Perioperative pupil size in low-energy femtosecond laser-assisted cataract surgery

Surgical time and efficacy of illuminated chopper-assisted cataract surgery involving miosis after femtosecond laser pretreatment

PURPOSE

To evaluate the efficacy of the illuminated chopper-assisted cataract surgery in terms of shortening the surgical time in eyes with miosis after femtosecond laser pretreatment.

METHODS

As retrospective study, three hundred thirty-six eyes of 336 consecutive patients who underwent the femtosecond laser and illuminated chopper-assisted cataract surgery were included. Cases with pupil less than 6 mm after femtosecond laser pretreatment were included in the miosis group. Pupil diameter, surgical time, and improved efficacy (100/surgical time×pupil size) were compared between eyes with and without miosis.

RESULTS

Of 336 eyes, 20 were included in the miosis group (6.0%). Pupil diameter was smaller in eyes with miosis than in those without miosis (5.23 ± 0.38 mm vs 7.35 ± 0.64 mm, p < 0.001); however, surgical time was not different (6.86 ± 0.73 min vs 6.60 ± 1.27 min, p = 0.071) between the two groups. Mechanical pupil dilations were not needed in any cases. As a result, improved efficacy was calculated to be higher in patients with miosis (2.83 vs 2.14, p < 0.001).

CONCLUSION

In terms of surgical time and improved efficacy, using the illuminated chopper simplified cataract surgery involving miosis after femtosecond laser pretreatment. The use of an illuminated chopper is expected to be a good solution for femtosecond laser-assisted cataract surgeries.

Update on Femtosecond Laser-Assisted Cataract Surgery: A Review

The advent of femtosecond lasers has resulted in a new standard in cataract surgery, intended to overmatch the paradigm of conventional phacoemulsification. Femtosecond laser-assisted cataract surgery (FLACS) enables a higher level of reproducibility, precision, accuracy, and customization when performing several steps of cataract (or lens) surgery. Capsulotomy, corneal incisions, lens fragmentation, and arcuate incisions are the main procedures performed using FLACS. As the demand for better refractive outcomes and spectacle independence increases, the features of FLACS are highly relevant, especially when considering the implantation of premium intraocular lenses, such as toric, enhanced depth-of-focus, or multifocal lenses. The present article reviews the state of the art of femtosecond laser-assisted cataract (lens) surgery, contemplating the advantages and limitations of the two types of femtosecond laser pulses available (high and low energy) by evaluating their reported outcomes and complications.

The necessity of pretreatment with 0.1% pranoprofen for femtosecond-assisted cataract surgery: A single-center, randomized controlled trial

Purpose

To explore the effect of the variation of pupil diameter (PD) and intraocular pressure (IOP) induced by femtosecond laser treatment on the subsequent phacoemulsfication and intraocular lens implantation. And whether the application of 0.1% pranoprofen could significantly reduce the miosis and increased IOP caused by femtosecond laser treatment in femtosecond laser-assisted cataract surgery (FLACS).

Methods

In this study, patients were pretreated with (trial group) or without (control group) topical 0.1% pranoprofen. The PD and IOP were measured at different time points within 30 ​min after the completion of the femtosecond laser treatment.

Results

The comparisons of the two groups showed the PD of patients pretreated with 0.1% pranoprofen was significantly larger than that of the control only at 15 ​min after FLACS (P ​= ​0.046), and there was no significant difference in IOP at any time point (P ​> ​0.05). Neither the ratio of significant miosis (PD ​≤ ​5 ​mm) nor intraocular hypertension (IOP ≥30 ​mmHg) was significantly different between the control group (1.72%, 6.67%) and the trial group (1%, 4.17%) (P ​> ​0.05).

Conclusions

The PD and IOP of patients undergoing FLACS showed fluctuations within a small range. The rates of significant miosis and intraocular hypertension are very low, it is safe for surgeons to complete the follow-up procedures within 30 ​min after femtosecond laser treatment. Pretreatment with 0.1% pranoprofen exerted a slight, albeit significant prophylactic effect preventing pupil miosis. However, it provided only a limited benefit in patients undergoing FLACS without other complications.

Cataract Grade and Pupil: Comparison Between Conventional Phacoemulsification and Low-Energy Femtosecond Laser Assisted Cataract Surgery

Purpose

This study presents a comparison of pupil changes according to cataract grade between low-energy femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification (CP) in the same patient.

Patients and Methods

Data from surgical records from patients submitted to cataract surgery with CP in one eye and FLACS in the other were retrospectively reviewed. The inclusion criterion was both eyes of the same patient having the same cataract grade in accordance with Lens Opacity Classification System (LOCS) III. Total pupil variation (TPV) was measured after recorded images, with intraindividual comparison between techniques, according to cataract grade (≤3 and >3), age and cumulative dissipated energy (CDE).

Results

The study included a total of 124 eyes of 62 patients (mean age 72.65 ± 7.64 years). Analysis showed a statistically significant difference in TPV between techniques in the grade ≤3 cataract group (0.08 ± 0.22 mm²; p=0.034), with less pupil narrowing with FLACS, but not in the grade >3 group (0.01 ± 0.23 mm²; p=0.849). Regarding CDE, a significant difference (p<0.001) was found between techniques in both softer and harder cataracts, with lower values for FLACS. Correlation between CDE and TPV was significant for CP (p=0.021) but not for FLACS (p=0.922). TPV was significantly lower in older patients (age >74 years) for both techniques (p<0.001).

Conclusion

There was a statistically significant difference between techniques (although of mild clinical relevance), with less reduction of pupil area with FLACS in softer cataracts (grade ≤3), as compared to CP. Higher levels of CDE are associated with more pupil narrowing in CP.

Pupil Status with Low-Energy Femtosecond Laser-Assisted Cataract Surgery versus Conventional Phacoemulsification: An Intraindividual Comparative Study

Purpose

To compare the pupil changes in low-energy femtosecond laser-assisted cataract surgery (FLACS) with conventional phacoemulsification (CP) intraindividually.

Patients and Methods

A retrospective review of registered surgical data from patients that undergone uncomplicated cataract surgery in a single centre, with randomly assigned femtosecond laser-assisted cataract surgery (FLACS) to one eye and conventional phacoemulsification (CP) to the other, was performed. The recorded pupil images were evaluated at pre and post laser treatment (after suction release) and at several surgical timepoints for both techniques (FLACS and CP). Pupil areas were calculated and compared in the same eye undergone FLACS (pre vs post laser treatment), between eyes (CP vs FLACS) in the same patient and between groups. Subgroups were built regarding age and ocular comorbidity.

Results

This study involved a total of 164 eyes of 82 patients (55 female, 27 male). No statistical differences regarding the total duration of surgery (p=0.805) between FLACS and CP. Pupil measurements between pre and post laser treatment in the FLACS group showed no statistically significant differences (p=0.107). The mean change in pupil area from the beginning until the end of surgery (total variation) was 6.59±2.08 mm² in the FLACS group and 6.67±2.13 mm² in the CP group, associated to less narrowing of pupil area with FLACS, although not statistically significant (p=0.080). Comorbidity group analysis revealed less, but not significant, pupil narrowing with the FLACS technique (p=0.071). No statistically significant differences between FLACS and CP concerning age subgroups were registered.

Conclusion

This study shows no significant pupil changes, namely myosis, after low-energy FLACS pre-treatment. Comparison between techniques showed less pupil variation in FLACS as compared to CP, more markedly in eyes with comorbidities (particularly with shallow anterior chamber), although non-statistically significant.

The Effects of High Energy Capsulotomy on Aqueous Cytokine Profiles and Pupil Size During Femtosecond Laser-Assisted Cataract Surgery

PURPOSE

To assess whether aqueous cytokine profiles and pupil size are altered when high capsulotomy energy is used in eyes undergoing femtosecond laser-assisted cataract surgery (FLACS), and if preoperative use of a topical non-steroidal anti-inflammatory drug (NSAID) has an effect on this.

METHODS

This prospective study recruited 83 eyes (63 patients) that were allocated to four treatment groups: conventional phacoemulsification (n = 20 eyes); FLACS with 90% capsulotomy energy without NSAID pretreatment (n = 20 eyes); FLACS with 90% capsulotomy energy with NSAID pre-treatment (n = 21 eyes); and FLACS with 150% capsulotomy energy with NSAID pretreatment (n = 22 eyes). Aqueous humor was collected before and after phacoemulsification to assess cytokine profiles. Pupil size was measured before and after laser capsulotomy.

RESULTS

FLACS increased aqueous concentrations of pros-taglandin E₂ (PGE₂), interferon γ (IFN-γ), and interleukin 6 (IL-6) compared to conventional phacoemulsification. However, when increasing capsulotomy energy from 90% to 150% (with topical NSAID pretreatment), there was no significant increase in aqueous concentrations of PGE₂ (37.7 ± 21.7 vs 33.6 ± 27.6 pg/mL, P = .99), IFN-γ (3.6 ± 1.1 vs 3.6 ± 0.8 pg/mL, P = .99), or IL-6 (7.1 ± 2.9 vs 6.3 ± 2.4 pg/mL, P = .99). For 90% and 150% capsulotomy energy, there was significant miosis following laser capsulotomy. Increased PGE₂ concentration was significantly correlated with a reduction in pupil area (r = -0.58, P < .001) and pupil diameter (r = -0.57, P < .001). However, when a topical NSAID was given preoperatively, there was no difference in the degree of miosis between the 90% and 150% capsulotomy energy groups.

CONCLUSIONS

Pretreatment with a topical NSAID prevented a rise in PGE₂, IFN-γ, and IL-6 levels and excessive miosis when a higher capsulotomy energy was used. When a topical NSAID is used preoperatively, it is safe to use higher capsulotomy energy settings (with a low pulse energy femtosecond laser system) to achieve a satisfactory capsulotomy. [J Refract Surg. 2022;38(9):587-594.].

Randomized Controlled Trial Comparing 1-Year Outcomes of Low-Energy Femtosecond Laser-Assisted Cataract Surgery versus Conventional Phacoemulsification

Purpose: To compare 1-year clinical outcomes, phacoemulsification energy, aqueous profiles, and patient-reported outcomes of low-energy femtosecond laser-assisted cataract surgery (FLACS) vs. conventional phacoemulsification.

Methods: The study is a randomized controlled trial (RCT) with paired-eye design. Eighty-five patients were randomized to receive FLACS (Ziemer LDV Z8) in one eye and conventional phacoemulsification in the fellow eye. Clinical data including phacoemulsification energy parameters (cumulative dissipated energy, phacoemulsification power, and phacoemulsification time), uncorrected and corrected distance visual acuities (UCDVA and BCDVA), manifest refraction spherical equivalent (MRSE), central corneal thickness (CCT), endothelial cell count (ECC), anterior chamber flare, and post-operative complications were obtained for 1 year. Aqueous humor was collected for the analysis of prostaglandin (PGE)₂, cytokines and chemokines concentrations. Patients' reported-outcomes on surgical experiences were evaluated using an in-house questionnaire.

Results: Compared to conventional phacoemulsification, the low-energy assisted FLACS group had significantly less ECC reduction at 3 months (1.5 ± 0.3% vs. 7.0 ± 2.4%; P < 0.01) and 1 year (8.2 ± 2.8% vs. 11.2 ± 3.6%; P = 0.03). There were no significant differences in the phacoemulsification energy parameters, UCDVA, BCDVA, MRSE, CCT, occurrence of post-operative complications between the 2 groups throughout post-operative 1 year. Patients' subjective surgical experiences, including the surgical duration and perceived inconvenience, were comparable between the 2 groups. FLACS resulted in significantly higher aqueous PGE₂ (P < 0.01), interleukin (IL)-6 (P = 0.03), IL-8 (P = 0.03), and interferon (IFN)-γ (P = 0.04) concentrations and greater anterior chamber flare at 1 day (P = 0.02).

Conclusions: Our RCT presented 1-year longitudinal clinical and laboratory data. The long-term ECC result was more favorable in low-energy FLACS. The rest of the intraoperative and post-operative outcomes, as well as patient-reported outcomes, were comparable between these two procedures.