Outcome of intrastromal corneal ring segment relative to depth of insertion evaluated with scheimpflug image

Purpose: to report the results of intrastromal corneal ring segment (keraring; mediphcose,belo horizonte,brazil) implantation relative to depth of insertion in keratoconic patients. methods: in this retrospective,observational study,we evaluated 29 eyes of 27 patients with keratoconus who underwent implantation of keraring si-5 with mechanical tunnel creation. in the mean follow-up of 8.8 months,all eyes underwent scheimpfluge image of pentacam (oculus,germany) to determine insertion depth. based on the measured implantation depth,cases were categorized into: 40-59% thickness group,60-79% thickness group,and ≥80% thickness group. visual,refractive,and shape outcomes were evaluated relative to implantation depth. results: the mean insertion depth was 61.7%.we had 41.4% of cases were in the 40-59% thickness group,51.7% in the 60-79% group,and 6.9% in the >80% group. results were similar in 40-59% and 60-79% thickness groups: uncorrected visual acuity (ucva) and best spectacle corrected va (bscva) improved 3 and 2 lines,respectively,maximum keratometry (kmax) decreased 2.6 d,refractive cylinder improved 2.04 d,and q value 8 mm anterior changed by 0.35. in the ≥80% thickness group,ucva and bscva improved less than 1 lines,kmax change was less than 0.5 d,and rc decreased less than 0.25 d. conclusion: implantation of keraring with mechanical tunnel creation in 40-80% of stromal thickness despite the variable insertion depth is effective. © 2015 iranian society of ophthalmology.