Study: Better Alignment, Visual Acuity with Femtosecond Laser-Assisted Capsulotomy Markings Than Slit Lamp-Assisted Manual Markings

Patients whose cataract surgeries were performed using femtosecond laser-assisted capsulotomy markings (CM) showed significantly higher axis alignment than those who received conventional slit lamp-assisted manual marking (MM), resulting in lower residual astigmatism and better visual outcomes, according to new research.

Researchers conducted a prospective study to compare the accuracy of both toric intraocular lens (IOL) alignment and visual outcomes using the two marking methods. Investigators assessed 57 eyes from 57 patients with cataracts who underwent toric IOL implantation between November 2016 and May 2017. The marking method was decided by each participant, with a full understanding of potential risks and benefits. Patients were then divided into 2 groups based on the method they chose. The MM group consisted of 31 eyes (mean age 68.94±11.52 years; 19 females) and the CM group, which consisted of 26 eyes (mean age 72.69±10.75; 14 females).

All participants were evaluated via comprehensive ophthalmologic examination prior to surgery. Participants were also evaluated at 1 and 3 months postoperatively, with modulation transfer function used as an objective measure of visual quality.

All operations were completed successfully. Both groups achieved good postoperative outcomes for both visual acuity and astigmatism correction. For the CM group, mean uncorrected distance visual acuity (UCDVA) (logMAR)  was 0.16±0.09 1 month postoperative and 0.15±0.09 at 3 months. Both outcomes were significantly different from preoperative assessments (P <.05).

In this study, astigmatism was significantly reduced in both cohorts. Toric IOL alignment was also excellent in both groups, although the authors noted that toric IOL misalignment was significantly lower in the CM group.

Residual astigmatism was 0.62±0.28D and 0.64±0.26D in the MM group and 0.35±0.22D and 0.30±0.18D in the CM group at postoperative months 1 and 3, respectively.

The CM group experienced significantly better UCDVA outcomes compared with the MM group at postoperative months 1 and 3 (P <.05). Best-corrected distance visual acuity (BCDVA) was not significantly different between the cohorts at postoperative month 3.

Results of a correlation analysis indicated that postoperative UCDVA (logMAR) was positively correlated with residual astigmatism (r=0.339) and IOL misalignment (r=0.317) and negatively correlated with AR value (r=-0.272; P <.05 for all). No correlation was noted between BCDVA and residual astigmatism, IOL misalignment, or AR value (P >.05).

Study limitations include differing surgical methods between the 2 groups, which may affect astigmatism correction effect and rotational stability of the toric IOL.

“[Femtosecond laser-assisted capsulotomy marking] is a safe and accurate method for toric IOL marking and provides better astigmatism correction and visual outcomes than using manual marking for postoperative IOL alignment,” the authors concluded.

Reference

Qingzhong C, Guangbin Z. Iris-registration capsulotomy marking versus manual marking for toric intraocular lens alignment in cataract surgery. Am J Ophthalmol. [published online September 1, 2020]. doi: 10.1016/j.ajo.2020.08.041