Femtosecond cataract surgery addresses capsulotomy challenges in small pupils

Take-Home Message: The safety and efficacy of femtosecond laser cataract surgery was evaluated in a small series of patients with small pupils.

By Lynda Charters; Reviewed by William B. Trattler, MD

Miami-Patients with small pupils who require cataract surgery represent a special challenge because adequate pupillary dilation is paramount to the success of that procedure.

One of the challenges for patients with small pupils, where assistance with femtosecond laser would be helpful, is that the capsulotomy may end up on the smaller side.

While some surgeons have reported their experience with dilation of the pupil with viscoelastic and a Myalugin ring before femtosecond laser, one wonders whether the outcomes with femtosecond laser where the capsulotomy is on the smaller side will have good surgical outcomes.

Small series

In a review of patients with small pupils who underwent cataract surgery with a femtosecond laser platform (LensAR Laser System, LensAR Inc.), all patients did well, and there were no intraoperative or postoperative complications, according to William B. Trattler, MD, from the Center for Excellence in Eye Care, Miami.

When planning femtosecond laser cataract surgery, one expects the capsulotomy to be well constructed, allowing for a safe and efficient procedure.

In situations where the capsulotomy is not well constructed, there is an increased risk of anterior capsular tears, which can potentially extend to the equator, and increase the risk of intraoperative and postoperative complications.

Potential complications with large anterior capsular tears include vitreous loss and dropped nucleus IOL decentration. These complications can lead to postoperative complications that can include cystoid macular edema, retinal detachment, and posterior shift of the implanted IOL.

The presence of comorbidities-such as uveitis, pseudoexfoliation, zonular dehiscence, hard crystalline lenses, glaucoma, and floppy iris syndrome-also make cataract surgery more challenging in patients with small pupils.

Femtosecond lasers used for cataract surgery are in the near-infrared wavelength and cannot treat posterior to opaque or pigmented ocular tissue, such as the iris, Dr. Trattler explained.

The result is that a small pupil can interfere with imaging of the anterior segment and delivery of the femtosecond laser.

In a retrospective chart review, Dr. Trattler evaluated the safety and efficacy of femtosecond laser cataract surgery performed with the laser platform in 32 consecutive patients with intraoperative pupillary sizes that were smaller than 6 mm in diameter.

The patients-19 men and 13 women, who were a mean age of 76 ± 8.3 years-underwent femtosecond laser-assisted cataract surgery from January 2013 to January 2014. Seven surgeons performed the procedures.

The mean pupillary size in these patients was 5.2 ± 0.24 mm and the mean capsulotomy size was 4.7 ± 0.3 mm, with the smallest capsulotomy diameter being 4.1 mm. Patients were followed for a mean of 3.4 ± 3.4 months postoperatively.

Postoperative uncorrected distance visual acuity was 20/40 or better in 53.3% of eyes, and postoperative distance-corrected visual acuity was 20/40 or better in 84.2% of eyes.

Importantly, no complications developed in any patient.

Dr. Trattler commented, “Femtosecond laser-assisted cataract surgery enhances the precision and safety in eyes undergoing cataract surgery and IOL implantation compared with standard phacoemulsification because of the potential for reduced risk of intraoperative complications-especially in eyes with pseudoexfoliation, decreased effective ultrasound power in the eye, a shorter phacoemulsification time, and the potential for a more stable and predictable positioning of the IOL.”

However, Dr. Trattler pointed out, femtosecond laser-assisted cataract surgery requires adequate dilation for imaging and treatment as it cannot treat posterior to opaque or pigmented ocular tissue, such as the iris.

If the pupillary size is smaller than the intended capsulotomy size, making a predictable, well-centered, well-shaped, femtosecond laser capsulotomy becomes challenging for the surgeon.

All patients in the study had a successful surgery and IOL implantation, even though the mean pupillary size was 5.2 mm using the femtosecond laser system following instillation of topical mydriatic drugs preoperatively.

If the pupils cannot be adequately dilated with preoperative mydriatic drugs, one can still consider the use of femtosecond laser, Dr. Trattler noted.

Once the manual portion of the procedure has started, additional steps can be taken to enlarge the pupil. For example, intracameral pharmacologic agents may help dilate the pupil.

In addition, even though a capsulotomy has already been created, one can still place a Myalugin ring to help with visualization during phacoemulsification, irrigation/aspiration, and IOL placement.

Based on the results, femtosecond laser cataract surgery performed using the laser platform is safe and effective in patients with small pupils, Dr. Trattler concluded.

Care must be taken, however, to avoid anterior capsular tears-one of the biggest risks when capsulotomy is on the small side.

William B. Trattler, MD

E: wtrattler@earthlink.net

This article was adapted from Dr. Trattler’s presentation during the 2015 meeting of the American Society of Cataract and Refractive Surgery. Dr. Trattler is a consultant to Abbott Medical Optics, Alcon Laboratories, Bausch + Lomb, and LensAR.