Use Of Ophthalmic Viscosurgical Devices Research Articles

Primary Posterior Continuous Circular Capsulorhexis without the Use of Ophthalmic Viscosurgical Device.

Performing primary posterior capsulorhexis (PPCCC) during cataract surgery is an effective prevention of secondary cataracts. It is important not to damage the anterior vitreous membrane to minimize the possible complications and adverse side effects of this step of the surgery. Most authors use a viscoelastic material to protect the anterior vitreous membrane, injected into the space between the posterior lens capsule and the vitreous membrane through a small hole in the posterior capsule. The creation of posterior capsulorhexis using 25G forceps under an implanted intraocular lens while continuously filling the anterior chamber with irrigation fluid from an irrigation cannula, without the use of a viscoelastic material is, in our opinion, a safe, fast and cheap technique of PPCCC. This technique could theoretically lead to a lower incidence of postoperative complications such as higher postoperative intraocular pressure or anterior segment inflammatory response.

Thermal Profile of Pulse Precision Capsulotomy: In vivo and In vitro Infrared Thermography Study.

PurposeThis study aimed to elucidate the thermal safety of precision pulse capsulotomy (PPC) via in vivo and in vitro evaluation of the thermal profile using infrared thermography.MethodsThis prospective observational study enrolled 15 eyes from 15 participants who underwent cataract surgery using the Zepto PPC. All patients underwent temperature measurements of the incision site and the entire cornea using an infrared thermographer during the capsulotomy procedure. To accurately analyze the temperature change of the Zepto PPC, infrared thermography was performed with the Zepto handpiece while exposed to air and then in porcine eyes. Moreover, in each case, the difference in temperature change according to the use of an ophthalmic viscosurgical device (OVD) was also checked to determine the temperature buffering effect.ResultsIn the clinical evaluations, the mean temperature elevation around the corneal incision and time duration from baseline to peak temperature during the Zepto capsulotomy were 4.0°C ± 1.9°C and 4.43 ± 1.26 seconds, respectively, with a mean peak temperature of 32.6°C ± 2.0°C. The mean peak temperature and rise time of the naïve Zepto nitinol ring, as measured from the bottom side, were 109.0°C ± 22.9°C and 43.40 ± 11.06 seconds in the experimental procedures, respectively. In the porcine eyes, the mean elevation of temperature and rise time of the Zepto nitinol ring were 6.2°C ± 1.6°C and 11.67 ± 2.08 seconds with the use of OVDs, and 10.5°C ± 3.3°C and 14.00 ± 3.61 seconds without OVDs, respectively.ConclusionsZepto PPC has the potential to generate extremely high thermal energy, according to an in vitro study. However, the temperature rise of the Zepto capsulotomy can be minimized by using OVDs.

Preclinical Safety Evaluation of Ophthalmic Viscosurgical Devices in Rabbits and a Novel Mini-Pig Model.

IntroductionTo establish the preclinical safety and equivalency of ophthalmic viscosurgical devices (OVDs) comprised of bacterially sourced sodium hyaluronate (HA) to animal sourced HA using pyrogenicity and aqueous exchange models in rabbits and a novel mini-pig model to evaluate corneal endothelial cell protection in vivo.MethodsHEALON OVD and HEALON5 OVD containing animal-derived HA and HEALON PRO OVD and HEALON5 PRO OVD containing bacterial-derived HA were used. Two rabbit aqueous exchange studies were conducted where aqueous humor was exchanged with OVDs in six animals each to observe potential ocular inflammation, intraocular pressure (IOP) response, corneal health and pachymetry until 7 days post procedure, as well as overall assessment of the OVDs. Endothelial cell protection was evaluated in a Yucatan mini-pig cataract surgery model where HEALON PRO and HEALON5 PRO OVDs were compared to HEALON and HEALON5 OVDs, respectively. Following cataract surgery with use of OVDs in six animals per study, animals were evaluated for ocular and general health, IOP, corneal thickness, ocular inflammation, and endothelial cell protection on days 1, 3, 7 and 14 post-surgery.ResultsAll rabbit studies demonstrated equivalence between bacterial-derived and animal-derived OVDs. Mild, post-surgical irritation, IOP increase, and corneal thickness measurements were not significantly different in HEALON PRO OVD and HEALON5 PRO OVD compared to HEALON and HEALON5 OVDs, respectively. The mini-pig model developed to investigate endothelial cell protection was successful in demonstrating equivalence between the OVDs studied. Changes in IOP mirrored actual surgical procedures, while corneal pachymetry and endothelial cell density remained constant for all OVDs used. Slit lamp observations showed expected inflammation following surgical procedures, likely due to challenges encountered during surgical procedures.ConclusionRabbit pyrogenicity and aqueous exchanged paired with a novel simulated cataract surgery mini-pig model demonstrate equivalence of OVDs regardless of HA source. Albeit with challenges, the mini-pig model was shown to be a promising tool for endothelial cell evaluation during the development of new OVDs for ophthalmic use.FundingJohnson & Johnson Surgical Vision, Inc.

Balanced Salt Solution-Assisted Intraocular Lens Implantation in Phacoemulsification Surgery: Intraocular Pressure and Endothelial Cell Effects.

Objectives:The purpose of this study was to evaluate the effect of balanced salt solution (BSS)-assisted intraocular lens (IOL) implantation on postoperative intraocular pressure (IOP) and endothelial cells and to compare BSS-assisted IOL implantation with the use of ophthalmic viscosurgical devices during IOL implantation.Methods:A total of 52 eyes of 40 patients (25 female, 15 male) with a cataract who underwent phacoemulsification surgery with BSS-assisted (26 eyes) or viscoelastic-assisted IOL implantation (26 eyes) were evaluated. BSS-assisted IOL implantation was performed with the aid of irrigation cannula and BSS without using a viscoelastic substance. Viscoelastic-assisted IOL implantation was performed according to standard procedures to facilitate IOL implantation. IOP measurements and endothelial changes after phacoemulsification surgery, as well as the surgical time were noted and compared. The eyes were also evaluated in terms of cataract density preoperatively and phaco parameters were assessed peroperatively.Results:The mean age of the patients was 67.5±7.8 years in the BSS-assisted group and 67.8±9.4 years in the viscoelastic group. The mean preoperative IOP and postoperative IOP on day 1, week 1, and month 1 was 14.2±2.3, 14.7±3.1, 13.2±1.5, and 13.8±2.7 mmHg, respectively, for the BSS-assisted group and 14.1±2.9, 19.1±3.4, 13.8±3.1, and 13.2±2.9 mmHg, respectively, for the viscoelastic-assisted IOL implantation group. The IOP increase was significantly greater on the first day in the viscoelastic-assisted IOL implantation group (p=0.007). The surgical time was 12.3±2.1 minutes in the BSS group and 14.6±3.1 minutes in the viscoelastic group (p=0.035). The difference in endothelial changes was not statistically significant between groups (p=0.88).Conclusion:IOL implantation using BSS in phacoemulsification surgery is a reliable technique, and this method has a significantly shorter surgery time and a much smaller postoperative IOP increase. The reduced IOP increase after cataract surgery might be particularly helpful for glaucoma patients.

Evaluation of the Protective Effect of an Ophthalmic Viscosurgical Device on the Ocular Surface in Dry Eye Patients during Cataract Surgery.

PurposeTo evaluate the protective effect of applying an ophthalmic viscosurgical device (OVD) to the ocular surface during cataract surgery and its ability to prevent dry eye syndrome.MethodsTwenty-four patients aged 50 to 75 years who underwent cataract surgery at Seoul National University Bundang Hospital and agreed to participate in the study were included and divided into two groups: a study group who underwent cataract surgery after application of an OVD to the ocular surface, and a control group who underwent cataract surgery without application of an OVD. DisCoVisc was used as the OVD in the study group, while other factors including surgical techniques and administration of anesthetic agents were performed in both groups in the same manner. Indicators of dry eye syndrome including ocular staining score, tear break-up time, and tear osmolality were analyzed. Ocular surface disease index and a visual analog scale were analyzed for dry eye symptoms, and the amount of balanced salt solution used during surface irrigation and operation time were also analyzed.ResultsSignificant improvement in the tear break-up time, corneal ocular staining score, and ocular surface disease index score in the study group compared with the control group one week after operation (by the Mann-Whitney test). Use of OVD was associated with longer operating time.ConclusionsOVD applied to the ocular surface during cataract surgery had a protective effect on the ocular surface one week after surgery.

Comparison of two techniques for toric intraocular lens implantation: hydroimplantation versus ophthalmic viscosurgical devices

BackgroundTo compare the results between hydroimplantation of a single-piece, acrylic foldable toric intraocular lens (IOLs) and conventional implantation using an ophthalmic viscosurgical device (OVD).MethodsIn this study, 60 eyes with cataract and preexisting regular corneal astigmatism of 1.0 to 3.0 diopters (D) underwent the implantation of the AcrySof toric IOLs (Alcon Laboratories, Inc.). The patients were randomly assigned to a conventional implantation technique with an OVD or a hydroimplantation technique. Comparison of preoperative and postoperative parameters was performed using paired Student t tests, and independent Student t test was used to compare between the two groups.ResultsThree months postoperatively, the mean subjective astigmatism was 0.45 D ± 0.24 (SD) in the OVD group and 0.49 ± 0.29 D in the hydroimplantation group (P = 0.492). The mean endothelial cell density (ECD) loss was 7.54% ± 0.82% and 7.32% ± 0.59%, respectively (P = 0.117). The mean absolute IOL rotation was 4.77 ± 2.32 degrees and 4.70 ± 1.95 degrees, respectively (P = 0.334). The mean time for IOL implantation was 71.50 ± 8.10 s and 37.60 ± 3.90 s, respectively (P < 0.001). Two hours, 1 day, 1 week, 1 month, and 3 months postoperatively, there was no significant difference in IOP between the two groups (P > 0.05), although IOP two hours postoperatively seemed to be a little higher in the OVD group.ConclusionsCompared with the use of OVDs for toric IOLs implantation, the hydroimplantation technique provided advantages of increased efficiency, reduced surgical time and cost, and no concerns of OVD-induced elevated IOP.Trial registrationCurrent Controlled Trials ISRCTN55696872, Retrospectively registered (Date of registration: 25 March 2018).

Corneal Endothelium and Phacoemulsification.

Phacoemulsification has become the most commonly used procedure in cataract surgery owing to the development of new devices and surgical techniques; however, corneal endothelial damage still represents a serious complication. Although several factors are known to cause corneal endothelial damage, effects of irrigating pressure and temperature rise in the anterior chamber should also be considered. Furthermore, free radical formation is another important harmful factor. Ultrasound in aqueous solution induces cavitation, which results in the formation of hydroxyl free radicals that damage the corneal endothelium. The best protection is the use of ophthalmic viscosurgical devices. In addition, the use of H2 gas as an anti-free radical agent in the irrigating solution is discussed. At present, corneal endothelial injury is usually assessed using the limited range of specular microscopy. Corneal volume might be a new parameter with which to assess total corneal endothelial function.

Intraocular lens implantation without the use of ophthalmic viscosurgical device.

The purpose of this study was to determine whether single-piece hydrophilic acrylic intraocular lens can be safely implanted without the use of ophthalmic viscosurgical devices. This retrospective study comprised 100 eyes having phacoemulsification and intraocular lens implantation without the use of ophthalmic viscosurgical device. 80 eyes with the use of a viscosurgical device are used as control group. In this intraocular lens implantation technique, the anterior chamber was maintained with an irrigation cannula and intraocular lens was implanted with a lens injector. Visual acuity, corneal clarity and edema, intraocular pressure, and corneal endothelial cell count were evaluated preoperatively and postoperatively at days 1, 7, and 30. Corneal endothelial cell count was repeated 2weeks after surgery. Complications of this technique were also evaluated. No significant complications of this intraocular lens implantation technique, such as posterior capsule rupture, intraocular lens buttonholing, zonular dialysis, Descemet's tear/detachment, occurred. On the seventh postoperative day, 90% of eyes achieved 20/20 or better vision. There was no difference in corneal endothelial cell loss between viscoelastic device-used and not-used cases (p=0.356). When implanting intraocular lens without the use of ophthalmic viscosurgical device, significant intraoperative complications did not occur. The possible advantages are shortened surgery time, avoidance of postoperative IOP spike from ocular viscosurgical device (OVD) remnant, and reduced cost.

Modified corneal incisions in intraoperative floppy iris syndrome (IFIS)-prone patients.

We aimed to report a simple technique that involves modified anterior (to the limbus) elongated corneal incisions in order to reduce the incidence and severity of intraoperative floppy iris syndrome (IFIS) and related complications. This was a retrospective study of phacoemulsification cataract surgeries performed by a single surgeon on patients receiving tamsulosin or alfuzosin between 1 January 2009 and 31 July 2012 at Meir Medical Center, Kfar-Sava, Israel. We recorded preoperative gender, age, α-antagonist medication, coexisting pseudoexfoliation (PXF), and intraoperative use of ophthalmic viscosurgical devices (OVDs), pupil size, complications, IFIS grading and the need for additional operative strategies to manage IFIS. Elongated corneal incisions were performed approximately 1 mm anterior to the limbus. Ninety-three eyes of 81 men were included. Mean age was 76.5 years (range 55 to 96 years). Forty-seven eyes (40 patients) had documented use of alfuzosin and 45 eyes (40 patients) of tamsulosin. One patient received both. The overall rate of IFIS was 22.6 % (n = 21). Eyes of patients who were treated with alfuzosin had a milder grading (p < 0.001) and an overall lower percentage of IFIS compared to tamsulosin (4.26 % versus 42.22 % respectively, p < 0.001). No additional strategies were used to manage IFIS during surgery. No intraoperative complications occurred. Anterior elongated incisions are simple and efficient in preventing IFIS, exempting the surgeon from the use of additional expensive devices or materials in most cases. They do not limit the surgeon to one strategy, and therefore, if necessary, another may be applied at any given time.

Laser-Assisted Cataract Surgery in Small Pupils Using Mechanical Dilation Devices

To describe methods for performing laser-assisted cataract surgery in small pupils. Iris retractors or a Malyugin Ring (Microsurgical Technology, Redmond, WA) were used for mechanical pupil dilation before laser capsulotomy and lens fragmentation. The laser treatment can be performed with or without use of ophthalmic viscosurgical devices (OVD). In 73 eyes with small pupils, laser treatment was possible after mechanical dilation device installation. With and without an OVD, no flattening of the anterior chamber or other complications occurred during re-docking, laser treatment, or the manual part of the operation. Small adhesions of the anterior capsulotomy were more frequent when the anterior chamber was still filled with the OVD and did not occur when the OVD was removed. A small, poorly dilating pupil constitutes a major challenge in cataract surgery, particularly when performing capsulorhexis. Femtosecond laser treatment can be employed with considerable benefit for the patient, even in these difficult cases.

Femtosecond Laser-Assisted Cataract Surgery Without Ophthalmic Viscosurgical Devices

To describe a technique for performing femtosecond laser-assisted cataract surgery without the use of ophthalmic viscosurgical devices (OVDs). After laser pretreatment, the anterior chamber is stabilized with balanced salt solution during lens and cortex aspiration. A preloaded intraocular lens is implanted under irrigation. In 23 eyes undergoing surgery without the use of OVDs, no complications were observed within a 1-month follow-up period. The time for surgery and the amount of fluid that went into the eye were similar to those of a standard procedure. There was no remarkable increase in intraocular pressure or corneal thickness. All patients achieved a significant increase in corrected distance visual acuity after surgery. The significant reduction of phacoemulsification use after femtosecond laser application might render the use of OVDs obsolete in many cases.

The Use of Ophthalmic Viscosurgical Devices During Donor's Corneal Harvesting

Purpose of the study: To evaluate the protective effect of Biolon© (sodium-hyaluronate 1%) use on corneal endothelium, during donor's corneal harvesting.Materials and methods: A prospective, randomized, double blind, comparative study was performed on 120 corneas donated from 60 donors. One cornea from each donor (n = 60) was harvested using intracameral injection of ophthalmic viscosurgical device (OVD), and the fellow cornea with no use of OVD (n = 60, control group). Endothelial cell density (ECD) values were obtained at the center of each corneal graft with a specular microscope one day after harvesting.Results: ECD in the OVD group were 2839 ± 412.5 cells/mm2 and in the control group 2748 ± 429.7 cells/mm2. (p = 0.03). Distribution curve of the difference in ECD between the OVD and no OVD eyes showed that 47% of the donors had > 100 cells/mm2 difference, and 32% of donors had >200 cells/mm2 difference in favor of the OVD group.Conclusions: Intracameral OVD injection during corneal graft harvesting may protect the endothelium from the mechanical damage induced during the procedure. Further investigation is needed before routine the use of intracameral OVD should be considered in this setting.

First postoperative day intraocular pressure rise in resident-performed cataract surgery

Sir, We read the article by Kim et al1 with interest and would like to highlight some concerns regarding their data and conclusions. The title and purpose of the study seems to indicate outcomes for a particular surgeon group (residents in training); however, the conclusions are not supported by the data. Amongst 1582 procedures, after excluding surgery complicated with vitreous loss, 305/1582 procedures were performed by attending surgeons and further excluded from analysis. The outcomes of these 305 surgeries is reported in the discussion as having an incidence of first postoperative day intraocular pressure (IOP) elevation no higher than the trainee-performed surgery (P=0.94, χ2-test). The authors have surprisingly chosen to present the study as a consecutive case series instead of a more useful comparative study. There is a discrepancy in the use of ophthalmic viscosurgical device (OVD). The methodology states use of two agents: Healon (1% sodium hyaluronate) initially in 2001 to 2005 and thereafter Duovisc, which is composed of two OVDs, the cohesive Provisc (1% sodium hyaluronate) and dispersive Viscoat (sodium chondroitin sulphate 4%–sodium hyaluronate 4%). However, in Table 2 the OVD reported as used is Healon GV, a hyaluronic acid product with a 10-times higher viscosity than Healon, preferred in complicated procedures (vitreous pressure, flat anterior chamber, so on) and thus probably chosen for resident surgery. The effect of OVDs with higher molecular weight and viscosity on postoperative IOP is well documented.2, 3 This may well explain the reason for this case series having a higher postoperative IOP 24 h after cataract surgery (22%, >23 mm Hg and 14.9%, >26 mm Hg) than the previously reported values of 2.57%4 and 11.8%,5 respectively. The effect of trainee surgeons on early IOP rise after cataract surgery can be a consequence of relatively more manipulations, residual OVD, and subsequent increased inflammation. This hypothesis maybe better supported by data on central corneal thickness, aqueous flare, surgery duration, phacoemulsification power etc as well as a comparative case–control study design.

Comparison of OVD and BSS for Maintaining the Anterior Chamber during IOL Implantation

PurposeTo compare surgical results between conventional intraocular lens (IOL) implantation using an ophthalmic viscosurgical device (OVD) and IOL implantation using a balanced salt solution (BSS) after irrigation/aspiration (I/A) of the lens cortex.MethodsA randomized prospective study was conducted on 62 patients who underwent cataract surgery. Following completion of conventional I/A of the lens cortex, we divided patients into two groups according to whether or not BSS was used. In group A (n = 31), the anterior chamber and the capsular bag were completely filled with an OVD before IOL implantation. On the other hand, in group B (n = 31), BSS was irrigated into the anterior chamber through a previous side port during IOL implantation. Surgical results were compared between the two groups.ResultsIn both groups, IOP peaked six hours after surgery. The occurrence of an IOP spike by postoperative day one was observed in six cases (6 / 31) in group A and in no cases (0 / 31) in group B, a difference that was statistically significant (p = 0.024). The values of endothelial cell density, central corneal thickness, anterior chamber inflammation, myopic shift, and posterior capsule opacification were not significantly different between the two groups.ConclusionsCompared with the use of OVD for IOL implantation, use of BSS during IOL implantation resulted in reductions in postoperative IOP spike and OVD removal time.

Comparison of corneal endothelial cell loss during phacoemulsification using continuous anterior chamber infusion versus those using ophthalmic viscosurgical device: Randomized controlled trial

AimWe conducted this study to evaluate and compare corneal endothelial cell loss between phacoemulsification with continuous anterior chamber infusion using anterior chamber maintainer (ACM) and phacoemulsification using ophthalmic viscosurgical device (OVD).Materials and MethodsThis was a prospective, randomized controlled trial. Fifty eyes of 47 patients of senile cataract undergoing phacoemulsification were included. Patients were randomly allocated into two groups of 25 eyes each. Cataract surgery was performed by phacoemulsification with anterior chamber (AC) continuous infusion with balanced salt solution (BSS) plus and ACM without OVD in Group A, and in Group B, phacoemulsification was performed using OVD with BSS plus. Corneal endothelial cell count and pachymetry were performed preoperatively and postoperatively on day 1, day 7, and day 30.ResultsThe mean increase in pachymetry was 4.86%, 2.94%, and 1.94%, (Group A) and 5.95%, 3.94%, and 0.51%, (Group B) on first, seventh, and 30th postoperative day respectively. The difference between the percentage increase in pachymetry between the two groups was not significant at day 1 (P = 0.441), day 7 (P = 0.298), and day 30 (P = 0.174) postoperatively. The density of endothelial cells decreased postoperatively (day 30) by 7.38% (Group A) and 7.47% (Group B) without any significant statistical difference (P = 0.983) between two groups.ConclusionUse of ACM for continuous AC infusion and omission of OVD during phacoemulsification did not cause significant difference in corneal swelling or endothelial cell loss in the immediate postoperative period up to one month.

Preloaded injector for intraocular lens implantation without the use of ophthalmic viscosurgical devices

To evaluate a new preloaded intraocular lens (IOL) injector (KS-VF) that uses ordinary irrigating solution alone to implant a foldable IOL and form and maintain the anterior chamber and capsular bag formation and maintenance. Department of Ophthalmology, Kitasato University, School of Medicine, Kanagawa, Japan. The KS-VF disposable injector is preloaded with a 3-piece silicone IOL, which is ejected after the injector is filled with ordinary irrigating solution via an irrigation/aspiration tube connected to the injector body. The space created by the irrigating solution in the anterior chamber and the capsular bag was compared with that created by conventional preloaded injectors filled with an ophthalmic viscosurgical device in a post-phacoemulsification porcine eye. Intraocular lens ejection speed and resistance with the KS-VF injector and with the conventional preloaded injectors were also measured and compared. In addition, intraocular pressure was measured in the porcine eye and in 11 eyes of 11 patients. In vitro examination revealed no significant difference in the IOL ejection mechanism between the KS-VF and conventional preloaded injectors. The use of irrigating solution was not inferior to that of OVD and provided sufficient space in the anterior chamber and capsular bag. In clinical use, IOLs were successfully implanted without incident into the capsular bag formed with the irrigating solution. The KS-VF implants a foldable IOL with irrigating solution alone and requires no intraocular injection or removal of OVD. Possible advantages include improvements in surgical efficiency, avoidance of postoperative IOP rise from residual OVD, and reduced surgical cost.

Ophthalmic viscosurgical devices

The indications for ophthalmic viscosurgical devices have expanded with the introduction of newly developed ophthalmic viscosurgical devices. The characteristics of different ophthalmic viscosurgical devices and their specific uses in anterior segment surgery and possible problems are discussed. Ophthalmic viscosurgical devices were first introduced to maintain space in the eye during the implantation of intraocular lenses. With the development of different types of ophthalmic viscosurgical devices, additional indications have been discussed. To protect the corneal endothelium, the ability of ophthalmic viscosurgical devices to be retained during phacoemulsification was compared. To enlarge and stabilize the size of the pupil, specific ophthalmic viscosurgical devices are used in patients with small pupils or intraoperative floppy iris syndrome. On the other hand, complications associated with the use of ophthalmic viscosurgical devices and their prevention have been discussed. Postoperative elevations of intraocular pressure have been reported and complete removal of the ophthalmic viscosurgical device at the end of surgery is the key factor to avoiding these elevations. Wound burns during phacoemulsification may occur and creating a fluid space around the phacoemulsification tip is necessary to avoid them. The rheologic characteristics of the different types of ophthalmic viscosurgical device should be considered, and the appropriate use of ophthalmic viscosurgical devices in specific cases would improve the surgical outcomes.

Adjunct devices for managing challenging cases in cataract surgery: capsular staining and ophthalmic viscosurgical devices

Cataract surgeons should employ all reasonable technology to facilitate safe and consistent outcomes. Knowledge of adjunct devices to enhance visualization of the capsular bag and appropriate use of ophthalmic viscosurgical devices allow for enhanced protection of intraocular structures and reduced rates of complication. Trypan blue is US Food and Drug Administration-approved for facilitating visualization of the anterior capsule. Animal data demonstrate Brilliant Blue G to be an effective capsular stain with a superior safety profile. Healon5 is a safe viscosurgical device that is particularly useful in children, poorly dilating pupils, intraoperative floppy-iris syndrome, and intumescent cataracts. The viscoadaptivity of Healon5 enables its utility throughout the procedure of cataract extraction. The recent literature on capsular dyes and advances in ophthalmic viscosurgical technology is reviewed. Inadequate capsular visualization and poor tissue stabilization/protection increase the chance of discontinuous capsulorhexis, retained nuclear material, vitreous loss and corneal decompensation. Utilization of adjunctive tools in the setting of challenging cataract cases can significantly limit adverse intraoperative outcomes and result in reproducible surgical success.

Mini-nuc technique

We agree with Keskinbora's comments that the mini-nuc technique1 is a cost-effective alternative to phacoemulsification. We have also found it to be a useful stepping stone in the learning curve of phacoemulsification. It enables the trainee to grasp the fundamentals of a self-sealing incision, a closed surgical system, and capsulorhexis without necessitating the use of the phacoemulsification machine. We have not found its learning curve longer than that of phacoemulsification. Doubts are often expressed about the effect of the mini-nuc technique on the cornea. We studied 64 eyes having this surgery. All eyes had a slitlamp examination and corneal endothelial cell count and morphology study preoperatively. Eyes with corneal pathology or an endothelial cell count of less than 1000 cells/mm2 were excluded. The eyes had uneventful cataract extraction by the mini-nuc technique and implantation of a poly(methyl methacrylate) posterior chamber intraocular lens. Postoperatively, 5 cases (7.8%) had transient corneal edema, which cleared by the seventh postoperative day. The mean endothelial cell loss at 6 months was 9.21% ± 2.49% (SD). This is not different from that reported after phacoemulsification.2 Fears regarding the effect of the mini-nuc technique on the cornea are unfounded. The use of an anterior chamber maintainer facilitates surgery that is safe for the cornea even without the use of ophthalmic viscosurgical devices.3 This should make the technique more attractive to surgeons in developing nations. Vikas Chadha Basudeb Ghosh Ashish Lall aEdinburgh, United Kingdom bNew Delhi, India

Irrigating chopper and vacuum capsulorhexis*1, *2A new technique in phacoemulsification

A continuous curvilinear capsulorhexis (CCC) technique for cataract extraction surgery by phacoemulsification is described. The technique replaces a forceps or needles with vacuum traction and further modifies vacuum capsulorhexis. The technique was performed in 30 patients. The achieved CCCs were compared with the desired CCC of approximately 6.0 mm (range 5.8 to 6.2 mm). The desired CCC was achieved in 19 patients; 7 patients had a smaller-diameter CCC and 2, a larger-than-desired diameter. Two patients had partial capsule tear. The mean diameter was 5.79 mm ± 0.57 (SD). This technique allows CCC to be performed through small incisions (1.0 mm) without the use of ophthalmic viscosurgical devices.