Purpose: To evaluate the responsiveness of three phacoemulsification and aspiration (PEA) systems and a new handpiece to occlusion break by measuring anterior chamber depth (ACD) and intraocular pressure (IOP). Methods: ACD change during intentional occlusion breaks was observed and evaluated using the slit side view (SSV) method and IOP measurement with the Centurion^® Vision System (group 1), Centurion^® Vision System with Active Sentry^® (group 2), Infiniti^® Vision System (group 3), and Constellation^® Vision System (group 4). Fives eyes were included per group. Occlusion breaks were triggered at IOP of 30 mmHg, vacuum limits of 550 mmHg, and aspiration rate of 40 mL/min. ACD change ratio, surge duration, and surge volume were analyzed from videos of SSV and IOP measurement. Results: The smallest ACD change was observed in group 2 with SSV. ACD change ratios in groups 1–4 were 17.5 ± 3.9%, 7.3 ± 1.2%, 35.7 ± 9.5%, and 74.1 ± 7.7%, respectively. Surge duration and surge volume were calculated only for groups 1 and 2 and were significantly lower in group 2 than in group 1 (0.32 ± 0.03 vs 1.17 ± 0.07 s; 18.91 ± 4.70 vs 45.70 ± 0.83 µL). In these two groups, ACD change ratio correlated with surge volume. Conclusion: This study evaluated the responsiveness of three PEA systems and a new handpiece to occlusion breaks by measuring IOP and ACD. The Active Sentry system was useful for maintaining ACD even during occlusion breaks.

Purpose: To investigate temperature alterations in the aqueous humor and the corneal endothelium during phacoemulsification, and to evaluate the effect of ophthalmic viscosurgical devices in preventing a temperature rise at the corneal endothelium during phacoemulsification. Methods: Temperatures of the aqueous humor and corneal endothelium were measured using two temperature probes set in the anterior chamber during ultrasound oscillation in porcine eyes, with or without ophthalmic viscosurgical devices. Results: Without an ophthalmic viscosurgical device, temperatures in both the aqueous humor and the corneal endothelium rapidly rose during the ultrasound oscillation, while with an ophthalmic viscosurgical device, the temperature elevation of the corneal endothelium site was suppressed compared with the aqueous humor. Conclusion: Surgeons need to be especially aware of ophthalmic viscosurgical device retention during phacoemulsification, because it can protect the corneal endothelium from heat generated during this procedure.

To evaluate changes in the aqueous humor temperature using 2 phacoemulsification units (Stellaris 28.5 kHz device and Whitestar Signature 40 kHz device). Nippon Medical School, Musashikosugi Hospital, Kawasaki City, Kanagawa, Japan. Experimental study. Aqueous humor temperatures were measured with a temperature probe set in the anterior chamber during ultrasound (US) oscillation in porcine eyes under 5 conditions. Continuous longitudinal oscillation caused a rapid rise in aqueous humor temperature, while the pulse and elliptical modes suppressed temperature elevation. Reducing the number of US tip vibrations did not reduce the temperature in the anterior chamber. However, raising the vacuum setting allowed the aspirations to rise to the set value, thereby lowering the temperature in the anterior chamber. Because differences in the phacoemulsification settings can lead to temperature elevations in the anterior chamber, surgeons must carefully monitor these settings to prevent corneal tissue damage.

Due to recent technical advances in cataract surgeries, there has been a significant improvement in the safety and surgical outcomes of phacoemulsification. However, the corneal endothelium can be damaged during phacoemulsification by multiple factors. Therefore, we used a slit lamp to analyze the fluid dynamics of ophthalmic viscosurgical devices (OVDs) in the anterior chamber during phacoemulsification. In this experimental study, extracted porcine eyes were injected with OVDs stained with fluorescein through a side port of the eye and then fixed on a slit lamp microscope. After inserting a phaco tip, phacoemulsification simulation was then performed on the iris plane. Subsequent movements of OVDs in the anterior chamber were observed during the procedure by using a slit lamp microscope. Aspiration and removal of cohesive OVDs from the inside of the anterior chamber occurred within a few seconds after the ultrasonic vibration. Aspiration of dispersive OVDs occurred gradually, with some of the OVDs remaining on the side of the anterior chamber side in an irregular shape. This shape enabled the OVD to trap the air, thereby preventing the air from directly touching the corneal endothelium. Viscoadaptive OVDs remained inside the anterior chamber as a lump, with the infusion solution flowing between the corneal endothelium and the OVD, thus leading to the eventual aspiration of the OVD. Viscous dispersive OVDs remained as a lump between the corneal endothelium and the phaco tip. However, once the infusion solution flowed between the cornea and the OVD, the OVD detached from the corneal endothelium, indicating that this type would likely be aspirated and removed. This method, termed the “slit side view,” enables viewing of the movement of OVDs during surgery, as well as observation of the fluid dynamics in the anterior chamber.

Purpose: To evaluate usefulness of a new semicircular capsulotomy marker in continuous curvilinear capsulorrhexis (CCC). Methods: In 20 eyes of 20 patients who underwent cataract surgery, a newly designed semicircular marker with an internal diameter of 5.5 mm was used to place a circular mark directly on the lens capsule. The mark was then used as a guide to complete CCC of the set diameter. The resultant size of CCC in each case was confirmed by analysis of the video image. Results: The average CCC diameter size was 5.2 ± 0.3 mm. In all cases, the edge of the intraocular lens was completely covered by the anterior capsule. Conclusion: The semicircular capsulotomy diameter marker was useful in making a complete CCC of a set diameter.

Capsular stabilization devices were evaluated in a zonular fiber defect model using the slit side view (SSV) system to confirm their utility for capsular stabilization during phacoemulsification. A zonular fiber defect model was made by cutting Zinn’s zonule under observation with a slit lamp microscope in a porcine eye. Phacoemulsification was performed, and the movement of the lens capsule and the depth of the anterior chamber were observed using the SSV in three groups: control group: no surgical instruments used, CE group: a capsule expander was inserted, and CTR group: a capsular tension ring was inserted. In the control group, the equator of the lens was unstable and was easily suctioned to the port of the ultrasound handpiece. The lens capsule was stable in both in the CE and CTR groups. In the CTR group, the equator responsible for the zonular rupture also returned and closed true to its original position. The utility of the capsular stabilization devices in this zonular fiber defect model was confirmed with the SSV system.