospective review included 80 eyes of 76 patients who underwent implantation of the Ferrara intrastromal corneal ring segment with 210° of arc.
Investigators assessed uncorrected distance visual acuity, corrected distance visual acuity, refraction and keratometry before and after surgery.
Uncorrected distance visual acuity improved from 20/350 preoperatively to 20/136 postoperatively (P = .001). Corrected distance visual acuity improved from 20/125 preoperatively to 20/50 postoperatively (P = .0001).
Mean spherical equivalent diminished from –5.22 D preoperatively to –2.26 D postoperatively. The difference was statistically significant (P = .05).
Corneal flattening occurred in all eyes, based on corneal tomography with the Pentacam Scheimpflug camera (Oculus).
The mean keratometry value for the flattest meridian decreased from 51.49 D preoperatively to 47.40 D postoperatively; the reduction was statistically significant (P = .00014). The mean keratometry value for the steepest meridian decreased from 54.33 D to 49.14 D (P = .00022).
Two patients had to undergo penetrating keratoplasty in addition to ring segment implantation, the authors said.