[Toric lens implantation in cataract surgery: Automatic versus manual horizontal axis marking, analysis of 50 cases]

SUBJECT

The main objective of our study is to evaluate the contribution of automated conjunctival recognition in the alignment of toric implants by comparing the automatic alignment optimized with Callisto™ to the manual marking of the horizontal axis.

MATERIALS AND METHODS

We performed a prospective, descriptive, and monocentric study on patients undergoing cataract surgery with toric implantation (Asphina 709 Zeiss), operated by a surgeon with good experience in toricity, between September 2016 and March 2017. We analyzed the agreement between the manual marking of the 0°-180° axis versus the one automatically generated by the Callisto™, as well as the alignment of the IOL and the refractive results at 1 month.

RESULTS

We included 50 eyes of 26 patients. The corrected mean astigmatism was 1.9 D. The mean difference between the 2 axes was 4.7° [0°-12.3°]. Only 50 % of the preoperative manual markings were consistent with the automatic measurement (<5°). At one month, the average rotation recorded was 4.3° [0°-29°]. The alignment was identical for 70 % (n=35) of the IOL (≤5°). As for residual subjective astigmatism, it was on average 0.58 D. The mean visual acuity without correction was 8/10 and 55 % had 10/10 without correction.

DISCUSSION

The refractive performance depends on the preoperative measurement, the correct alignment of the IOL and its stability in the bag. Our study shows the value of automatic conjunctival recognition in the determination of the axis of peroperative alignment, even in an experienced operator. This precision is essential for a good refractive result, especially since the residual astigmatism in case of misalignment will increase with the power of the implant.

CONCLUSION

Our study shows excellent refractive results, whatever the initial astigmatism, using the automatic alignment. The precision of the toric implantation opens the way to the toric multifocal implantation under the best conditions.

Toric intraocular lens outcomes with a new protocol for IOL selection and implantation

INTRODUCTION

The published literature on toric intraocular lenses (IOL) reports postoperative refractive cylinder less than or equal to 0.5 D in anywhere from 25% to 100% of implantations with both the Acrysof^® Toric and Tecnis^® Toric IOL, depending upon the article. However, the majority of articles tend to cite rates between 70% and 80%.

PURPOSE

The purpose was to evaluate my personal outcomes for both models of toric IOL, in terms of one-month postoperative refractive cylinder, after implementation of new methods of IOL selection, calculation and implantation.

MATERIALS AND METHODS

The new protocol included measurement of centroid surgically induced astigmatism by vector analysis; calculations using only the Barrett toric calculator, for which the keratometry values were obtained by optical biometry, while the keratometric axes were chosen by visual inspection of the axial topographic map; preoperative marking with the toriCAM cell phone appliance; and corneal incisions performed either manually or with a femtosecond laser. A prospective, observational study was conducted of all consecutive monofocal toric IOL implantations from September 2016 through April 2017. One-month postoperative refractive cylinder was recorded for each eye.

RESULTS

Seventy eyes were implanted with monofocal toric IOL, 31 Acrysof^® Toric and 39 Tecnis^® Toric. Mean postoperative refractive cylinder was 0.48 D (0.00-1.50) for the Acrysof^® Toric group and 0.46 D (0.00-1.00) for the Tecnis^® Toric group. There were no statistically significant differences in postoperative refractive cylinder between IOL models or methods of incision. The percentage of eyes achieving postoperative refractive cylinder ≤0.50 D ("success") was 77% for the Acrysof^® Toric group (82% for laser-assisted and 75% for manual) and 72% for the Tecnis^® Toric group (80% for laser-assisted and 69% for manual).

CONCLUSION

The implementation of the new protocol resulted in an overall surgical success rate of 77% for Acrysof^® Toric IOL and 72% for Tecnis^® Toric IOL (P=0.7702). Femtosecond laser-assisted surgery resulted in higher success rates than manual surgery (82% vs. 75% for Acrysof^® Toric and 80% vs. 69% for Tecnis^® Toric), but these differences were not statistically significant (Acrysof^® Toric P=0.7336; Tecnis^® Toric P=0.8862).

[Optical quality after 2.2mm microincisional cataract surgery with bimanual I/A in 154 eyes]

PURPOSE

A prospective study to analyze the effects of 2.2mm microincisional coaxial phacoemulsification with bimanual irrigation/aspiration on the optical quality of the cornea and whole eye.

METHODS

We compare two groups. Group A: 102 consecutive eyes undergoing this three-incision procedure and implanted with an Alcon® SN60WF IQ aspheric intraocular lens. Astigmatism, corneal and total asphericity, as well as H/B ratio were measured by OPD scann II, Nidek®, Japan, preoperatively (Day 0), 15 days postoperatively (Day 15) and 1 month postoperatively (M1). Group B: 52 eyes with corneal astigmatism greater than 1.25D, undergoing the same procedure but implanted with a Toric IOL (Alcon® Toric IQ SN6AT), followed in the same manner but with additional follow-up at 1 year.

RESULTS

Corneal surgically induced astigmatism (SIA) was essentially neutral: 0.065D ± 0.86 at Day 30 in group A, and 0.06D ± 0.34 at 1 month and -0.008D ± 0.4 at 12 months in group B. Corneal topographic astigmatism underwent a mean axis shift of 29.95° ± 27.6 in group A compared to 5.3° ± 3.7 in Group B, and remained stable at 1 year. Corneal asphericity did not change significantly between Day 0 and 30 in either group. H/B ratio increased significantly in both groups, with a gain of 22 % to 24 % after surgery.

CONCLUSIONS

This three-incision procedure does not degrade the optical quality of the cornea. Postoperative shift in the axis of astigmatism is only an issue in cases of low or asymmetric astigmatism and must be kept in mind for low-power toric IOL implantation.