In vitro behavior of ophthalmic viscosurgical devices during phacoemulsification

PURPOSE: To evaluate the behavior and aspiration of several ophthalmic viscosurgical devices (OVDs) during phacoemulsification. SETTING: Department of Ophthalmology, Tokyo Dental College Suidobashi Hospital, Tokyo, Japan. METHODS: Cohesive OVDs (sodium hyaluronate 1.0% [Healon and Provisc]), dispersive OVDs (sodium hyaluronate 3.0%-chondroitin sulfate 4.0% [Viscoat]), and new-generation OVDs such as viscoadaptive (sodium hyaluronate 2.3% [Healon5]) and viscodispersive (hyaluronic acid 1.65%-chondroitin sulfate 4.0% [DisCoVisc]) OVDs, were stained with fluorescein sodium. The movement of the OVDs during simulated cataract surgery was recorded in porcine eyes under an operating microscope and with a side-view video camera. The initial and complete aspiration times of each OVD during phacoemulsification using 20 and 40 mL/min flow rates and sleeves and the removal times using the irrigation and aspiration (I/A) tip at the end of surgery were evaluated from the recorded videos. RESULTS: The complete aspiration time of the cohesive OVDs was less than 3 seconds but up to 20 seconds with a low flow rate of 20 mL/min with a smaller sleeve. Other OVDs remained in the anterior chamber during phacoemulsification with both flow rates. The removal time for cohesive OVDs was less than 4 seconds and for new-generation OVDs, 10 to 15 seconds. The dispersive OVD required a significantly (P<.05) longer removal time than other OVDs. CONCLUSIONS: Cohesive OVDs are removed easily during phacoemulsification; however, the aspiration rate can be affected by fluidics. New-generation OVDs, such as Healon5 and DisCoVisc, remained in the anterior chamber during phacoemulsification and were removed easily by I/A at the end of surgery. The behavior of these OVDs is preferable during phacoemulsification.     

Alteration of free radical development by ophthalmic viscosurgical devices in phacoemulsification

PURPOSE: To determine the effect of ophthalmic viscosurgical devices (OVDs) and irrigation/aspiration (I/A) settings on free radical development during phacoemulsification. SETTING: Department of Ophthalmology, Nippon Medical School, Tokyo, Japan. METHODS: Free radicals were detected by the electron spin resonance (ESR) spin-trap method. After a spin-trapping agent, 5,5-dimethyl-1-pyrroline N-oxide 1%, was mixed with the irrigating solution, phacoemulsification simulation was performed in an eye model at 100% ultrasound power levels for 10, 20, and 30 seconds. A high I/A setting (35 mL/min with 250 mm Hg vacuum) and a low I/A setting (15 mL/min with 60 mm Hg vacuum) were used in combination with no OVD, sodium hyaluronate 1% (Healon), sodium hyaluronate 2.3% (Healon5), sodium hyaluronate 3%-chondroitin sulfate 4% (Viscoat), or sodium hyaluronate 1% (Opegan). Immediately after phacoemulsification, the solution in the anterior chamber was collected and signals from the spin adduct were measured using an ESR spectrometer. RESULTS: With the low setting, all OVDs significantly suppressed the signals for up to 20 seconds. At 30 seconds, the signals were still significantly smaller in all OVD groups, except Healon, than those in the no-OVD. With the high setting, the effect was not significant in the Healon and Opegan groups at 10 seconds; by 20 seconds and after, only Viscoat showed significant suppression. CONCLUSIONS: Free radical development in phacoemulsification can be altered by OVD properties and I/A settings. To reduce oxidative stress to the corneal endothelium, attention should be paid to the retention of OVDs in the anterior chamber during phacoemulsification.     

Removal times for a dispersive and a cohesive ophthalmic viscosurgical device correlated with intraocular lens material

PURPOSE: To investigate the removal times of ophthalmic viscosurgical devices (OVDs) with different intraocular lens (IOL) designs and materials. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA, and Heidelberg IOL & Refractive Surgery Research Group, Department of Ophthalmology, Ruprecht-Karls-University of Heidelberg, Heidelberg, Germany. METHODS: In a standardized laboratory setup, the Miyake-Apple posterior view video technique was used to evaluate OVD removal from capsular bags in human autopsy eyes implanted with poly(methyl methacrylate) (PMMA), silicone, and acrylic IOLs. The cohesive OVD ProVisc (sodium hyaluronate 1.0%) and the dispersive OVD Viscoat (sodium hyaluronate 3.0% and chondroitin sulfate 4.0%) were stained with fluorescein for better visualization. The open-sky preparation and an Alcon Series 20000 Legacy phaco machine with a flow rate of 25 mL/min and a vacuum setting of +500 mm Hg (maximum irrigation/aspiration) were used. The time needed for complete removal of the cohesive and dispersive OVDs with each IOL type was measured and analyzed statistically. RESULTS: The mean removal times for both OVDs were as follows: Alcon MZ60BD PMMA IOL-25.0 seconds +/- 3.7 (SD) (Viscoat), 15.9 +/- 6.9 seconds (ProVisc); Alcon AcrySof MA60BM IOL-35.5 +/- 10.0 seconds (Viscoat), 25.6 +/- 4.7 seconds (ProVisc); Chiron/Bausch & Lomb C1043 silicone IOL-46.5 +/- 10.5 seconds (Viscoat), 17.3 +/- 2.1 seconds (ProVisc); AMO SI-30 silicone IOL-33.5 +/- 3.1 seconds (Viscoat), 15.3 +/- 6.3 seconds (ProVisc); and Pharmacia 912 silicone IOL-18.3 +/- 5.8 seconds (Viscoat), 19.8 +/- 4.3 seconds (ProVisc). CONCLUSIONS: Differences in OVD removal times were detected. The removal time for the cohesive OVD correlated with the IOL material. Overall, the time needed for complete removal was significantly longer for the dispersive OVD than for the cohesive OVD.     

Quantitative thermographic analysis of viscoelastic substances in an experimental study in rabbits

PURPOSE: To measure the temperature parameters on the corneal surface during the delivery of standardized ultrasound energy assisted with ophthalmic viscosurgical devices (OVDs) or different temperatures of irrigating solutions in an experimental animal model. SETTING: Department of Ophthalmology and Visual Rehabilitation, Medical University of Lodz, and Central Institute for Labor Protection, National Research Institute, Warsaw, Poland. METHODS: Thirty rabbits (60 eyes) were randomly divided into 6 groups in which different OVD or balanced salt solutions (BSS) were used: group 1: Viscoat (sodium hyaluronate 3%-chondroitin sulfate); group 2: Provisc (sodium hyaluronate 1%); group 3: soft-shell technique; group 4: Celoftal (hydroxypropyl methylcellulose 2%); group 5: BSS 22 degrees C; and group 6: BSS 4 degrees C. After the nucleus and lens cortex were removed, the anterior chamber was filled with OVD or BSS and a phaco tip was introduced into the pupillary plane and switched on. The same phaco tip parameters were used in all groups. For thermographic measurements (ie, maximal temperature [MT], dynamic rise in temperature [DRT], and time when the maximal level of temperature [TMLT] was achieved), a thermocamera was used. RESULTS: Mean preoperative temperature on the rabbit corneal surface was 22.76 degrees C +/- 1.48 degrees C (SD). Working with a phaco tip increased the temperature in each group. A significantly higher MT was observed in group 5 (27.85 degrees C +/- 0.52 degrees C), followed by group 2 (27.75 degrees C +/- 0.54 degrees C), group 3 (27.74 degrees C +/- 0.46 degrees C), and group 4 (27.25 degrees C +/- 0.60 degrees C), than in group 6 (26.81 degrees C +/- 0.34 degrees C) and group 1 (26.52 degrees C +/- 0.48 degrees C) (P<.05). Significantly higher values of DRT and shorter TMLT values were observed in group 5 (1.16 degrees C/s +/- 0.42 degrees C/s, 4 seconds) and group 6 (0.91 degrees C/s +/- 0.13 degrees C/s, 5 seconds) than in groups 2, 3, 1, and 4 (0.09 degrees C/s +/- 0.07 degrees C/s, 30 seconds; 0.08 degrees C/s +/- 0.04 degrees C/s, 40 seconds; 0.07 degrees C/s +/- 0.03 degrees C/s, 45 seconds; 0.06 degrees C/s +/- 0.02 degrees C/s, 50 seconds, respectively) (P<.0001). CONCLUSIONS: Currently used OVDs potentially offer different levels of protection against the increase in temperature that occurs during phacoemulsification. Therefore, the surgeon should consider this aspect when choosing an OVD, particularly in difficult cases (ie, hard nucleus, shallow anterior chamber, endothelial abnormalities).     

Retention and removal of a new viscous dispersive ophthalmic viscosurgical device during cataract surgery in animal eyes

AIMS: To assess the retention and removal properties of a new viscous dispersive ophthalmic viscosurgical device (OVD), DisCoVisc, in comparison with those of cohesive (Provisc), dispersive (Viscoat), and viscoadaptive (Healon5) OVDs. METHODS: In 20 porcine eyes, cataract surgery was simulated using one of the four OVDs which were stained with fluorescein for better visualisation. Three parameters were measured. Firstly, the presence/absence of OVDs in the chamber at the completion of phacoemulsification was recorded. Secondly, the time until the OVDs were completely removed from the anterior chamber using the phaco needle was measured. Thirdly, after intraocular lens (IOL) implantation, the time needed to completely remove the OVDs from the chamber with irrigation/aspiration tip was recorded. RESULTS: At the completion of phacoemulsification, the OVDs retained in 0% (0/5) for Provisc, 80% (4/5) for Healon5, 100% (5/5) for DisCoVisc, and 100% (5/5) for Viscoat. The retention of OVDs during phacoemulsification was greatest with Viscoat followed by, in descending order, DisCoVisc, Healon5, and Provisc. The removal of OVDs after IOL implantation took longest with Viscoat followed by Healon5, DisCoVisc, and Provisc. CONCLUSION: The viscous dispersive DisCoVisc showed excellent retention during phacoemulsification, while its removal after IOL implantation was very easy. When compared with the viscoadaptive Healon5, DisCoVisc was retained better in the chamber and was easier to remove. These features of DisCoVisc should be highly advantageous when considering covering the entire cataract surgery procedure with a single OVD.     

Quantitative assessment of ophthalmic viscosurgical device retention using in vivo confocal microscopy

PURPOSE: To develop and apply a new laboratory method for in vivo quantitative assessment of the retention of ophthalmic viscosurgical devices (OVDs) following phacoemulsification. SETTING: Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, USA. METHODS: Studies of both eyes of New Zealand White rabbits were performed. Six OVDs were evaluated: Provisc and Healon (both sodium hyaluronate 1%), Healon5 (sodium hyaluronate 2.3%), Amvisc Plus (sodium hyaluronate 1.6%), Viscoat (sodium hyaluronate 3%-chondroitin sulfate 4%), and a new viscous-dispersive OVD, DisCoVisc (sodium hyaluronate 3%-chondroitin sulfate 4%). The OVD was injected to fill the anterior chamber and a phacoemulsification needle inserted with the tip positioned just anterior to the lens capsule. Simulated phacoemulsification was performed for 1 minute using flow rates of 20, 40, and 60 mL/min; a vacuum level of 300 mm Hg; and ultrasound power of 60% using a Legacy phacoemulsification unit. The needle was removed, and silicone oil (1000 centistokes) was injected into the anterior chamber. The distance between the corneal endothelium and the OVD-silicone oil interface was measured using in vivo confocal microscopy through-focusing (CMTF). RESULTS: Significant differences in residual thickness were found between the OVDs tested. Specifically, the residual thickness of both DisCoVisc (mean 324.5 microm +/- 163.7 [SD]) and Viscoat (251.4 +/- 100.9 microm) was significantly greater than that of Provisc (9.5 +/- 16.7 microm), Healon (3.8 +/- 11.3 microm), Healon5 (0.6 +/- 2.4 microm), and Amvisc Plus (65.6 +/- 134.0 microm) (P < .05, Dunn test). Ophthalmic viscosurgical device retention was greatest with DisCoVisc; however, there was no statistically significant difference between DisCoVisc and Viscoat in residual thickness. The flow rate did not have a significant effect on the residual thickness (Friedman 2-way analysis of variance by ranks). CONCLUSIONS: Residual OVD thickness following simulated phacoemulsification could be quantitatively measured using in vivo CMTF. The results are consistent with human surgical experience in that the dispersive OVD (Viscoat) was better retained than the cohesive compounds. DisCoVisc, a new viscous-dispersive OVD, also showed retention compared with Viscoat under the experimental conditions.     

Phaco-chop versus stop-and-chop nucleotomy for phacoemulsification

PURPOSE: To perform a comparative evaluation of phaco-chop versus stop-and-chop nucleotomy techniques of phacoemulsification. SETTING: Dr. Rajendra Prasad Center for Ophthalmic Sciences, New Delhi, India. METHODS: Forty eyes of 40 patients with immature senile cataract were included in the study. Twenty eyes each were randomly assigned to have phaco-chop (Group 1) or stop-and-chop (Group 2) nucleotomy during phacoemulsification. The main parameters were corneal endothelial count, effective phaco time, volume of infusion fluid used, central corneal pachymetry, best corrected visual acuity (BCVA), and intraoperative complications during nucleotomy. Follow-up visits were scheduled at 1, 4, and 12 weeks. RESULTS: The mean effective phaco time was 27 seconds +/- 18 (SD) in Group 1 and 28 +/- 16 seconds in Group 2. The mean corneal endothelial cell loss was 6.89% and 7.17%, respectively, at the end of 12 weeks. The difference between groups was not significant. An anterior capsule tear occurred in 3 eyes in Group 1 and 1 eye in Group 2. All eyes achieved a BCVA of 20/20 at the end of 4 weeks. There were no significant between-group differences in any intraoperative or postoperative parameter. CONCLUSIONS: The phaco-chop and the stop-and-chop nucleotomy techniques were equally efficacious for nuclear management during phacoemulsification.     

Scheimpflug photography study of ophthalmic viscosurgical devices during simulated cataract surgery

PURPOSE: To evaluate by Scheimpflug photography the capacity of several commercially available ophthalmic viscosurgical devices (OVDs) to remain in the anterior chamber and maintain anterior chamber depth (ACD) during simulated cataract surgery in porcine cadaver eyes. SETTING: Department of Preclinical Ophthalmology, Pharmacia & Upjohn AB, Uppsala, Sweden. METHODS: Eighty eyes from newly slaughtered pigs were used. They were distributed equally among 8 OVDs: Amvisc Plus (sodium hyaluronate 1.6%), Biolon (sodium hyaluronate 1.0%), Biolon Prime (sodium hyaluronate 1.2%), Healon (sodium hyaluronate 1.0%), Healon GV (sodium hyaluronate 1.4%), Healon5 (sodium hyaluronate 2.3%), Provisc (sodium hyaluronate 1.0%), and Viscoat (sodium hyaluronate 3.0%-chondroitin sulfate 4.0%). Scheimpflug photographs were taken using a Nidek EAS-1000 instrument before surgery (control), after injection of the OVD, after continuous curvilinear capsulorhexis (CCC), and after lens extraction by phacoemulsification. Differences in the ACD with a P value less than 0.05 were considered statistically significant. The retention capacity was visually assessed. RESULTS: Healon5 had a significantly higher capacity to maintain the ACD than the other OVDs after CCC and phacoemulsification. After injection, Healon5, Viscoat, and Biolon Prime showed similar ACD-maintaining capacities. CONCLUSIONS: The capacity of Healon5 to maintain the ACD during cataract surgery, ie, neutralizing the vitreous pressure and stabilizing the anterior segment of the eye, was significantly higher than that of the other OVDs.     

Intraocular pressure after bilateral cataract surgery using Healon, Healon5, and Healon GV

PURPOSE: To determine whether there is a difference in frequency or severity of postoperative intraocular pressure (IOP) spikes after bilateral phacoemulsification with complete ophthalmic viscosurgical device (OVD) removal when Healon5 (sodium hyaluronate 2.3%), Healon (sodium hyaluronate 1%), or Healon GV (sodium hyaluronate 1.4%) is used. SETTING: York Finch Eye Associates and Humber River Regional Hospital, Toronto, Ontario, Canada. METHODS: Bilateral cataract surgery was performed in 99 patients; 50 were randomly assigned to receive Healon5 in 1 eye and Healon GV in the fellow eye and 49, Healon in 1 eye and Healon GV in the fellow eye. The IOP was measured preoperatively as well as 5 and 24 hours and 7 days postoperatively. The mean IOP and standard deviation at each time interval were calculated for each OVD. The results were compared among the OVDs using Student t tests for each time at which IOP was assessed. RESULTS: There were no significant differences in postoperative IOP spikes among the Healon5, Healon, and Healon GV groups; however, patients receiving lower viscosity OVDs had a lower mean IOP at 24 hours. All groups had increased IOP at 5 and 24 hours and reduced IOP at 7 days. CONCLUSIONS: Within a family of molecularly similar OVDs, lower viscosity OVDs appear to cause slightly lower mean elevations in IOP in normal patients at 24 hours. However, if the OVD is removed, postoperative IOP spikes above 21 mm Hg appear related more to patient factors (eg, predisposition in glaucoma patients) and surgically induced trauma than to the specific long-chain non-cross-linked hyaluronan OVD used.     

Effects of topical dorzolamide on IOP after phacoemulsification with different types of ophthalmic viscosurgical devices

PURPOSE: To evaluate the effect of topical dorzolamide on postoperative intraocular pressure (IOP) after routine phacoemulsification surgery with different type of ophthalmic viscosurgical device (OVD). METHODS: Patients who were scheduled for phacoemulsification with intraocular lens (IOL) implantation were evenly divided into four groups. Group I (83 eyes) received one drop of topical dorzolamide immediately after surgery and 1.4% NaHa (BD Visc) was used as a cohesive OVD during IOL implantation. Group II (83 eyes) did not receive any topical antiglaucoma medication after operation and 1.4% NaHa was used as a cohesive OVD. Group III (83 eyes) received topical dorzolamide and 1% NaHa (Healon) was used, and Group IV (83 eyes) did not receive any topical and 1% NaHa was used in operation. Mean postoperative IOPs were compared between groups. RESULTS: Eyes with 1.4% NaHa usage (18.2+/-9.2 mmHg) had higher mean postoperative IOPs than eyes with 1% NaHa usage (15.5+/-5.3 mmHg) (p=0.002). Mean postoperative IOPs were lower in eyes with dorzolamide application (15.6+/-7.2 mmHg) than in eyes without any medication (18.1+/-8.5 mmHg) both in eyes with 1.4% NaHa and 1% NaHa usage (p=0.003). Dorzolamide application caused an average 2.5 mm decrease in mean postoperative IOPs in both groups. CONCLUSIONS: Effects of OVDs on IOP rises after phacoemulsification surgery are closely related to their molecular structure. Increase in viscosity rendered higher postoperative IOP increments. However, topical dorzolamide application effectively reduced postoperative IOP increments in eyes with both Healon and BD Visc use.     

The Clinical Study of Healon 5 in Phacoemulsification and IOL Implantation

Purpose: To compare a new ophthalmic viscoelastic device (OVD) Healon 5 with two other kinds of OVDs commonly used in China during phacoemulsification and intraocular lens (IOL) implantation in terms of removal time, intraocular pressure, corneal and anterior chamber response.Methods: This prospective randomized study, in which patients and observers are masked, comprises niety eyes. They were randomly divided into 3 groups with different OVDs. Healon 5 (sodium hyaluronate 5 000 2.3%) was compared with Healon GV (sodium hyaluronate 7 000 1.4%) and Iviz (sodium hyaluronate 1.0%) . The surgeries were performed with temporal corneal incision, phacoemulsification in situ and foldable lens intracapsular implantation. The characteristic and the removal time of the viscoelastic material as well as the postoperative IOP, corneal reaction and anterior chamber reactions of the eyes were observed preoperatively and 24 hrs postoperatively. Exclusion criteria were glaucoma, a preoperative dilated pupil diameter small     

Comparison of Nagahara phaco-chop and stop-and-chop phacoemulsification nucleotomy techniques

PURPOSE: To compare intraoperative and postoperative effects of Nagahara phaco-chop and stop-and-chop phacoemulsification nucleotomy techniques. SETTING: Department of Ophthalmology, SBMU First Aid and Traumatology Hospital, Ankara, Turkey. METHODS: Seventy patients were evaluated prospectively in 2 groups. The Nagahara phaco-chop nucleotomy technique was performed in Group 1 (35 eyes) and the stop-and-chop technique in Group 2 (35 eyes). There were no significant between-group differences. The mean phaco time, phaco power, effective phaco time, time to achieve maximum vision, corneal thickness increase relative to the preoperative values, and time to return to the preoperative values were determined. All parameters in both groups were statistically compared using the chi-square test and the independent-samples t test. RESULTS: The mean phaco time was 1.3 minutes +/- 0.7 (SD), phaco power was 16.7% +/- 5.0%, and effective phaco time was 14.9 +/- 11.8 seconds in Group 1 and 1.8 +/- 0.9 minutes, 20.0% +/- 6.2%, and 22.3 +/- 14.2 seconds, respectively, in Group 2. The mean time to achieve maximum vision postoperatively was 6.9 +/- 3.7 days in Group 1 and 11.7 +/- 7.7 days in Group 2. The mean postoperative corneal thickness increase in Group 1 and Group 2 was 52.3 +/- 84.5 microm and 111.6 +/- 151.2 microm, respectively, and the mean time to return to preoperative pachymetry values, 9.8 +/- 5.7 days and 13.7 +/- 10.0 days, respectively. There were significant between-group differences in these parameters. CONCLUSIONS: The Nagahara phaco-chop technique had fewer negative effects on the corneal endothelium as less ultrasonic energy was used. This accelerated the functional healing process and the return to preoperative physiologic values.     

Effect of Healon5 and 4 other viscoelastic substances on intraocular pressure and endothelium after cataract surgery

PURPOSE: To compare the ophthalmic viscoelastic device (OVD) Healon5 (sodium hyaluronate 2.3%) with 4 other commonly used OVDs during phacoemulsification and intraocular lens implantation in terms of influence on intraocular pressure (IOP) postoperatively and endothelial cells preoperatively and postoperatively. SETTING: Department of Ophthalmology, Ruprecht-Karls-University Heidelberg, Germany. METHODS: This clinical randomized prospective study, in which patients and observer were masked, comprised 81 eyes. Seventy-four eyes (mean patient age 71.2 years +/- 7.8 [SD]) completed all preoperative and 5 postoperative examinations. The OVDs used were OcuCoat and Celoftal (hydroxypropyl methylcellulose 2.0%), Viscoat (sodium hyaluronate 3.0%-chondroitin sulfate 4.0%), Healon GV (sodium hyaluronate 1.4%), and Healon5 (sodium hyaluronate 2.3%). Intraocular pressure was measured by standard Goldmann applanation tonometry preoperatively and 4 to 6 and 24 hours and 7, 30, and 90 days postoperatively. Endothelial cell counts were done preoperatively and 90 days postoperatively using a Pro/Koester WFSCM contact endothelial microscope. Exclusion criteria were IOP greater than 21 mm Hg at the preoperative examination, age younger than 40 years, significant corneal pathology, and a history or presence of uveitis or pseudoexfoliation syndrome. RESULTS: All groups had increased IOP 4 hours postoperatively. The Healon5 group had the highest mean pressure (24.9 mm Hg) followed by the Viscoat group (23.6 mm Hg). The mean IOP in the other OVD groups was less than 22.1 mm Hg. These differences were not significant. Twenty-four hours postoperatively and at all subsequent examinations, mean IOP was below 20 mm Hg. The Healon5 group had the lowest mean endothelial cell loss (6.2%), significantly lower than in the other groups (P < .02). CONCLUSION: With all 5 OVDs, endothelial cell loss was found, with the lowest in the Healon5 group, and IOP was increased 4 to 6 hours postoperatively. After 24 hours, no significant increases in IOP were noted.     

Clinical evaluation of endothelial cell decrease with VisThesia in phacoemulsification surgery

PURPOSE: To assess the endothelial cell decrease after the use of sodium hyaluronate 0.3% and lidocaine hydrochloride 2% (VisThesia) to determine whether the addition of lidocaine 1% to sodium hyaluronate 1.5% makes the solution more toxic to the cornea. SETTING: Instituto de Oftalmologia Avanzada, Madrid, Spain, and Unita Operative Oculistica, Cesena, Italy. METHODS: VisThesia is an ophthalmic viscosurgical device (OVD) that incorporates lidocaine 1% to provide better comfort to patients under topical anesthesia. Fifty eyes 50 patients were operated on following the same patient selection and surgical technique. After the povidone-iodine (Betadine) ocular asepsis, 1 full ampoule of VisThesia Topical was applied over the corneal surface. The intracameral product was used as a routine OVD during the phacoemulsification procedure. The endothelium of the central cornea was examined preoperatively and 3 months after surgery using a noncontact endothelium microscope. RESULTS: At the last follow-up visit, the mean best corrected visual acuity was 0.88 +/- 0.18 and the mean manifest SE was -0.36 +/- 1.78 D. The mean endothelial cell density had decreased from 2363.57 +/- 435.4 cells/mm2 preoperatively to 2222.6 +/- 537.69 cells/mm2 at 3 months. These values are comparable with results obtained in other investigations published in the literature using other, similar OVD. CONCLUSIONS: The results observed in this investigation indicate that the addition of lidocaine to the sodium hyaluronate in VisThesia does not induce additional toxicity nor does it result in increased endothelial cell loss when compared with other, similar OVDs.     

Hyaluronic acid combined with mannitol to improve protection against free-radical endothelial damage: experimental model

PURPOSE: To evaluate the protective properties of combined sodium hyaluronate 2% and mannitol 0.5% (Visiol) on the corneal endothelium in the presence of oxidative stress induced by hydrogen peroxide (H(2)O(2)). SETTING: Instituto Oftalmológico de Alicante, Universidad Miguel Hernández, Alicante, Spain. METHODS: This was an exploratory randomized controlled parallel-group, masked-assessor study of 3 sodium hyaluronate-based ophthalmic viscosurgical devices (OVDs): Visiol, Healon (sodium hyaluronate 1%), and Viscoat (sodium hyaluronate 3%-chondroitin sodium 4%). The OVDs were tested for protective effects on the endothelium following oxidative stress induced by H(2)O(2) at increased concentrations: control (lactated Ringer's solution), 1 mM, 10 mM, and 100 mM. Groups without OVD were used as controls at the same concentrations of peroxide. Each animal received the same treatment in both eyes (10 eyes per group). Endothelial cell lesion was assessed using the Janus green photometry absorbance technique. RESULTS: At 10 mM peroxide concentration, the value of endothelial cell lesion was significantly lower in the Visiol (16.8%, P=.0056), Healon (22.2%, P=.0302), and Viscoat (21.6%, P=.0336) groups than in the control group (29.4%, no OVD). There was a trend in favor of Visiol to more efficiently reduce cell lesions of the endothelium, than Healon (P=.055) and Viscoat (P=.1013). Values of endothelial cell lesion at peroxide concentrations of 1 mM and 100 mM showed the same trends than those observed at 10 mM. CONCLUSIONS: All of the OVDs tested efficiently reduced endothelial lesions against free radicals compared with the control group in which no OVD was used. The following sequence for the efficacy of endothelial cell protection was established: Visiol>Viscoat>Healon>no OVD.     

Comparison of sonic and ultrasonic phacoemulsification using the Staar Sonic Wave system

PURPOSE: To compare the performance of sonic phacoemulsification with that of ultrasonic phacoemulsification in regard to 1-day postoperative visual acuity, corneal edema, and procedure efficiency. SETTING: Oregon Eye Institute, Eugene, Oregon, USA. METHODS: This prospective nonrandomized study comprised 86 eyes with mild to moderate nuclear sclerotic cataract. Forty-three eyes had sonic and 43 ultrasonic phacoemulsification using the Staar Sonic Wave phacoemulsification system. The mean age was 76 years in the ultrasonic group and 71 years in the sonic group. The mean nuclear sclerosis was 2.0+ in the sonic group and 1.9+ in the ultrasonic group. Patient age, lens density, postoperative corneal edema, 1-day postoperative uncorrected visual acuity (UCVA), and the percentage of eyes with a visual acuity of 20/40 or better were determined. In addition, the mean ultrasonic and sonic times, mean percentage phaco power, and mean effective phaco time (EPT) were calculated in each group. RESULTS: Both groups had a 5% incidence of trace corneal edema. The mean UCVA was 20/41 in the ultrasonic group and 20/42 in the sonic group. Seventy-nine percent of eyes in the ultrasonic group and 74% in the sonic group had a UCVA of 20/40. The mean percentage phaco power was 7.2% and 7.6% in the ultrasonic group and sonic group, respectively. The mean EPT was low in both groups, 4.0 and 2.9 seconds, respectively. CONCLUSION: Sonic technology yielded outcomes similar to those of ultrasonic phacoemulsification with respect to postoperative visual acuity and corneal edema in patients with average density nuclear sclerotic cataract.     

The influence of viscoelastic substances on the corneal endothelial cell population during cataract surgery: a prospective study of cohesive and dispersive viscoelastics

PURPOSE: To compare the ability of cohesive and dispersive ophthalmic viscoelastic devices (OVDs) to protect the corneal endothelium following in-the-bag phacoemulsification with implantation of a foldable posterior chamber intraocular lens (IOL). METHODS: In a prospective single-masked randomized study, 60 eyes of 60 cataract patients were assigned to three groups of 20 patients each, according to which OVD was used: Celoftal, Vitrax or Healon. The corneal response to surgery was evaluated by measuring the endothelial cell loss, the variation in mean cell area of the endothelial cells (CV), the frequency of hexagonal cells, and the central corneal thickness. Data were recorded preoperatively and 3 months postoperatively. RESULTS: Preoperatively, no significant difference was observed in cell count, CV, hexagonal pattern or pachymetry among groups. Postoperatively, all three groups had a significant decrease in cell count, but the decrease was significantly less in the Vitrax group (6.97%) than in the Celoftal (18.03%) and Healon groups (18.46%). No changes in CV, hexagonality or corneal thickness were observed within any of the three groups or among the groups. There was an equal and significant increase in visual acuity. CONCLUSIONS: Phacoemulsification with implantation of a posterior chamber lens is known to affect the density and morphology of corneal endothelial cells. Viscoelastics facilitate cataract surgery and protect the corneal endothelium during the procedure. Choosing a dispersive hyaluronate OVD during the phaco procedure may allow for protection of the endothelial cells while suppressing the formation of free radicals. This may be the reason for the superior protective effect on the corneal endothelial cells of Vitrax compared with Celoftal and Healon.     

Survey of ophthalmic viscosurgical devices

PURPOSE OF REVIEW: Cataract treatment is evolving, thanks to new phaco systems and innovative surgical techniques. Recent ophthalmic viscosurgical devices (OVDs) play an important role in the development of new approaches to surgery. Knowledge of the new techniques and advances in new OVDs is crucial to performing routine and complicated surgeries. RECENT FINDINGS: Viscoadaptive substances have been introduced as a particular kind of OVD and are distinguished by high viscosity at a low flow rate and a tendency to fracture at higher flow rates, assuming pseudodispersive behavior. The ultimate soft shell technique emphasizes the rheology of viscoadaptive OVDs to perform phacoemulsification procedures, exploiting all the useful properties of these OVDs in terms of space maintenance and tissue protection. Recent studies have highlighted some new and interesting aspects of the use of OVDs. Current reports suggest that the association of lidocaine and OVD seems to be safe and useful in providing anesthesia during cataract surgery. Concern has been expressed in other studies regarding the presence of contaminants, such as endotoxins, which may be responsible for postoperative uveitis-like reactions. Finally, OVDs are widely known to protect the corneal endothelium during cataract surgery. Their role is also assuming relevance in vitreoretinal surgery. SUMMARY: New OVDs and related techniques represent an advancement in cataract surgery.     

Effect of incisional friction and ophthalmic viscosurgical devices on the heat generation of ultrasound during cataract surgery

PURPOSE: To determine the thermal features of the Legacy (Alcon) and Sovereign (Advanced Medical Optics) phacoemulsification machines in a cadaver eye and with 7 ophthalmic viscosurgical devices (OVDs). SETTING: In situ and in vitro study. METHODS: Temperature without occlusion was recorded at the sleeve placed in the wound of a cadaver eye, and temperature over baseline was determined after 60 seconds. The result was then compared with the results in a previous study that used balanced salt solution (BSS) in artificial chambers. In the second portion of the experiment, with irrigation and aspiration lines occluded, temperature was recorded at the sleeve placed in an artificial chamber filled with sodium hyaluronate 2.3% (Healon5), sodium hyaluronate 1.4% (Healon GV), sodium hyaluronate 1.0% (Healon), sodium hyaluronate 1.6% (Amvisc Plus), sodium hyaluronate 1.0% (Provisc), sodium hyaluronate 3.0%-chondroitin sulfate 4.0% (Viscoat), or hyaluronate 3.0% (Vitrax). Temperature over baseline was also determined after 60 seconds. These results were compared with each set of OVD data and with the results in the prior BSS study. RESULTS: In the eye-bank model, the Legacy machine had a 62% temperature increase from incisional friction and the Sovereign machine had a decrease of 8.6% over results in an artificial anterior chamber. The OVD temperature increases were greater for the Sovereign (P<.001) and followed the same general trend for the Legacy. The least temperature increase was with Amvisc Plus, Healon, and Healon GV; the intermediate increases were with Provisc and Vitrax; and the greatest increases were with Viscoat and Healon5. The OVD findings did not correlate with viscosity or pseudoplasticity. CONCLUSIONS: Incisional friction alone increased heat generation in the Legacy, a stroke-length driven instrument, more than in the Sovereign, a power-driven instrument. Ophthalmic viscosurgical devices are not only a concern due to outflow occlusion but can also add up to 6 times the heat in comparison with BSS. The need to aspirate the OVD before using ultrasound is thus verified.     

Two-compartment technique to remove ophthalmic viscosurgical devices

To avoid postoperative intraocular pressure peaks, complete removal of all ophthalmic viscosurgical devices (OVDs) used during cataract surgery is important. Depending on the kind of OVD used, different removal techniques have been applied. We describe a technique that was used in more than 250 eyes for safe removal of OVDs, especially viscoadaptive OVDs such as sodium hyaluronate 2.3% (Healon5). It takes advantage of the viscoadaptive properties of Healon5 and was named the 2-compartment technique.