Effect of hydrodynamic parameters on corneal endothelial cell loss after phacoemulsification

Phacoemulsification using an active fluidics system at physiologic vs high intraocular pressure: impact on anterior and posterior segment physiology

PURPOSE

Evaluate the impact of high vs low intraoperative intraocular pressure (IOP) during phacoemulsification on anterior and posterior physiology.

SETTING

Private practice in Des Moines, Iowa.

DESIGN

Prospective, randomized, paired-eye clinical trial of patients anticipating bilateral cataract surgery.

METHODS

27 participants randomized at the time of their first cataract surgery to either low IOP or high IOP group. The subsequent cataract surgery was performed under the alternate condition. During phacoemulsification and cortex removal, IOP was maintained either at low (≤28 mm Hg) or at high (≥55 to 60 mm Hg) levels. The primary outcome was fluid usage, with secondary outcomes of central corneal thickness, foveal avascular zone area, foveal and macular thickness, endothelial cell density (ECD), and postoperative inflammation.

RESULTS

Surgery with low IOP settings used less fluid (40.0 mL vs 55.6 mL, P < .0001). Corneal thickness changes were smaller in low IOP eyes at 1 day and 1 week (3.0% vs 8.1%, P = .01; 3.1% vs 4.4%, P = .01) but were similar by 1 and 3 months. ECD dropped less in low IOP eyes at 1 and 3 months (-1.7% vs -12.3%, P = .001, 2.1% vs -8.9%, P = .0003.) IOP remained a significant predictor of ECD change when relationship was controlled for fluid use and phacoemulsification energy. Retinal parameters did not vary among all eyes or when compared by IOP setting. Visual acuity was similar at all timepoints.

CONCLUSIONS

Low IOP settings resulted in less inflammation and less corneal trauma, as evidenced by a smaller drop in ECD and less postoperative corneal edema, when compared with high IOP settings. Retinal parameters did not change significantly. The different outcomes did not result in a difference in visual acuity.

Narrative review after post-hoc trial analysis of factors that predict corneal endothelial cell loss after phacoemulsification: Tips for improving cataract surgery research

PURPOSE

Identifying pre/perioperative factors that predict corneal endothelial-cell loss (ECL) after phacoemulsification may reveal ways to reduce ECL. Our literature analysis showed that 37 studies have investigated one or several such factors but all have significant limitations. Therefore, the data of a large randomized controlled trial (PERCEPOLIS) were subjected to post-hoc multivariate analysis determining the ability of nine pre/perioperative variables to predict ECL.

METHODS

PERCEPOLIS was conducted in 2015-2016 to compare two phacoemulsification techniques (subluxation and divide-and-conquer) in terms of 3-month ECL. Non-inferiority between the techniques was found. In the present study, post-hoc univariate and multivariate analyses were conducted to determine associations between ECL and age, sex, cataract density, preoperative endothelial-cell density, phacoemulsification technique, effective phaco time (EPT), and 2-hour central-corneal thickness. The data are presented in the context of a narrative review of the literature.

RESULTS

Three-month data were available for 275 patients (94% of the randomized cohort; mean age, 74 years; 58% women). Mean LOCSIII cataract grade was 3.2. Mean EPT was 6 seconds. Mean ECL was 13%. Only an older age (beta = 0.2%, p = 0.049) and higher EPT (beta = 1.2%, p = 0.0002) predicted 3-month ECL. Cataract density was significant on univariate (p = 0.04) but not multivariate analysis. The other variables did not associate with ECL.

CONCLUSIONS

Older age may amplify ECL due to increased endothelial cell fragility. EPT may promote ECL via cataract density-dependent and -independent mechanisms that should be considered in future phacoemulsification research aiming to reduce ECL. Our literature analysis showed that the average ECL for relatively unselected consecutively-sampled cohorts is 12%.

Effect of elevated irrigation bottle height during cataract surgery on corneal endothelial cells in porcine eyes

BACKGROUND

Cataract surgery induces corneal endothelial cell loss (ECL). This study investigates the relationship between bottle height (BH) and ECL induced due to irrigation and aspiration (I/A) in cataract surgery and quantifies protective effects of intraoperatively used ophthalmic viscoelastic substances.

METHODS

Intermittent I/A without phacoemulsification was performed in porcine eyes for 10 min with varying BHs of 100 cm (BH100), 125 cm (BH125), 150 cm (BH150) or no treatment (control, no I/A). Additionally, in one group a dispersive ophthalmic viscoelastic substance was injected into the anterior eye chamber before treatment with I/A at a BH of 150 cm (BH150 + V). After exposure of the corneal endothelium to I/A, the corneas were prepared to split corneal buttons on day 0 and cultivated for 15 days. Endothelial cell density (ECD) was analyzed blinded on days 1, 8 and 15.

RESULTS

Relative ECL significantly correlated with irrigation BH (control (n = 13): -9.69 ± 6.03% (average ± standard deviation); BH100 (n = 12): -9.69 ± 4.81%-p = 1.000; BH125 (n = 14): -19.44 ± 7.30% - p < 0.001; BH150 (n = 13): -21.99 ± 6.70%-p < 0.001). I/A-induced ECL was significantly decreased by the injection of ophthalmic viscoelastic, as BH150 + V (n = 14; -10.92 ± 4.09%-p = 1.000) showed a cell loss comparable to the control group.

CONCLUSIONS

ECL is altered by I/A BH and reduced when viscoelastic substances are used.

Corneal densitometry: an innovative method to quantitatively evaluate corneal changes after phacovitrectomy

BACKGROUND

To quantitatively investigate corneal changes and the correlation between corneal densitometry (CD) and endothelial parameters after phacovitrectomy.

METHODS

Thirty-eight eyes with idiopathic full-thickness macular holes (iFTMHs) and cataracts underwent phacovitrectomy. Examinations were conducted at baseline and Day 1, Day 7, Month 1, and Month 3 postoperatively. CD and central corneal thickness (CCT) were measured using Pentacam. Corneal endothelial cell density (ECD), coefficient of variation (CV), and hexagonality (HEX) were measured using specular microscopy.

RESULTS

ECD and HEX significantly decreased after surgery and the change in HEX occurred prior to CV. CCT increased immediately after surgery and recovered 3 months postoperatively. CD values increased significantly 1 day after surgery and then gradually decreased. For CD in the 0-2 mm zone, it took 1 month to recover in the central and posterior layers and 3 months in the anterior and total layers. For CD in the 2-6 mm zone, the central layer recovered at Day 7, the anterior and total layers recovered at 1 month, and the posterior layer did not recover until 3 months postoperatively. The CD within all layers in the 0-2 mm zone was positively correlated with CCT. Posterior CD in the 0-2 mm zone was negatively correlated with ECD and HEX.

CONCLUSIONS

CD is not only correlated with CCT, ECD, and HEX but also reflects the state of the whole cornea and each layer. CD can be an objective, rapid, and noninvasive tool that reflects corneal health and undetectable edema and monitors the process of lesion repair.

TRIAL REGISTRATION

This study was registered with the Chinese Clinical Trial Registry (31/10/2021, ChiCTR2100052554).

Bilensectomy: Safety and Visual Outcomes in Angle-Supported, Iris-Fixated, and Posterior Chamber Phakic Intraocular Lenses

PURPOSE

To report the visual and refractive outcomes, intraoperative and postoperative complications, and main causes of bilensectomy in the different types of phakic intraocular lenses (pIOLs).

METHODS

This was a retrospective multicenter study that included 234 eyes of 185 patients that underwent bilensectomy. Patients were divided into three groups depending on the pIOL that was explanted (angle-supported, iris-fixated, or posterior chamber). The main reasons leading to the indication for bilensectomy, time elapsed between pIOL implantation and bilensectomy, intraoperative and postoperative complications, uncorrected and corrected distance visual acuity (UDVA and CDVA), and endothelial cell density loss 1 year after bilensectomy were evaluated.

RESULTS

There was a statistically significant improvement in UDVA and CDVA after bilensectomy in all groups. Cataract development was the main reason for bilensectomy, followed by significant endothelial cell density loss. Time between pIOL implantation and bilensectomy was significantly greater in eyes with an anterior chamber pIOL.

CONCLUSIONS

Bilensectomy outcomes in general are good. Iris-fixated lenses, particularly hyperopic, are more prone to intraoperative complications and endothelial cell loss than the other pIOLs models. The results show that bilensectomy is a safe and effective procedure with a relatively low rate of intraoperative and postoperative complications and acceptable refractive predictability. [J Refract Surg. 2023;39(3):128-134.].

The safety and efficacy of phacoemulsification surgery in uncomplicated cataracts with and without an ophthalmic-viscosurgical-device

PURPOSE

To compare and evaluate the results of phacoemulsification surgery involving and not involving an ophthalmic-viscosurgical-device (OVD).

METHODS

A prospective, randomized controlled trial included 60 eyes of 60 patients scheduled to receive phacoemulsification surgery. In order of presentation, patients were randomized into two groups to undergo different surgical techniques: the OVD-free group (n = 30) and the OVD group (n = 30). Each patient's operating time, total ultrasonography (U/S) time, cumulative dissipated energy (CDE), aspiration time, and volume of balanced salt solution (BSS) aspirated were recorded. At 1 day, 1 week, and 1 and 3 months postoperation, measurements of endothelial cell density (ECD) and intraocular pressure (IOP), were taken and compared between the groups.

RESULTS

Total U/S time (p = .567) and CDE (p = .168) were similar between the groups. In the OVD group, operating time (p = .011), aspiration time (p < .001), and volume of BSS aspirated (p < .001) were greater than in the OVD-free group. The change in ECD between the groups was not statistically significant at all visits (p = .433, p = .147, p = .379, p = .534; respectively). Although IOP increased in the OVD group at 1 day postoperation (p = .001), no difference emerged between the groups at 3 months postoperation (p = .121).

CONCLUSION

Phacoemulsification surgery without an OVD took less time than with the OVD and caused no significant loss in ECD. Surgeons concerned about elevated IOP following cataract surgery should apply the OVD-free method.

Effect of simulated lenticular debris on corneal endothelial cells: experimental study in rabbit eyes

PURPOSE

To evaluate mechanical damage of simulated lenticular debris on corneal endothelial cells during phacoemulsification.

SETTING

University setting, Salt Lake City, Utah.

DESIGN

Experimental study.

METHODS

12 New Zealand rabbits underwent bilateral surgery. After incision, 10 1.0 mm beads were injected into the anterior chamber of test eyes to simulate lenticular debris. A balanced salt solution was injected into the contralateral eyes with the same injector. The Intrepid Balanced Tip of the Centurion Ozil handpiece was inserted into the anterior chamber, and 60% torsional ultrasound was applied for 20 seconds with 50 mL/min flow, 70 mm Hg intraocular pressure, and 600 mm Hg vacuum. Cumulative dissipated energy (CDE) was noted. After euthanasia and enucleation, the corneas were removed, stained with trypan blue/alizarin red, and photographed in a standardized manner (×400 photographs from 5 specific areas and 1 overview photograph from each corneal button). The ImageJ program was used to evaluate cell damage and loss in the photographs.

RESULTS

CDE was 4.64 ± 0.19 for test eyes with beads and 4.66 ± 0.17 for control eyes without beads ( P = .58). The percentage of intact cells was statistically higher in the control group ( P = .0005), whereas the percentages of damaged and lost cells were statistically higher in the test group ( P = .0010 and .0005, respectively). This was observed in the analysis of the ×400 photographs and overview photographs.

CONCLUSIONS

This study suggests that lenticular debris swirling around the anterior chamber may cause significant damage to the corneal endothelium, providing further insight on mechanisms of damage during phacoemulsification.

Comparative anatomical outcomes of high-flow vs. low-flow phacoemulsification cataract surgery: A systematic review and meta-analysis

Background

Phacoemulsification is an effective and widely performed technique in cataract surgery, but the comparative anatomical outcomes, including endothelial cell loss (ECL), central corneal thickness (CCT), and central macular thickness (CMT), between high-flow and low-flow phacoemulsification cataract surgery remain unclear.

Methods

This study followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. Random-effects models were applied to measure pooled mean differences (MD) with 95% confidence intervals (CI) of anatomical outcomes between high-flow and low-flow phacoemulsification cataract surgery. We judged overall certainty of evidence (CoE) based on Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria.

Results

We included six randomized controlled trials (RCTs) totaling 477 participants. The meta-analysis showed similar changes associated with these two surgery types in both ECL at postoperative days 2–14 (MD: −1.63%; 95% CI: −3.73 to 0.47%; CoE: very low), days 15–42 (MD: −0.65%; 95% CI −2.96 to 1.65%; CoE: very low) and day 43 to month 18 (MD: −0.35%; 95% CI: −1.48 to 0.78%; CoE: very low), and CCT at postoperative day 1 (MD: −16.37 μm; 95% CI: −56.91 to 24.17 μm; CoE: very low), days 2–14 (MD: −10.92 μm; 95% CI: −30.00 to 8.16 μm; CoE: very low) and days 15–42 (MD: −2.76 μm; 95% CI: −5.75 to 0.24 μm; CoE: low). By contrast, low-flow phacoemulsification showed less increase in CMT at postoperative days 15–42 (MD, −4.58 μm; 95% CI: −6.3 to −2.86 μm; CoE: low).

Conclusions

We found similar anatomical outcomes, except in CMT, for both high-flow and low-flow phacoemulsification cataract surgery. Future head-to-head RCTs on visual outcomes should confirm our findings.

Systematic review registration

PROSPERO, identifier: CRD42022297036.

The effect of phacoemulsification fluid flow on the corneal endothelium: An experimental study in rabbit eyes

PURPOSE

To quantify the damage to the corneal endothelium from the flow of balanced salt solution during phacoemulsification.

SETTING

John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

DESIGN

Experimental Study.

METHODS

Twelve New Zealand white rabbits received bilateral surgery. Six eyes served as controls with no irrigation (incision only). In 18 eyes, the Intrepid Balanced tip of the Centurion (Alcon) Ozil handpiece was inserted into the anterior chamber for continuous irrigation at 50mL/minute with either 250 mL or 500 mL of balanced salt solution (BSS). After euthanasia and enucleation, the corneas were removed, stained with trypan blue/alizarin red, and photographed in a standardized manner (X400 photographs from 5 specific areas, and 1 overview photograph from each corneal button). The ImageJ program was used to evaluate cell damage and loss in the photographs obtained from each cornea.

RESULTS

Analysis of the X400 photographs showed no statistical differences between control, 250 mL, and 500 mL groups in the percentage of intact, damaged, or lost cells (P= 0.896, 0.851, and 0.972 respectively). For the overview photos, the differences in areas of intact and damaged cells among the groups were statistically significant, likely due to the peripheral areas of damage related to touches between the phaco tip and the endothelium during irrigation.

CONCLUSION

The volume of BSS flow alone does not appear to be a major contributing source of endothelial cell damage and loss, providing further insight on mechanisms of corneal endothelium damage during phacoemulsification.

Optical coherence tomography angiography evaluation of the effects of phacoemulsification cataract surgery on macular hemodynamics in Chinese normal eyes

PURPOSE

To quantitatively evaluate the possible effects of phacoemulsification cataract surgery on macular hemodynamics using optical coherence tomography angiography (OCTA).

METHODS

This was a prospective observational study. Superficial and deep macular vascular densities, as well as parameters of foveal avascular zone (FAZ), were measured preoperatively (baseline) and at 1 day, 1 week, and 4 weeks postoperatively in normal eyes (≥ 22 mm and ≤ 24 mm) of patients scheduled for phacoemulsification cataract surgery with intraocular lens implantation. The correlations between the rate of change of pre- and postoperative vascular densities and surgical parameters were analyzed.

RESULTS

A total of 107 eyes of 107 patients were included in this study. Compared to the baseline measurements, no statistically significant variation was found in macular vascular densities at 1 day after the surgery (P > 0.05). Both superficial and deep macular vascular densities were significantly increased postoperatively at weeks 1 and week 4 (P < 0.05; P < 0.05); however, no statistically significant differences were detected in any of the FAZ parameters between the baseline measurements and the entire follow-up period (P > 0.05 for all). Also, no statistically significant correlations were established between main surgical parameters and macular vascular densities changes.

CONCLUSIONS

In normal eyes, macular blood perfusion gradually increased after phacoemulsification cataract surgery and was stabilized in one week. The foveal avascular zone was stabilized before and after the surgery. The main parameters and intraoperative perfusion of phacoemulsification surgery may not be the key factors affecting macular hemodynamics.

The Effect of Mesenchymal Stem Cell Secretome on Corneal Endothelial Cell Preservation in an Oxidative Injury Model

PURPOSE

To describe a reproducible oxidative injury model in ex vivo porcine corneas and to investigate the effects of corneal mesenchymal stem cell (Co-MSC) secretome and specific factors on the preservation of corneal endothelium after oxidative injury.

METHODS

Porcine corneas underwent vital staining with trypan blue and alizarin red with different concentration and time points. Ex vivo porcine corneas were exposed (endothelial side) to varied concentrations of hydrogen peroxide. After injury, 3 groups of 5 corneas underwent treatment with secretome from either a wild-type (WT) murine Co-MSC, a pigment epithelium derived factor (PEDF) knock out (K/O) murine Co-MSC, or basal media for 4 hours at 37°C. The viability of the endothelium was evaluated using the optimized vital staining protocol.

RESULTS

The optimal vital staining was achieved with 0.4% trypan blue for 60 seconds and 0.5% alizarin red for 90 seconds. The optimal oxidative injury (for consistency and level of damage) was obtained with 1% hydrogen peroxide for 15 seconds. Treatment with both WT Co-MSC and PEDF K/O Co-MSC secretome significantly reduced the endothelial damage compared with control (17.2% ± 10.0%, 33.5% ± 11.6%, and 68% ± 17%, respectively, P < 0.01). The WT Co-MSC secretome was significantly more effective compared with PEDF K/O Co-MSC secretome (P < 0.05).

CONCLUSIONS

A reproducible model of vital staining and oxidative injury is described for studying porcine corneal endothelial survival. Our results demonstrate a beneficial role of a corneal MSC secretome in reducing oxidative damage to the corneal endothelium. In addition, it suggests a potential role for PEDF in this process.

Corneal endothelial damage in phacoemulsification using an anterior chamber maintainer compared with using an ophthalmic viscosurgical device

PURPOSE

To compare the effects of phacoemulsification surgery (PE) using an anterior chamber maintainer (ACM) and conventional PE using an ophthalmic viscosurgical device (OVD) on corneal endothelial cells.

SETTING

Department of Ophthalmology, Celal Bayar University, Manisa, Turkey.

DESIGN

Prospective randomized controlled trial.

METHODS

Eyes in the OVD group (n = 50) underwent conventional PE, whereas eyes in the ACM group (n = 50) underwent PE using an ACM. Endothelial cell density (ECD), coefficient of variation (CV), hexagonality (HEX), and noncontact central corneal thickness (CCT) measurements were performed by specular microscopy before and at 1 month, 3 months, and 6 months after PE.

RESULTS

This study included 100 eyes of 97 patients undergoing PE. The mean age was 64.7 ± 10.6 years in the OVD group, 64.0 ± 12.6 years in the ACM group (P > .05). The groups did not differ significantly in preoperative ECD, CV, HEX, and CCT or total PE time (P > .05 for all). ECD was significantly lower in the ACM group compared with the OVD group at postoperative 1 month, 3 months, and 6 months (P = .002, P = .002, and P = .001, respectively). Similarly, ECD loss compared with preoperative value was greater in the ACM group at all postoperative timepoints (P = .003, P = .001, and P = .001, respectively). CV increased and HEX decreased in both groups postoperatively (P > .05 for both). CCT showed a transient increase of less than 10 μm at postoperative 1 month in both groups (P = .296).

CONCLUSIONS

PE with ACM was associated with greater corneal ECD loss compared with conventional PE. ACM should not be used during PE in patients with limited corneal endothelial reserve.

Accelerated Corneal Endothelial Cell Loss after Phacoemulsification in Patients with Mildly Low Endothelial Cell Density

By evaluating preoperative endothelial cell density (ECD), ECD loss after phacoemulsification can be predicted. In this retrospective cross-sectional study, we compared outcomes of phacoemulsification with different levels of preoperative ECD. Three-hundred-and-fifty-three patients aged between 18 and 90 years received phacoemulsification at Chang Gung Memorial Hospital. Age (p = 0.003), preoperative logMAR (p = 0.048), cataract grade (p = 0.005), preoperative ECD (p < 0.001), operation time (p = 0.043), phacoemulsification time (p = 0.001), and phacoemulsification energy (p < 0.001) were significantly associated with postoperative ECD change (%). Patients were divided into three groups according to preoperative ECD levels. Level of ECD, coefficient of variation (CV), cell hexagonality (HEX), central corneal thickness (CCT), visual acuity, underlying diseases, and complications were analyzed. With regard to groups, 29, 71, and 252 patients were respectively allocated into the markedly low (group A; ECD below 1000 cells/mm²), mildly low (group B; ECD between 1000 to 2000 cells/mm²), and normal (group C; ECD above 2000 cells/mm²) ECD level groups. The highest CV (40.8 ± 13.9%; p < 0.001) and lowest HEX (58.4 ± 14.6%; p < 0.001) were found in group A. Significant ECD loss was found in group B (28.9 ± 9.2%) as compared to group A (19.9 ± 5.4%) and C (15.0 ± 12.0%) (p < 0.001). No significant differences were found with regard to changes in CV (p = 0.941), HEX (p = 0.937), CCT (p = 0.346), and logMAR (p = 0.557) among the three groups. In conclusion, preoperative ECD level could be a novel predictive value for postoperative cell loss, which was the most prominent in mildly low ECD level group. Less phacoemulsification energy, earlier surgical intervention, or novel topical medications could be suggested for patients with an ECD range from 1000 to 2000 cells/mm².

N-palmitoyl-D-glucosamine, a Natural Monosaccharide-Based Glycolipid, Inhibits TLR4 and Prevents LPS-Induced Inflammation and Neuropathic Pain in Mice

Toll-like receptors (TLRs) are key receptors through which infectious and non-infectious challenges act with consequent activation of the inflammatory cascade that plays a critical function in various acute and chronic diseases, behaving as amplification and chronicization factors of the inflammatory response. Previous studies have shown that synthetic analogues of lipid A based on glucosamine with few chains of unsaturated and saturated fatty acids, bind MD-2 and inhibit TLR4 receptors. These synthetic compounds showed antagonistic activity against TLR4 activation in vitro by LPS, but little or no activity in vivo. This study aimed to show the potential use of N-palmitoyl-D-glucosamine (PGA), a bacterial molecule with structural similarity to the lipid A component of LPS, which could be useful for preventing LPS-induced tissue damage or even peripheral neuropathies. Molecular docking and molecular dynamics simulations showed that PGA stably binds MD-2 with a MD-2/(PGA)3 stoichiometry. Treatment with PGA resulted in the following effects: (i) it prevented the NF-kB activation in LPS stimulated RAW264.7 cells; (ii) it decreased LPS-induced keratitis and corneal pro-inflammatory cytokines, whilst increasing anti-inflammatory cytokines; (iii) it normalized LPS-induced miR-20a-5p and miR-106a-5p upregulation and increased miR-27a-3p levels in the inflamed corneas; (iv) it decreased allodynia in peripheral neuropathy induced by oxaliplatin or formalin, but not following spared nerve injury of the sciatic nerve (SNI); (v) it prevented the formalin- or oxaliplatin-induced myelino-axonal degeneration of sciatic nerve. SIGNIFICANCE STATEMENT We report that PGA acts as a TLR4 antagonist and this may be the basis of its potent anti-inflammatory activity. Being unique because of its potency and stability, as compared to other similar congeners, PGA can represent a tool for the optimization of new TLR4 modulating drugs directed against the cytokine storm and the chronization of inflammation.

Clinical Comparison of the Performance of Two Marketed Ophthalmic Viscoelastic Devices (OVDs): The Bacterially Derived Healon PRO OVD and Animal-Derived Healon OVD

This clinical investigation compared the clinical performance of two marketed ophthalmic viscoelastic devices (OVDs): the bacterially derived Healon PRO OVD (test) and the animal-derived Healon OVD (control) under normal use conditions during cataract removal and lens implantation. This prospective, multicenter, randomized, parallel, participant/evaluator masked, postmarket investigation enrolled 139 subjects (170 eyes), 116 (143 eyes) of which were treated (73 test; 70 control group). Both test and control OVDs were used, at a minimum, to inflate the anterior chamber and protect the endothelium prior to cataract extraction according to the standard procedure. The surgeon completed a postsurgery OVD clinical performance questionnaire, and intraocular pressure (IOP) was measured before surgery and at the 1 day postoperative visit with Goldmann applanation tonometry. Any IOP measurement of 30 mmHg or higher was considered a “spike” and recorded as a study-specific, serious adverse event. The bacterially derived Healon PRO OVD was found to be statistically noninferior to the overall clinical performance of the animal-derived Healon OVD control; thus, the primary hypothesis was satisfied. There were no statistically significant differences between OVD groups for any of the additional endpoints relating to IOP changes or to safety, thus satisfying additional hypotheses. The Healon PRO OVD showed statistically significant improvements in surgeon ratings for ease of injectability, transparency/visibility, and ease of IOL placement. The safety profile was also similar between OVD groups with regards to serious and/or device-related adverse events, as well as medical and lens findings. The results of this clinical investigation support the safety and effectiveness of the bacterially derived, currently marketed Healon PRO OVD and indicate that the intraocular surgical performance was similar between the two OVDs.

Effects of ultrasound energy on the porcine corneal endothelium - Establishment of a phacoemulsification damage model

PURPOSE

The purpose of this study was to establish a standardized in vitro phacoemulsification damage model for future investigations of the effects of phacoemulsification, surgical devices, protective ophthalmic viscoelastic devices (OVDs), irrigation solutions and other aspects related to cataract phacoemulsification surgery on the corneal endothelium using porcine eyes.

METHODS

Thirty-four porcine eyes were randomly assigned to three groups (phacoemulsification (n = 13), irrigation (n = 9), control (n = 12)). A total of 5 min of ultrasound energy with intermittent irrigation/aspiration was applied in the eyes of the phacoemulsification group. The eyes of the irrigation group received the identical treatment, but without the application of ultrasound energy. The control group was left untreated. All eyes were then prepared to split corneal buttons followed by 15 days of cultivation. Endothelial cell density (ECD) was assessed blinded on day 15.

RESULTS

Endothelial cell density declined significantly more until day 15 in the phacoemulsification group (2567 ± 317/267 cells/mm² (median ± 25%/75%-quartiles), -32.5 ± 7.0/6.4%) compared to the irrigation (3450 ± 350/383 cells/mm², -11.8 ± 5.3/2.6%; p < 0.001) and the control group (3650 ± 288/258 cells/mm², -10.2 ± 3.2/4.6%; p < 0.001).

CONCLUSION

The phacoemulsification damage model presented in this study is sensitive to phacoemulsification energy and may reliably be used to investigate various factors involved in phacoemulsification with regard to their influence on corneal endothelial cells. This method is able to replace animal experiments or in vitro cell culture experiments that often do not translate well to the in vivo situation in humans.

Combined treatment of phacoemulsification and single-port limited pars plana vitrectomy in acute angle-closure glaucoma

AIM

To evaluate the efficacy of combined treatment of phacoemulsification (PE) and micro-incisional single-port transconjunctival limited pars plana vitrectomy (PPV) in acute angle-closure glaucoma (AACG).

METHODS

A retrospective study included 26 patients who underwent PE diagnosed with AACG. Among them, 16 patients (16 eyes) underwent PE alone, 10 patients (10 eyes) underwent combined limited vitrectomy and PE. Then we compared intraocular pressure (IOP), anterior chamber angle, anterior chamber depth, central corneal thickness and corneal endothelial cell count before and after surgery, and effective PE time during cataract surgery.

RESULTS

Effective PE time was shorter in the combined surgery group than in the single surgery group (P=0.040). There was no statistically significant difference in IOP and best-corrected visual acuity between the two groups postoperatively. At 6mo postoperatively, there was no difference in the anterior chamber angle, anterior chamber depth, and central corneal thickness between two groups, but corneal endothelial cell count was higher in the combined surgery group than in the single surgery group (P=0.046). No complication such as vitreoretinal disease, endophthalmitis, bullous keratopathy was noted.

CONCLUSION

Combined micro-incisional single-port transconjunctival limited PPV and PE are more effective and safer than PE alone because of less operation time and fewer complications for management of AACG.

New ex vivo model of corneal endothelial phacoemulsification injury and rescue therapy with mesenchymal stromal cell secretome

PURPOSE

To develop a reproducible ex vivo model of corneal endothelial cell injury using phacoemulsification in porcine eyes and to evaluate the effects of mesenchymal stromal cell secretome in this injury model.

SETTING

Department of Ophthalmology, University of Illinois at Chicago, Illinois, USA.

DESIGN

Experimental study.

METHODS

A corneal endothelial injury model was optimized using different powers and durations of ultrasound energy inside ex vivo porcine eyes. Conditioned media from corneal mesenchymal stem cells was collected under serum-free conditions from passages 4 to 6. Immediately after the phacoemulsification injury, the anterior chamber fluid was replaced with unconditioned media or conditioned media and incubated at 37°C for 4 hours. At the end, endothelial cell viability was evaluated using trypan blue staining and analyzed with ImageJ software.

RESULTS

Using specific parameters (50% power for 30 seconds), phacoemulsification inside fresh porcine eyes led to a consistent level of endothelial cell injury. Incubation with corneal mesenchymal stromal cell-conditioned media after the injury significantly reduced endothelial cells loss compared with unconditioned media (mean 1.29% ± 0.91% [SD] and 5.33% ± 3.24%, respectively, P < .05).

CONCLUSIONS

Phacoemulsification inside fresh porcine eyes provided a reproducible model to study endothelial cell injury. Treatment with corneal mesenchymal stromal cell secretome after injury appeared to significantly enhance the survival of corneal endothelial cells. This might provide a new strategy for preventing corneal endothelial cell loss after phacoemulsification or other endothelial injuries. Further in vivo studies are necessary to determine the therapeutic potential.

Prospective randomized comparative study between venturi and peristaltic pumps in WhiteStar Signature® phacoemulsification machine

Purpose

To compare intraoperative parameters between venturi and peristaltic pump in WhiteStar Signature^® phacoemulsification machine using the bevel-down technique.

Setting

Hospital Oftalmológico de Brasília, Brasília, Federal District, Brazil.

Design

Prospective, comparative, patient-masked study.

Methods

Three hundred eyes were randomly assigned to have a phacoemulsification procedure with WhiteStar Signature^® using either peristaltic (n=150 eyes) or venturi (n=150 eyes) pumps by a single surgeon (WTH). Elliptical ultrasound setting and prefracture (prechop or preslice) techniques were used in all cases. Cataract nucleus density was graded using lens opacities classification system III and Pentacam Nucleus Staging classification. Clinical measurements included preoperative- and postoperative- corrected visual acuity, preoperative and 2-month postoperative endothelial cell counts, and preoperative and 1-day postoperative central corneal thickness. Intraoperative measurements at the end of the case were phaco time, fluid used, total case time, and Efx energy.

Results

There were no statistically significant differences between groups regarding age, cataract density, and phaco time (P>0.05). Intraoperatively, we observed significantly less ultrasound energy (P=0.011), case time (P=0.0001), and balanced saline solution (P=0.001) usage in the venturi group. Clinically, both fluidic settings can provide similar clinical outcomes and visual recovery, regarding corrected distance visual acuity, endothelial cell count, and central corneal thickness.

Conclusion

Our data show that to minimize fluid use, case time, and energy with the prefracture technique, the venturi pump was the most efficient system and was statistically superior to peristaltic pump.

Long-term (≥10 years) results of corneal endothelial cell loss after cataract surgery

OBJECTIVE

To investigate the extent of long-term corneal endothelial loss after uneventful cataract surgery and the factors associated with decreases in corneal endothelial cell density (ECD).

DESIGN

Retrospective case series.

PARTICIPANTS

Patients who had undergone uncomplicated cataract surgery.

METHODS

This study comprised 81 eyes of 48 patients who had undergone cataract surgery >10 years previously by a single surgeon with the same intraocular lens and visited the outpatient clinic between January 2014 and February 2017. Long-term (≥10 years) changes in visual outcome and ECD after uncomplicated cataract surgery were evaluated. To analyze factors correlated with endothelial cell loss, preoperative biometric variables, including cataract grade, anterior chamber depth, axial length, and postoperative corneal edema, were evaluated.

RESULTS

The mean ± SD preoperative and long-term postoperative ECD was 2793 ± 351.09 and 2148 ± 478.38 cells/mm², respectively. The mean follow-up period was 11.08 ± 1.06 years and 10-year ECD loss rate was 20.62 ± 13.63%. Preoperative nuclear firmness was most statistically correlated with 10-year ECD loss (β-coefficient 0.394 [95% CI 3.402-9.448]; p < 0.001). The degree of postoperative corneal edema was also a significant predictive factor of 10-year ECD loss after cataract surgery (β-coefficient 0.378 [95% CI 2.854-8.358]; p = 0.002).

CONCLUSION

Preoperative nuclear firmness and postoperative corneal edema were predictors of long-term (≥10 years) endothelial cell loss and severe endothelial cell loss after cataract surgery. It is important to remember that eyes with increased nuclear firmness have a significantly higher risk of long-term enhanced ECL.

Phacoemulsification in the anterior chamber: An alternative surgical technique in post-vitrectomy cataract

Objective

To evaluate the characteristics, safety and effectiveness of a modified technique of phacoemulsification in post-vitrectomy cataracts.

Methods

This retrospective clinical trial comprised 31 patients (31 eyes) with post-vitrectomy cataract, who had undergone phacoemulsification combined with intraocular lens implantation. An alternative surgical technique known as phacoemulsification in the anterior chamber was used for nucleus management in those cases. The following parameters were evaluated: best corrected visual acuity (BCVA), ocular inflammation, intraocular pressure, endothelial cell count and surgical complications.

Results

Three months after surgery, the BCVA improved significantly compared with that before surgery (Z=-10.547; p<0.05). There were no significant differences in IOP before and after surgery (Z=-0.474; p>0.05). There was a statistically significant postoperative decrease in endothelial cell densities (Z=-3.916; p<0.05). The mean endothelial cell loss was -8.71%. A little inflammatory response in the anterior chamber in 11 eyes and mild corneal edema in 8 eyes were observed on the first day after surgery, which subsided after a week. The posterior capsular opacification were observed in three eyes, two of which were denser, and the YAG laser was performed for posterior capsular incision. No obvious surgical complications occurred.

Conclusion

The modified technique of phacoemulsification, with phacoemulsification in the anterior chamber, is safe and effective to deal with post-vitrectomy cataracts.

Nanosecond laser-assisted cataract surgery: Endothelial cell study

PURPOSE

To evaluate corneal endothelial cell density (ECD) and morphology after cataract surgery using coaxial ultrasound (US) phacoemulsification or a recently introduced coaxial nanosecond laser technique.

SETTING

Department of Ophthalmology, Medical University of Sofia, Sofia, Bulgaria.

DESIGN

Prospective cohort study.

METHODS

Coaxial US phacoemulsification was performed in 1 eye (US group) and coaxial nanosecond laser-assisted cataract surgery in the contralateral eye (laser group) of the same patient. Nuclear sclerosis was graded from nuclear opalescence (NO) 3, nuclear color (NC) 3 to NO4, NC4 using the Lens Opacities Classification System III. The central ECD, coefficient of variation (CoV) in cell size (objective measure of polymegethism), and percentage of hexagonal cells (an index of pleomorphism) were evaluated.

RESULTS

Eighty-two eyes (41 patients) had uneventful surgery. The mean ECD was 2517 cells/mm(2) ± 137 (SD) preoperatively and 2287 ± 155 cells/mm(2) at 2 years in the US group and 2521 ± 233 cells/mm(2) and 2420 ± 292 cells/mm(2), respectively, in the laser group (both P < .001). The mean CoV was 0.27 ± 2.4 preoperatively and 0.30 ± 2.4 at 2 years in the US group and 0.27 ± 2.8 and 0.27 ± 2.0, respectively, in the laser group (both P < .001). The mean percentage of hexagonal cells was 42.3% ± 3.6% preoperatively and 37.74% ± 3.54% at 2 years in the US group and 42.8% ± 3.2% and 43.00% ± 2.68%, respectively, in the laser group (both P < .001).

CONCLUSION

Nanosecond laser phacoemulsification had advantages over US phacoemulsification in terms of endothelial cell structure preservation.

FINANCIAL DISCLOSURES

Dr. Kanellopoulos is consultant to Alcon Surgical, Inc., Allergan, Inc., Avedro, Inc., Keramed, Inc., Optovue, Inc., i-Optics Corp., and Carl Zeiss Meditec AG. Neither of the other authors has a financial or proprietary interest in any material or method mentioned.

Prophylactic exposure of human corneal endothelial cells to Rho-associated kinase inhibitor reduced apoptosis rate after phacoemulsification: Ex vivo study

PURPOSE

To evaluate whether prophylactic exposure of corneal endothelial cells (CECs) to a selective Rho-associated kinase (ROCK) inhibitor will inhibit CEC apoptosis after phacoemulsification.

SETTING

Laboratory evaluations at the Edith Wolfson Medical Center, Holon, Israel and the Chaim Sheba Medical Center, Tel-Hashomer, Ramat-Gan, Israel and the Chaim Sheba Medical Center, Tel-Hashomer, Ramat-Gan, Israel.

DESIGN

Experimental study.

METHOD

Human donor corneolimbal rings were divided into fragments that were stored in commercial storage media with or without the addition of 10 mM ROCK inhibitor for 1 week and were then exposed to phacoemulsification energy. Samples were dissociated into single cells by trypsin digestion and CECs were targeted using the antihuman CD166 antibody, a new biomarker. The CEC survival was evaluated for early and late apoptosis rate with flow cytometric analysis of annexin-V and propidium iodide (PI) double staining.

RESULTS

Six corneoscleral rings from 4 donors were studied. After phacoemulsification, CEC exposed to ROCK inhibitor demonstrated a 37.06% reduction in early apoptosis rate (29.36% ± 4.33% [SD] versus 46.65% ± 1.51%, P = .006) and 45.27% reduction in late apoptosis rate (17.6% ± 16.81% versus 32.16% ± 26.30%, P = .007), compared with controls. Subsequently, ROCK levels in apoptotic CECs were significantly lower in cells incubated with ROCK inhibitor than the control medium.

CONCLUSIONS

In this ex vivo study, ROCK inhibitor reduced endothelial loss and thus, could be used to limit or slow down CEC loss. Rho-associated kinase inhibitor might be used before cataract surgery, especially in high risk patients. This might be a promising new method for preventing pseudophakic bullous keratopathy.

Intra-correlations between cataract density based on Scheimpflug image, phacodynamics, surgery duration, and endothelial cell loss after phacoemulsification

Purpose

To assess intra-correlations between lens density based-on Scheimpflug Imaging System, power used during surgery, surgery duration, and endothelial cell loss in eyes with nuclear cataract.

Setting

Department of Ophthalmology, King Fahd Hospital of the University, Alkhobar, Saudi Arabia.

Design

Prospective cross-sectional observational study.

Methods and material

The objective lens density and endothelial cell density were measured using the Scheimpflug system and specular microscopy, respectively. Intra-operatively, all phacodynamic parameters and duration of the surgery were documented.

Results

This study of 62 patients (71 eyes) with a mean age of 58.56 ± 10.4 years. The mean Scheimpflug-measured lens density was 13.93 ± 3.27. The mean phacodynamic parameters, namely, power, ultrasound time, and elliptical motion were 13.63 ± 6.38, 1.27 ± 1.12, and 50.56 ± 50.06, respectively. There were a positive linear correlations between the Scheimpflug-measured lens density and phacodynamic parameters, power (AVG %), ultrasound time, and elliptical motion (r = 0.501, r = 0.620, and r = 0.641, respectively; all P < .001), amount of endothelial loss (r = 0.445, P < .001), and surgery duration (r = 0.346; P < .01). Phacodynamic parameters were positively correlated with degree of endothelial loss (P < .01). The length of the surgery failed to show any correlation with damage happened to the endothelium (r = 0.210, P > .05).

Conclusion

A positive correlations were observed between Scheimpflug-measured lens density with phacodynamic parameters, surgery duration, and endothelial loss. A strong correlation was observed between the degree of endothelial cell loss and phacodynamic parameters but not with the length of the procedure.

Evaluation of Corneal Endothelial Cell Loss After Uncomplicated Phacoemulsification Cataract Surgery With Intracameral Phenylephrine

PURPOSE

To study the effects of intracameral phenylephrine 1.5% on corneal endothelial cell loss and morphological changes in patients who had uneventful phacoemulsification surgery.

DESIGN

A double-blind randomized controlled trial.

METHODS

This study comprised 295 patients who were randomized into the intracameral (ICM) mydriatic group or topical mydriatic group. Central corneal endothelial cell density (ECD), coefficient of variation (CV), and percentage of hexagonal cells were measured preoperatively and postoperatively at 1 week, 6 weeks, and 3 months with specular microscope.

RESULTS

There was no significant difference in endothelial cell density and endothelial cell loss between the topical and ICM mydriatic groups. At 3 months, the mean endothelial cell density in the ICM group was 2129.76 ± 423.53 cells/mm2 and 2100.54 ± 393.00 cells/mm2 in the topical group (P = 0.539). The endothelial cell loss was 18.60 ± 12.79% in the IC M group and 19.44 ± 11.24% in the topical group (P = 0.550). No significant difference was seen in the percentage of hexagonal cells and coefficient of variation of patients between the 2 groups.

CONCLUSIONS

Intracameral phenylephrine was not associated with increased risk of postoperative endothelial cell loss or morphological changes. It can be safely injected into the anterior chamber for pupil dilatation before phacoemulsification cataract surgery.

A Rabbit Model Study to Determine the Efficacy of a Prototype Corneal Endothelium Protector during Cataract Surgery

Purpose. We evaluated the efficacy and safety of a mechanical device, the P-chute, in corneal endothelium preservation during phacoemulsification in a rabbit model. Methods. Twenty-four rabbits were randomly assigned into 2 groups. One eye of each rabbit underwent phacoemulsification that simulated the removal of a dense nucleus, with or without the P-chute. Serial slit-lamp examinations, anterior segment optical coherence tomography (ASOCT) scans, and specular microscopy were performed. Three rabbits from each group were sacrificed on postoperative days (PODs) 1, 5, 7, and 14. Histological analysis of the corneas was performed. Results. There was a trend towards lesser endothelial cell loss for the P-chute group at POD1 (4.9% versus 12.5%, p = 0.53), POD5 (10.4% versus 12.2%, p = 0.77), and POD7 (10.5% versus 17.2%, p = 0.52). There was no significant difference in the corneal thickness (p = >0.05) between the 2 groups. The insertion of the device was challenging. The use of the P-chute only added an extra 15% to the surgical time. Conclusions. There was a trend towards better endothelium preservation with the P-chute even though the results were not statistically significant. We believe that the device could be useful in certain surgical situations. Further work is needed to improve the device insertion.

Analyses of Factors Affecting Endothelial Cell Density in an Eye Bank Corneal Donor Database

PURPOSE

To analyze the factors affecting central corneal endothelial cell density (ECD) in an eye bank corneal donor database.

METHODS

The Lion's Eye Institute corneal donor database consisting of 18,665 donors (34,234 corneas) aged 20 years or older was analyzed. In particular, differences in the ECD based on age, sex, race, prior ocular surgery, a history of systemic diseases, and smoking were investigated. Furthermore, risk factors for donor cell count inadequacy (defined here as ECD less than 2000/mm) were identified.

RESULTS

ECD decreased with age. Regarding race, the average ECD of African American donors was higher than those of white or Hispanic donors. A history of diabetes mellitus (DM) and ocular surgery were associated with a lower ECD. Donor medical history of hypertension, glaucoma, depression, dementia, Parkinson disease, hyper- or hypothyroidism, or smoking did not seem to affect the ECD. The risk factors for donor cell count inadequacy, based on binary logistic regression analyses were advanced age [65-74 years yielded an odds ratio of 17.8; confidence interval (CI), 10.6-29.8; P < 0.001; and 75-99 years yielded an odds ratio of 24.6 (CI, 14.5-41.61; P < 0.001) when compared with 20-34 years], cataract surgery (odds ratio, 4.3; CI, 4.0-4.8; P < 0.001), and DM (odds ratio, 1.2; CI, 1.1-1.3; P = 0.001).

CONCLUSIONS

Age, race, ocular surgery (cataract and refractive), and DM seem to significantly affect donor corneal ECD. Of these variables, age, a history of cataract surgery, and DM were found to be the greatest risk factors for inadequate donor cell density (less than 2000/mm).

Effect of fluidics on corneal endothelial cell density, central corneal thickness, and central macular thickness after phacoemulsification with torsional ultrasound

Aim:

To study the relative effects of high and low fluidic parameters on endothelial cell density (ECD), central corneal thickness (CCT), and central macular thickness (CMT) after phacoemulsification with torsional ultrasound.

Settings and Design:

Prospective, randomized clinical trial based on a tertiary eye hospital.

Subjects and Methods:

The study included 65 patients in each group. Patients were randomized to either the high or the low flow group using a computerized random number table. The study was patient and examiner masked. All patients underwent phacoemulsification with torsional ultrasound. Visual acuity, ECD, CCT, and CMT were measured for all patients preoperatively at 2 weeks and 6 weeks postoperatively.

Statistical Analysis Used:

The Shapiro–Wilks test was used to assess the normality of the data. Mann–Whitney U-test with the P value set at 0.05 was used to compare the two groups.

Results:

Cumulative dissipated energy was significantly higher in the low flow group (16.44 ± 9.07 vs. 11.74 ± 6.68; P = 0.002). No statistically significant difference was noted between the two groups in the ECD, CCT, CMT, or corrected distance visual acuity at the end of 6 weeks.

Conclusions:

No significant difference was noted in the postoperative outcome between high and low flow groups. Parameters can be modified to suit the surgeon's preference, as both high and low flow parameters were found to have comparable postoperative outcomes.

Corneal endothelial cell loss after pars plana vitrectomy and combined phacoemulsification-vitrectomy surgeries

OBJECTIVE

To compare postoperative corneal endothelial cell density (ECD) loss in eyes undergoing pars plana vitrectomy (PPV), or combination of cataract extraction (using phacoemulsification) and intraocular lens implantation with vitrectomy (CE/IOL-PPV) surgeries.

METHODS

Institutional setting. Best-corrected visual acuity (BCVA) and ECD by specular microscopy were measured preoperatively and 3 months postoperatively in both groups. Relative postoperative ECD loss was the primary outcome measure. Change in BCVA was the secondary outcome measure.

RESULTS

Forty eyes of 40 patients undergoing PPV and 46 eyes of 46 patients undergoing CE/IOL-PPV were included in the final analysis. Postoperative ECD was decreased slightly more in the CE/IOL-PPV group compared with the PPV group (13.9% ± 15.5% vs 9.0% ± 14.6%), although this was not statistically significant (p = 0.10). The improvement in the logMAR BCVA was, however, statistically more significant in the CE/IOL-PPV group compared with the PPV group (-56.6% ± 24.3% vs -38.6% ± 45.5%, p = 0.04).

CONCLUSIONS

PPV and the combination CE/IOL-PPV surgeries lead to modest and statistically similar postoperative decline in ECD. The combination surgery may lead to slightly more postoperative cells loss, but also more improvement in visual acuity.

Clinical outcomes of the glued intraocular lens scaffold

PURPOSE

To report the visual outcomes and complications of the glued intraocular lens (IOL) scaffold procedure in patients with intraoperative posterior capsule rupture and retained nuclear fragments, subluxated cataract, and Soemmerring ring associated with aphakia and deficient posterior capsule.

SETTING

Dr. Agarwal's Eye Hospital, Chennai, India.

DESIGN

Retrospective noncomparative interventional case series.

METHODS

Medical records of patients who had a glued IOL scaffold procedure performed were reviewed. The main outcome measures were visual acuity at final follow-up and intraoperative and postoperative complications during the entire follow-up.

RESULTS

The mean preoperative and mean final postoperative corrected distance visual acuity (CDVA) (Snellen decimal equivalent) in 19 eyes of 17 patients were 0.39 ± 0.13 (SD) and 0.73 ± 0.27, respectively (P = .002, Wilcoxon test). No eye lost CDVA. The CDVA was stable in 7 eyes, improved 1 line in 2 eyes, and improved 2 lines or more in 10 eyes. Postoperatively, 20/20 visual acuity was attained in 9 eyes. Intraoperatively, Soemmerring ring drop into the vitreous cavity in 1 eye and hyphema in 2 eyes were observed. Postoperative complications included corneal edema (2 eyes), choroidal detachment (1 eye), mild vitritis (1 eye), ocular hypertension (1 eye), and fibrin reaction in the anterior chamber that resolved with medical management (2 eyes).

CONCLUSION

The glued IOL scaffold enabled a closed-chamber approach with proper placement of an IOL in cases with inadequate sulcus or iris support and allowed safe emulsification of the retained nuclear fragments with good visual outcomes.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Comparison of Phacoemulsification Cataract Surgery with Low versus Standard Fluidic Settings and the Impact on Postoperative Parameters

Purpose

To compare complications after cataract surgery using 2 different phacoemulsification fluidic settings.

Methods

One cataract surgeon (M.K.) performed phacoemulsification cataract surgery in one eye of 43 patients in this randomized prospective clinical study conducted at St. Erik Eye Hospital, Stockholm, Sweden. The patients were randomized to phacoemulsification with low fluidic settings in one group and standard fluidic settings in the other group. Corrected distance visual acuity (CDVA), central corneal thickness (CCT), endothelial cell density (ECD), anterior chamber flare, intraocular pressure (IOP), and macular thickness were measured preoperatively and postoperatively, with a final evaluation at 3 months. Surgical time, ultrasound energy, and amount of balanced saline solution used intraoperatively were recorded.

Results

Twenty-one patients were included in the group with standard settings and 22 patients were in the group with low settings. There were no significant differences between the groups in CDVA, CCT, flare, IOP, macular thickness, or ECD at 1 day, 3 weeks, or 3 months postoperatively. The surgical time was significantly (p = 0.009) longer and cumulative dissipated energy was significantly (p<0.001) higher in the group with low fluidic settings.

Conclusions

Although the surgical time and ECD were significantly higher in the group with low fluidic settings, there were no differences in the CCT, ECD, macular thickness, or inflammation postoperatively between the low and standard fluidic settings during phacoemulsification.

Symmetric bimanual phacofragmentation: a new approach for nucleus disassembly

PURPOSE

To describe a new technique to split the lens nucleus inside the capsular bag, using a novel pair of instruments.

METHODS

Two identical instruments are employed on the horizontal axis to promote nuclear splitting into 2 or more fragments. Each instrument has a portion that functions as a hook (H); an anterior edge, opposite to the hook, which acts as a knife (K); and a surface area located between the hook and knife, which functions as a cracker (C).

RESULTS

Nuclei up to grade 4 nuclear sclerosis were successfully fractured employing this technique.

CONCLUSIONS

Symmetric bimanual phacofragmentation with HKC instruments provides effective bimanual splitting of nuclei for phacoemulsification, also allowing depth adjustment of cleavage plane, and can be applied for a wide range of nuclear densities.

The use of femtosecond lasers in cataract surgery: review of the published results with the LenSx system

PURPOSE

To review the published literature describing the use of the LenSx femtosecond laser technology (Alcon Laboratories, Inc., Fort Worth, TX) in cataract surgery.

METHODS

Literature review.

RESULTS

The LenSx system has been used in more than 200,000 cataract surgery procedures to date. Pre-clinical evaluations have shown that this system produces accurate and reproducible capsulorhexes, and that both the energy required for phacoemulsification and total phacoemulsification time are less than with conventional phacoemulsification. In comparative studies, femtosecond lasers have been shown to produce more precise and reproducible capsulorhexes than manual procedures, and better intraocular lens placement; capsule overlap, circularity of capsulotomy, and centration of the intraocular lens are consistently better with femtosecond lasers than with manual procedures. The improved quality of capsulorhexis and intraocular lens positioning are reflected in favorable visual and refractive outcomes. As with any new technology, there is a significant learning curve: prospective cohort studies have shown that the incidence of intraoperative complications such as suction breaks or anterior capsular tears or tags decreases with experience. In general, the incidence of such complications is within the range (< 2%) considered in recent evidence-based guidelines to be feasible and desirable.

CONCLUSIONS

Although femtosecond laser cataract surgery is in its infancy, the technology is evolving rapidly and offers the potential for more consistent and predictable results after cataract surgery.

Femtosecond-laser assisted cataract surgery: a review

Introduced in 2008, the femtosecond laser is a promising new technological advance which plays an ever increasing role in cataract surgery where it automates the three main surgical steps: corneal incision, capsulotomy and lens fragmentation. The proven advantages over manual surgery are: a better quality of incision with reduced induced astigmatism; increased reliability and reproducibility of the capsulotomy with increased stability of the implanted lens; a reduction in the use of ultrasound. Regarding refractive results or safety, however, no prospective randomized study to date has shown significant superiority compared with standard manual technique. The significant extra cost generated by this laser, undertaken by the patient, is a limiting factor for both its use and study. This review outlines the potential benefits of femtosecond-laser-assisted cataract surgery due to the automation of key steps and the safety of this new technology.

A clinical comparison of safety and efficacy in phacoemulsification with versus without ophthalmic viscoelastic device

PURPOSE

To evaluate in a comparative manner the safety and efficacy of 1.0% sodium-Hyaluronate used during capsulorhexis and intraocular lens (IOL) implantation in phacoemulsification surgery.

MATERIALS AND METHODS

1.0% sodium-Hyaluronate, which is commonly used as one of the ophthalmic viscoelastic devices, was compared to intraocular irrigating solution, which can bring up these effects. In addition, the effect of both methods on occurring corneal endothelial cell (CEC) loss was investigated.

RESULTS

Each group comprised 19 eyes. The mean preoperative CEC density was 2525.68 ± 181.85 in Group H and 2514.16 ± 174.59 in Group V; no statistically significant difference was found between the groups (p > 0.05). Preoperative and postoperative first and twelfth week CEC densities were 2438.21 ± 198.12 (p < 0.001) and 2390.74 ± 202.31, respectively, in group H (p < 0.001). Preoperative and postoperative first and twelfth week CEC densities were 2415.32 ± 197.24 (p < 0.001) and 2353.47 ± 212.69 in group V (p < 0.001). Compared with preoperative values, decrease in CEC density on the postoperative first and twelfth weeks was not statistically significant in either group (p > 0.05).

CONCLUSION

Although it was found that there was no statistically difference in terms of preventing CEC loss between 1.0% sodium-Hyaluronate and the irrigation method during phacoemulsification, it was observed clinically that 1.0% sodium-hyaluronate can make the procedure easy, safer, very helpful, especially for understanding phacoemulsification.

Corneal endothelial cell loss and corneal thickness in conventional compared with femtosecond laser-assisted cataract surgery: three-month follow-up

PURPOSE

To quantify changes in endothelial cell counts and corneal thickness measurements in patients having standard phacoemulsification compared with femtosecond laser-assisted cataract removal.

SETTING

Ruhr University Eye Clinic, Bochum, Germany.

DESIGN

Prospective randomized intraindividual cohort study.

METHODS

One eye of each patient had standard phacoemulsification (control group) and the other eye had femtosecond laser-assisted phacoemulsification (study group), both with intraocular lens implantation. Pulsed ultrasound energy was used for phacoemulsification. Noncontact endothelial cell microscopy and corneal pachymetry were performed preoperatively and 1 day, 3 to 4 days, 7 to 10 days, 50 to 60 days, and 90 to 100 days postoperatively.

RESULTS

The mean endothelial cell loss was 7.9% ± 7.8% (SD) 1 week postoperatively and 8.1% ± 8.1% 3 months postoperatively in the study group and 12.1% ± 7.3% and 13.7% ± 8.4%, respectively, in the control group. The mean relative change in corneal thickness from the preoperative values was -0.0% ± 1.9% at 1 day, 2.8% ± 1.8% at 1 week, and 3.3% ± 1.7% at 3 months in the study group and -0.9% ± 2.3%, 2.4% ± 1.5%, and 3.2% ± 1.4%, respectively, in the control group.

CONCLUSION

The femtosecond laser did not add to the endothelial damage caused by cataract surgery and might be beneficial in eyes with low preoperative endothelial cell values (eg, cornea guttata cases).

Correlation between cataract grading by Scheimpflug imaging and phaco time in phacoemulsification using peristaltic and venturi pumps

PURPOSE

To study the correlation among cataract grading system by Scheimpflug imaging (Oculus Pentacam® Nucleus Grading System [PNS]), effective phaco time (EPT), and surgical time (ST) using peristaltic and venturi pumps on the Whitestar Signature Phaco System (Abbott Medical Optics, Inc., Santa Ana, California, USA). 


METHODS

Patients scheduled to have bimanual microincision phacoemulsification by the same surgeon (T.F.) had Pentacam® Scheimpflug assessment using PNS and were randomly distributed into 
2 groups. In group 1, surgery was performed using peristaltic pump, and in group 2, using venturi pump. Parameters assessed in both groups included EPT and ST. 


RESULTS

Sixty eyes that had uneventful clear cornea phacoemulsification with implantation of foldable intraocular lens (IOL) were evaluated, 30 in each group. The EPT was statistically superior with higher nuclear density grades for both groups 1 and 2 (group 1 Spearman R = 0.739, p<0.001; group 2 Spearman R = 0.924, p<0.001). The ST statistically increased with nucleus density for both groups 1 and 2 (group 
1 Spearman R = 0.620, p<0.001; group 2 Spearman R = 0.643, p<0.001). Group 2 presented statistically significant reduction on median ST compared with group 1 for nucleus grading 2, 3, 4, and 5.

CONCLUSIONS

The PNS is an objective and reproducible method of grading nuclear cataract density and had a correlation with EPT. Peristaltic and venturi pumps in Signature Phaco System were similar in EPT but venturi pump reduced the median ST in nucleus with higher PNS, without repercussion on complications or anterior chamber stability.

Central corneal volume and endothelial cell count following femtosecond laser-assisted refractive cataract surgery compared to conventional phacoemulsification

PURPOSE

To compare the effect of conventional phacoemulsification and femtosecond laser-assisted cataract surgery on the cornea using Scheimpflug imaging and noncontact specular microscopy.

METHODS

In each group, 38 eyes (38 patients) underwent cataract surgery using either femtosecond laser-assisted (Alcon LenSx laser) (femtolaser group) or conventional phacoemulsification (phaco group). Central corneal thickness, 3-mm corneal volume, and Pentacam Nucleus Staging (PNS) were determined by a rotating Scheimpflug camera (Pentacam HR, Oculus Optikgeräte GmbH), and the volume stress index was calculated at 1 day and 1 month postoperatively. Endothelial cell count was measured by noncontact specular microscopy preoperatively, 1 day, 1 week, and 1 month postoperatively.

RESULTS

Central corneal thickness was significantly higher in the phaco group (607±91 μm) than in the femtolaser group (580±42 μm) on day 1, but did not differ significantly preoperatively and at 1 week and 1 month. Volume stress index at day 1 was significantly lower in the femtolaser group than in the phaco group (P<.05) but did not differ significantly at 1 month. Multivariate regression analysis showed that the type of surgery had a significant effect on central corneal thickness.

CONCLUSIONS

Femtosecond laser-assisted cataract surgery causes less corneal swelling in the early postoperative period and may cause less trauma to corneal endothelial cells than manual phacoemulsification.