Abstract
Purpose :
Compare the refractive predictability of low power versus medium power toric intra ocular lenses (IOL).
Methods :
We realized a retrospective, monocentric, comparative, not randomized study. Eighty operated eyes were randomly recruited in 2015. We used 709MP+1D (Carl Zeiss Meditec, Jena, Germany) and SNAT2 (Alcon, Forth Wroth Texas, USA) for low powers IOLs ; and 709MP+1,5D (Carl Zeiss Meditec, Jena, Germany) and SN6AT3 (Alcon, Forth Wroth Texas, USA) for medium powers IOLs. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, keratometry, topography, aberrometry, biometry, biomicroscopy, dilated fundus examination were evaluated preoperatively and 1 month postoperatively. Total astigmatism and corneal astigmatism were compared pre and postoperatively for each patient. Statistical calculations were performed using the Student T test.
Results :
Eighty eyes of 71 patients were assigned into 2 groups according to the IOL toric power, 37 eyes in group 1 (T2/+1) and 43 eyes in group 2 (T3/+1,5). The mean age was 74,6±2,21 years old in group 1, not statistically different from group 2. The preoperative total astigmatism was statistically different between the 2 groups (p=0,002). The residual postoperative total astigmatism was 0,56D±0,17 in group 1, versus 0,63D±0,25 in group 2 (p=0,52). The postoperative spherical equivalent weren’t different between the 2 groups, 0,037 in group 1, versus -0,076 in group 2 (p=0,37). The postoperative UDVA was 0,12 logMAR in group 1 versus 0,06 logMAR in group 2 (p=0,09). The group 2 showed a better proportion of astigmatism corrected by the IOL (p=0,02). The mean variation of toric IOL axis was statistically significant between pre and postoperative mesures in the 2 groups : 19,3 degrees (p=0,02). This variation was higher in group 1 : 27 degrees (p=0,01).
According to the group 1 subanalysis between SNAT2 (n=15) and 709MP+1 (n=22), there is no significant refractive difference between the two IOLs.
Conclusions :
Refractive results from group 2 (medium powers IOLs) are more predictable. The axis variation of astigmatism in group 1 could explain this difference. There are no significant differences between the two low power toric IOLs.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.