Effect of the Morcher capsular tension ring on refractive outcome

PURPOSE: To evaluate the effect of the Morcher capsular tension ring (CTR) on refractive outcome in patients having cataract extraction by phacoemulsification complicated by zonular instability. SETTING: Dean A. McGee Eye Institute, Oklahoma City, Oklahoma, USA. METHODS: A retrospective case-control series of 19 eyes of 19 patients with a CTR were compared with a control population of 24 eyes without zonular instability having routine cataract surgery. A subset of 9 patients with a CTR in 1 eye but milder zonular instability in the contralateral eye not requiring a CTR was analyzed. The main outcome measures were the mean arithmetic and absolute refractive prediction errors (ArRPE, AbRPE) and variances used to gauge accuracy and precision. RESULTS: The CTR and control groups were compared using SRK/T and Holladay 2. There was no statistically significant difference in ArRPE or AbIRPE, but lower variances in eyes with a CTR were identified. The CTR subset demonstrated a trend toward more accurate outcomes when using Holladay 2 but not SRK/T when compared with contralateral eyes without a CTR. Both formulas showed lower variances in the CTR eyes than in the contralateral eyes. CONCLUSIONS: In this small population, there was no consistent effect on refractive outcome when a Morcher CTR was placed that would necessitate modification of intraocular lens power calculations. The eyes with a CTR had refractive outcomes as accurate as and more precise than the outcomes in the contralateral eyes with milder zonular instability and the control population of eyes without zonular instability in either eye. The Morcher CTR is not only a tool to assist in complicated cataract surgeries, but a device that can deliver more accurate and precise refractive outcomes.