effects of intracorneal ring segment on corneal biomechanics in keratoconic eyes

purpose : to evaluate the biomechanical changes of cornea after intracorneal ring segment (icrs) implantation in keratoconic eyes methods : in this study, 1 or 2 icrs were inserted in 17 keratoconic eyes. best spectacle-corrected visual acuity (bscva), uncorrected visual acuity (ucva), refraction, and keratometry were evaluated preoperatively and 1 and 3 months after surgery. corneal hysteresis (ch) and corneal resistance factor (crf) were also measured preoperatively and postoperatively with ocular response analyzer (ora). results : icrs was inserted in 17 keratoconic eyes (12 patients). mean ucva significantly increased from 0.72±0.37 logmar to 0.54±0.27 logmar (p=0.027) and 0.46±0.30 logmar (p=0.01) 1 and 3 months after surgery, respectively. mean bscva increased from 0.41±0.29 logmar to 0.32± 0.26 logmar at the end of the 1st month and 0.32±0.27 logmar at the end of 3rd month postoperatively. these changes were not significant. spherical equivalent (se) significantly decreased from -5.64±3.21 diopter (d) to -3.36±2.74 d (p=0.009) 1 month and -3.51±2.04 d (p=0.002) at the 3 months after surgery. mean keratometry also significantly decreased from 49.82±4.33 d to 48.10±3.64 d (p=0.010) and 47.40±3.47 d (p=0.003) at 1- and 3- month follow-ups, respectively. mean ch was 7.48±1.65 mmhg and mean crf was 5.98±2.06 mmhg, preoperatively. at 1-month follow-up, their values were 7.13±1.56 mmhg and 5.74±1.60 mmhg, respectively. at 3-month follow-up, their values were 7.20±1.23 mmhg and 5.80±1.72 mmhg, respectively. the ch and crf changes at 1- and 3-month follow-ups were not significant. conclusion : after icrs insertion in keratoconic eyes, no significant changes were observed in mean values measured with the ora at 1- and 3-month follow-ups.    iranian journal of ophthalmology 201022(4):25-30 © 2010 by the iranian society of ophthalmology