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

Intraocular pressure before and after capsulorhexis using two viscoelastic substances and two surgical approaches in enucleated porcine eyes

AIM

To investigate the influence of ophthalmic viscoelastic devices (OVDs) and different surgical approaches on the intraocular pressure (IOP) before and after creation of the curvilinear circular capsulorhexis (CCC) as a measure for anterior chamber stability during this maneuver.

METHODS

Prospective experimental WetLab study carried out on enucleated porcine eyes. IOP was measured before and after CCC with the iCare Rebound tonometer (iCare ic200; iCare Finland Oy, Vantaa, Finland). The OVDs used were a cohesive one [Z-Hyalin, Carl Zeiss Meditec AG, Germany; hyaluronic acid (HA)] and a dispersive [Z-Celcoat, Carl Zeiss Meditec AG, Germany; hydroxy propylmethylcellulosis (HPMC)]. The CCC was created using Utrata forceps or 23 g microforceps in different combinations with the OVDs.

RESULTS

Using the Utrata forceps the IOP dropped from 63.65±6.44 to 11.25±3.63 mm Hg during the CCC. The use of different OVDs made no difference. Using the 23 g microforceps the IOP dropped from 65.35±8.15 to 36.55±6.09 mm Hg. The difference between IOP drop using either Utrata forceps or 23 g microforceps was highly significant regardless of the OVD used.

CONCLUSION

Using the sideport for the creation of the capsulorhexis leads to a lesser drop in IOP during this maneuver compared to the main incision in enucleated porcine eyes. The use of different OVD has no significant influence on IOP drop.

Cumulative Dissipated Energy (CDE) in Three Phaco-Fragmentation Techniques for Dense Cataract Removal

Purpose

To determine the energy expenditure in phacoemulsification surgery expressed as cumulative dissipated energy (CDE) among the divide and conquer, ultrachopper-assisted divide and conquer, and phaco-chop techniques for dense cataract removal.

Patients and Methods

The clinical data were obtained from the medical charts of dense cataracts patients undergoing routine phacoemulsification employing any of three phaco-fragmentation techniques, including divide and conquer using the Kelman 0.9 mm tip, the ultrachopper tip, and the phaco-chop technique using the Kelman 0.9 mm tip. Cumulated dissipated energy (CDE), longitudinal ultrasound time (UST), and endothelial cell loss were compared among groups at the one-month postoperative.

Results

Surgeries from 90 eyes were analyzed, among whom the conventional divide-and-conquer technique group included 30 patients, 32 in the ultrachopper group, and 28 in the phaco-chop technique group. The average CDE in the conventional divide and conquer group was 44.52 ± 23.00, the ultrachopper technique was 43.27 ± 23.18, and 20.11 ± 11.06 in the phaco-chop group. Phaco-fragmentation chop demonstrated significantly lower CDE than the other techniques (p= <0.0001). The phaco-chop technique showed statistically significantly lower CDE when compared to the other two groups (p=<0.0001) with 93.96 ± 39.71 seconds. There were no statistically significant differences in postoperative endothelial cell density between groups (p=0.4916).

Conclusion

The use of the phaco-chop technique in hard cataract phacoemulsification represents a lower energy expenditure than divide and conquer and ultrachopper techniques; nevertheless, no differences regarding endothelial density loss were evidenced.

Comparative evaluation of the results of phacoemulsification using domestic and foreign viscoelastics

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

Comparative anatomical outcomes of high-flow vs. low-flow phacoemulsification cataract surgery: A systematic review and meta-analysis

Background

Phacoemulsification is an effective and widely performed technique in cataract surgery, but the comparative anatomical outcomes, including endothelial cell loss (ECL), central corneal thickness (CCT), and central macular thickness (CMT), between high-flow and low-flow phacoemulsification cataract surgery remain unclear.

Methods

This study followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. Random-effects models were applied to measure pooled mean differences (MD) with 95% confidence intervals (CI) of anatomical outcomes between high-flow and low-flow phacoemulsification cataract surgery. We judged overall certainty of evidence (CoE) based on Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria.

Results

We included six randomized controlled trials (RCTs) totaling 477 participants. The meta-analysis showed similar changes associated with these two surgery types in both ECL at postoperative days 2–14 (MD: −1.63%; 95% CI: −3.73 to 0.47%; CoE: very low), days 15–42 (MD: −0.65%; 95% CI −2.96 to 1.65%; CoE: very low) and day 43 to month 18 (MD: −0.35%; 95% CI: −1.48 to 0.78%; CoE: very low), and CCT at postoperative day 1 (MD: −16.37 μm; 95% CI: −56.91 to 24.17 μm; CoE: very low), days 2–14 (MD: −10.92 μm; 95% CI: −30.00 to 8.16 μm; CoE: very low) and days 15–42 (MD: −2.76 μm; 95% CI: −5.75 to 0.24 μm; CoE: low). By contrast, low-flow phacoemulsification showed less increase in CMT at postoperative days 15–42 (MD, −4.58 μm; 95% CI: −6.3 to −2.86 μm; CoE: low).

Conclusions

We found similar anatomical outcomes, except in CMT, for both high-flow and low-flow phacoemulsification cataract surgery. Future head-to-head RCTs on visual outcomes should confirm our findings.

Systematic review registration

PROSPERO, identifier: CRD42022297036.