Determination of Corneal Hysteresis Pre and Post Intracorneal Ring

Abstract

Purpose: : Compare the corneal hysteresis in patients with queratocono and postsurgical implantation of intracorneal rings, and justify its therapeutic use, stabilizing corneal biomechanics in these patients.

Methods: : This is a comparative, cross-sectional study; our statically analysis was made with a non paired T test with a 0.05 alpha. We studied a series of 43 eyes that were divided in two groups, the first one involves 21 eyes with the diagnosis of queratocono and the second one involves 22 eyes postsurgical implantation of intracorneal rings. This study was made in the Departament of Cornea and Refractive Surgery of the Instituto de Oftalmología, Fundación Conde de Valenciana I.A.P., Mexico City. Of this series the quantification of the corneal hysteresis was made with the ocular response analyzer (ORA), pre and postsurgical implantation of intracorneal rings. Other variables that were included are sex, age, visual acuity, refractive error and type of ring.

Results: : We study 25 patients, total of 43 eyes, the mean age was 26.3 years (range 17-35), 50% were male and 50% were female. The visual acuity previous surgery varied from count fingers at one feet to 20/70, postsurgical implantation of the rings the visual acuity remain the same in quantity but better in quality, less refractive error in some cases, and with regard to biomechanics of the corneal hysteresis the mean deviation was 7.10 in the first group and 6.95 in the second group, variance of 2.03 in the first group and 1.39 in the second group, with p of 0.69, no significant statistically.

Conclusions: : The expected biomechanical properties changes of the cornea did not were demonstrated by the hysteresis corneal results using the ORA.

Keywords: keratoconus • refractive surgery: other technologies • cornea: clinical science