Soft-shell Technique Research Articles

Comparison of endothelial cell loss in Viscoless phacoemulsification versus soft shell technique of phacoemulsification: A retrospective study

Objectives: The purpose of this study was to compare the consequences of soft shell and viscoless technique on corneal endothelial cells (CECs) in cataract patients after phacoemulsification. Materials and Methods: This is a retrospective study. A total of 206 eyes of 139 patients (75 males and 64 females) who underwent phacoemulsification surgery during the period from September 2019 to December 2019 were enrolled in the study. The patients who underwent phacoemulsification were divided into two groups depending on the type of surgery performed, that is, viscoless or soft shell technique. The pre-operative and post-operative records were compared. The primary outcome measure was endothelial cell count (ECC) measured at baseline and postoperatively. The differences between the two groups were analysed statistically. The study was done at Sohum Eye Care Centre, Mumbai, India. Results: No statistically significant differences were observed between the two groups in terms of age, gender, diabetic status and cumulative dissipated energy (CDE), as P > 0.05. The inter-group mean difference between CDE did not differ significantly (P = 0.0626 and 0.1075, for 1 and 3 months inter-group comparison) between the two groups. However, a statistically significant mean difference of 99.9516 cells/mm2 (P < 0.0001), 116.4146 cells/mm2 (P = 0.0031) after one month and 90.4468 cells/mm2 (P = 0.0051), 145.2895 cells/mm2 (P < 0.0001) 3 months of surgery, between pre- and post-operative ECC, was observed in group 1 and group 2, respectively. The values of Pearson’s correlation (r = −0.3 to +0.3) suggested a very weak and non-significant strength of association of endothelial cell loss with age, gender, diabetic status and CDE postoperatively. Intergroup post-operative endothelial cell loss did not show any significant difference after 1 (P = 0.0644) and three months (P = 0.052) of phacoemulsification. Conclusions: Viscoless phacoemulsification surgery may be recommended in appropriate patients to avoid the side effects of ophthalmic viscosurgical devices.

OPHTHALMIC VISCOSURGICAL DEVICES

Ophthalmic viscoelastic devices (OVDs) are recently used in cataract surgery and have expressivelyupgraded the safety and effectiveness of this surgical procedure. 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 evaluation of the results of phacoemulsification using domestic and foreign viscoelastics

BACKGROUND: Phacoemulsification, being the safest technique, is the golden standard of cataract surgery worldwide. However, as any surgery, it is accompanied by inevitable damage to intraocular structures. The most prevalent among them is the loss of corneal endothelial cells. In order to prevent these complications, various viscoelastics with particular features and characteristics are widely used.
 AIM: To compare the anatomical and functional state of ocular structures after standard phacoemulsification with monofocal posterior chamber intraocular lens (IOL) implantation using domestic (Kogevisc and Adgevisc) and foreign (Viscoat and Amvisc Plus) viscoelastics.
 MATERIALS AND METHODS: 60 cataract patients (60 eyes) were included in the clinical study, which were divided into two equal groups. In the first group (30 patients, 30 eyes), Adgevisc and Kogevisc (Solofarm, Russia) were used during the procedure. The mean age of the patients was 66 11 years. In the second group (30 patients, 30 eyes), Viscoat (Alcon) and Amvisc Plus (BauschLomb) were used. The mean age of the patients was 69.03 10.44 years. All patients underwent phacoemulsification with the implantation of the AcrySof IOL (model SA60AT, Alcon) according to the standard technique. Visual acuity, IOP level, CCT, corneal endothelial cell density were assessed. All studies were performed before surgery, the next day, 7 days and 1 month after surgery.
 RESULTS: In patients of the second group, on the 1st (p 0.05) and 7th day (p 0.01) after surgery, a statistically significant increase in IOP was revealed compared to the first group. The central cornea thickness in the early postoperative period was higher in patients of the second group, however, it was not statistically significant. The loss of corneal endothelial cells 1 month after surgery was 8.5 7.0% (p 0.01) in the first group and 6.6 6.4% in the second group (p 0.01). The mean value of endothelial cell loss in patients of the first group was higher, however, it was not statistically significant. The best corrected visual acuity in both groups at all stages of follow-up after surgery (days 1, 7 and 30) was comparable, there was no significant difference between the groups.
 CONCLUSIONS: The clinical efficacy of domestic adhesive and cohesive viscoelastics Adgevisc and Kogevisc (Solofarm, Russia) in phacoemulsification using the soft-shell technique is comparable to the foreign analogues Viscoat (Alcon) and Amvisc Plus (Bausch Lomb), which is confirmed by the absence of statistically significant differences in the studied parameters of the postoperative state of ocular structures and explained by their similar composition, molecular weight and viscosity.

Cataract Surgeries in Patients with Fuchs Endothelial Dystrophy.

Patients with Fuchs endothelial dystrophy often develop visual symptoms between 50 - 60 years of age, which is the same time that the first symptoms of a developing cataract start to appear. On the other hand, in patients with a clinically significant cataract, corneal guttata may be detected by chance during a routine clinical workup. In both situations, the surgeon has to decide whether DMEK or cataract surgery should be performed alone or in combination. In the case of advanced Fuchs dystrophy with or without a clinically significant cataract, a combined surgery known as the triple procedure seems favorable as the clinical course after this procedure is the same as following sequential surgery. Furthermore, the affected patients will only have to undergo one surgery and will reach the final visual acuity much faster. Posterior lamellar keratoplasty alone can only be an option in the case of young patients with advanced Fuchs dystrophy, intact accommodation, and no signs of cataract. In the case of a clinically significant cataract combined with corneal guttata, clinical features including central corneal thickness and endothelial cell density, among others, can help to decide which surgical procedure seems to be the best. In case of cataract surgery alone, the surgeon needs to protect the corneal endothelium as well as possible. The softshell technique can help to reduce the loss of endothelial cells during cataract surgery, whereas femtosecond laser assisted cataract surgery is still controversial. The following review will discuss the most important preoperative, perioperative, and postoperative factors that need be considered in order to achieve the best result for our patients.

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.

Effects of Combinations of Ophthalmic Viscosurgical Devices and Suction Flow Rates on the Corneal Endothelial Cell Damage Incurred during Phacoemulsification.

We examined the effects of different ophthalmic viscosurgical devices (OVDs) and suction flow rates during phacoemulsification on the amount of ultrasound power used and damage to the corneal endothelium. In total, 48 eyes of 24 patients who underwent phacoemulsification and intraocular lens insertion with different OVD settings in the left and right eye between February and August 2018 were examined retrospectively from medical records. Each of the following types of OVDs was used in either the right or left eye of each patient: a viscoadaptive OVD (V group) or a combination of dispersive and cohesive OVDs (soft-shell technique; S group). There was no significant difference in the lens nucleus hardness between the two groups. A 2.4 mm transconjunctival scleral incision was made, and phacoemulsification was performed by the same surgeon. The cumulative dissipated energy (CDE) and ultrasound time intraoperatively were compared between the two groups. The CDE was significantly larger in the V group (9.9 ± 4.6) than the S group (6.4 ± 3.0; p=0.006). The reduction rate of the endothelial cell density at the center of the cornea was significantly higher in the V group (4.1% ± 6.7%) than the S group (0.3% ± 4.5%; p=0.03) at 1 week postoperatively. Both groups had a good postoperative course. There was less corneal endothelial damage with the soft-shell technique combined with a normal flow setting than the viscoadaptive OVD combined with a low flow setting.

Corneal endothelial cells' protection against thermal injury: influence of ophthalmic viscoelastic substances in experimental study on rabbits.

To quantify the maximal level of temperature and the time the maximal temperature is achieved and correlate the temperature parameters to the mean rate of endothelial cell loss after standardized ultrasound delivery assisted with four viscoelastic substances or different temperature of balanced salt solution (BSS). Thirty rabbits (60 eyes) were divided into six groups in which different viscoelastic substances or different temperature of BSS were used: Group 1, Viscoat; 2, Provisc; 3, soft shell technique; 4, Celoftal; 5, BSS 22 C; and 6, BSS 4 C. The same parameters of ultrasound energy were delivered by standard phaco tip introduced into pupillary plane. Thermocamera was employed for measurements of temperature parameters. Endothelium cell count was measured before surgery and 1 month postoperatively. Maximal level of temperature was measured as follows: Group 5, 27.85 0.52 C; Group 2, 27.75 0.54 C; Group 3, 27.74 0.46 C; Group 4, 27.25 0.60 C; Group 6, 26.81 0.34 C; Group 1, 26.52 0.48 C (p<0.05). The time the maximal temperature is achieved was statistically shorter in Groups 5 and 6: 4 seconds, 5 seconds, respectively, p<0.0001, as compared with Group 2 (30 seconds), Group 3 (40 seconds), Group 1 (45 seconds), and Group 4 (50 seconds). The mean rate of endothelial cell loss was calculated as follows: Group 1, 4.35%2.55%; Group 2, 8.43%5.2%; Group 3, 6.25%4.20%; Group 4, 6.53%4.65%; Group 5, 14.3%3.85%; and Group 6, 8.78%4.45%. Viscoelastic substances offer different levels of endothelial cell protection against temperature increase during phacoemulsification. The mean rate of endothelial cell loss correlates with the time the maximal temperature is achieved rather than with the value of maximal level of temperature. This implicates that surgical strategy should consider the choice of the most effective viscoelastic substances, particularly in difficult cases, e.g., hard nucleus, shallow anterior chamber, primary endothelial abnormality.

Effects of senofilcon A mechanical protector on corneal endothelial cells during phacoemulsification in rabbit eyes: Pilot study

To evaluate the effects of a senofilcon A mechanical protector against corneal endothelial cell damage induced by phacoemulsification in rabbit eyes. Department of Ophthalmology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, South Korea. Experimental study. The endothelial cell count, intraocular pressure (IOP), and central corneal thickness (CCT) were measured before and 3days after the experiment in 26 rabbit eyes randomized into a test group and control group (6 per group). In study 1, a senofilcon A mechanical protector was inserted into the anterior chamber in the hard-shell group (test group) whereas, an ophthalmic viscosurgical device (OVD) was injected in the cohesive group (control group). Phacoemulsification was performed for a total of 5minutes (10-second intervals). In study 2, the soft-shell technique was used in the control group with 5minutes of continuous phacoemulsification. In 2 eyes, the safety and toxicity of the mechanical protector were evaluated. In study 1, there was a 4% loss of endothelial cells associated with the mechanical protector and an 18% loss after phacoemulsification in eyes injected with an OVD; the difference between them was not statistically significant (P=.394). The IOP and CCT also showed nonsignificant differences in both studies. In study 2, the hard-shell technique induced significantly less endothelial cell damage than the soft-shell group (P=.026). Endothelial cell loss caused by the mechanical protector was negligible. The senofilcon A mechanical protector had a protective effect against corneal endothelial cell damage during phacoemulsification in rabbits.

In vitro experiment to elucidate the mechanism of the 'soft shell technique' for preventing subretinal migration of perfluoro-octane.

Perfluorocarbon liquid (PFCL) can migrate into subretinal space in detached and stiffened retina with open holes during vitreoretinal surgery. An innovative 'soft shell' technique was introduced to reduce the complication using hyaluronate (HA) to 'cover' the retinal hole. This study aims to study the effectiveness of this technique in vitro. Ex vivo porcine retina was mounted on a transwell insert. Beneath the retina was an aqueous solution. Two retinal holes were made using needle punctures. One of the two retinal holes was covered with HA. Perfluoro-n-octane (PFO) was added above the retina incrementally using a syringe pump. The height of PFO required to cause the migration of PFO through the retinal holes was measured. The 'pendant drop' method was carried out to measure the interfacial tensions between the PFO and aqueous, and between PFO and four different concentrations of HA solution. A statistically higher PFO level was required to cause the migration of PFO through the retinal hole with HA coating than without HA coating (Tobit regression with p<0.05). The use of HA was associated with 2.39-fold increase in hydrostatic pressure before the collapse of the PFO interface at the retinal holes. The interfacial tension between PFO and HA solution with concentrations of 0.05%, 0.25%, 0.5% and 1% were 54.2±0.6, 55.3±0.6, 59.5±1.5 and 68.3±1.3 mN/m, respectively (mean±SD). The interfacial tension between PFO and aqueous with 1% HA coating (68.3±1.3 mN/m) was significantly higher than that without (37.4±3.4 mN/m) (p<0.05). The interfacial tension between HA and PFO is higher than that between aqueous and PFO. This is a plausible physical explanation of how the 'soft shell' technique might work to prevent subretinal migration of PFCL.

The Soft Shell Technique To Prevent Leakage of Perfluorocarbon Liquid Into The Subretinal Space

PurposePerfluorocarbon liquid (PFCL) can be used to unfold the retina during vitreoretinal surgery. The subretinal migration of PFCL is an undesirable complication of its use in cases with posterior retinal breaks particularly with associated proliferative vitreoretinopathy. The ‘soft shell’ technique, which is the use of hyaluronate (HA) to cover the break, has been described to prevent such migration. Our aim is to assess the scientific basis of this technique.MethodsA porcine retina model with two holes on a transwell was used to mimic the retinal breaks in vivo. HA solution was used to cover one of the holes. Perfluoro‐n‐octane (PFO) was added on top of the retina model incrementally using a syringe pump. The liquid level of PFO required to cause rupture of the PFO/aqueous interface with or without the HA coating at the two holes was measured. The interfacial tensions between the PFO against water and against HA solution with different aqueous concentrations were measured using pendant drop analysis.ResultsThe interfacial tension between PFO and aqueous with HA coating (68.3 ± 1.29 mN/m) is statistically significant higher than the PFO/aqueous interface without hyaluronate (37.4 ± 3.40 mN/m) (p &lt; 0.05). A higher PFCL level is required to cause the rupture of the PFO/aqueous interface at the hole with HA coating.ConclusionsA greater hydrostatic pressure is needed to rupture the PFO/aqueous interface in the presence of HA coating at the break. The increase may due to the increase in interfacial tension at the interface. This study provides the scientific explanation how the soft shell technique may work.

Introduction on the experience in the ingenious application of viscoelastics for the phacoemulsification beginner

The phacoemulsification is the most effective treatment for cataract nowadays. For those Phaco beginners who wants to do cataract surgery safely and smoothly, the viscoelastics will be very helpful to resolve the difficulties happening during surgery such as increased pressure of posterior chamber, shallow anterior chamber, capsular radial tear, incomplete hydrodissection of nucleus, incomplete crack of nucleus and bowl form of cataract. When these situations happened, the surgeon could use soft shell technique with the viscoelastics to fill anterior chamber, expand the capsular bag, depress, float or turn over nucleus, remove residual cortex and polish posterior capsule. Through this way, phaco beginners could strengthen confidence and perfect their phaco skills. Key words: Phacoemulsification; Viscoelastics, application, ingenious; Beginner

Tri-soft shell technique

Soft-shell techniques exist for lower viscosity dispersive with higher viscosity cohesive ophthalmic viscosurgical devices (OVDs) (soft-shell technique [SST]), viscoadaptive OVDs with balanced salt solution (ultimate soft-shell technique), intraoperative floppy-iris syndrome (soft-shell bridge), and many specific modifications for disinserted zonular fibers, frayed iris strands, Fuchs endothelial dystrophy, small holes in the posterior capsule with protruding vitreous, capsular dye use, and others. Soft-shell techniques exist because it is rheologically impossible to control the surgical environment with a single OVD as well as with an ordered combination of rheologically different OVDs. Surgeons frequently confuse these techniques because of their multitude. This paper unifies all SSTs into a single improved tri-soft shell technique (TSST), from which basic specific applications to unusual circumstances are simple and intuitive. As shown with previous SSTs, the TSST allows surgeons to perform complex tasks with greater surgical facility and to protect endothelial cells better than with single OVDs.

Outcomes of cataract surgery in eyes with a low corneal endothelial cell density

To evaluate the surgical outcomes of cataract surgery in eyes with a low preoperative corneal endothelial cell density (ECD) and analyze factors affecting the prognosis. Tokyo Dental College, Ichikawa General Hospital, Chiba, Japan. Noncomparative case series. Eyes with a preoperative ECD of less than 1000 cells/mm(2) that had cataract surgery between 2006 and 2010 were identified. Standard phacoemulsification with intraocular lenses was performed using the soft-shell technique. The rate of endothelial cell loss, incidence of bullous keratopathy, and risk factors were retrospectively assessed. Sixty-one eyes (53 patients) with a low preoperative ECD were identified. Preoperative diagnoses or factors regarded as causing endothelial cell loss included Fuchs dystrophy (20 eyes), laser iridotomy (16 eyes), keratoplasty (10 eyes), traumatic injury (3 eyes), trabeculectomy (3 eyes), corneal endotheliitis (2 eyes), and other (7 eyes). The corrected distance visual acuity improved from 0.59 ± 0.49 logMAR preoperatively to 0.32 ± 0.48 logMAR postoperatively (P<.001). The mean ECD was 693 ± 172 cells/mm(2) and 611 ± 203 cells/mm(2), respectively (P=.001). The mean rate of endothelial cell loss was 11.5% ± 23.4%. Greater ECD loss was associated with a shorter axial length (AL) (<23.0 mm) and diabetes mellitus. Bullous keratopathy developed in 9 eyes (14.8%) and was associated with posterior capsule rupture. The results suggest that modern techniques for cataract surgery provide excellent visual rehabilitation in many patients with a low preoperative ECD. Shorter AL, diabetes mellitus, and posterior capsule rupture were risk factors for greater ECD loss and bullous keratopathy.

The application of burst and soft shell techniques in phacoemulsification for complicated cataract

Objective To discuss the clinical effect of burst technique and soft shell technique in phacoemulsification on complicated cataract. Methods Totally 38 cases (45 eyes) of complicated cataract were observed. The cataract were characterized as post-antiglaucoma surgery,hard nucleus of degree Ⅳ～ degree Ⅴ, and corneal endothelial cell counting less than 1500/mm2. Burst pattern was used in phacoemulsification,and soft shell technique was used for protecting endothelial cell during the surgery. The power,effect phaco time and cumulative compound power parameter were recorded. A control group of 38 cases (45 eyes)was made with pulse technique in Phaco. The vision, corneal edema, dense of corneal endothelial cell and complications were observed. Results The effect phaco time of experimental group was (22.44 ± 13.24) s,with an actual phaco power of ( 14.37 ± 5.84) % and cumulative compound power parameter of (353.26 ±306.88). The va; ie pf cpmtrp; group was ( 79.02 ± 38.29 ) s, ( 25.44 ± 8. 34 ) % and ( 2402.97 ±2296.61 ) respectively. There were statistically significant difference ( P ＜ 0. 01 ). The cornea edema of experimental group was degree 0 to degree 2 one day postoperatively. The rate of corneal endothelial cell loss was 9.35% one month after surgery. There was no statistically significant difference between the preoperative one and the postoperative one (P ＞0.05 ). That of control group was degree 0 ～ degree 3 and 31. 19% postoperatively,which was significantly different from the preoperative one (P ＜0. 01 ). Conclusion The technique of burst and soft shell could decrease intraocular injury and improve the surgery outcome. Key words: phacoemulsification; burst; soft shell; complicate cataract

Protective effect of different ophthalmic viscosurgical devices on corneal endothelial cells during phacoemulsification: Rabbit model

To evaluate the protective effect of different ophthalmic viscosurgical devices on corneal endothelial cells during phacoemulsification in a rabbit model. Harlan Biotech Israel and Ophthalmology Department, Kaplan Medical Center, Rehovot, Israel. Experimental study. Rabbit eyes were randomly assigned to 3 equally sized groups. Endothelial cell counts were performed in all eyes before initiation of the study. The aqueous humor was completely replaced by Biolon (sodium hyaluronate 1.0%) in Group A, by a combination of Viscoat (sodium chondroitin sulfate 4.0%-sodium hyaluronate 3.0%) and Provisc (sodium chondroitin sulfate 1.0%) using the soft-shell technique in Group B, and by a combination of Visiol (sodium hyaluronate 2.0%-mannitol 0.5%) and Biolon using the soft-shell technique in Group C. The eyes were exposed to alternating 10 seconds of phacoemulsification and a 10-second pause until a total exposure time of 2.5 minutes elapsed. Endothelial cell counts were repeated 3 days after surgery. The study used 18 rabbit eyes, 6 in each group. Group A had the highest endothelial cell loss (13%) followed by Group B (7%), and Group C (4%). The difference in cell loss between Group C and Group A was statistically significant (P = .037). The study showed the efficiency and advantages of the soft-shell technique using the combination of Visiol and Biolon over Biolon alone.

Stability of corneal shape and morphology in patients with Fuchs’ dystrophy after phacoemulsification with soft shell technique.

Abstract Purpose To evaluate effectiveness of soft shell cataract surgery technique on the corneal structure in group of Fuchs’ dystrophy patients. Methods 24 patients (mean age 52,7±13,8), 31 eyes after phacoemulsification were examined before and 10 months after surgery. BCVA, mean central corneal thickness (CCT) and corneal endothelial cell density (CD) were evaluated. Corneal aberrations root‐mean‐square (RMS) was calculated 1 and 10 months after surgery for 4.0mm pupil. Results Corneal higher‐order aberrations (RMS) 1 month after surgery was 0,372±0,058 and 10 months after surgery was 0,345±0,076, BCVA 10 months after surgery was 0,75±0,27 (before surgery 0,32±0,28), the mean CCT was 563,37±21,42µm (before surgery 559,62±45,29µm), CD 1786,341±493,127 (before surgery 1912,783±381,963). Conclusion All patients revealed good stability and protection of the cornea confirming safety of the soft shell technique.

Clinical Outcomes of Cataract Surgery Using Torsional Mode Phacoemulsification and Soft Shell Technique

Purpose: To evaluate the additional protective effect of the soft shell technique on corneal endothelial cells in torsional mode phacoemulsification. Methods: Torsional mode phacoemulsification was performed on 60 eyes in 38 patients who were diagnosed with moderate cataracts. Thirty eyes were assigned to the soft shell technique group, and a control group with 30 eyes using only cohesive viscoelastics was created to evaluate ultrasound (US) time, mean US intensity, cumulative dissipated energy (CDE), and amount of used balanced salt solution. Corneal endothelium and corneal thickness were measured before and after the procedure. Results: There were no statistically significant differences in US time, mean US intensity, cumulative dissipated energy, and dosage of the balanced salt solution between the two groups. There were no statistically significant differences between the two groups in postoperative central corneal thickness. Corneal endothelial cell densities decreased significantly after surgery in both groups, but there were no statistically significant differences between the two groups. Conclusions: There are no significant differences in the intensity of ultrasound, the density of corneal endothelial cells or the thickness of the cornea between the two groups. Therefore, the soft shell technique is not needed under torsional mode phacoemulsification.

Application of hydrochop technique in cases with the soft-nucleus manual small incision cataract surgery

目的 探讨小切口手法碎核白内障手术软核处理巾运用水劈核技术的适应征、并发症及注意事项.方法 对20例(20眼)品状体核硬度为三级以下的小切口手法碎核向内障手术中运用水劈核技术处理软核.结果 16例水劈核成功,占80.00%,其中8例使用软壳技术后角膜内皮水肿得到明显控制.结论 水劈核技术适合处理硬度为三级以下的软核.选掸合适的软核是水劈核成功的关键.注意保护角膜内皮。

DisCoVisc versus the soft-shell technique using Viscoat and Provisc in phacoemulsification: Randomized clinical trial

To compare the effects and outcomes of DisCoVisc (hyaluronic acid 1.6%-chondroitin sulfate 4.0%) with those of the soft-shell technique using Viscoat (sodium hyaluronate 3.0%-chondroitin sulfate 4.0%) and Provisc (sodium hyaluronate 1.0%) in phacoemulsification. Iladevi Cataract & IOL Research Centre, Ahmedabad, India. This prospective randomized clinical trial comprised 100 eyes having phacoemulsification by the same surgeon using a standardized technique. Eyes were randomly assigned to DisCoVisc (Group 1) or Viscoat and Provisc (Group 2). Preoperative and postoperative examinations included absolute change in pachymetry, percentage difference in endothelial cell density (ECD) and coefficient of variation (CV), and anterior segment inflammation. The mean postoperative central corneal thickness (CCT) in Group 1 and Group 2 was 590.96+/-46.05 microm and 586.94+/-50.57 microm, respectively, at 1 day; 554.14+/-35.45 microm and 551.65+/-37.69 microm, respectively, at 7 days; and 533.74+/-29.12 microm and 536.44+/-35.59 microm, respectively, at 1 month. The between-group differences in CCT were not statistically significant. At 3 months, the mean ECD was 2427.06+/-243.26 cells/mm2 and 2475.30+/-222.83 cells/mm2, respectively, and the mean CV, 42.38+/-7.94 cells/mm2 and 41.66+/-7.71 cells/mm2, respectively. There was no significant difference in the mean ECD between preoperatively and 3 months postoperatively or in corneal thickness between preoperatively and 1, 7, and 30 days postoperatively. A single injection of DisCoVisc was effective, and its postoperative outcomes were comparable to those of combined Viscoat and Provisc.

Soft‐shell technique using Viscoat® and Healon®5: a prospective, randomized comparison between a dispersive‐viscoadaptive and a dispersive‐cohesive soft‐shell technique

To compare the efficacy of the dispersive-viscoadaptive soft-shell technique using Viscoat and Healon 5 to the dispersive-cohesive soft-shell technique in reducing corneal endothelial cell damage during cataract surgery. In this prospective randomized study, 207 eyes of 171 cataract patients underwent phacoemulsification using the dispersive-viscoadaptive soft-shell technique (V-group, 102 eyes) with Viscoat and Healon5 or the dispersive-cohesive soft-shell technique (C-group, 105 eyes) with Viscoat and a cohesive agent (Opegan-Hi). Each group was divided into two subgroups depending on the amount of ultrasound (%Min) used during phacoemulsification. Corneal endothelial cell density was examined preoperatively and 3 months postoperatively. The endothelial cell loss was compared between the two groups, and also between the subgroups. The mean endothelial cell loss 3 months after surgery was 8.4 +/- 5.6% standard deviation (SD) in the V-group and 8.2 +/- 6.2% in the C-group (P = 0.787). In the subgroups with ultrasound of 10 %Min or less, the mean endothelial cell loss 3 months after surgery was 6.6 +/- 4.6% in the V-group and 5.5 +/- 5.0% in the C-group (P = 0.104). In the subgroups with ultrasound of over 10 %Min, this value was 10.6 +/- 6.3% in the V-group and 11.9 +/- 5.7% in the C-group (P = 0.413). The correlation coefficient of the endothelial cell loss rate and %Min was 0.245 (P = 0.0129) in the V-group and 0.501 (P < 0.0001) in the C-group. The dispersive-viscoadaptive soft-shell technique is as effective as the dispersive-cohesive soft-shell technique in protecting corneal endothelial cells during phacoemulsification regardless of the amount of ultrasound energy used.