[Current value of femtosecond laser-assisted cataract surgery]

Comparison of the actual diameter of capsulotomy and predicted diameter of capsulotomy after femtosecond laser-assisted capsulotomy

PURPOSE

To compare the consistency between the actual diameter of capsulotomy (ADC) and the predicted diameter of capsulotomy (PDC) in femtosecond laser-assisted cataract surgery (FLACS) and analyze the factors that influence the deviation of the diameter of capsulotomy (DDC) between the actual and predicted.

SETTING

Aier Eye Hospital of Wuhan University, China.

DESIGN

Retrospective observational case series.

METHODS

Patients who underwent FLACS from March 2020 to March 2021 were reviewed. The ADC in FLACS was measured and compared with the PDC. The effects of age, sex, and biometrics on DDC were analyzed.

RESULTS

412 eyes of 336 patients were included. The mean age was 53.0 ± 0.91 years (range 3 to 91 years). When the PDC was set to 4.50 mm, the results showed that the ADC was 5.21 ± 0.21 mm with a significant difference between them ( P < .05). However, when the PDC was set to 5.2 mm, the ADC was 5.10 ± 0.38 mm without a significant difference between them ( P > .05). No correlation ( P > .05) was found between the DDC and the axial length, the DDC and the anterior chamber depth (ACD), and the DDC and the mean keratometry (Km), but a negative correlation was found between the DDC and the lens thickness (LT) ( r = -0.21; P < .05) and the DDC with age ( r = -0.70; P < .05). Using curvilinear regression analysis, a development of an age-depending correction formula was predicted: ADC = PDC + 1.23 - 0.30 ln (x) (x = age ≥3) ( R2 = 0.65; F = 752.39; P = .00).

CONCLUSIONS

The consistency of the ADC and PDC was influenced by age and LT. For patients aged 40 years or younger, the younger the patient, the wider the DDC; for patients older than 40 years, the DDC was small. The thicker the LT, the smaller the DDC.

Femtosecond-Laser Assisted Surgery of the Eye: Overview and Impact of the Low-Energy Concept

This article provides an overview of both established and innovative applications of femtosecond (fs)-laser-assisted surgical techniques in ophthalmology. Fs-laser technology is unique because it allows cutting tissue at very high precision inside the eye. Fs lasers are mainly used for surgery of the human cornea and lens. New areas of application in ophthalmology are on the horizon. The latest improvement is the high pulse frequency, low-energy concept; by enlarging the numerical aperture of the focusing optics, the pulse energy threshold for optical breakdown decreases, and cutting with practically no side effects is enabled.

Stability of a non-applanating handheld liquid patient interface for femtosecond laser-assisted cataract surgery

PURPOSE

A stable and reliable vacuum is crucial for the correct planning and performance of femtosecond laser-assisted cataract surgery (FLACS) in order to avoid complications such as suction loss and cyclorotation. This study investigates, for the first time, the impact of different vacuum levels on the stability of the application of a liquid patient interface for FLACS in view of break-away forces.

METHODS

Break-away forces were measured using a multifunctional material testing machine with a mounted digital manometer. Sixteen porcine eyes were docked to the patient interface of a femtosecond laser platform (FEMTO LDV Z8), and the impact of different vacuum levels between 300 and 500 mbar investigated.

RESULTS

Mean break-away forces for each vacuum level were as follows: 1.78 N (± 0.58 N) for 300 mbar; 2.24 N (± 0.68 N) for 350 mbar; 2.66 N (± 0.68 N) for 400 mbar; 2.86 N (± 0.77 N) for 420 mbar; and 3.49 N (± 0.86 N) for 500 mbar.

CONCLUSION

The stability increases with the vacuum in a nearly linear manner. Vacuum levels higher than 500 mmHg and lower than 350 mmHg are not recommended for FLACS.