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

Minimal Posterior Pole Vitrectomy and Fixing the Inverted Internal Limiting Membrane Flap with DisCoVisc for Macular Hole: No Gas or Air Tamponade

PURPOSE

To investigate an alternative surgical method for macular hole repair without fluid-air exchange, gas tamponade, and prone positioning.

METHODS

Eighteen eyes of 17 patients with macular holes underwent minimal posterior pole vitrectomy with an inverted internal limiting membrane flap technique. Ophthalmic viscosurgical device was used to fix the inverted internal limiting membrane flap in the balanced salt solution. No fluid-air exchange, gas tamponade, or prone positioning was needed. Follow-ups were performed at 1 day, 1 week, and the last visit (ranging from 3 to 6 months) after surgery. Optical coherence tomography examination, intraocular pressure, and best-corrected visual acuity measurements were performed preoperatively and at every follow-up, postoperatively.

RESULTS

Primary closure of the macular hole was observed in all 18 eyes (100%). Optical coherence tomography showed U-type closure in 12 eyes, V-type closure in five eyes, and W-type closure in one eye. Preoperative, postoperative 1 week, and last follow-up best-corrected visual acuity were 0.90 (Snellen equivalent 20/159) ± 0.31 LogMAR, 0.72 (Snellen equivalent 20/105) ± 0.33 LogMAR, and 0.48 (Snellen equivalent 20/60) ± 0.32 LogMAR, respectively. Postoperative visual acuity was significantly improved compared with preoperative values ( F = 19.250, P = 0.000). No significant difference in intraocular pressure was found compared with preoperative values ( F = 1.933, P = 0.168). No significant complications were observed.

CONCLUSION

This surgical method can effectively close macular holes, improve visual acuity, enhance surgical efficiency, reduce surgical complications, and improve patients' postoperative experience without the need for fluid-air exchange, gas tamponade, or prone positioning.

Corneal endothelium protection provided by ophthalmic viscosurgical devices during phacoemulsification: experimental study in rabbit eyes

PURPOSE

To compare the protection of the corneal endothelium provided by a cohesive and a dispersive ophthalmic viscosurgical device (OVD) against damage from torsional ultrasound and simulated lenticular debris during phacoemulsification.

SETTING

University setting, Salt Lake City, Utah.

DESIGN

Experimental study.

METHODS

15 New Zealand rabbits were included. After incision, each eye received cohesive or dispersive OVD (ProVisc or Viscoat). 10 1.0 mm beads were injected to simulate lenticular debris. The Intrepid Balanced tip (Centurion Ozil handpiece) was inserted into the anterior chamber, and 60% torsional ultrasound with 50 mL/min flow, 70 mm Hg intraocular pressure, and 600 mm Hg vacuum was applied (20 seconds). Cumulative dissipated energy (CDE) was noted. After euthanasia and enucleation, corneas were removed, stained with trypan blue/alizarin red, and photographed (5 ×400 magnification photos and 1 overview photograph from each cornea). ImageJ was used to evaluate cell damage and loss.

RESULTS

CDE was 4.70 ± 0.26 and 4.64 ± 0.10 in the cohesive and dispersive OVD groups, respectively ( P = .8647). The analysis of the ×400 photographs showed that the percentage of intact cells was statistically higher in the dispersive OVD group ( P = .0002), whereas the percentages of damaged and lost cells were statistically higher in the cohesive OVD group ( P = .0002 and .0059, respectively). Overview photographs revealed the presence of residual OVD on the endothelium, especially in the dispersive group.

CONCLUSIONS

In this experimental study using a rabbit model, the corneal endothelium protection provided by the dispersive OVD was superior to that provided by the cohesive OVD.

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.

New ophthalmic dual-viscoelastic device in cataract surgery: a comparative study

Objective

To compare the performance and safety in cataract surgery of two ophthalmic viscoelastic devices (OVDs), each having separate dispersive and cohesive characteristics and different concentrations.

Methods and analysis

In this prospective, randomised, controlled clinical study, one eye of each patient was injected with OVD1 (Viscopack14) or OVD2 (DuoVisc) during phacoemulsification and intraocular lens implantation. Endothelial cell count, intraocular pressure (IOP), central corneal thickness (CCT), intraocular inflammation and corrected distance visual acuity (CDVA) were compared 3 months postoperatively.

Results

The study enrolled 127 patients. Randomisation assigned 50 eyes of as many patients to each arm of the study. The postoperative mean endothelial cell loss was 14.4% and 7.1% from baseline in the OVD1 and OVD2 groups, respectively (p=0.08). The incidence of IOP spikes at 2 hours was 0% and 8%, respectively (p=0.02). There were intergroup differences in postoperative IOP values, the OVD2 group showed significantly higher values at all of the follow-up visits starting from the 24 hours examination (p<0.05). There was no statistically significant difference in the CCT, intraocular inflammation and CDVA at the end of follow-up.

Conclusion

Both OVDs showed similar clinical performances and were equally effective during cataract surgery. Viscopack14 showed more corneal endothelial cell reduction, while DuoVisc had more occurrences of IOP values and spikes. Future studies are mandatory to support these preliminary results.

Comparison of the performance and safety of 2 ophthalmic viscosurgical devices in cataract surgery

PURPOSE

To compare the clinical performance and safety of 2 ophthalmic viscosurgical devices (OVDs)-Twinvisc (OVD 1) and Duovisc (OVD 2)-in cataract surgery.

SETTING

European multicenter study.

DESIGN

Prospective randomized controlled study.

METHODS

Patients with cataract had phacoemulsification and intraocular lens implantation in 1 eye. They were randomly assigned to receive OVD 1 or OVD 2. Preoperative and postoperative examinations over 3 months included mean intraocular pressure (IOP), incidence of IOP peaks (≥30 mm Hg and ≥24 mm Hg), endothelial cell count (ECC), corneal thickness, and intraocular inflammation. A subjective evaluation of the OVDs was performed.

RESULTS

The study comprised 220 patients. The incidence of IOP peaks and the mean IOP were not statistically significantly different between the 2 groups at any of the follow-up visits. At 6 hours, the incidence of IOP spikes 30 mm Hg or higher was 6.5% and 7.2% in the OVD 1 and the OVD 2 groups, respectively (P = .846). For the IOP spikes 24 mm Hg or higher, the incidence was 16.8% and 25.2%, respectively (P = .128). Three months postoperatively there was no statistically significant difference in ECC and pachymetry between the 2 groups. Mild inflammation was noticed up to 7 days postoperatively after which it resolved in both groups. Subjectively, the OVD 2 was easier to use, whereas the OVD 1 had better cohesive and dispersive properties.

CONCLUSIONS

Both OVDs have similar performance and safety profiles in phacoemulsification cataract surgery. No clinically relevant differences were found between the 2 devices regarding transient IOP spikes, mean IOP, corneal endothelium injury, or inflammation.

Dispersive viscosurgical devices demonstrate greater efficacy in protecting corneal endothelium in vitro

Objective

During phacoemulsification, the corneal endothelium is protected by an ophthalmic viscosurgical device (OVD). In this in vitro study, we assessed six different OVDs for their effectiveness in protecting the corneal endothelium.

Methods and analysis

Phacoemulsification was performed in cadaver eyes of young pigs. Five syringe units of six different OVDs were tested (Healon EndoCoat, Viscoat, Methylvisc, Healon, Healon GV, ProVisc). After surgery, the area of endothelium coated with OVD was determined in relation to the total endothelial surface. Additionally, an endothelial cell count was obtained. As a control, an endothelial cell count was obtained from freshly trephined corneas. Statistical analysis was performed using the Mann-Whitney U test and the Spearman correlation.

Results

The least postoperative endothelial coating and cell count were observed in the cohesive OVDs while the dispersive OVDs showed statistically significant higher values. Healon EndoCoat and Viscoat yielded a coating area of 86 (85-92)% and 85 (85-90)%, respectively. Endothelial cell count was highest in the two dispersive groups with 4065 (3928-4088) cells/mm² (Methylvisc) and 4032 (4015-4115) cells/mm² (Viscoat). Endothelial coating area and endothelial cell count correlated statistically significantly.

Conclusion

Dispersive OVDs from this study showed greater adherence to the endothelial surface than the cohesive ones. Furthermore, postoperative endothelial cell counts of corneas treated with dispersive OVDs were higher than of corneas treated with cohesive OVDs. Our in vitro results suggest that dispersive OVDs protect the corneal endothelium better during phacoemulsification than cohesive OVDs.

Mixed polymeric systems: New ophthalmic viscosurgical device created by mixing commercially available devices

PURPOSE

To evaluate the rheological properties of mixtures of different commercially available ophthalmic viscosurgical devices (OVDs) containing sodium hyaluronate and chondroitin sulfate.

SETTING

Eye Clinic, University of Trieste, Trieste, Italy.

DESIGN

Laboratory study.

METHODS

Blends were obtained combining a superviscous cohesive OVD (Healon GV [sodium hyaluronate 1%]) and a medium-viscosity dispersive OVD (Viscoat [sodium hyaluronate 3.0%-chondroitin sulfate 4.0%]). The 2 substances were combined in different ratios, and the rheological characteristics were analyzed to find the optimum proportion. A new viscous dispersive OVD, Discovisc (hyaluronic acid 1.6%-chondroitin sulfate 4.0%) was evaluated for comparison. The storage modulus, loss modulus, crossover point, complex viscosity, shear viscosity, and pseudoplasticity were studied.

RESULTS

The rheological properties of the mixed solution (1:1 and 3:1) showed intermediate characteristics in comparison with the 2 original substances, characterized by a viscosity comparable to that of the superviscous cohesive OVD, but at a higher shear rate (similar to the medium-viscosity dispersive OVD). The new viscous dispersive OVD performed similarly to the medium-viscosity dispersive OVD at low shear rates but was comparable to the superviscous cohesive OVD at high shear rates.

CONCLUSIONS

The mixture of dispersive and cohesive rheological properties in a single OVD might be an advantage during cataract surgery.

Preoperative Mannitolization Can Decrease Corneal Endothelial Cell Damage After Cataract Surgery

PURPOSE

To evaluate whether preoperative mannitolization can change ocular biometry and affect postoperative corneal endothelial cell density.

METHODS

Bilateral sequential cataract surgery was performed in 38 patients. Preoperative mannitolization was done in one eye of each subject. We checked the change in preoperative ocular biometry before and after intravenous mannitolization. We compared the postoperative corneal endothelial cell density between eyes with mannitolization and without mannitolization at postoperative week 1, 2, 5, and 8. We evaluated the relationship between change in ocular biometry and change in postoperative corneal endothelial cells in eyes that underwent preoperative mannitolization.

RESULTS

After mannitolization, eyes exhibited decreased intraocular pressure, axial length (AL), and vitreous chamber depth (VCD) and increased anterior chamber depth (ACD) and lens position (LP) compared to before mannitolization (p < 0.05). Preoperative mannitolization has a tendency to decrease the intraoperative use of phaco energy in eyes with moderate nucleosclerosis. Eyes with preoperative mannitolization showed less loss of postoperative corneal endothelial cells than eyes without preoperative mannitolization (p < 0.05). The ACD, LP, and AL changes by mannitolization were all negatively correlated with corneal endothelial cell loss (p < 0.05).

CONCLUSION

Preoperative mannitolization can decrease postoperative loss of corneal endothelial cells. The protective effect of preoperative mannitolization on the corneal endothelium may be due to the decreased need for phaco energy and changes in ocular biometry such as ACD, AL, and LP.

Advances in cataract surgery: preserving the corneal endothelium

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

A clinical comparison between DisCoVisc and 2% hydroxypropylmethylcellulose in phacoemulsification: a fellow eye study

OBJECTIVE

This study sought to compare the effects and outcomes of two ophthalmic viscosurgical devices, 1.6% hyaluronic acid/4.0% chondroitin sulfate and 2.0% hydroxypropylmethylcellulose, during phacoemulsification.

METHODS

This prospective, randomized clinical trial comprised 78 eyes (39 patients) that received phacoemulsification performed by the same surgeon using a standardized technique. Patients were randomly assigned to receive either 1.6% hyaluronic acid/4.0% chondroitin sulfate or 2.0% hydroxypropylmethylcellulose on the first eye. The other eye was treated later and received the other viscoelastic agent. Preoperative and postoperative examinations (5, 24 and 48 hours; 7 and 14 days; 3 and 6 months) included measurements of the total volume of the ophthalmic viscosurgical device, ultrasound and washout times to completely remove the ophthalmic viscosurgical device, intraocular pressure, central corneal thickness and best-corrected visual acuity. The corneal endothelial cell count was measured at baseline and at six months postoperatively. ClinicalTrials.gov: NCT01387620.

RESULTS

There were no statistically significant differences between groups in terms of cataract density or ultrasound time. However, it took longer to remove 2.0% hydroxypropylmethylcellulose than 1.6% hyaluronic acid/ 4.0% chondroitin sulfate, and the amount of viscoelastic material used was greater in the 2.0% hydroxypropylmethylcellulose group. In addition, the best-corrected visual acuity was significantly better in the hyaluronic acid/ chondroitin sulfate group, but this preferable outcome was only observed at 24 hours after the operation. There were no statistically significant differences between the two ophthalmic viscosurgical devices regarding the central corneal thickness or intraocular pressure measurements at any point in time. The corneal endothelial cell count was significantly higher in the hyaluronic acid/chondroitin sulfate group.

CONCLUSION

The ophthalmic viscosurgical device consisting of 1.6% hyaluronic acid/4.0% chondroitin sulfate was more efficient during phacoemulsification and was easier to remove after IOL implantation than 2.0% hydroxypropylmethylcellulose. In addition, the corneal endothelial cell count was significantly higher following the use of hyaluronic acid/chondroitin sulfate than with hydroxypropylmethylcellulose, which promoted an improved level of corneal endothelium protection.

Safety, efficacy, and intraoperative characteristics of DisCoVisc and Healon ophthalmic viscosurgical devices for cataract surgery

Purpose

To evaluate the safety and efficacy of DisCoVisc ophthalmic viscosurgical device (OVD, Alcon Laboratories, Inc) with respect to a comparator, Healon OVD (Advanced Medical Optics, Inc).

Patients and methods

In this prospective study, patients with cataracts were randomized to an OVD, and then received phacoemulsification and injection of an intraocular lens. After each surgery, unmasked investigators completed subjective questionnaires about OVD characteristics during each stage of the procedure. Masked technicians evaluated objective safety parameters of intraocular pressure (IOP) and endothelial cell density, with 90 days of follow-up.

Results

The DisCoVisc OVD group (128 eyes) and the Healon OVD group (121 eyes) had statistically similar outcomes for IOP and for endothelial cell loss. Subjectively assessed viscosity was statistically different (P < 0.0001), with Healon OVD most often rated “cohesive” and DisCoVisc OVD most often rated “both dispersive and cohesive”. Workspace maintenance differed between groups (P < 0.0001), with workspace most frequently rated “full chamber maintained” when using DisCoVisc OVD and most frequently rated “workspace maintained” when using Healon OVD. “Flat” or “shallow” workspace ratings occurred only in the Healon OVD group.

Conclusion

DisCoVisc OVD had both cohesive and dispersive properties, and was safe and effective for every stage of cataract surgery.

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

Background

Ophthalmic viscosurgical devices (OVDs) are widely used in phacoemulsification cataract surgery to maintain adequate intraocular space, stabilize ocular tissue during the operation and decrease the possible damage of the corneal endothelium. Our study has the purpose to compare the corneal and foveal changes of Viscoat and Visthesia in patients undergoing uneventful phacoemulsification cataract surgery.

Methods

Participants in our study were 77 consecutive patients, who were randomized into two groups based on type of OVD used during phacoemulsification: Viscoat or Visthesia. All patients underwent a complete ophthalmological examination i.e., measurement of best corrected visual acuity (BCVA) by means of Snellen charts, intraocular pressure examination by Goldmann tonometry, slit lamp examination, fundus examination, optical coherence tomography, specular microscopy and ultrasound pachymetry preoperatively and at three time points postoperatively (day 3, 15, 28 postoperatively). The differences in baseline characteristics, as well as in outcomes between the two groups were compared by Mann-Whitney-Wilcoxon test and Student's t-test, as appropriate.

Results

Intraoperatively, there was no statistically significant difference in the duration of the ultrasound application between the two groups, while Viscoat group needed more time for the operation performance. It is also worthy to mention that Visthesia group exhibited less intense pain than patients in Viscoat group. Postoperatively, there was a statistically significant difference in central corneal thickness, endothelial cell count and macular thickness between the two groups, but BCVA (logMAR) did not differ between the two groups.

Conclusions

Our study suggests that Viscoat is more safe and protective for the corneal endothelium during uneventful phacoemulsification cataract surgery, while Visthesia is in superior position regarding intraoperative pain. Patients of both groups acquired excellent visual acuity postoperative. Finally, this is the first study comparing OVDs in terms of macular thickness, finding that Visthesia cause a greater increase in macular thickness postoperatively than Viscoat, although it reaches normal ranges in both groups.

Subjective evaluation of intraoperative performance of DisCoVisc in complex ocular environments

PURPOSE

To subjectively evaluate the intraoperative characteristics of DisCoVisc during phacoemulsification in complex ocular environments.

PATIENTS AND METHODS

In this prospective observational study, two experienced surgeons (ARV and CZ) performed phacoemulsification on 100 consecutive patients with cataract associated with complex ocular environments. Inclusion criteria were eyes with shallow anterior chambers (anterior chamber depth (ACD) of <2.1 mm), inadequate pupillary dilation (3 mm), dense cataract, and white mature cataract. The surgeons subjectively assessed the endpoints at each phase of phacoemulsification and various behavioural aspects of the ophthalmic viscosurgical devices (OVDs) were subsequently evaluated.

RESULTS

The distribution was as follows: eyes with white mature cataract (n=18), eyes with grades 4 and 5 cataract (n=56), eyes with co-existing shallow ACD <2 mm (n=24), and co-existing small pupil size <2 mm (n=18). DisCoVisc behaved like a moderately cohesive viscoelastic in 94% of the cases. Injection of viscoelastic was easy in 38 (38%) eyes and very easy in 62 (62%) eyes. Visualization after the viscoelastic injection was excellent in 74% of the eyes. During phacoemulsification, DisCoVisc was moderately dispersive at all the stages of emulsification. The bag maintenance during IOL implantation was excellent in 56% eyes; IOL implantation was easy in 26% of the eyes and difficult in 20% of the eyes. Surgeons found viscoelastic removal easy in 68% of the eyes. At the time of OVD removal, DisCoVisc behaved like both a dispersive and a cohesive viscoelastic in 96% of the eyes.

CONCLUSION

DisCoVisc provides both cohesive and dispersive properties. DisCoVisc alone, even in complex ocular environments, enabled the surgeon to achieve good intraoperative performance.

The 'sweet' and 'bitter' involvement of glycosaminoglycans in lung diseases: pharmacotherapeutic relevance

The extracellular matrix (ECM) plays a significant role in the structure and function of the lung. The ECM is a three-dimensional fibre mesh, comprised of various interconnected and intercalated macromolecules, among which are the glycosaminoglycans (GAG). GAG are long, linear and highly charged, heterogeneous polysaccharides that are composed of a variable number of repeating disaccharide units (macromolecular sugars) and most of them, as their name implies, have a sweet taste. In the lung, GAG support the structure of the interstitium, the subepithelial tissue and the bronchial walls, and are secreted in the airway secretions. Besides maintaining lung tissue structure, GAG also play an important role in lung function as they regulate hydration and water homeostasis, modulate the inflammatory response and influence lung tissue repair and remodelling. However, depending on their size and/or degree of sulphation, and their immobilization or solubilization in the ECM, specific GAG in the lung either live up to their sweet taste/name, supporting normal lung physiology, or they are associated to 'bitter' effects, related to lung pathology. The present review discusses the biological role of GAG in the lung as well as the involvement of these molecules in various respiratory diseases. Given the great structural diversity of GAG, understanding the changes in GAG expression that occur in lung diseases may lead to novel targets for pharmacological intervention in order to prevent and/or to treat a range of lung diseases.