Femtosecond phacoemulsification: the business and the medicine

Intra-operative challenges encountered using the zepto nano-pulse precision capsulotomy device

Purpose

The Zepto nano-pulse precision capsulotomy is a novel device for capsulorhexis formation during cataract surgery. Few complications or challenges have been reported while using this device. The purpose of this paper is to highlight two intra-operative challenges that were encountered while using the Zepto device.

Observations

CASE 1 - A 65-year-old with advanced primary open angle glaucoma (POAG) and an in situ Ahmed Glaucoma Valve located in the anterior chamber. During a planned phacoemulsification procedure, the tube became trapped between the suction cup of the Zepto device and the lens, resulting in a sudden complete collapse of the anterior chamber. The procedure was completed after appropriate interventions. On post-operative day 1 Descemet folds were visible, and corneal endothelial cell density was reduced from 2101 cells/cm² preoperatively to 1355 cells/cm² at 19 months postoperatively. CASE 2 - A 66-year-old female with secondary cataract from chronic inflammation post trabeculectomy for advanced POAG. During a planned phacoemulsification procedure, despite synechialysis for the 360° posterior synechiae, the iris tissue was sucked into the suction cup of the Zepto device and became incarcerated over the lens. The procedure was completed after a successful intervention.

Conclusions and importance

Although not previously reported and possibly rare, intra-operative complications may be encountered while using the Zepto device, particularly in complex cataract cases. For the patient's safety and satisfactory post-operative and refractive outcomes, caution must be applied.

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.

[Femtolaser-assisted phacoemulsification of intumescent cataract]

PURPOSE

To optimize the technique of intumescent cataract phacoemulsification by involving the use of femtosecond lasers.

MATERIAL AND METHODS

Group 1 included 29 patients (30 eyes) with mature intumescent cataract, who underwent femtolaser-assisted phacoemulsification using a new, optimized technique. Group 2 included 20 patients (20 eyes), in whom the femtolaser stage was performed using the standard technique. Patients of groups 1 and 2 were almost identical in all preoperative parameters. The optimized femto-capsulorhexis technique included: preoperative assessment of intralenticular pressure, staining of the anterior capsule of the swelling lens with trypan blue, introduction of a viscoelastic with high molecular weight into the anterior chamber to balance intraocular and intralenticular pressures, increasing the laser energy when performing anterior capsulorhexis up to 10 mJ.

RESULTS

In group 1, there was a non-penetration of the anterior capsule in 2 eyes, in one of them in the 30° sector, in the second - in the 45° sector. Leakage of lens material into the anterior chamber and the floating anterior capsule were not observed in patients of group 1. In group 2, non-penetration of the anterior capsule was observed in 6 eyes, in the 45-60° sector - in 2 eyes, in the 90° sector - in 3 eyes, in the 180° sector - in 1 eye. Floating anterior capsule was observed in 5 cases. Leakage of lens material into the anterior chamber was observed in 9 eyes.

CONCLUSION

The optimized technique of femtolaser-assisted intumescent cataract phacoemulsification eliminates leakage of lens material into the anterior chamber and allows performing anterior capsulorhexis of given size and shape.

Phacoemulsification: Proposals for Improvement in Its Application

A cataract is defined as opacity of the crystalline lens. It is currently one of the most prevalent ocular pathologies and is generally associated with aging. The most common treatment for cataracts is surgery. Cataract surgery is a quick and painless process, is very effective, and has few risks. The operation consists of removing the opacified lens and replacing it with an intraocular lens. The most common intraocular lens removal procedure that is currently used is phacoemulsification. The energy applied in this process is generated by ultrasonic waves, which are mechanical waves with a frequency higher than 20 kHz. A great deal of research on the different ways to perform the stages of this surgical procedure and the analysis of the possible side effects of the operation has been published, but there is little information on the technical characteristics, the intensities applied, and the use of ultrasound-emitting (U/S) equipment for cataract removal. More studies on the method and depth of absorption of ultrasonic waves in our visual system when performing the phacoemulsification procedure are needed. It would be advisable for health authorities and medical professionals to develop guidelines for the handling and use of ultrasonic wave-emitting equipment, such as those that exist for ultrasound and physiotherapy. This could help us to reduce undesirable effects after the operation.

Clinical and Surgical Outcomes of Femtosecond Laser-Assisted Cataract Surgery (FLACS) on Hard Cataracts in the Egyptian Population

Objective

To evaluate the clinical and surgical outcomes of femtosecond laser-assisted cataract surgery (FLACS) in hard cataract of Egyptian population.

Setting

ICare Center, Alexandria, Egypt.

Design

Retrospective observational.

Methods

The study included 50 FLACS cases of 40 patients who had cataract; NO4 NC4 or more according to Lens Opacities Classification System III (LOCS III), performed between October 2018 and May 2019. The cases underwent anterior capsulotomy, lens fragmentation, and corneal incisions with the femtosecond laser. Arcuate keratotomy was performed in selected cases. Phacoemulsification and implantation of an intraocular lens are then performed.

Results

Patients mean age was 63.06 ± 7.75 yr, mean femtosecond laser energy was 12.92 ± 0.72 mJ, mean docking time was 3.00 ± 0.83 min and overall mean laser treatment time was 92.00 ± 25.01 sec. Mean laser treatment time was lower in cases that did not get astigmatic keratectomy (87.7 ± 18.97 vs 89.47 ± 13.43 sec; p < 0.73). Attempted refraction was -0.09 ± 0.52 D and achieved 12 months postoperative manifest sphere equivalent refraction (SER) was -0.19 ± 1.11 D (r = 0.8 and P˂0.001). Mean error (ME) was -0.2 ± 1.11 (range: -2.5-1.5) while mean absolute error (MAE) was 0.97 ± 0.57 (range: 0-2.5). Eighty percent and 92% of cases had 1 month postoperative SER within 1.0 D and 1.5 D, respectively. One eye (2%) had incomplete capsulotomy, 7 eyes (14%) had incomplete corneal incision and lens fragmentation was complete in all cases except 1 eye (2%). Thirty-four eyes (68%) showed postdocking conjunctival ecchymosis and 35 eyes (70%) had intraoperative miosis.

Conclusion

FLACS has low complication rate with effective results. High cost of technology is still the main barrier against its popularity.

Intraocular Pressure Changes during Femtosecond Laser-Assisted Cataract Surgery: A Comparison between Two Different Patient Interfaces

Purpose

The aim of this retrospective cohort study was to evaluate intraocular pressure (IOP) changes during femtosecond laser-assisted cataract surgery (FLACS) using two different patient interface systems.

Methods

116 eyes of 116 patients scheduled for cataract surgery were divided into 2 groups: group 1 (61 eyes) and group 2 (55 eyes) underwent FLACS using Catalys Laser with fluid interface (liquid optics interface, LOI) and LenSx Laser with curved interface and soft contact lens (SoftFit), respectively. IOP was assessed using a portable rebound tonometer (Icare®) preoperatively, after docking, immediately after surgery, at one and seven days postoperatively.

Results

In group 1, the mean IOP (±SD) was 14.1 ± 0.4 mmHg before surgery, 33.2 ± 1.1 mmHg after docking, and 21.4 ± 0.9 mmHg immediately after surgery. In group 2, the mean IOP was 13.8 ± 0.4 mmHg before surgery, 24.2 ± 1.4 mmHg after docking, and 20.2 ± 1.2 mmHg immediately after surgery. After the docking procedure, a statistically significant increase in IOP from the baseline was found in both groups (p < 0.001). Moreover, no statistically significant difference in IOP measured at 1 and 7 days postoperatively was observed compared with the preoperative values (p > 0.05) using both laser platforms. No intraoperative and postoperative complications were observed.

Conclusions

FLACS suction phase resulted in a transient increase of IOP in both groups, especially with the LOI system, and it is probably related to the greater pressure of a suction ring and suction generated through the vacuum, independently from the effect of femtosecond laser itself.

Clinical study using a new phacoemulsification system with surgical intraocular pressure control

PURPOSE

To compare cumulative dissipated energy (CDE), aspiration fluid used, and aspiration time during phacoemulsification cataract extraction using 2 surgical configurations.

SETTING

Two clinical sites in the United States and 1 in Spain.

DESIGN

Prospective randomized clinical case series.

METHODS

For each patient, the first eye having surgery was randomized to the active-fluidics configuration (Centurion Vision System with Active Fluidics, 0.9 mm 45-degree Intrepid Balanced tip, and 0.9 mm Intrepid Ultra infusion sleeve) or the gravity-fluidics configuration (Infiniti Vision System with gravity fluidics, 0.9 mm 45-degree Mini-Flared Kelman tip, and 0.9 mm Ultra infusion sleeve). Second-eye surgery was completed within 14 days after first-eye surgery using the alternate configuration. The CDE, aspiration fluid used, and aspiration time were compared between configurations, and adverse events were summarized.

RESULTS

Patient demographics and cataract characteristics were similar between configurations (100 per group). The CDE was significantly lower with the active-fluidics configuration than with the gravity-fluidics configuration (mean ± standard error, 4.32 ± 0.28 percent-seconds) (P < .001). The active-fluidics configuration used significantly less aspiration fluid than the gravity-fluidics configuration (mean 46.56 ± 1.39 mL versus 52.68 ± 1.40 mL) (P < .001) and required significantly shorter aspiration time (mean 151.9 ± 4.1 seconds versus 167.6 ± 4.1 seconds) (P < .001). No serious ocular adverse events related to the study devices or device deficiencies were observed.

CONCLUSION

Significantly less CDE, aspiration fluid used, and aspiration time were observed with the active-fluidics configuration than with the gravity-fluidics configuration, showing improved surgical efficiency.

FINANCIAL DISCLOSURES

Drs. Solomon and Cionni are consultants to Alcon Research, Ltd., and received compensation for conduct of the study. Dr. Lorente received compensation for clinical work in the study. Mr. Fanney is an employee of Alcon Research, Ltd.

Combined Femtosecond Laser-Assisted Cataract Surgery and Small-Gauge Pars Plana Vitrectomy Using Different Devices: A New Trend for Vitreoretinal Surgery?

BACKGROUND AND OBJECTIVE

To report the efficacy, safety, and benefits of femtosecond laser-assisted cataract surgery (FLACS) combined with sutureless 23-gauge pars plana vitrectomy (PPV).

PATIENTS AND METHODS

This multicenter, retrospective study evaluated patient records and videos of 43 cases with retinal pathologies and cataract who underwent the combined procedure.

RESULTS

In 44.2% and 55.8% of cases, respectively, the LenSx Laser (femtosecond machine; Alcon, Fort Worth, TX) and the Constellation (vitreous cutter; Alcon, Fort Worth, TX), and the Victus (femtosecond machine; Bausch + Lomb, Rochester, NY) and Stellaris PC (vitreous cutter; Bausch + Lomb, Rochester, NY) were used. No complications developed during capsulorrhexis, even without a red fundus reflex, retrobulbar block, or scleral indentation. Foldable intraocular lenses remained stable in the capsular bag during the vitreoretinal surgeries and postoperative visits. The mean times of femtosecond phacoemulsification, vitreoretinal surgery, and total surgery were 22.9 minutes ± 4.7 minutes, 43.1 minutes ± 9.8 minutes, and 65.3 minutes ± 8.6 minutes, respectively.

CONCLUSION

This emerging technology is safe and offers several potential benefits for the success of the combined procedure. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:374-379.].

Advances in femtosecond laser technology

Femtosecond laser technology has become widely adopted by ophthalmic surgeons. The purpose of this study is to discuss applications and advantages of femtosecond lasers over traditional manual techniques, and related unique complications in cataract surgery and corneal refractive surgical procedures, including: LASIK flap creation, intracorneal ring segment implantation, presbyopic treatments, keratoplasty, astigmatic keratotomy, and intrastromal lenticule procedures.

Comparing the Curative Effects between Femtosecond Laser-Assisted Cataract Surgery and Conventional Phacoemulsification Surgery: A Meta-Analysis

PURPOSE

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

METHODS

A comprehensive literature search of PubMed, EMBASE, and the Cochrane Controlled Trials Register was conducted to identify randomized controlled trials (RCT) and comparative cohort studies comparing FLACS with CPS. Endothelial cell loss percentage (ECL%), central corneal thickness (CCT), corrected and uncorrected distant visual acuity (CDVA and UDVA), and mean absolute error (MAE) of refraction were used as primary outcomes. Secondary outcomes included surgically induced astigmatism (SIA), mean effective phacoemulsification time (EPT), phacoemulsification power and circularity of the capsulorhexis.

RESULTS

Nine RCTs and fifteen cohort studies including 4,903 eyes (2,861 in the FLACS group and 2,072 in the CPS group) were identified. There were significant differences between the two groups in ECL% at one week, about one month and three months postoperatively, in CCT at one day, about one month postoperatively and at the final follow-up, in CDVA at one week postoperatively, and in UDVA at the final follow-up. Significant differences were also observed in MAE, EPT, phacoemulsification power, and the circularity of capsulorhexis. However, no significant differences were observed in CDVA at one week postoperatively or in surgically induced astigmatism.

CONCLUSIONS

Compared to CPS, FLACS is a safer and more effective method for reducing endothelial cell loss and postoperative central corneal thickening as well as achieving better and faster visual rehabilitation and refractive outcomes. However, there is no difference in final CDVA and surgically induced astigmatism between the two groups.

Femtosecond laser capsulotomy versus manual capsulotomy: a Meta-analysis

AIM

To perform a Meta-analysis on the precision and safety of femtosecond laser (FSL) capsulotomy compared with manual continuous curvilinear capsulotomy (CCC).

METHODS

We searched PubMed, EMBASE, Web of Science, the Cochrane Library databases, and Clinical Trials.gov that maintained our inclusion criteria. Reference lists of retrieved articles were also reviewed. The effects of morphology of capsulorhexis and the tears of anterior capsule were calculated by using random-effect models.

RESULTS

We identified 4 randomized and 7 nonrandomized studies involving 2941 eyes. The diameter of capsulotomy and the rates of anterior capsule tear showed no statistically difference between FSL group and manual group (MD=0.03; 95%CI, -0.03 to 0.09, P=0.31), and (OR=1.40; 95%CI, 0.28 to 6.97, P=0.68) respectively. In terms of the circularity of capsulotomy, FSL group had a more significant advantage than the manual CCC group (MD=0.09; 95%CI, 0.05 to 0.12, P<0.0001).

CONCLUSION

Our Meta-analysis shows that FSL can perform a capsulotomy with more precision and higher reliability than manual CCC. The results in diameter of capsulotomy and the rate of anterior capsule tears was no significant difference between FSL and manual CCC groups. However in terms of circularity, the FSL was superior to the manual procedure.

Evaluating the different laser fragmentation patterns used in laser cataract surgeries in terms of effective phacoemulsification time and power

PURPOSE

To evaluate the effects of the different fragmentation patterns for the lens nucleus in terms of the effective phacoemulsification time (EPT) and power.

SETTING

Shinagawa LASIK Center, Tokyo, Japan.

DESIGN

Comparison study.

METHODS

Seventy-one eyes of 71 patients had preoperative lens opacity grading based on the Emery-Little Classification (Grade 1 and Grade 2). Eyes underwent femtosecond laser-assisted cataract surgery (Catalys™ Precision Laser System), for capsulotomy and lens fragmentation. For the lens fragmentation, either the quadrants softened (Quadrant) or the quadrants complete (Complete) pattern was used. The mean EPT and phacoemulsification (phaco) power for each cutting pattern of Grades 1 and 2 cataracts were evaluated.

RESULTS

The mean EPT was 28.96 seconds in the Quadrant Group and 16.31 seconds in the Complete Group (P=0.006). The mean phaco power was 8.07% in the Quadrant Group and 4.77% in the Complete Group (P=0.0002). Comparing the Quadrant and Complete Groups of Grade 1 cataract showed no significant difference in EPT (P=0.16), but showed a significant difference in phaco power (P=0.033). Comparing the Quadrant and Complete patterns of Grade 2 cataract showed significant differences in both EPT (P=0.012) and phaco power (P=0.003). Using the Complete pattern showed a 44.7% reduction in EPT and a 40.9% reduction in phaco power when compared to the Quadrant Group.

CONCLUSION

Using the smaller fragmentation pattern in femtosecond laser cataract surgery, the phaco time and power were reduced significantly when compared to the procedure with the larger fragmentation pattern.

Investigating the ocular temperature rise during femtosecond laser lens fragmentation: an in vitro study

PURPOSE

To investigate the trend of temperature variation during lens fragmentation simulated by a femtosecond laser on an in vitro eye model.

METHODS

In our experimental study, a convex cylinder of gelatinous material, usually employed in femtosecond laser calibration, was used to simulate both an anterior segment and a crystalline lens during fragmentation performed with the Victus femtosecond laser (Technolas Perfect Vision GmbH, Germany; Bausch + Lomb Incorporated, USA). Two radiated energies (7000 nJ and 9000 nJ) and three cutting patterns (crosses, circles and cross + circle) were applied. Trends of temperature variation as a function of time were obtained using a T-type thermocouple.

RESULTS

The maximum value of temperature rise during lens fragmentation ranged from 3.53 to 5.13 °C; the rise was directly proportional to the intensity of the radiated energy (7000 nJ or 9000 nJ) and the cutting pattern performed. This behavior was experimentally represented by an asymmetric function with a characteristic bell curve shape, whereas it was mathematically described by a transport diffusive model.

CONCLUSIONS

Since the temperature rise at the fragmentation volume base resulted to be around 5 °C in our in vitro study, lens fragmentation performed using the Victus femtosecond laser might be considered safe form a thermal point of view.

Refractive and Visual Outcomes of Different Intraocular Lenses with Femtosecond Laser Cataract Surgery: The Expectation of Independence from Spectacles

PURPOSE

To evaluate the visual performance of different types of intraocular lens (IOL) in eyes submitted to femtosecond laser (FSL) cataract surgery and to analyze whether this technology could result in spectacles independence.

DESIGN

Retrospective comparative case series.

METHODS

Consecutive eyes that were scheduled for FSL cataract surgery were included in this study. After one month postoperative, patients were divided into two groups: cases that required prescription for eyeglasses and cases that did not require prescription. In addition, the patients were analyzed according to the type of IOL that was implanted (monofocal, monofocal toric, multifocal and multifocal toric).

RESULTS

Thirty-five cataract surgeries were analyzed. Twenty-three eyes had a monofocal IOL implanted, and 12 had a multifocal IOL implanted. After 1 month, 12 cases required prescription (Group 1), and 23 did not require prescription (Group 2). The proportion of eyes that did not require corrective lenses was significantly greater (P = 0.02) in eyes that received multifocal IOL (91.67%) compared with those that received monofocal IOL (47.83%). Additionally, 100% of eyes that received multifocal toric IOL did not require eyeglasses at one month postoperatively.

CONCLUSION

The FSL surgical precision associated with modern IOL technology may be an important factor related to vision satisfaction after cataract surgery.

Femtosecond laser-assisted cataract surgery--current status and future directions

Femtosecond laser-assisted cataract surgery (FLACS) putatively offers several advantages over conventional phacoemulsification. We review the current status of FLACS and discuss the evolution of femtosecond lasers in cataract surgery and the currently available femtosecond laser platforms. We summarize the outcomes of FLACS for corneal wound creation, limbal relaxing incisions, capsulotomy, and lens fragmentation. We discuss surgical planning, preoperative considerations, clinical experiences including the learning curve and postoperative outcomes with FLACS, and also the cost effectiveness of FLACS. We present the intraoperative complications and management of challenging cases where FLACS offers an advantage and also speculate on the future directions with FLACS. Further advancements in laser technology to refine its efficacy, advancement in intraocular lens design to harness the potential benefits of FLACS, and a reduction in cost are needed to establish a clear superiority over conventional phacoemulsification.

Preliminary clinical investigation of cataract surgery with a noncontact femtosecond laser system

Background and Objective

Femtosecond laser‐assisted cataract surgery (FLACS) is rapidly gaining popularity due to the improved consistency and predictability for capsulorhexis. This study aimed to investigate the preliminary clinical outcomes of FLACS with a noncontact femtosecond laser system.

Patients and Methods

This prospective study enrolled 25 eyes in the trial group underwent FLACS (LLS‐fs 3D, LENSAR, USA), and 29 eyes in the control group underwent conventional cataract surgery (Stellaris, Bausch & Lomb, USA). The phacoemulsification time, energy, and complications during operation were recorded. Postoperative refraction at 1 day, 1 week, 1 and 3 months, the capsulorhexis size and corneal endothelial density at 1 and 3 months were also measured.

Results

Compared to the control group, reduction in phacoemulsification time was 51.5% (P = 0.02), and in overall energy, 65.1% (P = 0.02) in the trial group. In the trial group and the control group, total time of cataract procedure was 10.04 ± 1.37 minutes, 10.52 ± 1.92 minutes, respectively (P = 0.31); the absolute difference between attempted and achieved capsulorhexis diameter at 1 month was 192.9 ± 212.0 µm, 626.9 ± 656.6 µm, respectively (P = 0.04), and at 3 months, 256.6 ± 181.9 µm, 572.1 ± 337.0 µm, respectively (P= 0.03); the absolute difference between attempted and achieved spherical equivalent at 3 months was 0.16 ± 0.16 D, 0.74 ± 0.65 D, respectively (P < 0.01); mean corneal endothelial cell loss at 1 month was 15.6% and 14.2%, respectively (P = 0.77), and at 3 months, 2.9%, 4.2%, respectively (P = 0.50).

Conclusions

With the noncontact femtosecond laser system, FLACS can significantly improve the accuracy and repeatability of capsulorhexis, reduce the phacoemulsification time and overall energy, and enhance the predictability and stability of postoperative refraction. Lasers Surg. Med. 47:698–703, 2015. © 2015 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

Efficacy and safety of femtosecond laser-assisted cataract surgery versus conventional phacoemulsification for cataract: a meta-analysis of randomized controlled trials

The aim of this study was to evaluate the efficacy and safety of femtosecond laser-assisted cataract surgery (FLACS) versus conventional phacoemulsification cataract surgery (CPCS) in the treatment of cataract. Randomized controlled trials (RCTs) were searched in PubMed, Embase and the Cochrane Central Register of Controlled Trials. Nine qualified studies with a total of 989 eyes were included. Compared with CPCS, FLACS significantly reduced mean phaco energy and effective phacoemulsification time (EPT) required in the surgery. Central corneal thickness (CCT) was significantly lower in FLACS at 1 day of follow-up, but CCT and corneal endothelial cells count was comparable at 1 week of follow-up or longer. FLACS achieved a better visual outcome at postoperative 1 week and 6 months, but the difference was not significant at postoperative 1-3 months. Regard to surgical complications, the incidences of intraoperative anterior capsule tear, postoperative macular edema and elevated intraocular pressure were similar. In conclusion, femtosecond laser pretreatment can reduce phaco energy and EPT, which may reduce the heat damage to ocular tissues by ultrasound. This novel technique might be beneficial for patients with dense cataract and/or low preoperative endothelial cell values. Well-designed RCTs with longer follow-up are still necessary to provide more reliable evidence.

Porcine Model to Evaluate Real-Time Intraocular Pressure During Femtosecond Laser Cataract Surgery

PURPOSE

To investigate the changes in intraocular pressure (IOP) in porcine eyes during femtosecond laser-assisted cataract surgery using a liquid-optic interface system.

MATERIALS AND METHODS

Femtosecond laser cataract surgery with the Catalys™ was performed on freshly enucleated porcine eyes in Oftalvist Moncloa, Madrid, Spain. Capsulorhexis and lens fragmentation were completed in all the eyes without complications. IOP was measured with a reusable blood pressure transducer connected by direct cannulation to the anterior chamber, recording data before suction (basal), at the beginning of the suction phase, every five seconds during femtosecond procedure and after the removal of the suction ring from the eye.

RESULTS

Nine porcine eyes were used in this study. Basal IOP before suction was 5.67 ± 2.39 mmHg, rising to 20.33 ± 4.18 mmHg at the beginning of the suction phase (p < 0.001). During femtosecond procedure, pressure reached a value of 19.74 ± 4.31 mmHg, remaining stable during the entire process. The IOP recorded prior to removal of the suction ring was 21.00 ± 6.93 mmHg, returning to basal values in all the eyes after the suction ring was removed, with no statistical differences between basal and post-suction IOPs. Total femtosecond procedure time was 125.9 ±  15.9 s.

CONCLUSIONS

Real-time IOP can be measured during surgery using a transducer connected to the anterior chamber. The results showed a significant increase in IOP during the procedure due to the pressure exerted by the suction ring but not by the effect of the femtosecond laser.

Introducing a New Surgical Technology: Controversies in Femtosecond Laser-assisted Cataract Surgery and Impact on Resident Surgical Training

Femtosecond laser-assisted cataract surgery is becoming more widely available as an option for patients considering cataract surgery. Controversies exist around determining the best platform for LCS, the potential global role and cost to the health care system of LCS, as well as the future of LCS in resident surgical training.

Femtosecond laser-assisted cataract surgery in residency training

PURPOSE OF REVIEW

To examine the current state of femtosecond laser-assisted cataract surgery (FLACS) with a focus on its incorporation into resident surgical education.

RECENT FINDINGS

To date, there are no published data on FLACS in residency training programs. Teaching FLACS concurrently with manual cataract surgery can theoretically allow a trainee to become proficient in both domains and to navigate the complexities and complications of both procedures in a dedicated learning environment.

SUMMARY

Early reports from completed projects at our institution suggest that incorporating FLACS into residency education is successful and well tolerated. The procedure appears to have a similar safety profile and delivers similar refractive results compared with conventional phacoemulsification cataract surgery, even during the initial surgical learning curve. More research needs to be carried out on the safety profile and outcomes of resident performed FLACS and its ultimate role in trainee education.

Femtosecond laser cataract surgery: updates on technologies and outcomes

PURPOSE

To describe femtosecond laser cataract surgery and discuss the published peer-reviewed articles to have a fair evaluation of this new technology and its comparisons to conventional phacoemulsification surgery.

METHODS

The technology information released in this article comes from the key individuals in each of the U.S. Food and Drug Administration-approved companies and from the available commercial information. Bibliographic research was performed in PubMed and MEDLINE for the published prospective or retrospective clinical studies.

RESULTS

The femtosecond laser has been reported to be safe intraoperatively and postoperatively, with less cornea and macula effect than conventional phacoemulsification. The incision is integrated, stable, and aberration free. Many studies reported the high precision of the capsulotomy over manual continuous curvilinear capsulorhexis, which favors less intraocular lens tilt, higher optical quality, and more accurate premium intraocular lens centration. The lens fragmentation is effective with significant reduction of the phacoemulsification power and effective phacoemulsification time. The refractive difference between femtosecond laser and standard phacoemulsification is minimal, with no difference in corrected distance visual acuity, but the optical quality and the internal aberrations results are significantly better for femtosecond laser phacoemulsification.

CONCLUSIONS

Femtosecond laser cataract surgery is a good addition to cataract surgery despite its few remarkable advantages among experienced phacoemulsification surgeons.

Preliminary Investigation of Corneal Wavefront Aberration following Femtosecond Laser Clear Corneal Incision for Cataract Surgery

Purpose

To investigate the early changes of the anterior corneal wavefront aberration (WA) following femtosecond laser clear corneal incision (FS-CCI) for cataract surgery.

Methods

Twenty consecutive patients (20 eyes) with cataract underwent phacoemulsification and were divided into 2 groups: the study group received a 2.75-mm FS-CCI using an iFS Intralase; the control group received a 2.75-mm manual CCI using disposable knives. High-order corneal WA was analyzed over 3.5- and 6.0-mm pupils and corneal astigmatism was evaluated using vector analysis pre-operatively, 1 week postoperatively, and 1 month postoperatively.

Results

At 1 month postoperatively, the mean surgically induced astigmatism (D) of the anterior cornea was 1.22 ± 0.60 at 144° and 1.04 D ± 0.64 at 90° in the study and control groups (p<0.05), respectively. Over 3.5-mm pupil, there were no changes of corneal high-order aberrations (p>0.05) following FS-CCI. Trefoil increased significantly (p<0.01) following manual CCI at 1 week postoperatively. Over 6.0-mm pupil, FS-CCI did not induce any statistically significant change in corneal WA during follow-up. One week after manual CCI, total root mean square–high order aberrations (p<0.01), spherical aberration (p<0.05), and trefoil (p<0.001) were statistically significantly higher than pre-operatively.

Conclusions

The CCI method was shown to influence changes in corneal WA during the first month postoperatively. The different changes of corneal high-order WA between the study and control groups may depend on the different CCI geometry. These preliminary data are valuable to improve understanding of FS-CCI design.

Femtosecond laser-assisted cataract surgery in eyes with a small pupil

PURPOSE

To evaluate the efficacy of different treatment modalities in eyes with small pupils before femtosecond laser-assisted cataract surgery.

SETTING

Ruhr University Eye Clinic, Bochum, Germany.

DESIGN

Prospective clinical trial.

METHODS

Eyes with an intraoperative pupil size smaller than 5.5 mm received sequential treatments to achieve a pupil larger than 5.5 mm in 3 steps: (1) intracameral administration of epinephrine solution, (2) additional viscomydriasis, and (3) implantation of a Malyugin ring pupil expander. When a step enlarged the pupil to at least 5.5 mm, femtosecond laser-assisted cataract surgery with an anterior capsulotomy diameter of at least 4.5 mm and 350 μm nuclear fragmentation grids, ultrasound phacoemulsification, and intraocular lens implantation were performed. Main outcome measures were achieved preoperative pupil size in each sequential treatment group and analysis of intraoperative complications.

RESULTS

Of 850 eyes scheduled for cataract surgery, 40 received sequential treatments. To achieve a pupil larger than 5.5 mm, epinephrine was sufficient in 7% of the eyes; additional viscomydriasis was necessary in 25%, and the pupil expander was implanted in 68%. The most frequent comorbidities were pseudoexfoliation of the lens capsule (30.0%) and intraoperative floppy-iris syndrome (12.5%). Tongue-like lesions of the capsulotomies were detected in 5 eyes.

CONCLUSIONS

The 3-step treatment allowed the surgeon to increase the efficiency and safety of femtosecond-assisted cataract surgery in eyes with a small preoperative pupil, providing good safety margins at the pupil boundary for the capsulotomy and the softened nuclear volume.

Visual and refractive outcomes of laser cataract surgery

PURPOSE OF REVIEW

Femtosecond laser is a promising new technology for the field of cataract surgery. Early studies have investigated many factors including visual outcomes, complication rates, and financial overhead costs. This review analyzes the most recent clinical studies of visual and refractive outcomes in laser cataract surgery, including those that make comparisons to outcomes found in conventional phacoemulsification cataract surgery.

RECENT FINDINGS

As femtosecond laser cataract surgery has only emerged recently, there is limited literature available regarding visual outcomes. Most but not all existing studies showed no statistically significant difference in visual acuity and mean absolute refractive error between laser and conventional cataract surgery cases.

SUMMARY

The majority of studies examined found visual acuity or refractive outcomes of femtosecond laser to be statistically equivalent to those of conventional phacoemulsification cataract surgery. However, the learning curve involved with laser use may account for these early results, which could potentially improve as better technology and surgical techniques are developed. Further long-term outcomes studies are necessary to more accurately evaluate the benefits and drawbacks of femtosecond laser cataract surgery.

Initial evaluation of a femtosecond laser system in cataract surgery

PURPOSE

To report the early experience and complications during cataract surgery with a noncontact femtosecond laser system.

SETTING

Hong Kong Sanatorium and Hospital, Hong Kong Special Administrative Region, China.

DESIGN

Retrospective case series.

METHODS

All patients had anterior capsulotomy or combined anterior capsulotomy and lens fragmentation using a noncontact femtosecond laser system (Lensar) before phacoemulsification. Chart and video reviews were performed retrospectively to determine the intraoperative complication rate. Risk factors associated with the complications were also analyzed.

RESULTS

One hundred seventy eyes were included. Free-floating capsule buttons were found in 151 eyes (88.8%). No suction break occurred in any case. Radial anterior capsule tears occurred in 9 eyes (5.3%); they did not extend to the equator or posterior capsule. One eye (0.6%) had a posterior capsule tear. No capsular block syndrome developed, and no nuclei were dropped during irrigation/aspiration (I/A). Anterior capsule tags and miosis occurred in 4 eyes (2.4%) and 17 eyes (10.0%), respectively. Different severities of subconjunctival hemorrhages developed in 71 (43.8%) of 162 eyes after the laser procedure. The mean surgical time from the beginning to the end of suction was 6.72 minutes ± 4.57 (SD) (range 2 to 28 minutes).

CONCLUSIONS

Cataract surgery with the noncontact femtosecond laser system was safe. No eye lost vision because of complications. Caution should be taken during phacoemulsification and I/A to avoid radial anterior capsule tears and posterior capsule tears.

Femtosecond laser cataract incision morphology and corneal higher-order aberration analysis

PURPOSE

Analysis of the femtosecond laser refractive lens surgery corneal incision configuration and corneal higher-order aberration (HOA) effect from the first postoperative day.

METHODS

High-resolution anterior segment optical coherence tomography was used to assess 20 eyes undergoing femtosecond laser refractive lens surgery with 2.2-mm minimal incision. The primary incision (tri-planar) actual length, cord length, surface angle, surface irregularity, and regional pachymetry values and the secondary incision (uni-planar) length, angle, surface irregularity, and pachymetry values were analyzed. Hartmann-Shack aberrometer was used to assess corneal HOAs to correlate the effect. Assessment was done preoperatively and 1 month postoperatively.

RESULTS

The actual length, cord length, and surface angle means for the primary incision in the first postoperative day and month were 1.50 ± 0.1 and 1.47 ± 0.2 mm (P = .5), 1.41 ± 0.1 and 1.42 ± 0.2 mm (P = .8), and 27° ± 4° and 23° ± 5° (P = .07), respectively. The length and surface angle for the secondary incision in the first postoperative day and month were 1.17 ± 0.01 and 1.04 ± 0.1 mm (P = .05) and 52° ± 3° and 42° ± 5° (P = .007). The regional pachymetry values for the primary and secondary incisions were significantly increased in the first postoperative day and then significantly decreased after 1 month. All irregularities occurred in the posterior surface (endothelium): 2 cases of posterior gap (first day) and 1 case of posterior retraction (first month). The HOAs had not significantly changed preoperatively and after 1 month.

CONCLUSIONS

The femtosecond laser refractive lens surgery incision is stable and does not significantly change the HOA.

Age-related eye disease

As with many organs, compromised function of the eye is accompanied with age and has become increasingly prevalent with the aging population. When decreased visual loss becomes significant, patients' ability to perform activities of daily living becomes compromised. This decrease in function is met with morbidity and mortality, as well as a large socioeconomic burden throughout the world. This review summarizes the most common age-related eye diseases, including cataract, glaucoma, diabetic retinopathy, retinal vein occlusion, and age-related macular degeneration. Although our understanding of the genetic and biochemical pathways of these diseases is sill at its primitive stages, we have become able to help our patients improve the quality of life as they age.