Viscoat versus Visthesia during phacoemulsification cataract surgery: corneal and foveal changes

Corneal endothelial cell loss and intraocular pressure following phacoemulsification using a new viscous-cohesive ophthalmic viscosurgical device

PURPOSE

To compare results of two ophthalmic viscosurgical devices (OVDs)-Viscoat (a dispersive OVD, Alcon) and FR-Pro (a viscous-cohesive OVD, Rayner), in phacoemulsification surgery.

METHODS

A prospective randomized controlled study. Patients undergoing phacoemulsification were randomly assigned to receive one of the two OVDs. Exclusion criteria were age under 40, preoperative endothelial cell count (ECC) below 1,500 cells/mm2 and an eventful surgery. The primary outcome was change in ECC from baseline to postoperative month one and month three. Secondary outcomes were the difference between ECC at postoperative month one and month three, changes in IOP and occurrence of an IOP spike ≥ 30 mmHg after surgery.

RESULTS

The study included 84 eyes-43 in the Viscoat group and 41 in the FR-Pro group. Mean cell density loss at month one and month three was 17.0 and 19.2%, respectively, for the Viscoat group and 18.4 and 18.8%, respectively, for the FR-Pro group, with no statistically significant difference between the groups (p = 0.772 and p = 0.671, respectively). The mean ECC difference between the month one and month three visits was 50.5 cells/mm2 and was not statistically significant (p = 0.285). One eye in each group had an IOP spike ≥ 30 mmHg, both normalized by postoperative week one.

CONCLUSIONS

Viscoat and FR-Pro have comparable results following phacoemulsification surgery, suggesting that while FR-Pro is not a dispersive OVD, its endothelial cell protection may be comparable to one, perhaps due to the addition of sorbitol. Furthermore, a one-month follow-up of ECC seems sufficient in such trials.

Corneal Outcomes Following Cataract Surgery Using Ophthalmic Viscosurgical Devices Composed of Chondroitin Sulfate-Hyaluronic Acid: A Systematic Review and Meta-Analysis

Background

Ophthalmic viscosurgical devices (OVDs) are commonly used during cataract surgery to protect the corneal endothelium. A systematic literature review and meta-analysis were conducted to assess the clinical evidence of OVDs composed of chondroitin sulfate-hyaluronic acid (CS-HA) versus other OVDs in maintaining endothelial cell density (ECD) and corneal thickness (CT).

Methods

MEDLINE and EMBASE databases were searched from 2000 to 2020. Randomized controlled trials (RCTs, N ≥ 20 per group) comparing an OVD containing CS-HA (ie, VISCOAT^®, DuoVisc^® or DisCoVisc^®) to any other OVD were included. The identified comparators were limited to the OVDs found in the literature, which included those composed of HA-only or hydroxypropyl methylcellulose (HPMC). Outcomes of focus included changes in ECD (baseline to 3 months) and CT (baseline to 24 hours). Meta-analyses were performed using R software, to assess mean differences (MD) in ECD and CT change between CS-HA OVDs and HA-only or HPMC OVDs.

Results

A total of 966 abstracts were screened, and data were extracted from 12 RCTs. Meta-analyses using a random-effects model revealed significantly lower percent (%) decrease in ECD for CS-HA OVDs compared to both HA-only (MD: -4.10%; 95% CI: -5.81 to -2.40; p < 0.0001; 9 studies) and HPMC (MD: -6.47%; 95% CI: -10.41 to -2.52; p = 0.001; 2 studies) products. Similarly, % CT increase was significantly lower with CS-HA than with HA-only OVDs (MD: -3.22%; 95% CI: -6.24% to -0.20%; p = 0.04; 4 studies). However, there were no significant differences when comparing % CT change between CS-HA and HPMC OVDs (MD: 2.65%; 95% CI: -0.43% to 0.95%; p = 0.4; 2 studies).

Conclusion

CS-HA OVDs lead to less postoperative loss of endothelial cells and may better protect corneal endothelium during cataract surgery, relative to other OVDs. Future randomized studies may be needed to solidify these findings.

Corneal endothelial protection during manual small-incision cataract surgery: A narrative review

Cataract causes bilateral blindness in 20 million people globally, the vast majority of whom live in developing countries. Manual small-incision cataract surgery (MSICS) has emerged as an efficient and economical alternative to phacoemulsification, giving comparable results in terms of final visual gain. One of the important determinants of postoperative visual gain is the status of the corneal endothelium. Multiple factors such as corneal distortion, irrigation solution turbulence, mechanical trauma by instruments, nuclear fragments, intraocular lens contact, and free oxygen radicals, all have been implicated in causing corneal damage during cataract surgery. MSICS with posterior chamber intraocular lens implantation has been reported to cause an endothelial cell loss of 15.83%, which is comparable with other modes of cataract surgery like extracapsular cataract extraction and phacoemulsification. Thorough preoperative assessment of endothelial status and taking necessary steps for endothelial protection during surgery can decrease the endothelial cell loss and overall burden of pseudophakic bullous keratopathy. In addition to surgical techniques, the type of irrigating solutions, ocular viscoelastic devices, intracameral dyes, and drugs all affect the endothelial cell status. This review presents a summary of available literature on the protection of endothelial cells during different steps of MSICS. This is especially relevant for developing countries where large-scale MSICS cataract surgeries are performed to decrease the cataract blindness burden.

Descemetorhexis Without Endothelial Keratoplasty in Fuchs Endothelial Corneal Dystrophy: A Systematic Review and Meta-Analysis

PURPOSE

Descemetorhexis without endothelial keratoplasty (DWEK) is an innovative corneal intervention and potentially effective against Fuchs endothelial corneal dystrophy (FECD). We aimed to conduct a systematic review and meta-analysis on the outcomes of DWEK, associated or not with phacoemulsification (PKE) and rho-kinase inhibitor (RHOKI) in FECD.

METHOD

PubMed, Cochrane Library, Embase, ClinicalTrials.gov , and Science Direct were searched for studies until November 29, 2020. We performed random-effects meta-analyses and meta-regressions, stratified by the type of intervention and descemetorhexis size (PROSPERO CRD42020167566).

RESULTS

We included 11 articles (mainly case series, both prospective and retrospective), representing 127 eyes of 118 patients. DWEK globally improved visual acuity (effect size = -1.11, 95% confidence interval, -1.70 to -0.52, P < 0.001) and pachymetry (-1.25, -1.92 to -0.57, P < 0.001), without significant effects on endothelial cell count (-0.59, -2.00 to 0.83, P = 0.419). The 3 types of interventions (ie, DWEK ± RHOKI, DWEK ± PKE, and DWEK ± PKE ± RHOKI) improved visual acuity and pachymetry in FECD. A descemetorhexis size ≤4 mm improved visual acuity (-0.72, -1.29 to -0.14, P < 0.001) and pachymetry (-0.68, -0.98 to -0.38, P < 0.001), whereas >4 mm did not. Overall, DWEK failure (ie, the prevalence of EK after DWEK) was 17% (7%-27%, P < 0.001), with 4% (0%-8%, P = 0.08) for a descemetorhexis size ≤4 mm.

CONCLUSIONS

Despite the lack of comparative studies, DWEK seemed to improve visual acuity and pachymetry in early stages of FECD. A descemetorhexis size ≤4 mm was associated with the best visual outcomes and pachymetry.

The safety and effectiveness of a new ophthalmic viscosurgical device-a randomized, controlled study

ClearVisc was significantly noninferior to Viscoat in the mean percentage of ECD loss from baseline to 3 months and proportion of patients with postoperative IOP ≥30 mm Hg at any follow-up.

To evaluate the safety and effectiveness of a new dispersive ophthalmic viscosurgical device (OVD) (ClearVisc) compared with an approved dispersive OVD (Viscoat) when used in cataract surgery.

The Pathomechanism, Antioxidant Biomarkers, and Treatment of Oxidative Stress-Related Eye Diseases

Oxidative stress is an important pathomechanism found in numerous ocular degenerative diseases. To provide a better understanding of the mechanism and treatment of oxidant/antioxidant imbalance-induced ocular diseases, this article summarizes and provides updates on the relevant research. We review the oxidative damage (e.g., lipid peroxidation, DNA lesions, autophagy, and apoptosis) that occurs in different areas of the eye (e.g., cornea, anterior chamber, lens, retina, and optic nerve). We then introduce the antioxidant mechanisms present in the eye, as well as the ocular diseases that occur as a result of antioxidant imbalances (e.g., keratoconus, cataracts, age-related macular degeneration, and glaucoma), the relevant antioxidant biomarkers, and the potential of predictive diagnostics. Finally, we discuss natural antioxidant therapies for oxidative stress-related ocular diseases.

Comparison of Femtosecond Laser-Assisted Cataract Surgery and Conventional Phacoemulsification on Endothelial Cell Density When Using Torsional Modality

Purpose

To compare the effects of femtosecond laser assisted cataract surgery (FLACS) and manual phacoemulsification on cumulative dissipated energy (CDE), torsional amplitude, and endothelial cell density (ECD).

Patients and Methods

This prospective, randomized study was conducted at Oka Eye Clinic (Fukuoka, Japan). Surgeries were performed using FLACS (with LenSx) or conventional technique in adults ≥20 years with grade 2–4 cataracts. Visits included preoperative, surgery day, and 5 postoperative visits (days 1, 4–10, 20–40, 60–120, and 150–210). Primary endpoint was CDE. Secondary endpoints included ECD percent change at day 150–210 versus preoperative visit and average torsional amplitude on surgery day. Exploratory endpoints included central corneal thickness and corrected distance visual acuity (CDVA). Superiority of FLACS to conventional technique was evaluated using t-tests based on a mixed model for repeated measures.

Results

Full analysis set included 53 eyes per group. Mean cataract grade was 2.92±0.58 in FLACS and 2.94±0.57 in conventional group. FLACS versus conventional method had significantly lower mean CDE (0.213±0.334 versus 1.718±0.898%-seconds, respectively; P<0.0001), demonstrating superiority of FLACS. Low endothelial cell loss (ECL) was achieved with both FLACS and conventional methods (1.5±5.6% and 2.7±5.2%; P=0.260). Torsional amplitude was significantly lower for FLACS versus conventional method (19.6±16.0% versus 31.1±6.6%; P<0.0001). Central corneal thickness was comparable for both methods at all visits except day 1; CDVA was comparable for both methods at all postoperative visits.

Conclusion

FLACS achieved significantly lower CDE compared with the conventional surgical method (P<0.0001). Low ECL was achieved with both FLACS (1.5%) and conventional (2.7%) methods.

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Ophthalmic Viscosurgical Devices (OVDs) in Challenging Cases: a Review

Ophthalmic viscoelastic devices (OVDs) are currently used in cataract surgery and have significantly improved the safety and effectiveness of this surgical procedure. OVDs are classified according to the zero-shear viscosity and the cohesion-dispersion index in cohesive, dispersive, and viscoadaptives. OVDs create and maintain anterior chamber depth and visibility, protecting the corneal endothelium and other intraocular tissues during surgery. The selection of the most adequate OVD is especially relevant when performing cataract surgery in challenging cases, such as in hard, mature cataracts, flat anterior chamber, pseudoexfoliation syndrome, intraoperative floppy iris syndrome, or glaucoma surgery. In such cases, OVD is crucial for facilitating the surgical procedure and the associated minimal complication rate. The use of a combination of OVDs (soft-shell technique and modifications), the use of blue-colored OVDs, and the combination of sodium hyaluronate with lidocaine have also been described as useful tools in some of these challenging cases.

Comparative study of phacoemulsification parameters with and without nitinol filament nuclear disassembly

PURPOSE

The purpose of this study was to evaluate the impact of nitinol microfilament lens disassembly using the miLOOP device on phacoemulsification parameters in routine cataract surgery.

SETTING

Private practice in Cleveland, Ohio.

DESIGN

Retrospective comparative consecutive case series.

METHODS

A chart review of consecutive cataract surgery cases in a single center operated by a single surgeon was conducted. Eyes were grouped by whether they underwent nitinol filament nuclear disassembly. Phacoemulsification energy, phacoemulsification time, and irrigation/aspiration (I/A) recorded during the operation were compared. Bilateral eyes were included only if the contralateral eye was in the opposite group.

RESULTS

A total of 212 eyes in 131 patients were eligible for analysis, including 81 subjects with both eyes. Most eyes (93%) had grade 2+ or 3+ nuclear sclerotic cataracts. A total of 102 eyes (48%) underwent nitinol filament nuclear disassembly preceding phacoemulsification. For all eyes, there was a 16% reduction in phacoemulsification energy, with a larger drop in grade 3+ eyes (-22%). Phacoemulsification and I/A times also reduced significantly (-19% and -37%, respectively, P < .02).

CONCLUSIONS

Nitinol microfilament nuclear disassembly reduced total phacoemulsification energy and time during cataract surgery, particularly in severe cataracts.

Impact of Ophthalmic Viscosurgical Devices in Cataract Surgery

Background

Ophthalmic viscoelastic devices (OVDs) used during small-incision cataract surgery have numerous advantages. However, OVDs have longer retention time in an eye after surgery resulting in intraocular pressure (IOP) spikes. The purpose of this study is to analyze and quantify the effect of various OVDs on both IOP and best corrected visual acuity (BCVA) by systematically reviewing the literature and performing meta-analysis.

Methods

Numerous databases from January 1, 1985, to present were systematically searched. Thirty-six (3893 subjects) of 3313 studies identified were included for analysis. Standardized mean difference (SMD) was computed, and meta-analysis was performed.

Results

A total of 3313 records were retrieved including 1114 from database search and 2199 from grey literature search. Significant increase in postoperative IOP in 1-day follow-up with Healon (SMD = 0.37, CI: [0.07, 0.67]), Viscoat (SMD = 0.29, CI: [0.13, 0.45]), Provisc (SMD = 0.46, CI: [0.17, 0.76]), and Soft Shell (SMD = 0.58, CI: [0.30, 0.86]) was computed. On the other hand, results implied a nonsignificant increase in postoperative IOP with Healon GV (SMD = 0.07, CI: [−0.28, 0.41]), Healon5 (SMD = 0.15, CI: [−0.33, 0.64]), 2% HPMC (SMD = 0.32, CI: [−0.0, 0.64]), and OcuCoat (SMD = 0.26, CI: [−0.37, 0.9]). Additionally, a nonsignificant reduction in postoperative IOP was inferred with Viscoat + Provisc (SMD = −0.28, CI: [−2.23, 1.68]).

Conclusion

Improvement in IOP was shown with Viscoat + Provisc. Additionally, IOP nonsignificant upsurge was observed with Healon GV, Healon5, 2% HPMC, and OcuCoat compared to significant upsurge with Healon, Viscoat, and Soft Shell.

Topical anaesthesia plus intracameral lidocaine versus topical anaesthesia alone for phacoemulsification cataract surgery in adults

BACKGROUND

Phacoemulsification cataract surgery is usually performed in adults under local anaesthesia. Topical anaesthesia, which involves instilling anaesthetic drops to the ocular surface prior to and during surgery, has found large acceptance internationally. It is safe and allows for rapid patient turnover and visual recovery. Some surgeons have supplemented topical anaesthesia with intracameral lidocaine, reasoning that this may further reduce intraoperative pain, particularly during surgical stages involving manipulation of intraocular structures and rapid changes in fluid dynamics. This review, originally published in 2006 and updated in 2020, explores the efficacy and safety of using supplementary intracameral lidocaine in phacoemulsification cataract surgery.

OBJECTIVES

To assess whether supplementing topical anaesthesia with intracameral lidocaine for phacoemulsification cataract surgery in adults reduces intraoperative and postoperative pain, and to assess differences in participant satisfaction, need for additional intraoperative anaesthesia, surgeon satisfaction, measures of intraocular toxicity, and adverse effects attributable to choice of anaesthesia.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS BIREME iAH, and six trial registries on 4 February 2020. We also searched the reference lists of identified studies. There were no language restrictions.

SELECTION CRITERIA

We included only randomized controlled trials (RCTs) where participants underwent phacoemulsification for age-related cataract under topical anaesthesia with or without intracameral lidocaine either in two eyes of the same participant, or in different participants. We also included studies that used oral or intravenous sedation in addition to local anaesthesia.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial methodological quality using standard Cochrane procedures.

MAIN RESULTS

We identified five new RCTs in this updated review. We included a total of 13 trials in the review, conducted in the UK, the USA, Australia, Italy, Canada, Taiwan, Singapore, India, and Pakistan, and comprising 2388 eyes of 2355 participants (one study was a paired-eye study with each participant acting as their own control). The age range of participants was 34 to 95 years. We excluded studies that only included low-risk participants and excluded more difficult operative cases, for example hard lens nuclei or small pupils. We excluded studies assessing only participants with Fuchs' endothelial dystrophy. We judged one study as at high risk for selection bias. We assessed five studies as having an unclear risk of bias for random sequence generation and seven studies an unclear risk of bias for allocation concealment. We judged three studies as at high risk of performance bias, as the surgeon was not blinded, and two studies as at unclear risk of bias for this domain. No studies were judged as at high risk for detection bias, but five studies were judged to have an unclear risk of bias for this domain. We judged all 13 included studies to have a low risk of attrition bias and an unclear risk of reporting bias. Data from eight RCTs favoured topical anaesthesia plus intracameral lidocaine 0.5% to 1% over topical anaesthesia alone for reducing intraoperative pain when measured using a 10-point visual analogue scale, analysed as a continuous outcome. Mean pain score was 0.26 lower in the supplemental intracameral lidocaine group (95% confidence interval (CI) -0.39 to -0.13, 1692 eyes, moderate-quality evidence). Data from seven RCTs favoured supplemental intracameral lidocaine for reducing intraoperative pain when measured as a dichotomous outcome. The odds ratio of experiencing any pain was 0.40 versus the topical anaesthesia-only group (95% CI 0.29 to 0.57, 1268 eyes, moderate-quality evidence). Data from four RCTs did not show any additional benefit on postoperative pain when measured using a 10-point visual analogue scale (mean difference 0.12 points, 95% CI -0.29 to 0.05, 751 eyes, moderate-quality evidence). The impact on participant satisfaction was uncertain as only one small study investigated this outcome. The study suggested no difference between groups (mean difference 0.1 points, 95% CI -0.47 to 0.27, 60 eyes, low-quality evidence). Data from seven RCTs did not demonstrate a difference between groups in the need for additional intraoperative anaesthesia (odds ratio 0.88, 95% CI 0.56 to 1.39, 1194 eyes of 1161 participants; low-quality evidence), although this result is uncertain. A variety of measures were reported relating to possible intraocular toxicity. Data from four RCTs did not demonstrate a difference between groups in mean percentage corneal endothelial cell count change from pre- to postoperatively (mean difference 0.89%, 95% CI -1.12% to 2.9%, 254 eyes of 221 participants, moderate-quality evidence). Synthesis of the evidence from eight RCTs identified no difference in intraoperative adverse events between groups (odds ratio 1.00, 95% CI 0.32 to 3.16, 1726 eyes, low-quality evidence). This result should be interpreted with caution, mainly due to a lack of clear definitions of adverse events, low numbers of events, heterogeneity between studies, and large confidence intervals. Large observational studies may have been more appropriate for looking at this outcome.

AUTHORS' CONCLUSIONS

There is moderate-quality evidence that supplementation of topical anaesthesia with intracameral lidocaine 0.5% to 1% for phacoemulsification cataract surgery in adults reduces participant perception of intraoperative pain. The odds of experiencing any pain (as opposed to no pain) were 60% less for the topical anaesthesia plus intracameral lidocaine group versus the topical anaesthesia-only group. However, the numerical amplitude of the effect may not be of great clinical significance on the continuous pain score scale. Generally, the pain scores were consistently low for both techniques. We found moderate-quality evidence that there is no additional benefit of intracameral lidocaine on postoperative pain. There is insufficient evidence to determine the impact on participant satisfaction and need for additional intraoperative anaesthesia due to low-quality evidence. There is moderate-quality evidence that intracameral lidocaine supplementation does not increase measures of intraocular toxicity, specifically loss of corneal endothelial cells. There is low-quality evidence that the incidence of intraoperative adverse events is unchanged with intracameral lidocaine supplementation, but as RCTs are not the optimum medium for looking at this, this result should be interpreted with caution. Further research specifically investigating the adverse effects of intracameral anaesthesia might help to better determine its safety profile. Economic evaluations would also be useful for detailing cost implications.

Changes in corneal endothelium cell characteristics after cataract surgery with and without use of viscoelastic substances during intraocular lens implantation

PURPOSE

To evaluate whether the use of balanced salt solution (BSS) or an ophthalmic viscoelastic device (OVD) during hydrophilic acrylic intraocular lens (IOL) implantation variously impacts corneal endothelial cell characteristics in eyes undergoing uneventful phacoemulsifications.

METHODS

Prospective nonrandomized observational clinical trial. Patients were assigned either to the BSS plus(®) or to the OVD Z-Celcoat™ group depending on the substance used during IOL implantation. Corneal endothelium cell characteristics were obtained before, 1 week, and 6 weeks after surgery. Intraoperative parameters (eg, surgery time, phacoemulsification energy) were recorded.

RESULTS

Ninety-seven eyes were assigned to the BSS plus and 86 eyes to the Z-Celcoat group. Preoperative corneal endothelium cell density (ECD) and endothelium cell size were 2,506±310 cells/mm(2)/2,433±261 cells/mm(2) and 406±47 µm(2)/416±50 µm(2) (P=0.107/P=0.09). After 1 and 6 weeks, ECD decreased and endothelium cell size increased significantly in both groups (each P<0.001) without significant differences between both groups (each P>0.05). Irrigation-aspiration suction time (30.3±16.6 versus 36.3±14.5 seconds) and overall surgical time (7.2±1.2 versus 8.0±1.4 minutes) were significantly longer in the OVD Z-Celcoat group (each P<0.001). No complications or serious side effects occurred.

CONCLUSION

Implantation of a hydrophilic acrylic IOL under BSS infusion seems to be a useful and faster alternative in experienced hands without generating higher ECD loss rates.

Results of endocapsular phacofracture debulking of hard cataracts

Purpose/aim of the study

To present a phacoemulsification technique for hard cataracts and compare postoperative results using two different ultrasonic tip motions during quadrant removal.

Materials and methods

A phacoemulsification technique which employs in situ fracture and endocapsular debulking for hard cataracts is presented. The prospective study included 56 consecutive cases of hard cataract (LOCS III NC [Lens Opacification Classification System III, nuclear color], average 4.26), which were operated using the Infiniti machine and the Partial Kelman tip. Longitudinal tip movement was used for sculpting for all cases which were randomized to receive longitudinal or torsional/interjected longitudinal (Intelligent Phaco [IP]) strategies for quadrant removal. Measurements included cumulative dissipated energy (CDE), 3 months postoperative surgically induced astigmatism (SIA), and corneal endothelial cell density (ECD) losses.

Results

No complications were recorded in any of the cases. Respective overall and longitudinal vs IP means were as follows: CDE, 51.6±15.6 and 55.7±15.5 vs 48.6±15.1; SIA, 0.36±0.2 D and 0.4±0.2 D vs 0.3±0.2 D; and mean ECD loss, 4.1%±10.8% and 5.9%±13.4% vs 2.7%±7.8%. The differences between longitudinal and IP were not significant for any of the three categories.

Conclusion

The endocapsular phacofracture debulking technique is safe and effective for phacoemulsification of hard cataracts using longitudinal or torsional IP strategies for quadrant removal with the Infiniti machine and Partial Kelman tip.

Prospective Randomized Study Comparing Combined Phaco-ExPress and Phacotrabeculectomy in Open Angle Glaucoma Treatment: 12-Month Follow-Up

Purpose of the Study. To compare the efficacy and safety of phacotrabeculectomy (P-Trab) and phacoemulsification with the ExPress (P-ExPress) mini glaucoma shunt implantation. Study Plan. Prospective randomized study. Material and Methods. 85 eyes with cataract and unregulated open angle glaucoma. There were 46 eyes in the P-ExPress and 39 the P-Trab group. Intraocular pressure (IOP), the number of antiglaucoma medications, qualified and complete surgical success (defined as IOP ≤ 18.0 mmHg), visual acuity (CDVA), the number of endothelial cells, and postoperative complications and additional procedures were assessed. Results. After 12 months of observation, the average IOP in the P-Express group went from 26.4 ± 9.3 down to 17.1 ± 5 mmHg (P < 0.05) and from 27.9 ± 12.9 down to 15.9 ± 2.7 mmHg in the P-Trab group (P < 0.05). No significant differences in the amount of medications used after surgery and CDVA were discovered between the groups. In the P-ExPress group, greater loss of endothelial cells was noted (CD_loss%), compared to the P-Trab group. Conclusions. Both P-ExPress and P-Trab have comparable efficacy and similar early postoperative complication profile. The presence of additional implant (as is the case of the ExPress mini glaucoma shunt implantation) may cause progressive loss of endothelial cells.

The Impact of Reused Phaco Tip on Outcomes of Phacoemulsification Surgery

PURPOSE

To evaluate the impact of reused phaco tip on intraoperative performance and postoperative outcomes after 2.2 mm micro-coaxial torsional and transversal phacoemulsification.

MATERIAL AND METHODS

This prospective randomized study enrolled 136 eyes of 136 cataract patients; 68 eyes in torsional group (34 eyes with single use tip, 34 eyes with reused tip) and 68 eyes in transversal group (34 eyes with single use tip, 34 eyes with reused tip). Intraoperative measurements were total ultrasound (U/S) time, torsional U/S time, cumulative dissipated energy (CDE), estimated fluid use (EFU) in the torsional group and total phacoemulsification time (TPT), and effective phacoemulsification time (EPT) in transversal phacoemulsification. The central endothelial cell density (ECD) and the central corneal thickness (CCT) were evaluated preoperatively and postoperatively at 1 and 30 days using noncontact specular microscopy.

RESULTS

Intraoperative measurements in torsional phacoemulsification showed significant increase in total U/S time (p = 0.01), torsional U/S time (p = 0.01), and CDE (p = 0.01) with the reused tip. The EFU was similar in both tip groups (p = 0.36). The total U/S time, torsional U/S time, and CDE in torsional group were significantly increased with the reused tip for grade III (p = 0.03 for all parameters) and grade IV cataracts (p = 0.005 for torsional U/S time and CDE; p = 0.006 for total U/S time). Intraoperative measurements in transversal phacoemulsification showed no differences in TPT and EPT between tip groups (p > 0.05). The change in ECD and CCT in torsional and transversal phacoemulsification groups were similar in both tip groups (p > 0.05).

CONCLUSIONS

This study showed that sharpness of phaco tip edge increases the efficiency of torsional phacoemulsification for hard cataracts. This result does not mean that reused phaco tip may be used in soft and medium cataracts. As the timing of tip's change is a user-dependent procedure, a new single phaco tip should be used in each case if possible.

Advances in cataract surgery: preserving the corneal endothelium

PURPOSE OF REVIEW

Cataract surgery is known to lead to some degree of corneal endothelial cell loss (ECL). The purpose of this review is to describe how recent technological advancements such as femtosecond laser-assisted cataract surgery (FLACS) affect corneal endothelium during cataract surgery.

RECENT FINDINGS

It has been suggested that FLACS may reduce the amount of required ultrasound energy used in cataract surgery, a factor known to be directly related to ECL. Several recent studies demonstrate either no difference or less ECL with FLACS than with standard phacoemulsification 1-3 months after surgery. However, results at 6 months show comparable ECL between the two techniques. Other recent advancements in surgical technique, such as biaxial microincision surgery, result in similar ECL rates to that of standard phacoemulsification. The use of ultraviolet light in the newly developing light-adjustable intraocular lenses does not increase ECL. Studies show either similar results or less ECL with the use of the newer viscous-dispersives when compared with other viscoelastic devices. Other aspects such as the use of intracameral injections have no adverse effects on corneal endothelium.

SUMMARY

Newly emerging cataract surgical techniques cause comparable ECL to that of conventional phacoemulsification. Femtosecond laser-assistance may reduce ECL, but likely only in the early postoperative period. Further studies are needed to better elucidate short and long-term effects of FLACS on the corneal endothelium. Viscous dispersives may offer equal or increased protection of the corneal endothelium during surgery compared with viscoelastic devices currently in wide use, but further studies are required to support these results.

The effect of an Ahmed glaucoma valve implant on corneal endothelial cell density in children with glaucoma secondary to uveitis

PURPOSE

To assess the effect of Ahmed glaucoma valve implants on corneal endothelial cell density (ECD) in children with uveitic glaucoma.

DESIGN

Cross-sectional study.

METHODS

setting: Institutional. patientpopulation: Eighty eyes from 42 patients diagnosed with uveitis before the age of 16. Twenty-eight eyes had an Ahmed glaucoma valve implant because of secondary glaucoma. Fifty-two eyes without an implant served as controls. intervention orobservationprocedure(s): Corneal ECD was examined cross-sectionally using a noncontact specular microscope. Univariate and multivariate generalized estimating equations analyses with correction for paired eyes were performed. mainoutcomemeasure(s): Correlation of ECD with the presence of an Ahmed glaucoma valve implant and with the time following implantation.

RESULTS

ECD was significantly lower in the Ahmed glaucoma valve group than in controls (2359 and 3088 cells/mm(2), respectively; P < .001) following an average of 3.5 years after Ahmed glaucoma valve implantation. Presence of an Ahmed glaucoma valve implant, previous intraocular surgery, age, duration of uveitis, and history of corneal touch by the implant tube were all significantly associated with decreased ECD. Following a multivariate analysis, presence of an Ahmed glaucoma valve implant (B = -340; adjusted P < .011) and older age (B = -58; adjusted P = .005) remained independently associated with decreased ECD. Within the implant group, the age-adjusted time interval following Ahmed glaucoma valve implantation was highly correlated with decreased ECD (B = -558, P < .001).

CONCLUSIONS

Ahmed glaucoma valve implants in children with uveitic glaucoma are independently associated with decreased ECD, and this effect is associated with the time interval following Ahmed glaucoma valve implantation.

The changing fate of the corneal endothelium in cataract surgery

PURPOSE OF REVIEW

Corneal endothelial cell loss remains a well known, undesirable side-effect of cataract surgery that may, in severe cases, negatively impact patients' postoperative visual outcomes. This article reviews the current literature and describes in detail how the degree of corneal endothelial cell loss is influenced by specific patient risk factors, as well as the arrival of newer surgical techniques and technologies.

RECENT FINDINGS

Recent studies have demonstrated a reduction in corneal endothelial cell loss after phacoemulsification with the use of viscoelastic materials and modifications in phacoemulsification technology. Some patient characteristics may predispose patients to increased endothelial cell loss during cataract surgery.

SUMMARY

Advances in surgical technique, the implementation of newer surgical technologies such as torsional ultrasound and viscoelastic devices, and aspects of patients' preexisting medical history may lead to varying degrees of endothelial cell loss after cataract surgery. Appropriately addressing these issues during the perioperative period may improve the rate of endothelial cell loss, and thus further enhance the visual outcome of patients undergoing cataract surgery.