Capsular tension rings to reduce refractive shift
Reviewed by Inderpaul Sian

The study group aimed to determine whether the use of a capsular tension ring (CTR) can increase refractive stability in patients with implantation of two different trifocal intraocular lenses. This was a prospective, consecutive series of eyes which underwent refractive lens exchange with implantation of two different trifocal IOL designs: FineVision Micro F (non-toric) and FineVision POD FT (toric) (PhysIOL, Liege, Belgium). Power calculation was determined using the Haigis formula. Refractive lens exchange surgery was performed according to the standard Memira protocol. Refractive results and stability were assessed at two weeks and three months postoperatively. All surgeries were conducted by two surgeons under topical anaesthesia. The CTRs were inserted through a 2.2mm main incision prior to IOL insertion. Three hundred and eighty-eight eyes were included in the study analysis. Overall, 71% and 76% of MicroF eyes implanted with (n=139) and without (n=104) a CTR, respectively, had hyperopic shift; 9% of MicroF eyes with a CTR had a shift of greater than +0.50 to +0.75 or less diopters (D) and 4% had a shift of greater than +0.75 D. In MicroF eyes without a CTR, 12% and 3% of eyes experienced a refractive shift of greater than +0.50 to +0.75 D or less and greater than +0.75 D, respectively. In the POD FT group, 72% and 69% of eyes with (n=81) and without (n=64) a CTR, respectively, had hyperopic shift; 10% of POD FT eyes with a CTR had a change of greater than +0.50 to +0.75 D or less and 7% had a shift of greater than +0.75 D. In POD FT eyes without a CTR, 13% and 3% experienced a refractive shift of greater than +0.50 to +0.75 D or less and greater than +0.75 D, respectively. For the MicroF design, the best refractive stability was found in the CTR group and the poorest stability in the non-CTR group (P=.084). For the POD FT design, the best refractive stability was found in the non-CTR group and the poorest stability in the CTR group (P=.297). Up to 7% of eyes implanted with FineVision trifocal IOLs had a hyperopic shift of greater than +0.75 D approximately two weeks to three months postoperatively. Using a CTR in MicroF eyes had no statistically significant effect on refractive stability. Placing a CTR with POD FT IOLs appeared to reduce refractive stability, although not significantly. This study shows that a high proportion of patients with implantation of FineVision trifocal IOLs experience varying amounts of hyperopic shift. Using a CTR did not have any effect on the amount or direction of refractive shift for either trifocal design. Use of a CTR in patients with POD FT IOLs had a slightly negative effect on refractive stability and a minimal positive effect in patients implanted with the FineVision MicroF IOL. The study follow-up period was only three months, whether refractive shift with the IOL designs stops at three months requires further investigation.

The use of capsular tension rings to reduce refractive shift in patients with implantation of trifocal intraocular lenses.
Nistad K, Göransson F, Støle E, et al.
JOURNAL OF REFRACTIVE SURGERY
2017;33(12):802-6.