Intraocular pressure changes before and after a femtosecond laser procedure for cataract surgery

This study aimed to evaluate the changes in intraocular pressure (IOP) before and after femtosecond laser capsulorhexis and lens fragmentation for cataract surgery. We measured the IOP before, immediately, 30 min, and 1 h after the laser procedure in 47 eyes of 47 patients who underwent the femtosecond laser procedure. The mean IOP was 17.51 ± 3.28 mmHg, 30.23 ± 6.70 mmHg, 17.96 ± 3.75 mmHg, and 21.77 ± 5.88 mmHg before, immediately after, 30 min after, and 1 h after the laser procedure, respectively. The mean IOP significantly increased immediately (adjusted P < 0.001) and 1 h (adjusted P = 0.001) after the laser procedure compared with the pre-laser IOP. The mean IOP at 30 min after the laser procedure was significantly lower than that immediately after the procedure (adjusted P < 0.001). However, the IOP 1 h after the laser procedure became higher than that 30 min after the laser procedure. Additionally, the IOP 1 h after the laser procedure was positively correlated with the baseline IOP and negatively correlated with the axial length. In conclusion, this study demonstrated that cataract surgery should be commenced within 30 min after the femtosecond laser procedure to ensure a safe cataract surgery that reduces the risk of increased intraocular pressure.

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.

Anterior chamber cytokine production and postoperative macular edema in patients with diabetes undergoing FLACS

PURPOSE

To evaluate the effect of femtosecond laser-assisted cataract surgery (FLACS) and manual cataract surgery (MCS) on proinflammatory cytokine expression in patients with diabetes vs nondiabetic patients.

SETTING

Outpatient surgical center in Vaughan, Ontario, Canada.

DESIGN

Prospective cohort study.

METHODS

Patients with diabetes and nondiabetic patients undergoing noncomplicated MCS or FLACS were assigned into 4 cohorts: MCS nondiabetic (n = 30), FLACS nondiabetic (n = 42), MCS diabetic (n = 40), and FLACS diabetic (n = 40). Aqueous humor inflammatory mediator concentrations were evaluated at MCS onset and after femtosecond laser treatment. The presence of cystoid macular edema, anterior chamber (AC) inflammation, central retinal thickness, macular volume, and retinal microvascular changes (through optical coherence tomography angiography) were evaluated preoperatively and on postoperative day 1, week 1, month 1 (POM1), and month 3 (POM3).

RESULTS

Patients with diabetes receiving FLACS had a higher concentration of interleukin (IL)-7, IL-13, and interferon-induced protein-10 than MCS diabetic patients; they also demonstrated higher levels of vascular endothelial growth factor and lower levels of interferon (IFN)-γ, granulocyte colony-stimulating factor, and IFN-α2 compared with MCS nondiabetic patients. Macular volume appeared to be significantly higher in MCS diabetic vs MCS non-diabetic patients at POM1 and between FLACS diabetic vs FLACS nondiabetic patients at POM3. There were no other significant differences between the cohorts for any parameter.

CONCLUSIONS

FLACS use in patients with diabetes demonstrated some differences in AC cytokine expression compared with non-diabetic FLACS or diabetic patients undergoing MCS; however, there was no increase in clinical inflammatory biomarkers. FLACS seems to be a safe technique to use in patients with diabetes.

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.

Femtosecond laser-assisted cataract surgery: Update and perspectives

Cataract surgery is among the most frequently performed surgical procedures worldwide and has a tremendous impact on patients' quality of life. Phacoemulsification (PCS) is accepted as a standard of care; its technique has continuously evolved and already achieved good anatomical, visual, and refractive outcomes. Lasers in ophthalmology are widely used in clinical practice, femtosecond lasers (FSLs) for corneal surgery in particular. It was natural to assess the usefulness of FSL in cataract surgery as this technology was within reach. Indeed, precise and reproducible cuttings provided by FSL platforms could improve standardization of care and limit the risk associated with the human element in surgery and provide a step toward robot-assisted surgery. After docking and planning the procedure, femtosecond lasers are used to perform corneal incisions, capsulorhexis, lens fragmentation, and arcuate incisions in an automated manner. A well-constructed corneal incision is primordial as it offers safety during the procedure, self-seals afterward, and influences the refractive outcome. Capsulorhexis size, centration, and resistance to shearing influence the surgery, intraocular lens (IOL) centration and stability, and posterior capsular opacification formation. Lens fragmentation is where most of the energy is delivered into the eye, and its amount influences endothelial cell damage and potential damage to other ocular structures. The arcuate incisions offer an additional opportunity to influence postoperative astigmatism. Femtosecond laser-assisted cataract surgery (FLACS) has been a topic of research in many studies and clinical trials that attempted to assess its potential benefits and cost-effectiveness over PCS and is the subject of this mini-review.

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.].

Prostaglandin Release After Low-Energy Femtosecond Laser-Assisted Cataract Surgery Without Anti-Inflammatory Drug Premedication

PURPOSE

To compare prostaglandin E2 (PGE-2) levels in the aqueous and pupil diameter in patients undergoing low-pulse energy femtosecond laser-assisted cataract surgery (LCS) without non-steroidal anti-inflammatory (NSAID) pretreatment with either fragmentation or capsulotomy performed first.

DESIGN

Prospective, randomized, fellow-eye controlled comparison.

METHODS

This study was undertaken at the Department of Ophthalmology, Medical University of Vienna. The population consisted of 140 eyes of 70 patients with bilateral age-related cataract. Bilateral same-day LCS with either anterior capsulotomy before lens fragmentation (Caps-First) in one eye or vice versa (Frag-First) in a random sequence were performed. Aqueous was tapped 5 minutes after LCS and PGE-2 concentration was analyzed. Pupil diameters were recorded immediately before and after femtosecond laser pretreatment. The main outcome measure was PGE-2 concentrations in picograms/milliliter and pupil diameter in millimeters.

RESULTS

Mean PGE-2 concentrations were 42.0 ± 63.7 pg/mL in the Caps-First group versus 71.8 ± 160.7 pg/mL with the Frag-First group (P = .186). Mean pupil diameters before and after pretreatment were 7.6 ± 0.8 mm and 7.6 ± 0.8 mm, respectively (P = .871). Mean PGE-2 concentrations and pupil diameters did not show any significant difference between time points or groups.

CONCLUSIONS

Low-energy femtosecond laser pretreatment did not increase PGE-2 levels in the absence of NSAID pretreatment. This was independent of whether capsulotomy or fragmentation was performed first. Moreover, no pupillary miosis was observed.

Safety of femtosecond laser-assisted cataract surgery versus conventional phacoemulsification for cataract: A meta-analysis and systematic review

Purpose

To compare the complications of femtosecond laser-assisted cataract surgery (FLACS) with those of conventional phacoemulsification surgery (CPS) for age-related cataracts.

Methods

PubMed, Cochrane Library, and EMBASE were systematically searched for studies comparing FLACS and CPS. Outcomes were operative complications, including the intraoperative capsule tear, postoperative corneal edema, macular edema, uncontrolled IOP, etc. The effect measures were weighted with odds ratios with 95% CIs.

Results

Nineteen RCTs and 18 cohort studies, including 24,806 eyes (11,375 of the FLACS group and 13,431 of the CPS group), were identified. There were no significant differences between the two groups in anterior capsule tear, corneal edema, macular edema, uncontrolled IOP, vitreous loss, posterior vitreous detachment, etc. Posterior capsule tear rate showed a significantly lower in RCT subgroups (P ​= ​0.04) and without differences in total (P ​= ​0.63). Significant differences were observed in the incidence of descemet membrane tear/trauma (P ​= ​0.02) and IFIS/iris trauma (P ​= ​0.04. Additionally, The FLACS specific complications showed a significantly higher rate of miosis (P ​< ​0.0001), corneal epithelial defect (P ​= ​0.001), corneal haze (P ​= ​0.002), and subconjunctival hemorrhage (P ​= ​0.01).

Conclusions

FLACS maintains the same safety compared with CPS in terms of all intraoperative and postoperative complications. Although FLACS did show a statistically significant difference for several FLACS specific complications, it would not influence the visual outcome and heal itself.

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.

[Historical development of energetic cataract surgery]

This article reviews scientific literature analyzing the history of ultrasound and laser phaco surgery of combined or isolated designs: erbium YAG laser, 1.064 μm Nd:YAG laser for dissection of the lens capsule and nucleus, exclusively-laser technique of lens destruction with 1.44 µm Nd:YAG laser without manual, vacuum or ultrasonic action, femtosecond laser assistance with automated transcorneal delivery of radiation into the eye cavity.

Effect of preoperative eyedrops on cytokine concentrations in aqueous humor of patients undergoing femtosecond laser-assisted cataract surgery

PURPOSE

To compare the anti-inflammatory activity of preoperatively applied eyedrops, as determined by cytokine concentrations in aqueous humor collected during surgery in patients undergoing femtosecond laser-assisted cataract surgery.

METHODS

A total of 120 patients undergoing femtosecond laser-assisted cataract surgery were randomly assigned to four groups of 30 patients each. Groups were administered 0.1% fluorometholone eyedrops, 0.45% ketorolac tromethamine eyedrops, both 0.1% fluorometholone and 0.45% ketorolac tromethamine eyedrops, or no eyedrops. Eyedrops were instilled 1 h, 20 min, and just before surgery. After anterior capsulotomy and nuclear fragmentation using a femtosecond laser, 0.1 cc aqueous humor was obtained using a needle and syringe. Cytokine and prostaglandin E₂ (PGE₂) concentrations were quantitatively determined.

RESULTS

The 120 patients included 59 men and 61 women, of mean age 65.02 years. The mean interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) concentrations after treatment did not differ significantly in the four groups. The average interleukin-8 (IL-8) concentrations were significantly lower in the fluorometholone (4.80 pg/mL), ketorolac tromethamine (4.84 pg/mL), and fluorometholone + ketorolac tromethamine (4.68 pg/mL) groups than in the control group (6.83 pg/mL). Furthermore, the average PGE₂ concentrations were significantly lower in the ketorolac tromethamine (270.04 pg/mL) and fluorometholone + ketorolac tromethamine (239.00 pg/mL) groups, but not in the fluorometholone (393.16 pg/mL) group, than in the control group (472.36 pg/mL).

CONCLUSION

Preoperative fluorometholone instillation reduced IL-8, and ketorolac tromethamine instillation reduced IL-8 and PGE₂, in aqueous humor of patients undergoing femtosecond laser surgery, with the combination of both eyedrops being more effective than either alone.

TRIAL REGISTRATION

KCT0005717.

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

PURPOSE

To assess potential changes in pupil size during femtosecond laser-assisted cataract surgery (FLACS) using a low-energy laser system.

METHODS

The pupil sizes of eyes undergoing FLACS were measured using the Ziemer LDV Z8 by extracting images from the laser software after each of the following steps: application of suction, lens fragmentation, and capsulotomy. Furthermore, the pupil diameters were measured based on preoperative surgical microscope images and after releasing the suction. Paired t-test and the two one-sided tests (TOST) procedure were used for statistical analyses. The horizontal and vertical pupil diameters were compared in each of the steps with preoperative values.

RESULTS

Data were available for 52 eyes (52 patients, mean age 73.4 years, range 51-87 years). The equivalence between mean preoperative pupil size and status immediately after femtosecond laser treatment was confirmed (p<0.001; 95% confidence interval [-0.0637, 0.0287] for horizontal and p<0.001; 95% CI [-0.0158, 0.0859] for vertical diameter). There was statistically significant horizontal and vertical enlargement of pupil diameters between 0.15 and 0.24 mm during the laser treatment steps as compared with preoperative values (all p values <0.001).

CONCLUSIONS

No progressive pupil narrowing was observed using low-energy FLACS. Although a suction-induced, slight increase in pupil area became apparent, this effect was completely reversible after removing the laser interface.

Surgical outcomes with high and low pulse energy femtosecond laser systems for cataract surgery

Currently, there is no clear consensus in cataract surgery if low compared to high energy femto-lasers may enable better capsulotomy quality and induce lower inflammatory response. Therefore, the aim of this study was to compare the intra-operative outcomes achieved with high and low pulse energy femtosecond laser systems for cataract surgery. The charts of 200 eyes of 200 patients aged 68.3 ± 10.3 years who had undergone femtosecond laser-assisted cataract surgery using either group 1 high pulse energy: LenSx (Alcon Laboratories) (N = 100) or group 2 low pulse energy: FEMTO LDV Z8 (Ziemer) (N = 100) laser were reviewed retrospectively. Integrity of anterior capsulotomy, classified as (1) complete (free-floating or with minor microadhesions), (2) incomplete and (3) with capsular tears, intraoperative completeness of the clear corneal incisions (CCI, main incision and side port), incidences of intraoperative miosis and incidence of subconjunctival hemorrhage were evaluated and compared between the two groups. The proportion of complete capsulotomies was significantly higher in the group 2 than the group 1 (100% vs 94%; p = 0.03). The incidences of intraoperative miosis (0% vs 19%) and subconjunctival hemorrhage (1% vs 63%) were significantly lower in the group 2 than the group 1 (p < 0.001). Completeness of the main incision was comparable (97% vs 95%; p = 0.721) between the two groups. Although not statistically significant, the completeness of side-port incision was slightly better in the group 2 than the group 1 (91% vs 86%). Low energy laser system performed significantly better in terms of completeness of capsulotomy, intraoperative miosis and sub-conjunctival hemorrhage, compared with high energy laser; the CCI outcomes were comparable.

Cystoid Macular Edema Following Cataract Surgery with Low-Energy Femtosecond Laser versus Conventional Phacoemulsification

Purpose

To compare postoperative changes in central subfield macular thickness (CSMT) and prevalence of cystoid macular edema (CME) in patients undergoing cataract surgery with low-energy femtosecond laser versus standard phacoemulsification.

Design

This was a retrospective comparative real-world study.

Methods

Postoperative data of 252 eyes of 165 patients were collected: 138 eyes received low-energy femtosecond laser-assisted cataract surgery (FLACS) and 114 eyes underwent conventional phacoemulsification cataract surgery (CPCS). Postoperative changes in CSMT and prevalence of CME were compared between the two groups.

Results

There was a significant increase in mean CSMT from preoperative to postoperative values at 2.5 months in both the FLACS and CPCS group (p<0.001). Mean change (preoperation to 2.5 months postoperation) in CSMT was 6.2±11.5 µm in the FLACS group and 7.3±26.6 µm in the CPCS group, which was statistically significant but clinically not relevant. Comparison of mean changes in CSMT (preoperation to 2.5 months postoperation) between the FLACS and CPCS groups revealed no significant differences. The rate of pseudophakic CME (PCME) development was lower in the FLACS group (1.4%) than the CPCS group (4.4%; p=0.247). When using PREMED criteria to define clinically significant PCME, only 0.7% patients in the FLACS group and 1.8% in the CPCS group showed development of clinically significant PCME (p=0.586).

Conclusion

The mean change in CSMT and occurrence of postoperative CME was lower in the low-energy FLACS group than the standard-phacoemulsification group; however, the difference was not statistically significant.

Comparative evaluation of femtosecond laser-assisted cataract surgery and conventional phacoemulsification in eyes with a shallow anterior chamber

PURPOSE

To compare intraoperative performance and postoperative outcomes between femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification in eyes with a shallow anterior chamber (AC).

SETTING

Iladevi Cataract & IOL Research Centre, India.

DESIGN

Prospective randomized masked clinical study.

METHODS

Patients undergoing cataract surgery with a shallow AC (<2.5 mm) were randomized to have FLACS (Group 1, n = 91) or conventional phacoemulsification (Group 2, n = 91). Patients were followed up at 1 day, 1 week, and at 1, 3, and 6 months. The primary outcome measure was central corneal thickness (CCT). The secondary outcome measures were corneal clarity, AC cells and flare, endothelial cell density (ECD), coefficient of variance, hexagonality, and uncorrected distance visual acuity (UDVA) at 1 week.

RESULTS

The study comprised 182 eyes (91 in each group) The cumulative dissipative energy was lower in the FLACS group (P < .05). The mean CCT was significantly lower with FLACS (540.40 μm + 49.40 [SD] vs 556 + 12.5 μm, P = .03) at 1 day and 1 week (535.5 + 44.3 μm vs 551 + 40.8 μm, P = .04), with fewer eyes having higher than grade 2 AC cells and flare with FLACS (85% vs 72%, P = .056) at 1 day and 1 week (15% vs 28%, P = .03). At 1 week, the UDVA was better with FLACS (0.089 ± 0.31 logarithm of the minimum angle of resolution [logMAR] vs 0.178 ± 0.65 logMAR, P = .042). At 6 months, the reduction in ECD was lower in the FLACS group; however, the difference was not statistically significant.

CONCLUSION

In eyes with shallow ACs, compared with conventional phacoemulsification, FLACS maintained clearer corneas, showed less increase in CCT, lower AC inflammation, and better UDVA in the early postoperative period.

[Prevention of intraoperative miosis in femtosecond laser-assisted phaco surgery]

INTRODUCTION

Prevention of intraoperative miosis in hybrid (femtosecond laser-assisted) phacoemulsification is a relevant problem of cataract surgery.

PURPOSE

Development and clinical study of an effective method for preventing intraoperative miosis in hybrid (femtosecond laser-assisted) phacoemulsification.

MATERIAL AND METHODS

Hybrid phacoemulsification was performed in 300 patients (300 eyes). The first group (100 eyes) 3 days prior to the surgery was prescribed instillations of 0.1% indomethacin 3 times a day and 3 times in 2 hours before surgery at 30 minute intervals. The second group (100 eyes) 3 days prior to the surgery was prescribed instillations of 0.1% indomethacin 3 times a day, 3 times in 2 hours before the surgery at 30 minute intervals, and 1 hour before the surgery an additional intramuscular injection of diclofenac. The third group (control, 100 eyes) 2 hours before the operation was prescribed instillations of 0.1% indomethacin, 3 times at 30 minute intervals. The diameter of the pupil was evaluated before the beginning of femtosecond laser stage and before the opening of anterior chamber during the second stage of the operation.

RESULTS

When the interval between the femtosecond laser stage and emulsification of the nucleus fragments was maintained at less than 15 minutes, pronounced decrease of the pupil (more than 2 mm) was noted in 8.2% of cases in the first group, 6.7% in the second group and 14.1% in third (control) group; mean values of pupil narrowing were 0.68±0.27 mm in the 1st group, 0.63±0.25 mm in the 2nd group, and 0.93±0.39 mm (p<0.05) in the third group.

CONCLUSION

The clinical study showed high efficiency of the proposed methods for prevention of intraoperative miosis in hybrid (femtosecond laser-assisted) phaco surgery. An important factor affecting intraoperative narrowing of the pupil is the time interval between the femtolaser stage of the operation and emulsification of the nucleus fragments, which should not exceed 15 minutes.

Changes in Pupil Area during Low-energy Femtosecond Laser-assisted Cataract Surgery

Purpose

To study the potential changes in pupil area within low-energy femtosecond-laser assisted cataract surgery (FLACS).

Methods

A retrospective assessment of the pupil size was performed in the eyes undergoing FLACS using the Ziemer LDV Z8. We measured the pupil diameters as part of the images taken preoperatively and at the completion of laser pretreatment (after releasing the suction). We calculated the pupil area in 40 eyes of 40 patients (14 right and 26 left eyes). The mean ± standard deviation (SD) of age of the patients was 74 ± 7.4 years (range: 51-87). Paired t-test was used for statistical analyses. Subgroups were built with reference to age and preoperative pupil area (smaller than or equal to the median versus larger than the median).

Results

The mean ± SD axial length, anterior chamber depth, white-to-white distance and lens thickness were 24.01 ± 1.47, 3.23 ± 0.4, 11.97 ± 0.49, and 4.59 ± 0.41 mm, respectively. The mean ± SD pupil area was 39.33 ± 7.1 mm 2 preoperatively and 39.3 ± 6.75 mm 2 after laser pretreatment. The mean ± SD change in pupil area was -0.03 ± 2.12 mm 2 . There were no statistically significant changes between preoperative and post-laser pupil areas (P = 0.93, 95% CI: -0.71 to 0.65). Comparisons within subgroups also did not detect pupil area reduction.

Conclusion

This study did not detect statistically significant changes in pupil area after laser pretreatment using low-energy FLACS. This observation is in contrast to previous studies using other laser platforms.

Comparison of vitreous loss rates between manual phacoemulsification and femtosecond laser-assisted cataract surgery

PURPOSE

To compare the vitreous loss complication rate of manual phacoemulsification cataract surgery with that of femtosecond laser-assisted cataract surgery.

SETTING

Mercy Eye Specialists, Springfield, Missouri, USA.

DESIGN

Retrospective single-center case series.

METHODS

Cataract surgeries from 2010 to 2014 performed by 4 surgeons were audited for rates of vitreous loss. Vitreous loss data were statistically analyzed with and without exclusions.

RESULTS

Of the total 7155 cases from 2010 to 2014, 3784 were consecutively performed using manual phacoemulsification from 2010 to 2012 and 3371 were performed using femtosecond laser-assisted cataract surgery from 2013 to 2014. The rate of vitreous loss with exclusions was 1.17% in the manual phacoemulsification group and versus 0.65% femtosecond laser-assisted group; without exclusions, the rate was 1.40% versus 0.77%. In absolute terms, the rate decreased for every surgeon in the study. The chi-square test showed a statistically significant association between the date of surgery, and thus technique, and vitrectomy cases (P < .05). Odds ratio analysis with exclusions versus without exclusions indicated that surgeries performed from 2010 to 2012 using manual phacoemulsification were 1.6 times and 1.8 times, respectively, more likely to have vitreous loss than surgeries performed from 2013 to 2014 using the femtosecond laser-assisted cataract surgery technique.

CONCLUSIONS

Conversion from manual phacoemulsification to femtosecond laser-assisted cataract surgery resulted in a statistically significant decrease in vitreous loss. Because vitreous loss increases the risk for other serious complications of cataract surgery, this new finding has important implications for the safety of cataract surgery.

FINANCIAL DISCLOSURE

Proprietary or commercial disclosures are listed after the references.

Efficacy of 0.015% intracameral epinephrine for significant miosis induced by photodisruption during femtosecond laser-assisted cataract surgery

Despite the various advantages of femtosecond laser-assisted cataract surgery (FLACS), pupillary constriction during laser photodisruption is considered one of the most unfavorable events. This study aimed to investigate the efficacy of intracameral 0.015% epinephrine injection for miosis after laser pretreatment during FLACS.A total of 82 patients who underwent FLACS for age-related cataracts were investigated in this retrospective study. The epinephrine group included patients who received intracameral epinephrine injection for miosis after femtosecond laser pretreatment, while the no-epinephrine group included the patients who underwent FLACS without intracameral epinephrine due to minimal miosis. Quantitative pupil area measurements were performed through the analysis of captured images extracted from surgical videos of both femtosecond laser pretreatment and phacoemulsification.Laser photodisruption induced miosis in both groups, although the degree of miosis was greater in the epinephrine group (4.65 ± 0.87 mm) than in the no-epinephrine group (6.30 ± 0.65 mm; P < .001). The intracameral epinephrine injection significantly increased the pupil diameter from 4.65 ± 0.87 to 5.49 ± 0.76 mm (21.61 ± 22.68%; P < .001) and the pupil area from 70.28 ± 24.46 to 96.49 ± 25.24 mm (52.89 ± 63.54%; P < .001). After additional viscomydriasis, there was no difference between groups in pupil diameter (epinephrine vs no-epinephrine group; 6.10 ± 0.77 vs 6.39 ± 0.65 mm; P = .073).A single intracameral injection of 0.015% epinephrine provided immediate and appropriate redilation of pupil in patients with significant miosis after femtosecond laser photodisruption. Intracameral epinephrine is a simple and practical option for pupil redilation in case of miosis during FLACS.

The Effect of NSAID Pretreatment on Aqueous Humor Prostaglandin E2 Concentration in Eyes Undergoing Femtosecond Laser-Assisted Capsulotomy

PURPOSE

To assess aqueous humor concentration of prostaglandin E2 (PGE2) after capsulotomy creation using a femtosecond laser (FLAC) in patients pretreated with short-term topical ketorolac versus patients without pretreatment.

METHODS

This prospective study comprised consecutive patients scheduled to undergo cataract surgery using a femtosecond laser platform to perform only capsulotomies. An identical protocol for preoperative mydriasis was used for all the eyes included in the study, while aqueous humor was extracted from the anterior chamber of all patients immediately after the initial side port incision. ELISA was performed to quantify aqueous humor PGE2. The patients were divided into 2 groups; in group 1, the patients received short-term topical ketorolac preoperatively, while the patients in group 2 did not receive NSAID pretreatment.

RESULTS

Twenty eyes of 20 patients were included in the study (10 eyes in each group). Mean concentration of aqueous humor PGE2 after FLAC was 392.16 ± 162.00 pg/ml and 622.63 ± 331.84 pg/ml for groups 1 and 2, respectively. A statistically significant difference in aqueous humor PGE2 concentration between the two groups (p < 0.05) was demonstrated, with the eyes that received ketorolac pretreatment demonstrating a lower concentration of PGE2.

CONCLUSION

Short-term topical use of ketorolac prior to FLAC seems to prevent excessive release of PGE2 in the anterior chamber of the eyes that received NSAID pretreatment when compared to the eyes that did not receive NSAIDs preoperatively.

Femtosecond laser-assisted cataract surgery, technology, outcome, future directions and modern applications

Since its introduction in 2009 femtosecond laser-assisted cataract surgery (FLACS) has promised to revolutionize cataract surgery. Despite its promise, the assessment of FLACS's perceived benefits has proven to be far more complicated than initially might have been thought. Most studies to date have not provided validation of FLACS technology as a clinically significant advancement on our current techniques. We review FLACS technology and outcomes including detailed analysis of safety, efficacy, cost effectiveness and future prospects using data from the literature and our own published clinical experience.

Current and effective advantages of femto phacoemulsification

PURPOSE OF REVIEW

The purpose is to review the current and effective advantages of femtosecond laser-assisted cataract surgery (FLACS).

RECENT FINDINGS

FLACS has advantages over manual phacoemulsification in its precision, and predictability and may be especially advantageous in difficult situations such as shallow anterior chamber, subluxated cataracts, white cataracts, and so on. However, the femtosecond capsulorhexis may not be as strong as a manual rhexis. Laser-induced miosis is also a potential disadvantage.

SUMMARY

There may be increased surgeon confidence and patient satisfaction with FLACS and it may be friendlier to the internal structures of the eye. However, it is not superior to manual phacoemulsification in terms of primary outcomes such as visual and refractive outcomes or overall complications. Further refinements in technology may be needed to give it distinct advantages over manual phacoemulsification and to make it the norm in cataract surgery.