Real-time dynamic intraocular pressure fluctuations during microcoaxial phacoemulsification using different aspiration flow rates and their impact on early postoperative outcomes: a randomized clinical trial

Phacoemulsification using an active fluidics system at physiologic vs high intraocular pressure: impact on anterior and posterior segment physiology

PURPOSE

Evaluate the impact of high vs low intraoperative intraocular pressure (IOP) during phacoemulsification on anterior and posterior physiology.

SETTING

Private practice in Des Moines, Iowa.

DESIGN

Prospective, randomized, paired-eye clinical trial of patients anticipating bilateral cataract surgery.

METHODS

27 participants randomized at the time of their first cataract surgery to either low IOP or high IOP group. The subsequent cataract surgery was performed under the alternate condition. During phacoemulsification and cortex removal, IOP was maintained either at low (≤28 mm Hg) or at high (≥55 to 60 mm Hg) levels. The primary outcome was fluid usage, with secondary outcomes of central corneal thickness, foveal avascular zone area, foveal and macular thickness, endothelial cell density (ECD), and postoperative inflammation.

RESULTS

Surgery with low IOP settings used less fluid (40.0 mL vs 55.6 mL, P < .0001). Corneal thickness changes were smaller in low IOP eyes at 1 day and 1 week (3.0% vs 8.1%, P = .01; 3.1% vs 4.4%, P = .01) but were similar by 1 and 3 months. ECD dropped less in low IOP eyes at 1 and 3 months (-1.7% vs -12.3%, P = .001, 2.1% vs -8.9%, P = .0003.) IOP remained a significant predictor of ECD change when relationship was controlled for fluid use and phacoemulsification energy. Retinal parameters did not vary among all eyes or when compared by IOP setting. Visual acuity was similar at all timepoints.

CONCLUSIONS

Low IOP settings resulted in less inflammation and less corneal trauma, as evidenced by a smaller drop in ECD and less postoperative corneal edema, when compared with high IOP settings. Retinal parameters did not change significantly. The different outcomes did not result in a difference in visual acuity.

Intraoperative Performance and Early Postoperative Outcomes Following Phacoemulsification With Three Fluidic Systems: A Randomized Trial

PURPOSE

To compare intraoperative performance and early postoperative outcomes following phacoemulsification with two systems using active fluidics and one using gravity-based fluidics.

METHODS

In this prospective randomized trial, 200 eyes were randomized to the traditional and Active Sentry groups (n = 80 eyes each) where the Centurion Vision System was used with traditional or Active Sentry (Alcon Laboratories, Inc) hand-pieces, respectively, or the Infinit group (n = 40 eyes) where the Infiniti Vision System (Alcon Laboratories, Inc) was used. Within the traditional and Active Sentry groups, there were two subgroups with low (30 mm Hg) or high (55 mm Hg) intraocular pressure (IOP) used. Outcome measures compared were: cumulative dissipated energy (CDE), percentage change in central corneal thickness (CCT) at 1 day, 1 week, and 1 month, anterior chamber cells at 1 day and 1 week, rate of rise and fall of IOP following occlusion break, corneal endothelial cell density (ECD), and macular thickness 6 months postoperatively.

RESULTS

CDE was significantly lower in group II compared to the traditional group (2.96 ± 1.4 vs 4.14 ± 2.2, P = .001). With 30 mm Hg IOP, the Active Sentry group had significantly less percentage change in CCT at 1 week postoperatively compared to the traditional handpiece group (0.01% vs 0.02%, P = .008). Incidence of anterior chamber cells less than grade 2 on day 1 was significantly higher in the Active Sentry group (82.9% vs 52%, P = .03). Percentage change in ECD was significantly lower in the Active Sentry group (-0.957 vs -0.98%, P = .005). Significantly faster rise of IOP to baseline following occlusion break was seen in the Active Sentry group.

CONCLUSIONS

The use of Active Sentry handpiece was associated with lower CDE, less postoperative increase in CCT, fewer anterior chamber cells, and faster rise of IOP following occlusion break. [J Refract Surg. 2024;40(5):e304-e312.].

Visual Outcome and Complications in White Mature Cataracts after Phacoemulsification

PURPOSE

To identify risk factors and perioperative complications and assess postoperative visual outcome in patients of white mature cataracts undergoing phacoemulsification surgery.

METHODS

This cross-sectional study was conducted on 46 patients of white mature cataract undergoing phacoemulsification. Preoperatively, a detailed ocular examination was done, and anterior chamber depth (ACD) and lens thickness (LT) were measured on ultrasound biomicroscopy. Intraoperative and postoperative complications (on days 1, 7, and 30) and best-corrected visual acuity on postoperative day 30 were noted.

RESULTS

The mean age of patients was 60.78 ± 9.001 years. The study group consisted of 41.3% of males and 58.7% of females. 8 (19.56%) cases encountered complications during phacoemulsification surgery. The intraoperative complications were capsulorhexis-related in 5 (10.86%) patients, posterior capsular rent in 2 (4.3%) patients, and 1 (2.17%) case had zonular dialysis. There was no difference in mean ACD and LT in cases who developed complications and those who underwent uneventful surgery (P > 0.05). The commonly observed postoperative complications on day 1 were corneal edema (41.3%), anterior chamber flare (45.65%), and cells (39.13%) which resolved with routine topical medications. All patients showed a significant reduction in postoperative intraocular pressure (P < 0.001). A total of 37 (80.43%) eyes regained vision between 6/6 and 6/9 postoperatively (P < 0.001).

CONCLUSION

Phacoemulsification surgery is safe in white mature cataract that results in significant visual improvement. Common intraoperative complications are capsule related, while frequently encountered postoperative complications are corneal edema and anterior chamber reaction. Preoperative ACD and LT have no role in predicting intraoperative complications.

Effect of Conventional Cataract Surgery and Femtosecond Laser-Assisted Cataract Surgery on Bruch's Membrane Opening-Minimum Rim Width, Retinal Nerve Fiber Layer, and Macular Thickness

Purpose

To evaluate the effect of conventional cataract surgery (CCS) and femtosecond laser-assisted cataract surgery (FLACS) on Bruch's membrane opening-minimum rim width (BMO-MRW), peripapillary retinal nerve fiber layer thickness (RNFL), and macular thickness (MT) using spectral-domain optical coherence tomography (SD-OCT).

Methods

BMO-MRW, RNFL, and MT were measured using SD-OCT preoperatively, 1 month and 6 months after surgery in both CCS and FLACS groups. Differences between preoperative and postoperative values were evaluated in both groups. The postoperative changes were evaluated in each group and compared between groups.

Results

A total of 146 eyes of 146 patients were included in this study, 65 underwent CCS, and 81 underwent FLACS. One month after surgery, there was an increase (in microns) of 20.93 in BMO-MRW, 4.26 in RNFL, and 7.85 in MT in CCS group (P < 0.001), and 17.7, 3.73, and 5.65, respectively, in FLACS group (P < 0.001). Six months after surgery, there was an increase of 12.53 in BMO-MRW, 1.42 in RNFL, and 4.72 in MT in CCS group (P < 0.001), and 13.7, 1.88, and 4.14, respectively, in FLACS group (P < 0.001). The postoperative changes in CCS group were similar to those in FLACS group.

Conclusion

CCS as well as FLACS result in a slight increase in BMO-MRW, RNFL, and MT values one month and six months after surgery. Neither CCS nor FLACS lead to a deterioration in the parameters that define the structure of the optic nerve head and the macula. These results suggest that FLACS is as safe as CCS regarding the optic nerve head and the macula in normal eyes.

Effect of a new phacoemulsification and aspiration handpiece on anterior chamber stability

PURPOSE

To evaluate the responsiveness of 3 phacoemulsification and aspiration (PEA) systems and a new handpiece to occlusion break by measuring anterior chamber depth (ACD) and intraocular pressure (IOP).

SETTING

Zengyo Suzuki Eye Clinic, Kanagawa, Japan.

DESIGN

Experimental study.

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). 5 eyes were included per group. Occlusion breaks were triggered at IOP of 30 mm Hg, vacuum limits of 550 mm Hg, 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 to 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 seconds; 18.91 ± 4.70 vs 45.70 ± 0.83 μL). In these 2 groups, ACD change ratio correlated with surge volume.

CONCLUSIONS

This study evaluated the responsiveness of 3 PEA systems and a new handpiece to occlusion breaks by measuring IOP and ACD. The Active Sentry system was useful for maintaining the ACD even during occlusion breaks.

Torsional Power and Tip Shape Greatly Change Irrigation Flow Feeding Rate

BACKGROUND

It is important to maintain intraocular pressure during cataract surgery. When the intraocular pressure sharply drops during phacoemulsification, it is important to ensure a compensatory maximum fluid supply. To the best of our knowledge, this is the first study presenting the maximum irrigation flow supply using an ultrasonic tip shape and torsional power setting.

METHODS

The weight of BSS PLUS 500 ejected during torsional oscillation fitted with a mini-tip or balanced tip and nano sleeve with IOP set at 20 mmHg (IOP20) or 40 mmHg (IOP40) was measured. The weight of the BSS ejected from the sleeve over 3.0 s (15 measurements taken at 200-ms intervals) was measured to calculate the irrigation flow feeding rate. Measurements were made four times at each torsional power setting (TP).

RESULTS

With a balanced tip, the irrigation flow rate rose as TP was increased, whereas, at 60% or 90% TP, the irrigation flow rate markedly decreased. With the mini-tip, the irrigation flow rate remained relatively stable, up to 60% or 80% TP but decreased dramatically at higher power settings. Compared with IOP20, the irrigation flow rate increased by 1.21- to 1.28-fold with the balanced tip and by 1.28- to 1.41-fold with the mini-tip at IOP40. At IOP20, the irrigation flow rate was higher with the mini-tip at 0% and 5% TP but equal to or higher with the balanced tip at TP of ≥10%. At IOP40, the irrigation flow rate with the mini-tip was equal to or higher than that with the balanced tip at all TP.

CONCLUSIONS

The irrigation flow rate tends to vary with changes in TP and tip shape.

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.

Real-time dynamic changes in intraocular pressure after occlusion break: comparing 2 phacoemulsification systems

PURPOSE

To compare real-time intraocular pressure (IOP) response to occlusion break event in 2 phacoemulsification systems.

SETTING

Iladevi Cataract and IOL Research Center, India.

DESIGN

Randomized, experimental study.

METHODS

Rabbits were randomized to:Group I (n = 10 eyes), Centurion Vision system with active fluidics, or, Group II (n = 10 eyes), Centurion with Active Sentry. Within each group, parameter set 1 (IOP 30 mm Hg, aspiration flow rate [AFR] 20 mL/min, and vacuum 600 mm Hg) and parameter set 2 (IOP 50 mm Hg, AFR 25 mL/min, and vacuum 600 mm Hg) were tested. Real-time rate of drop and rise of IOP after occlusion break event (mm Hg per second) and percentage reduction of IOP from maximum during nuclear fragment removal were compared.

RESULTS

10 rabbits (20 eyes) were included. Rate of drop of IOP after occlusion break was not significantly different between groups. Rate of rise of IOP was statistically significantly higher in Group II with both parameter sets (199.09 ± 69.28 vs 94.33 ± 45.66 in parameter set 1, P = .006; and 256 ± 45.05 vs 165.25 ± 51.80 in parameter set 2, P = .005), suggesting faster recovery to baseline IOP after occlusion break. The mean percentage reduction of IOP from maximum was significantly higher in Group I (P = .003).

CONCLUSIONS

Rise of IOP to baseline after occlusion break event was faster and mean percentage reduction of IOP from maximum during nuclear fragment removal was lower when using the Centurion Vision system with the Active Sentry upgrade compared with the traditional handpiece. The ability to sense IOP at the level of the handpiece with the Active Sentry upgrade allows faster mitigation of surge response.

Active sentry versus ozil hand piece - A prospective randomized comparative study

PURPOSE

To compare the safety and efficacy of active sentry hand piece with ozil hand piece for centurion phacoemulsification system.

SETTING

Tertiary eye centre, South India.

DESIGN

Prospective observational study.

METHODS

A total of 204 eyes of 204 patients with uncomplicated cataract who underwent phacoemulsification cataract surgery with centurion vision system were randomized into two groups: Ozil hand piece (n=101) and active sentry hand piece (n =103). Intra-operative factors like patient's pain perception, surgeon's comfort level, amount of phacoemulsification energy and aspiration fluid used, frequency of activation of active surge mitigation (ASM) were analyzed and post-operatively corrected distance visual acuity (CDVA) and corneal edema on day one were compared.

RESULTS

Patient's pain perception was comparable between the groups with no significant differences in proportion of patients who had pain free surgery (66% vs 61.3%) or those experienced moderate pain (24.3% vs 28.7%). Surgeons were more comfortable using ozil hand piece during entry into anterior chamber and emulsification of hard nuclei (48.5% vs 28.6%). The mean CDE for soft cataracts was 5.6 and 4.8 and for hard cataracts it was 9.3 and 9.4 for ozil and active sentry group respectively. ASM was activated for 53 (51.5%) eyes, of which 42 (79.2%) eyes had soft cataract and 11 (20.7%) had hard cataract. Post-operative CDVA and incidence of corneal edema was comparable between the groups.

CONCLUSION

For centurion vision system, active sentry hand piece is safe and efficacious as the ozil hand piece with added benefit of operating at lower IOP levels.

Injection time related to intraocular pressure using a CO2 driven preloaded injector: An experimental laboratory study

PURPOSE

Experimental study to measure the intraocular lens (IOL) injection time and injection speed at different intraocular pressure (IOP) settings when using the AutonoMe® injector.

METHODS

In this experimental study, following phacoemulsification in porcine cadaver eyes, a trocar was inserted at pars plana with a connected infusion and IOPs of 20, 50 and 80 mmHg were generated by altering the infusion height. Twelve CO2 gas-driven injectors were used to implant an IOL via a corneal incision of 2.2 mm. For each IOP setting, the duration of the IOL injection and the injection speed was measured by analyzing a video recording of the procedure.

RESULTS

The mean ±SD injection time (seconds) was 4.47±0.50 at 20 mmHg, 4.98±0.55 at 50 mmHg and 5.47±0.20 at 80 mmHg. The mean ±SD injection speed (millimeters per seconds) was 1.36±0.15 at 20 mmHg, 1.22±0.14 at 50 mmHg and 1.10±0.04 at 80 mmHg. There was a significant (p<0.05) difference between the 20 and 80 mmHg groups in mean injection duration and injection speed.

CONCLUSION

The CO2 gas driven injector allows a safe IOL injection even at elevated IOP. Although the implantation time is slightly extended at higher IOPs, this does not seem to be clinically relevant. No IOL damage was observed at these pressure settings.

Cataract Surgery (Phacoemulsification with Intraocular Lens Implantation) Combined with Endoscopic Goniosynechialysis for Advanced Primary Angle-Closure Glaucoma

PURPOSE

To evaluate the efficacy and risk of cataract surgery (phacoemulsification with intraocular lens [IOL] implantation) combined with endoscopic goniosynechialysis (EGSL) for advanced primary angle-closure glaucoma (PACG).

DESIGN

Retrospective, continuous case series.

PARTICIPANTS

A total of 16 patients (18 eyes) with advanced PACG were enrolled in this study between February 2014 and March 2016. Advanced glaucoma inclusion criteria were based on the method proposed in the Advanced Glaucoma Intervention Study, with a visual field score of 18 points or more.

METHODS

All patients underwent cataract surgery with EGSL by the same experienced surgeon. Paired t test and generalized estimating equation analyses were performed.

MAIN OUTCOME MEASURES

The extent of peripheral anterior synechiae (PAS), number of intraocular pressure (IOP)-lowering drugs, IOP, best-corrected visual acuity (BCVA), and visual fields before and after surgery. The incidence of complications was recorded.

RESULTS

The mean follow-up duration was 13.8 months (standard deviation, 2.7 months). The mean difference (preoperative minus postoperative) in PAS was 202.7° (95% confidence interval [CI], 43.5°). The mean difference (preoperative minus postoperative) in the number of IOP-lowering drugs and IOP was 2.0 (95% CI, ±0.5), and 9.4 mmHg (95% CI, ±2.1 mmHg) respectively. The mean improvement in BCVA was 0.29 logMAR (95% CI, ±0.14). A positive correlation was found between the extent of postoperative PAS and postoperative IOP (B = 8.2; P < 0.001) and also between postoperative PAS and postoperative number of IOP-lowering drugs (B = 28.9; P < 0.001). Anterior chamber hemorrhage and exudation occurred in 4 patients and 2 patients, respectively, after surgery. Posterior capsular opacification occurred in 5 patients after surgery.

CONCLUSIONS

Cataract surgery with EGSL could be an effective surgical method for the treatment of advanced PACG.

Elevated intraocular pressure causes cellular and molecular retinal injuries, advocating a more moderate intraocular pressure setting during phacoemulsification surgery

PURPOSE

To evaluate the cellular and molecular retinal injuries induced by various intraocular pressure (IOP) settings in a mouse model of acute ocular hypertension (AOH), and to advise using a more moderate target IOP during phacoemulsification (phaco) surgery.

METHODS

A mouse model of AOH that mimics a transient IOP elevation during phacoemulsification cataract surgery was established. Six groups with various settings of target IOP were included. Retinal tissues were assessed with terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end-labeling (TUNEL) staining for neuron loss, immunofluorescence with Iba1 for microglia activation, and quantitative real-time polymerase chain reaction analysis with tight junction proteins (claudin-3 and claudin-5) or classic inflammation markers (IL-1β and eNOS) for impairment of the blood-retinal barrier (BRB) and inflammatory injury.

RESULTS

Compared with those in the 45-mmHg IOP group, significantly increased number of neurons loss and increased microglia activation were observed in 90-mmHg IOP group. In addition, the expression of claudin-3 and claudin-5 was significantly decreased, while the expression of IL1-β and eNOS was up-regulated, indicating impairment of the BRB and inflammatory injury in the retina. Furthermore, these findings of neuron loss, microglia activation, and inflammation in the 90-mmHg groups were exacerbated when an IOP-induced retinal injury was established 5 days earlier, while those in the 45-mmHg groups remained almost unchanged.

CONCLUSIONS

In conclusion, these results showed that a relatively commonly used high IOP setting (90 mmHg) could induce significantly more serious retinal injury. An IOP setting around 45 mmHg is relatively safe and might be recommended in phaco surgery, especially in patients with advanced glaucoma, previous acute angle closure crisis, or other diseases with fragile retina and optic nerve.

Effect of high-vacuum setting on phacoemulsification efficiency

PURPOSE

To evaluate the effect of a high-vacuum setting versus a low-vacuum setting on the efficiency of phacoemulsification.

SETTING

Sunderland Eye Infirmary, Sunderland, United Kingdom.

DESIGN

Prospective clinical trial.

METHODS

Consecutive patients having cataract surgery in 2014 were recruited. Cataract surgery was performed by 2 experienced surgeons using a phacoemulsification machine with monitored forced infusion. The cataractous lens was split into 2 heminuclei using the stop-and-chop technique; in 1 heminucleus, phacoemulsification and aspiration used a high-vacuum setting (600 mm Hg; treatment group) and in the other heminucleus, a low-vacuum setting (350 mm Hg; control group). The high and low settings were alternated by case per the operating list to reduce surgeon bias. The main outcome measures were cumulative dissipated energy (CDE) and active heminucleus removal time.

RESULTS

One hundred sixty patients (160 eyes) were enrolled in the study, and 158 were included in the analysis. The CDE per heminucleus was significantly lower with the high-vacuum setting than with the low-vacuum setting (mean 2.81 percent-seconds; 95% confidence interval (CI), 2.44-3.21 versus 3.81 percent-seconds; 95% CI, 3.38-4.20; P < .001). The active heminucleus removal time was significantly shorter in the high-vacuum group than the low-vacuum group (mean 27.77 seconds; 95% CI, 25.26-30.19 versus 33.59 seconds; 95% CI, 31.07-35.92; P < .001). The observed differences were independent of the surgeon, patient age and sex, incision size, and nucleus density. No intraoperative complications were observed in either group.

CONCLUSION

A high-vacuum setting improved phacoemulsification efficiency using an active fluidics system and torsional phacoemulsification.

Impact of fluidic parameters during phacoemulsification on the anterior vitreous face behavior: Experimental study

Purpose

To evaluate the eff ect of different aspiration flow rates (AFR) and bottle heights (BH) on vitreous face (AVF) during phacoemulsifi cation.

Methods

Experimental study in 20 porcine eyes. Transzonular viscodissection was performed between the posterior capsule(PC) and AVF to dissect out the Berger's space. Triamcinolone acetonide was injected into this space to aid visualization with ultrasound B-Scan(USG). Realtime USG was performed during phacoemulsifi cation. Eyes were divided randomly into-Group I: Low parameters(AFR = 20 cc/min, BH = 90 cm, vacuum = 400 mmHg),and Group II: High parameters (AFR = 40 cc/min, BH = 110 cm, vacuum=650 mm Hg).

Results

15 eyes were analysed (8 in Group I; 7 in Group II). In all eyes, forward and backward movement of the PC was seen when going from foot position 0 to 1, or on occlusion break. Amplitude of these movements was much greater in Group II compared to Group I. There was no PC rupture in either group. In 2 of the 7 eyes in Group II, USG showed a sudden, spontaneous dispersion appearance of sono-opaque echoes in the vitreous cavity alongwith disappearance of the well-defi ned, crescentic stained space despite an intact PC. This suggests rupture of the AVF, leading to dispersion of the triamcinolone into the entire vitreous cavity. No AVF rupture was seen in Group I.

Conclusion

We report a rarely described entity of AVF rupture with intact PC. The use of high AFR and BH may have clinically invisible detrimental consequences to the anterior vitreous face.

Effect of femtosecond laser-assisted lens surgery on the optic nerve head and the macula

AIM

To evaluate the effect of femtosecond laser-assisted lens surgery (FLALS; cataract surgery or refractive lens exchange) on the structure of the optic nerve head and the macula.

METHODS

This prospective longitudinal study included healthy eyes undergoing FLALS. Eyes with glaucoma or any other ocular disease that could alter optical coherence tomography results were excluded. Retinal nerve fiber layer (RNFL), Bruch's membrane opening-minimum rim width (BMO-MRW) and macular thickness (MT) were measured preoperatively, 1 and 6mo after surgery using spectral-domain optical coherence tomography (SD-OCT). Changes between preoperative and postoperative values were evaluated.

RESULTS

A total of 87 eyes of 46 patients were included in this study. Preoperative RNFL, BMO-MRW and MT in microns (µm) were 100.77±10.39, 330.31±49.99 and 276.30±33.39, respectively. Postoperative RNFL, BMO-MRW and MT were 104.74±11.55, 348.32±54.05 and 279.83±22.65 1mo after surgery and 102.93±11.17, 343.11±53.4 and 278.90±22.19 6mo after surgery, respectively; which equals an increase of 3.93%, 5.45% and 1.27%, respectively, 1mo after surgery, and 2.14%, 3.87% and 0.94% 6mo after surgery. The differences between the preoperative and the postoperative RNFL and BMO-MRW values were statistically significant (P<0.001). Regarding MT values, there were not statistically significant differences (P=0.26).

CONCLUSION

Our study suggests that FLALS does not have a negative impact on the structural status of the optic nerve head in healthy eyes, assessed by SD-OCT. There is a slight increase in the values of RNFL, BMO-MRW and MT 1mo and 6mo after surgery.

Phacoemulsification of the rock-hard dense nuclear cataract: Options and recommendations

We describe the essential steps in the successful phacoemulsification of the rock-hard, dense cataract. Appropriate and directed preoperative history, physical examination, and diagnostics allow the surgeon to select the best incision, anesthesia, and intended surgical technique for a given dense nuclear challenge. Hard nucleus-specific approaches for hydrodissection, pupil management, and zonular protection then allow the surgeon to approach the rock-hard nucleus with maximum safety. Dense nuclear dismantling options are then discussed in detail along with fluidic and power modulation considerations. Various specific phacoemusification machine settings for rock-hard cataracts from the authors representing several different phaco systems are then presented. The combination of these steps and considerations allow a more successful dense cataract removal and potential restoration of vision for patients. This paper represents the collective experience and advice of the Challenging and Complex Cataract Surgery Subcommittee.

Air pressure changes in the creation and bursting of the type-1 big bubble in deep anterior lamellar keratoplasty: an ex vivo study

PurposeTo measure the pressure and volume of air required to create a big bubble (BB) in simulated deep anterior lamellar keratoplasty (DALK) in donor eyes and ascertain the bursting pressure of the BB.Patients and methodsTwenty-two human sclera-corneal discs were used. Air was injected into the corneal stroma to create a BB and the pressure measured by means of a pressure converter attached to the system via a side port. A special clamp was designed to prevent air leak from the periphery of the discs. The pressure at which air emerged in the corneal tissue; the bursting pressure measured after advancing the needle into the bubble cavity and injecting more air; the volume of air required to create a BB and the volume of the BB were ascertained.ResultsType-1 BB were achieved in 19 and type-2 BB in 3 eyes. The maximum pressure reached to create a BB was 96.25+/- 21.61 kpa; the mean type-1 intrabubble pressure was 10.16 +/- 3.65 kpa. The mean bursting pressure of a type-1 BB was 66.65 +/- 18.65 kpa, while that of a type-2 BB was 14.77 +/- 2.44 kpa. The volume of air required to create a type-1 BB was 0.54 ml and the volume of a type-1 BB was consistently 0.1 ml.ConclusionsDua's layer baring DALK can withstand high intraoperative pressures compared to Descemet's membrane baring DALK. The study suggests that it could be safe to undertake procedures such as DALK-triple with a type-1 BB but not with a type-2 BB.

Effect of chamber stabilization software on efficiency and chatter in a porcine lens model

PURPOSE

To evaluate the effects of the use of programmable chamber stabilization software (Chamber Stabilization Environment) settings on efficiency and chatter in a porcine lens model.

SETTING

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

DESIGN

Experimental study.

METHODS

Porcine eyes were dissected and the lenses extracted. The lenses were then hardened and processed for the experiment. Phacoemulsification of the lens fragments was performed with the Whitestar Signature Pro with the Whitestar handpiece and a 0.9 mm straight Dewey tip with a 30-degree bevel. All arms of the study were run in peristaltic mode with 50 mL/minute aspiration, 100 cm bottle height, and on 100% power. The chamber stabilization software setting was used for each of the 4 study arms with a maximum vacuum of 500 mm Hg. Arm 1 included 20 runs with the up time set to 2000 milliseconds. Arm 2 was performed with similar settings but with an up time of 0 millisecond. Arms 3 and 4 were run with up times of 1000 milliseconds and 500 milliseconds, respectively.

RESULTS

The mean efficiency time of each run was as follows: 0 millisecond = 1.4 seconds, 500 milliseconds = 0.95 seconds, 1000 milliseconds = 0.88 seconds, 2000 milliseconds = 0.93 seconds. When compared with 0 millisecond, each of the other arms were significantly faster. Chatter events were comparable between the study arms.

CONCLUSION

The chamber stabilization software does not decrease efficiency when compared with full vacuum on if at least 500 milliseconds of up time is maintained.

Publication rates from the All India Ophthalmic Conference 2010 compared to 2000: Are we improving?

PURPOSE

To determine the publication rates of free papers and posters presented at the All India Ophthalmic Conference (AIOC) 2010 in peer-reviewed journals up to December 2015 and compare this with publication rates from AIOC2000 published previously.

METHODS

A thorough literature search was conducted using PubMed, Google Scholar, and the general Google search engine by two independent investigators. The title of the paper, keywords and author names were used to "match" the AIOC free-paper with the published paper. In addition, the "purpose," "methods," and "outcome measures" between the two were studied to determine the "match."

RESULTS

A total of 58 out of 394 free-papers (14.7%) from AIOC2010 were published till December 2015 compared to 16.5% from AIOC2000. Out of these, 52 (90%) were published in PubMed indexed journals. Maximum publications were seen in pediatric ophthalmology (50%) followed by glaucoma (24.4%) and cornea (23.8%). Fifteen out of 272 posters (5.5%) were published; orbit/oculoplastics had the highest poster publications (13%). Excluding papers in nonindexed journals and those by authors with international affiliations, the publication rate was approximately 12%.

CONCLUSION

The publication rate of free papers from AIOC2010 has marginally reduced compared to AIOC2000. Various causes for this such as lack of adequate training, motivation, and lack of incentives for research in the Indian scenario have been explored, and measures to improve this paradigm have been discussed. It will be prudent to repeat this exercise every decade to compare publication rates between periodic AIOC, stimulate young minds for quality research and educate policy makers toward the need for developing dedicated research departments across the country.

Vascular Occlusions following Ocular Surgical Procedures: A Clinical Observation of Vascular Complications after Ocular Surgery

Background

Ocular vascular occlusions following intraocular procedures are a rare complication. We report a case series of patients with retinal vascular occlusions or anterior ischemic optic neuropathy (AION) after anterior and posterior segment surgery and demonstrate possible risk factors.

Methods

Observational case series.

Results

In ten patients, vascular occlusions were observed within ten weeks after intraocular surgery: branch retinal arterial occlusion (BRAO) (n = 2), central retinal artery occlusion (CRAO) (n = 2), central retinal vein occlusion (CRVO) (n = 1), branch retinal vein occlusion (BRVO) (n = 1), anterior ischemic optic neuropathy (AION) (n = 3), and combined central artery and vein occlusion (n = 1). AION occurred later (27–69 d) than arterial occlusions (14–60 d) or venous occlusions (1-2 d). In all cases, either specific surgical manipulations or general vascular disorders were identified as risk factors. In addition to general cardiovascular risk factors (arterial hypertension n = 6, diabetes mellitus n = 4), internal workup disclosed bilateral stenosis of the carotid arteries (n = 1) and myeloproliferative syndrome (n = 1).

Conclusion

Vascular occlusions after surgical ocular procedures seem to be more frequent when cardiovascular diseases coexist. Surgical maneuvers and intra- or postoperative pressure changes may act as a triggering mechanism in patients with underlying systemic cardiovascular disorders. Affected patients should undergo thorough internal examination to identify possible underlying diseases.

Experimental anterior chamber maintenance in active versus passive phacoemulsification fluidics systems

PURPOSE

To evaluate the ability of phacoemulsifiers with active versus passive infusion fluidics control systems to maintain target intraocular pressures (IOPs) under varying flow conditions.

SETTING

Alcon Research, Ltd., Lake Forest, California, USA.

DESIGN

Experimental study.

METHODS

An acrylic test chamber was used to model the anterior chamber of the eye. Two passive (gravity-based) systems were tested using bottle heights yielding infusion pressures of 41, 75, and 109 cm of water under zero-flow conditions. One actively controlled system was tested using equivalent target IOPs of 30, 55, and 80 mm Hg. Test chamber IOPs were measured at aspiration flow rates of 15, 30, 45, and 60 cc/min.

RESULTS

The measured flow rates were similar between fluidics systems across the range of intended aspiration flow rates. All systems achieved the desired target IOPs under zero-flow conditions. After activation of aspiration flow, however, measured IOPs decreased from target IOPs for the 2 passive systems. Each 15 cc/min increase in the aspiration flow rate produced a pressure drop of 14.0 to 16.2 mm Hg or 9.3 to 14.2 mm Hg, depending on the system. Measured IOPs in the actively controlled system closely matched the targeted IOPs across all tested aspiration flow rates, deviating from targets by no more than 4.3 mm Hg.

CONCLUSIONS

All phacoemulsification aspiration infusion fluidics systems achieved target IOPs under zero-flow conditions. Only the actively controlled system maintained target IOPs across a range of aspiration flow rates. These experimental findings suggest that anterior chamber stability might be better in the clinical setting using an actively controlled system.

FINANCIAL DISCLOSURE

Dr. Dimalanta is an employee of Alcon Research, Ltd. Dr. Miller is an investigator and speaker for and a consultant to Alcon Laboratories, Inc. Dr. Nicoli has no financial or proprietary interest in any material or method mentioned.

Electroretinographic evaluations of retinal function before, just after, and after intravitreal injections

Intravitreal injections (IVI) have become a part of daily practice for a growing number of procedures. We evaluated the retinal function by recording intraoperative photopic electroretinograms (ERGs) before an injection (T1), just after the injection (T2), and after the aspiration of the anterior chamber fluid (T3) of 19 eyes of 19 patients (mean age 70.6 years; men = 11) who received an IVI of an anti-vascular endothelial growth factor. The mean amplitudes of the b-wave, photopic negative responses (PhNR), and oscillatory potentials (OPs) 1 and 2 at T2 were significantly smaller than that at T1, but no significant difference was observed between T3 and T1. The mean implicit times of the a-wave and OP1, 2, and 3 at T2 and the a-wave and the OP2 at T3 were significantly longer than that at T1. The mean intraocular pressure (IOP) at T2 (49.32 mm Hg) was significantly higher and the IOP at T3 (8.74 mm Hg) was significantly lower than that at T1 (21.05 mm Hg). The retinal function was reduced and the IOP elevated just after the IVI. The response of each ERG component was different suggesting a different sensitivity of each type of retinal neuron to IVI.

Comparison of intra-ocular pressure changes with liquid or flat applanation interfaces in a femtosecond laser platform

Cataract surgery is the most common surgical procedure and femtosecond laser assisted cataract surgery (FLACS) has gained increased popularity. FLACS requires the application of a suction device to stabilize the laser head and focus the laser beam accurately. This may cause a significant escalation in intra-ocular pressure (IOP), which poses potential risks for patients undergoing cataract surgery. In this study we aimed to assess the effect of the Ziemer LDV Z8 femtosecond cataract machine on IOP. We demonstrated through a porcine model that IOP was significantly higher with a flat interface but could be abrogated by reducing surgical compression and vacuum. Pressure was lower with a liquid interface, and further altering angulation of the laser arm could reduce the IOP to 36 mmHg. A pilot series in patients showed comparable pressure rises with the porcine model (30 mmHg). These strategies may improve the safety profile in patients vulnerable to high pressure when employing FLACS with the Ziemer LDV Z8.