Cataract Surgery Performed by High Frequency LDV Z8 Femtosecond Laser: Safety, Efficacy, and Its Physical Properties

Abstract

Background: The aim of our study was to investigate the safety and efficacy of the LDV Z8 femtosecond laser in cataract surgery compared to the conventional procedure.

Methods: This prospective study was performed at the Swiss Eye Research Foundation, Eye Clinic ORASIS, Reinach, Switzerland. The study included 130 eyes from 130 patients: 68 treated with femtosecond laser-assisted cataract surgery (FLACS) using the FEMTO LDV Z8 and 62 treated with conventional phacoemulsification. Capsulotomy and lens fragmentation in the laser group were performed with the FEMTO LDV Z8 femtosecond laser system, which employs a new, low-energy, high repetition rate laser process for cataract surgery. In the conventional group, the capsulotomy was performed by a cystotome, and lens fragmentation was achieved by the stop-and-chop.

Results: Ease of phacoemulsification (on a 4-point scale), the completeness of capsulotomy (on a 10-point scale), effective phacoemulsification time (seconds), uncorrected distance visual acuity (UCVA), best spectacle-corrected distance visual acuity (BSCVA), spherical equivalent (SE), and safety of the procedure were evaluated. The total follow-up time was three months.

Conclusions: FLACS with the FEMTO LDV Z8 system was characterized by complete and reproducible capsulotomy and highly effective lens fragmentation. Postoperative visual outcomes were excellent, and the safety of the procedure was optimal.

Keywords: cataract surgery; clinical outcomes; complications; femtosecond laser; physical properties.

Figure 1

(a) The large numerical aperture is the key for minimizing the focal volume which leads to low pulse energy and less bubbles (LDV Z8 femtosecond laser). (b) The small numerical aperture leads to higher pulse energy and more bubbles (conventional laser systems).

Figure 2

Femtosecond laser handpiece of the LDV Z8.

Figure 3

High-resolution OCT at a wavelength of 840 nm is mandatory for receiving a precise cut in the right position.

Figure 4

(a) The cutting process is limited to the focal spot size. Many pulses are needed to cut the tissue, so a high frequency repetition rate is needed. (b) The cutting process is mainly performed by mechanical forces of the expanding gas bubbles). Fewer pluses are needed but stress is generated in the tissue.

Figure 5

A complete capsulotomy is seen with the capsular button free floating in the anterior chamber, while there is nearly no accumulation of gas in the fragmented lens. There are minimal subcapsular bubbles in the anterior chamber.