A clinical comparison of safety and efficacy in phacoemulsification with versus without ophthalmic viscoelastic device

Effect of elevated irrigation bottle height during cataract surgery on corneal endothelial cells in porcine eyes

BACKGROUND

Cataract surgery induces corneal endothelial cell loss (ECL). This study investigates the relationship between bottle height (BH) and ECL induced due to irrigation and aspiration (I/A) in cataract surgery and quantifies protective effects of intraoperatively used ophthalmic viscoelastic substances.

METHODS

Intermittent I/A without phacoemulsification was performed in porcine eyes for 10 min with varying BHs of 100 cm (BH100), 125 cm (BH125), 150 cm (BH150) or no treatment (control, no I/A). Additionally, in one group a dispersive ophthalmic viscoelastic substance was injected into the anterior eye chamber before treatment with I/A at a BH of 150 cm (BH150 + V). After exposure of the corneal endothelium to I/A, the corneas were prepared to split corneal buttons on day 0 and cultivated for 15 days. Endothelial cell density (ECD) was analyzed blinded on days 1, 8 and 15.

RESULTS

Relative ECL significantly correlated with irrigation BH (control (n = 13): -9.69 ± 6.03% (average ± standard deviation); BH100 (n = 12): -9.69 ± 4.81%-p = 1.000; BH125 (n = 14): -19.44 ± 7.30% - p < 0.001; BH150 (n = 13): -21.99 ± 6.70%-p < 0.001). I/A-induced ECL was significantly decreased by the injection of ophthalmic viscoelastic, as BH150 + V (n = 14; -10.92 ± 4.09%-p = 1.000) showed a cell loss comparable to the control group.

CONCLUSIONS

ECL is altered by I/A BH and reduced when viscoelastic substances are used.

The safety and efficacy of phacoemulsification surgery in uncomplicated cataracts with and without an ophthalmic-viscosurgical-device

PURPOSE

To compare and evaluate the results of phacoemulsification surgery involving and not involving an ophthalmic-viscosurgical-device (OVD).

METHODS

A prospective, randomized controlled trial included 60 eyes of 60 patients scheduled to receive phacoemulsification surgery. In order of presentation, patients were randomized into two groups to undergo different surgical techniques: the OVD-free group (n = 30) and the OVD group (n = 30). Each patient's operating time, total ultrasonography (U/S) time, cumulative dissipated energy (CDE), aspiration time, and volume of balanced salt solution (BSS) aspirated were recorded. At 1 day, 1 week, and 1 and 3 months postoperation, measurements of endothelial cell density (ECD) and intraocular pressure (IOP), were taken and compared between the groups.

RESULTS

Total U/S time (p = .567) and CDE (p = .168) were similar between the groups. In the OVD group, operating time (p = .011), aspiration time (p < .001), and volume of BSS aspirated (p < .001) were greater than in the OVD-free group. The change in ECD between the groups was not statistically significant at all visits (p = .433, p = .147, p = .379, p = .534; respectively). Although IOP increased in the OVD group at 1 day postoperation (p = .001), no difference emerged between the groups at 3 months postoperation (p = .121).

CONCLUSION

Phacoemulsification surgery without an OVD took less time than with the OVD and caused no significant loss in ECD. Surgeons concerned about elevated IOP following cataract surgery should apply the OVD-free method.

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.

Effect of simulated lenticular debris on corneal endothelial cells: experimental study in rabbit eyes

PURPOSE

To evaluate mechanical damage of simulated lenticular debris on corneal endothelial cells during phacoemulsification.

SETTING

University setting, Salt Lake City, Utah.

DESIGN

Experimental study.

METHODS

12 New Zealand rabbits underwent bilateral surgery. After incision, 10 1.0 mm beads were injected into the anterior chamber of test eyes to simulate lenticular debris. A balanced salt solution was injected into the contralateral eyes with the same injector. The Intrepid Balanced Tip of the Centurion Ozil handpiece was inserted into the anterior chamber, and 60% torsional ultrasound was applied for 20 seconds with 50 mL/min flow, 70 mm Hg intraocular pressure, and 600 mm Hg vacuum. Cumulative dissipated energy (CDE) was noted. After euthanasia and enucleation, the corneas were removed, stained with trypan blue/alizarin red, and photographed in a standardized manner (×400 photographs from 5 specific areas and 1 overview photograph from each corneal button). The ImageJ program was used to evaluate cell damage and loss in the photographs.

RESULTS

CDE was 4.64 ± 0.19 for test eyes with beads and 4.66 ± 0.17 for control eyes without beads ( P = .58). The percentage of intact cells was statistically higher in the control group ( P = .0005), whereas the percentages of damaged and lost cells were statistically higher in the test group ( P = .0010 and .0005, respectively). This was observed in the analysis of the ×400 photographs and overview photographs.

CONCLUSIONS

This study suggests that lenticular debris swirling around the anterior chamber may cause significant damage to the corneal endothelium, providing further insight on mechanisms of damage during phacoemulsification.

The effect of phacoemulsification fluid flow on the corneal endothelium: An experimental study in rabbit eyes

PURPOSE

To quantify the damage to the corneal endothelium from the flow of balanced salt solution during phacoemulsification.

SETTING

John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

DESIGN

Experimental Study.

METHODS

Twelve New Zealand white rabbits received bilateral surgery. Six eyes served as controls with no irrigation (incision only). In 18 eyes, the Intrepid Balanced tip of the Centurion (Alcon) Ozil handpiece was inserted into the anterior chamber for continuous irrigation at 50mL/minute with either 250 mL or 500 mL of balanced salt solution (BSS). After euthanasia and enucleation, the corneas were removed, stained with trypan blue/alizarin red, and photographed in a standardized manner (X400 photographs from 5 specific areas, and 1 overview photograph from each corneal button). The ImageJ program was used to evaluate cell damage and loss in the photographs obtained from each cornea.

RESULTS

Analysis of the X400 photographs showed no statistical differences between control, 250 mL, and 500 mL groups in the percentage of intact, damaged, or lost cells (P= 0.896, 0.851, and 0.972 respectively). For the overview photos, the differences in areas of intact and damaged cells among the groups were statistically significant, likely due to the peripheral areas of damage related to touches between the phaco tip and the endothelium during irrigation.

CONCLUSION

The volume of BSS flow alone does not appear to be a major contributing source of endothelial cell damage and loss, providing further insight on mechanisms of corneal endothelium damage during phacoemulsification.

Corneal Endothelial Health after Phacoemulsification Cataract Surgery without Viscoelastic Substance

Purpose:

To evaluate corneal endothelial health after cataract surgery without viscoelastic substance (VS).

Methods:

A prospective, non-randomized, case-series study was developed, and phacoemulsification cataract surgery without VS was performed on 1324 eyes between September 2015 and September 2018. As main outcomes, mean endothelial cell density (ECD) and mean central corneal thickness (CCT) were assessed before surgery and then 6 and 12 months after surgery. Data are summarized as mean, standard deviation (SD), and 95% confidence intervals (CI).

Results:

A total of 1324 eyes were operated, and 31 were excluded by intraoperative complications. The mean ECD baseline was 2506 cells/mm² (SD = 215, CI = 2494–2518); 6 months after surgery, it was 2328 cells/mm² (SD = 213, CI = 2316–2340); and 1 year after surgery, it was 2265 cells/mm² (SD = 214, CI = 2253–2277). In terms of percentage differences, the mean ECD decrease was 9.4% after 1 year. The mean preoperative CCT was 531.6 μm (SD = 34.8, CI = 529.7–533.5); 6 months after surgery, it was 537.7 μm (SD = 38.2, CI = 535.6–539.8); and 1 year after surgery, it was 537.9 μm (SD = 37.9, CI = 535.8–540.0). The mean CCT increased 1.2% 1 year after surgery.

Conclusions:

Phacoemulsification cataract surgery can be completely performed without VS, with very low intraoperative complications. The postoperative ECD and CCT changes occurred primarily during the first 6 months, and the changes decreased during the second semester.

Pure phaco: phacoemulsification without ophthalmic viscosurgical devices

The ophthalmic viscosurgical device (OVD) is an essential part of modern phacoemulsification surgery. Many times, OVDs are blamed for intraocular pressure spikes, toxic anterior segment syndrome, and capsular bag distension syndrome. To avoid these complications, we developed a technique in which phacoemulsification can be done without using OVDs. The irrigating cannula, on a continuous irrigation mode, was introduced through a side port, and capsulorhexis and incision construction were performed under an irrigating balanced salt solution. No hydroprocedure was performed. Phacoemulsification was done by chopping technique. At the end of the procedure, the intraocular lens was implanted by wound assistance technique under a continuous irrigation mode.

Intraoperative Evaluation of Phacoemulsification Cataract Surgery with and without the Use of Ophthalmic Viscosurgical Devices

PURPOSE:

The purpose of this study was to compare the efficacy and safety of cataract surgery by the phacoemulsification technique with and without the use of ophthalmic viscosurgical devices (OVDs).

SETTING:

This study was conducted at a tertiary eye care center in a rural area of Central India.

DESIGN:

This was a prospective, randomized, observational study.

METHODS:

In this study, 220 patients underwent phacoemulsification for cataract surgery with OVDs (OVD group) or without OVDs (BSS group) (n = 110 in each group). Patients with operable, nuclear Grade 2–4 cataracts were included in the study. The study was conducted from June 2017 to September 2018. The frequency of intraoperative complications, surgical time, and ease of the surgical procedure (easy, difficult, or very difficult) were recorded.

RESULTS:

There was no statistically significant difference in the nuclear opalescence, axial length, and intraocular lens (IOL) power between the two groups. Capsulorhexis extension was seen in two eyes in the OVD group and none of the eyes in the BSS group. The problems that occurred during IOL implantation included flip (OVD group, 2; BSS group, 1), haptic breakage (OVD group, 1; BSS group, 1), sulcus implantation (OVD group, 0; BSS group, 2), and stuck haptic (OVD group, 1; BSS group, 3). The total surgical time was almost equal in the two groups (OVD group, 9.2 min ± 3; BSS group, 9.5 min ± 3.5; P = 0.521). None of the patients had iris trauma or posterior capsular rupture.

CONCLUSIONS:

OVD-less phacoemulsification surgery is a safe and effective technique for treating age-related cataracts that requires no additional instrumentation and saves the cost of the OVD.

Effects of ultrasound energy on the porcine corneal endothelium - Establishment of a phacoemulsification damage model

PURPOSE

The purpose of this study was to establish a standardized in vitro phacoemulsification damage model for future investigations of the effects of phacoemulsification, surgical devices, protective ophthalmic viscoelastic devices (OVDs), irrigation solutions and other aspects related to cataract phacoemulsification surgery on the corneal endothelium using porcine eyes.

METHODS

Thirty-four porcine eyes were randomly assigned to three groups (phacoemulsification (n = 13), irrigation (n = 9), control (n = 12)). A total of 5 min of ultrasound energy with intermittent irrigation/aspiration was applied in the eyes of the phacoemulsification group. The eyes of the irrigation group received the identical treatment, but without the application of ultrasound energy. The control group was left untreated. All eyes were then prepared to split corneal buttons followed by 15 days of cultivation. Endothelial cell density (ECD) was assessed blinded on day 15.

RESULTS

Endothelial cell density declined significantly more until day 15 in the phacoemulsification group (2567 ± 317/267 cells/mm² (median ± 25%/75%-quartiles), -32.5 ± 7.0/6.4%) compared to the irrigation (3450 ± 350/383 cells/mm², -11.8 ± 5.3/2.6%; p < 0.001) and the control group (3650 ± 288/258 cells/mm², -10.2 ± 3.2/4.6%; p < 0.001).

CONCLUSION

The phacoemulsification damage model presented in this study is sensitive to phacoemulsification energy and may reliably be used to investigate various factors involved in phacoemulsification with regard to their influence on corneal endothelial cells. This method is able to replace animal experiments or in vitro cell culture experiments that often do not translate well to the in vivo situation in humans.

Effects of phacoemulsification with versus without viscoelastic devices on surgical outcomes

PURPOSE

The aim of this study is to report surgical outcomes in patients undergoing phacoemulsification surgery (PE) with versus without ophthalmic viscosurgical devices (OVDs).

METHODS

This is a comparative case series study. In total, 145 patients who performed PE with OVDs in 68 eyes (Group 1) and without OVD in 77 eyes (Group 2) were enrolled. A comprehensive ophthalmological examination was performed including slit-lamp, fundus examination. Best-corrected visual acuity (BCVA), intraocular pressure (IOP) specular endothelial microscopy (SM), and ultrasound pachymetry (UP) were also measured before surgery and at four-time points postoperatively. The differences in baseline characteristics as well as in outcomes were compared between the two groups.

RESULTS

The mean BCVA was 0.41 ± 0.26 logMAR in Group 1 and 0.54 ± 0.34 in Group 2 at postoperative first day, with a significant difference (p < 0.01). The mean BCVA, IOP, and UP at 6 months did not differ between the groups. The mean baseline and postoperative SMs were 2063 and 1910 cells/mm², respectively, and the endothelial cell loss (ECL) was 153.89 ± 189 in Group 1. The mean baseline and postoperative SMs were 2153 and 1948 cells/mm², respectively, and the ECL was 205 ± 200 in Group 2. The difference between the groups was not statistically significant (p = 0.105).

CONCLUSIONS

The ECL seemed to be higher in the Group 2, but the difference was not significant. The final clinical outcomes were similar between the groups. In selected cases, PE without OVD may be preferable to reduce the cost of surgery in places with low economic status and to prevent side-effects of these devices.