Correcting Corneal Astigmatism with Corneal Arcuate Incisions during Femtosecond Laser Assisted Cataract Surgery

Predictability of Astigmatism Correction by Arcuate Incisions with a Femtosecond Laser Using the Gaussian Approximation Calculation

Planning astigmatic correction is a complex task. Biomechanical simulation models are useful for predicting the effects of the physical procedure on the cornea. Algorithms based on these models allow preoperative planning and simulate the outcome of patient-specific treatment. The objective of this study was to develop a customised optimisation algorithm and determine the predictability of astigmatism correction by femtosecond laser arcuate incisions. In this study, biomechanical models and Gaussian approximation curve calculations were used for surgical planning. Thirty-four eyes with mild astigmatism were included, and corneal topographies were evaluated before and after femtosecond laser-assisted cataract surgery with arcuate incisions. The follow-up time was up to 6 weeks. Retrospective data showed a significant reduction in postoperative astigmatism. A total of 79.4% showed a postoperative astigmatic value less than 1 D. Clinical refraction was significantly reduced from -1.39 ± 0.79 D preoperatively to -0.86 ± 0.67 D postoperatively (p 0.02). A positive reduction in topographic astigmatism was also observed (p < 0.00). The best-corrected visual acuity increased postoperatively (p < 0.001). We can conclude that customised simulations based on corneal biomechanics are a valuable tool for correcting mild astigmatism with corneal incisions in cataract surgery to improve postoperative visual outcomes.

Femtosecond laser-assisted arcuate keratotomy for the management of corneal astigmatism in patients undergoing cataract surgery: Comparison with conventional cataract surgery

Purpose

To assess the effects of femtosecond laser arcuate keratotomy with femtosecond laser-assisted cataract surgery in the management of corneal astigmatism, compared with conventional phacoemulsification cataract surgery.

Design

Retrospective comparative interventional case series.

Methods

A total of 2,498 eyes of consecutive patients who presented with 3.00 diopters (D) or under of astigmatism were included. The patients were treated with conventional phacoemulsification cataract surgery (conventional group) and femtosecond laser arcuate keratotomy with femtosecond laser-assisted cataract surgery (femtosecond group).

Results

Surgically induced astigmatism (SIA) was higher in the femtosecond group than the conventional group (0.215, p < 0.001). Difference vector (DV) was lower in the femtosecond group (-0.136, p < 0.001). The cut-off value of the overcorrection in the femtosecond group was 0.752 D of target induced astigmatism (TIA). For patients with TIA 0.75 D or under, DV and the value of index of success (TIA into DV) were significantly higher in the femtosecond group (p = 0.022 and < 0.001). The overcorrection ratios were 48.8% in the conventional and 58.9% in the femtosecond group. (p < 0.001). For patients with TIA over 0.75 D, SIA and correction index (TIA into SIA) was higher in femtosecond group (0.310 and 0.250, p < 0.001 and < 0.001, respectively). Absolute angle of error was 20.612 ± 18.497 in the femtosecond group and higher than the conventional group (2.778, p = 0.010).

Conclusion

Femtosecond laser arcuate keratotomy in cataract surgery was effective in SIA between 0.75 to 3.00 D of corneal astigmatism. However, the overcorrection in the lower astigmatism and angle of error in the higher astigmatism were due to the postoperative corneal astigmatism not decreasing as much as SIA. Overcoming these challenges will lead to better management of corneal astigmatism.

Presbyopia Correction in Astigmatic Eyes Using a Toric Trifocal Intraocular Lens With Quadrifocal Technology

PURPOSE

To evaluate the visual performance after bilateral implantation of a toric diffractive aspheric multifocal intraocular lens (IOL) with a +2.17 diopters (D) (60 cm) intermediate and a +3.25 D (40 cm) addition (add) power.

METHODS

This prospective single-arm study was conducted at the Department of Ophthalmology, Goethe University, Frankfurt, Germany. Twenty-five patients (50 eyes) received bilateral implantation of the toric PanOptix IOL (AcrySof IQ PanOptix; Alcon Research LLC) before enrollment. Exclusion criteria were previous ocular surgeries excluding lens surgery and ocular pathologies or corneal abnormalities. Examination at 3 months postoperatively included manifest refraction; monocular and binocular uncorrected distance (UDVA) and distance-corrected (DCVA) visual acuity at 4 m and 80, 60, and 40 cm; and slit-lamp examination. At 3 months postoperatively, monocular and binocular defocus, binocular contrast sensitivity under photopic and mesopic conditions, and optical phenomena, and spectacle independence were evaluated.

RESULTS

Mean refractive spherical equivalent was 0.12 ± 0.380 D and mean refractive cylinder was -0.21 ± 0.237 D at 3 months postoperatively. A significant decrease in refractive cylinder was observed postoperatively (P < .05), with 98% showing a postoperative astigmatism below 0.75 D. Monocular UDVA was better than 0.14 logMAR in all distances. Binocular defocus curve showed peaks at 0.00 D (-0.09 logMAR) and -1.50 and -2.00 D (-0.02 and 0.00 logMAR). The worst values between far (4 m) and near (40 cm) distance were 0.04 logMAR at -1.00 D. Despite some optical phenomena, 92% of patients would choose the same IOL again and recommend it to others.

CONCLUSIONS

The visual performance of the toric PanOptix IOL showed good visual acuity at all distances; more than 90% achieved a decrease of refractive cylinder below 0.75 D, high patient satisfaction despite some optical phenomena, and high spectacle independence 3 months postoperatively. [J Refract Surg. 2020;36(10):638-644.].