Torsional power study using CENTURION phacoemulsification technology.

BACKGROUND: To evaluate the effect of varying levels of power on phacoemulsification efficiency using the CENTURION Vision System. METHODS: Formalin-soaked porcine lenses were divided into 2-mm cubes; 0.9-mm, balanced tips were used. Torsional power levels were tested from 10% to 100% at 10% intervals. Vacuum was set to 550 mmHg, aspiration to 50 ml/min, and intraocular pressure at 50 mmHg. Efficiency (time to lens removal) and chatter (number of lens fragment repulsions from the tip) were determined. RESULTS: Increasing torsional power up to 60% increased efficiency. This effect was linear from 30 to 60% power (R2 = .90; P < 0.05). There were no significant differences in efficiency past 60%. Chatter was highest at 10% power and decreased linearly (R2 = .87; P = 0.007) as power was increased up to 60% power, and chatter did not improve above this power level. CONCLUSIONS: Power improved efficiency only up to a 60% power level, and then was negligible. Chatter correlated well with power up to the 60% level, so that as power was increased, chatter decreased. Because there are no additional benefits in efficiency past 60% power, and because chatter is minimal at 60% power, we recommend torsional ultrasound at 60% as the optimal power setting for using the CENTURION System for phacoemulsification.l.

The effect of patient age on some new and older IOL power calculation formulas.

PURPOSE: To assess the accuracy of intraocular lens (IOL) power calculation in different age groups using various IOL calculation formulas. METHODS: Data from 421 eyes of 421 patients ≥60 years old (ages: 60-69, n = 131; 70-74, n = 105; 75-84, n = 158 and ≥85, n = 27), who underwent uneventful cataract surgery with SN60WF IOL implantation at John A. Moran Eye Center, Salt Lake City, USA, were retrospectively obtained. The SD of the prediction error (PE), median and mean absolute PEs and the percentage of eyes within ±0.25, ±0.50, ±0.75 and ±1.00 D were calculated after constant optimizations for the following formulas: Barrett Universal II (BUII), Emmetropia Verifying Optical (EVO) 2.0, Haigis, Hoffer Q, Hoffer QST, Holladay 1, Kane, Radial Basis Function (RBF) 3.0 and SRK/T. Results were compared between the different age groups. RESULTS: Predictability rates within 0.25D were lower for the eldest age group compared with the other groups using the EVO 2.0 (33% vs. 37%-53%, p = 0.045), Kane (26% vs. 35%-50%, p = 0.034) and SRK/T (22% vs. 31%-49%, p = 0.002). Higher median absolute refractive errors for all formulas were observed in the oldest group [range: 0.39 D (Haigis, Hoffer QSR)-0.48 D (Kane)], followed by the youngest group [range: 0.30 D (RBF 3.0)-0.39 D (Holladay 1, SRK/T)] but did not reach statistical significance. No significant differences between the groups in the distribution parameter were seen. CONCLUSION: Current IOL power calculation formulas may have variable accuracy for different age groups. This should be taken into account when planning cataract surgery to improve refractive outcomes.

Accuracy assessment of artificial intelligence IOL calculation formulae: utilizing the heteroscedastic statistics and the Eyetemis Analysis Tool.

OBJECTIVES: To analyse the accuracy of artificial intelligence (AI)-driven intraocular (IOL) calculation formulae, together with established formulae using the heteroscedastic methodology and the Eyetemis Analysis Tool. METHODS: Data from 404 eyes who underwent uneventful phacoemulsification with implantation of the SN60WF IOL were retrospectively reviewed. IOL power calculations were performed using the Barrett Universal II (BUII), EVO 2.0, Hoffer QST, K6, Ladas Super Formula (LSF), Nallasamy, PEARL-DGS and RBF 3.0 formulae. The SD of the prediction error (PE), served as the primary metric for accuracy. The mean absolute deviation (MAD) and the predictability rates within intervals from ±0.25 D to ±1.50 D were also evaluated. The Eyetemis Analysis Tool was used for further validation. RESULTS: The SD ranged from 0.468 (Nallasamy) to 0.510 (LSF). The Nallasamy formula had a significantly lower SD than the BUII (0.505, p = 0.025) and K6 (0.489, p = 0.022) formulae. The Nallasamy formula also exhibited the lowest MAD (0.358) with a significant difference compared with the Hoffer QST formula (0.384, p < 0.001). Finally, a significantly higher percentage of eyes achieving ± 0.50 D of the target refraction was seen using the Nallasamy formula (77.19%) compared with the Hoffer QST (71.04%, p = 0.019) and Ladas Super Formula (70.79%, p = 0.030) formulae. CONCLUSIONS: The Nallasamy formula, incorporating AI technology, demonstrated superior accuracy according to the analysis guidelines for PE statistics for non-gaussian datasets recommended by Holladay et al. and the online Eyetemis Analysis Tool.

Discrepancies in CDE and Measured Phaco Tip Energy: Comparison of Energy Produced in Longitudinal and Torsional Ultrasound Using Calorimetry.

Purpose: This study aims to investigate the differences between the heat energy produced during cataract surgery and Cumulative dissipated energy (CDE). CDE is often used as a medium for understanding the energy delivered to the eye during cataract surgery. However, the actual energy produced at the tip level of the tip is not well understood. We propose that a discrepancy may exist between the CDE reported by the surgical machine and the actual energy delivered to the eye. Methods: About 50 mL of distilled water were degassed and placed in an isobaric calorimeter. Using the Alcon Centurion and Ozil handpiece fitted with the balanced tip, an investigator immersed the phaco tip into the water and pressed the foot pedal to position 3. The device was set to 100% continuous power, vacuum to 0 mmHg, with aspiration 12 mL/min aspiration. To prevent system changes in the system within the calorimeter, the aspiration tubing was occluded. Temperature change recorded by another investigator was observed from 0 to 60 seconds. After 60 seconds the first researcher immediately released the pedal and removed the phaco tip from the water. Trials were performed 10 times using solely torsional or longitudinal settings and averaged. CDE also was recorded and averaged. Results: No significant difference was seen in the temperature change or energy calculated in Joules between ultrasound modalities, with torsional producing a magnitude of 163 J and longitudinal producing 172 J (P = 0.2). However, the CDE generated in the 60 seconds period was significantly different, with a magnitude of 61 for longitudinal compared to 24 for torsional (P < 0.001). Conclusion: Significantly more energy was generated using torsional ultrasound than longitudinal at the tip level of the tip. CDE did not appear to accurately reflect these differences. This suggests that other factors should be considered when evaluating CDE and surgical outcomes.

This study looked at possible differences between the energy generated during cataract surgery that is reported by the surgical device and the actual energy measured as thermal heat using different machine settings, namely longitudinal and torsional ultrasound. A common metric used for energy delivery to the eye is cumulative dissipated energy. The problem is that this measure accounts for the energy delivered to the eye where the surgical instrument passes through the cornea. Energy that is produced by the rest of the instrument that is inside the eye is less understood, although others have studied postoperative outcomes. We used a method called calorimetry to measure the thermal heat produced by the entire tip and compared this to what the machine reported as cumulative dissipated energy. Calorimetry calculates energy by measuring the change in temperature of liquids. The surgical instrument generated heat in a chamber containing water, and we used the change in temperature to calculate the energy produced by the surgical instrument. We found that longitudinal and torsional ultrasound produced similar heat energy, but the machine reported very different energy. Our results suggest that the machine may not be reporting all of the energy which the surgical instrument produces, and that surgeons may not be able to rely on cumulative dissipated energy to predict operative outcomes.

Efficiency of a polymer-coated phacoemulsification tip in cataract surgery.

PURPOSE: To determine whether there is a difference in efficiency during phacoemulsification when using the hybrid polymer tip compared with the metal balanced tip, as measured by cumulative dissipated energy (CDE) and total procedure time. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah. DESIGN: Experimental study. METHODS: Phacoemulsification was performed with the Centurion Vision System and Infiniti OZil handpiece, with a 30-degree bevel metal balanced tip and hybrid polymer tip. The vacuum was set at 500 mm Hg and the aspiration flow rate at 50 mL/min. Power was changed for torsional and longitudinal ultrasound (US) at 20%, 40%, 60%, 80%, and 100%. Hardened porcine lenses were cut into 200 two mm cubes, 10 for each specified tip/power setting. They were placed into an artificial anterior chamber filled with a balanced salt solution, and phacoemulsification was performed. A second observer randomly assigned the US type and power. The same observer timed trials with a stopwatch, and CDE was recorded. RESULTS: There were no significant differences in time or CDE for any power levels or US modes when comparing the 2 tips. CONCLUSIONS: No significant difference in efficiency was observed when comparing the metal balanced tip with the hybrid polymer tip. Given the known improved safety profile and the overall equivalent efficiency of the hybrid tip, it could improve the performance of beginning and advanced surgeons in the future. Future study is needed to evaluate other setting combinations and to evaluate the hybrid tip in clinical settings.

Effect of Modified Peristaltic Phacoemulsification Device on Efficiency and Post-Occlusion Pressure Surge.

Purpose: To evaluate efficiency of grooving, nuclear fragment removal, and changes in pressure control in the Oertli Faros using traditional peristaltic and Speed and Precision (SPEEP) features. The SPEEP mode uses novel peristaltic technology permitting independent control of flow and vacuum. Methods: A porcine lens model was used with an enclosed chamber simulating the anterior segment. Grooving efficiency is evaluated with flow rates of 10, 30, and 50 mL/min using whole lenses. Lens cubes were emulsified at 20, 40, 60, 80, and 100% power with both SPEEP and non-SPEEP modes. Surge was evaluated with pressure gauges placed on the irrigation tubing and aspiration tubing. Pressure readings were recorded per the following: fluid and vacuum were initiated for 15 seconds, vacuum tubing was occluded for 5 seconds, tubing patency was then re-introduced for 15 seconds. Differences between sensors were recorded. Results: No significant increase in efficiency was seen with increasing flow rate from 30 to 50 mL/min using SPEEP. No significant differences were shown in lens fragment removal in SPEEP and non-SPEEP modes at any power tested. Pressure difference measurements were not significantly different with SPEEP and non-SPEEP modes. Conclusion: We showed that lower flow rates show comparable efficiency of grooving when using the SPEEP mode. The SPEEP function did not show increased efficiency in nuclear fragment removal when compared to traditional mode. Surge control was also comparable with both SPEEP and non-SPEEP modes. We suggest that the SPEEP function included in the Oertli Faros may have some advantages.

Comparison of Phacoemulsification Grooving Efficiency in Longitudinal vs Transversal Handpieces.

Purpose: To determine the difference, if any, in grooving efficiency at various settings on the Whitestar Signature Pro phacoemulsification (phaco) system. Methods: Cataractous lenses were simulated by exposing porcine lenses to formalin for 2 hours. A total of 120 lenses were analyzed at various power settings on both longitudinal and transversal handpieces. Twenty trials each were performed with power set to 25%, 50%, and 75% on both handpieces. A Whitestar Phaco Handpiece System was used to provide longitudinal power, and a Whitestar Signature Ellipsis Handpiece provided transversal power. Lenses were placed within a plastic chamber and grooved by an investigator blinded to settings. A second investigator recorded times and adjusted settings. The Whitestar Signature Pro phaco system was used for grooving. Results: There was no significant difference in grooving times between the longitudinal and transverse handpieces at any power setting (P > 0.05). There was a significant decrease in grooving times when comparing the 25% power setting with the 75% power setting for the transversal handpiece (P=0.021). Conclusion: Both longitudinal and transversal handpieces on the Whitestar Signature Pro phaco system produce similar results to one another at each power setting. There is a general trend toward shorter grooving times, reflecting greater efficiency, at higher power settings. Grooving efficiency on the transversal handpiece may be more affected by changes in the power settings as compared with the longitudinal settings.

Effect of low and passive flow on OVD thermal properties during phacoemulsification.

OBJECTIVE: To study the thermal properties and response magnitude of a forced-infusion phacoemulsification machine on 4 ophthalmic viscosurgical devices (OVDs). DESIGN: Experimental study. METHODS: A phacoemulsification tip, thermocouple, and gauge were placed into an artificial anterior chamber with balanced saline solution (BSS) or approximately 0.1 mL of OVD. Once the thermocouple measured a consistent temperature, the pedal was engaged for 60 seconds; then the tip was removed. The machine was cooled for 5 minutes and flushed with BSS to return to baseline. This was repeated 10 times for each OVD. The research consisted of 2 scenarios: vacuum-blocked flow rate and low aspiration flow rate. RESULTS: All OVDs showed greater temperature changes than BSS. In the vacuum-blocked scenario, these increases were statistically significant. The medium viscosity dispersive OVD (DiscoVisc) reached temperatures exceeding 60°C. In the low-flow scenario, HEALON5 and DisCoVisc were significantly different at 5 seconds and only HEALON5 at 10 seconds. No temperature increases over BSS were greater than 1.0°C. CONCLUSIONS: The dispersive, cohesive, and viscoadaptive OVDs demonstrated higher temperature changes than BSS but did not reach the threshold for corneal incision contracture. The study team verified the need for at least a minimal flow rate before ultrasound, which is especially evident in the first 10 seconds, because a flow rate of only 20 mL/minute mitigated OVD-related thermal effects. Understanding thermal responses enables corneal incision contracture risk reduction.

Temperature Change of Ophthalmic Viscosurgical Devices in a Bi-Chamber Set-Up at a Flow of 0 and 20mL/min.

Purpose: To understand the role of ophthalmic viscosurgical devices (OVDs) in corneal incision contracture (CIC). Specifically, the aim was to evaluate with the tip of the phacoemulsification needle free of OVD, how various OVDs near the tip and sleeve may transmit thermal energy to the incision site. Methods: A small chamber was filled with balanced saline solution (BSS), and a thin membrane was placed on the surface. OVD was placed atop the membrane. A temperature probe was placed in the OVD, while the handpiece pierced the membrane. The experiment was run both with and without flow and vacuum. Temperature measurements were gathered for each of the OVDs at four separate time points at 0 and 20mL/min flow. Results: As expected, there was a more pronounced temperature increase in all test groups with no fluid flow. While the temperature increase was not significantly different from BSS for any of the OVDs tested at either 0 or 20mL/min, Viscoat showed the most variable results at both flow settings. Conclusion: As long as the phaco tip is not in OVD, residual OVD near the incision is not exothermic and so not an additional risk for CIC.

Patterns of Blindness in the Navajo Nation: A 9-Year Study.

The Navajo Nation is the largest Native American reservation by area and citizenship. The study sought to provide the first large-scale examination of ocular pathology within this population. A retrospective review of all Navajo patients seen at Moran Eye Center Navajo Nation Outreach Clinics from 2013 to 2021 for demographics, visual acuity, refractive, and eye pressure data was undergone. Further variables included comorbidity and eye diagnoses among patients at these clinics. Results: First-time patient visits totaled 2251 from 2013 to 2021. The median age was 53 (range, 18 to 92), and clinics had a predominance of female patients (1387:864). Among patients presenting without glasses, 20.67% (198/958), 9.71% (93/958), and 3.13% (30/958) had mild visual impairment (VI), moderate to severe VI, and blindness, respectively. Cataracts were the most common cause of blindness in these patients (40%, 12/30) and the need for glasses was the second most common cause (33%, 10/30). From 2016 to 2021, 17.71% (48/271) of diabetic patients were diagnosed with diabetic retinopathy (DR). Within the subset of Navajo patients that presented without any correction, 73% of bilateral blindness was preventable via glasses prescription or cataract surgery. This study comments on questions of equitable care for Navajo patients.

Gender Representation Among Presenters in Ophthalmology Subspecialties in 2019: A Retrospective Review.

PURPOSE: To describe gender representation at 8 national ophthalmology conferences, stratified by role, session category, and subspecialty. DESIGN: Retrospective cross-sectional study. METHODS: Data were examined on 3817 presenters at the 2019 American Academy of Ophthalmology subspecialty days, American Society of Cataract and Refractive Surgery, American Glaucoma Society, American Society of Retina Specialists, American Society of Ophthalmic Plastic and Reconstructive Surgery, American Association for Pediatric Ophthalmology and Strabismus, North American Neuro-Ophthalmology Society, and American Uveitis Society meetings. The main outcome measure was the gender of presenters in 7 subspecialties, stratified by category and role. RESULTS: The proportion of female presenters was less than the American Board of Ophthalmology (ABO)-estimated proportion of women in their respective fields in glaucoma (28.0% vs 39.8%), neuro-ophthalmology (35.3% vs 45.3%), and pediatrics (42.1% vs 53.3%) and greater than expected in retina (24.6% vs 19.8%). Overall, the proportion of female presenters exceeded the ABO-estimated proportion of women in ophthalmology (24.5%) for clinical (mean = 38.5%, 95% CI [35.8%, 41.4%]) and scientific (39.4% [30.3%, 49.2%]) sessions. For clinical subspecialty sessions, the proportion of female leaders exceeded the overall proportion of female leaders in the respective subspecialty in cornea (35.1% [30.4%, 40.1%] vs 24.6% all sessions). Females represented fewer than the expected number of surgical session leaders in cornea (22.0% [19.9%, 24.3%]), glaucoma (18.0% [13.2%, 24.1%]), pediatrics (22.0% [14.4%, 32.1%]), and retina (18.6% [14.2%, 24.1%]). CONCLUSIONS: Gender representation varied, with fewer than expected female presenters in glaucoma, neuro-ophthalmology, and pediatrics. Women led relatively more clinical sessions but were underrepresented in surgical sessions in most subspecialties.

A Double-Flipped Virtual Classroom Format for Medical Students Learning Ophthalmology: An Approach to Clinical Rotations in the Context of COVID-19.

Purpose The aim of this study was to assess efficacy of a virtual, double-flipped clinical rotation in ophthalmology for medical students during the coronavirus disease 2019 (COVID-19) pandemic. Methods We instituted a virtual, reverse-classroom clinical elective for eight medical students interested in ophthalmology as a career. The course included required prework, interactive case-based discussions, and follow-up quizzes (first flip) entirely prepared and delivered by the students as teachers (second flip). After completion of the course, we surveyed students on five domains: (1) Autonomy and Leadership, (2) Self-Efficacy, (3) Impact on Career Selection, (4) Quality of Educational Experience, and (5) Clear Goals and Feedback using a Likert scale of 1-5 (5 being the most positive). We also asked open-ended questions regarding the overall experience, that is, strengths, weaknesses, and future recommendations for the course. Due to the small N and exploratory nature of the study, no formal statistical inference was performed. Results Seven students responded to the survey. Aggregated mean survey scores for each domain are represented in parentheses. Responses were very positive in regard to "Autonomy and Leadership" (4.5), "Impact on Career Selection" (4.1), "Quality of Educational Experience" (5.0), and "Clear Goals and Feedback" (4.4). "Self-Efficacy," which had an emphasis on ability to perform an eye exam and basic knowledge of ophthalmology, had a lower mean (3.4). The subjective responses were also very positive, but similarly alluded to the limitation of learning examination skills virtually. Conclusions A medical school clinical elective can be successfully executed in a virtual format with an emphasis on student-directed learning. The novel "double-flipped" approach was highly rated by our small sample size. However, there remained a glaring limitation in the ability to transfer clinical skills in the virtual format. In the context of limited in-person contact due to the COVID-19 pandemic, we believe that the double-flipped, virtual format was a viable replacement for a traditional clinical rotation.

Measurement of Phacoemulsification Vacuum Pressure in the Oertli CataRhex3.

Purpose: To determine the actual vacuum pressure generated by the Oertli CataRhex 3® (Oertli), using an external measuring system. Methods: The effective vacuum pressure created by the Oertli was measured with a pressure device that was continuous with the vacuum tubing system while closed to the external environment. Measurements were taken with the machine set to 300 and 500 mmHg at flow rates of 20, 35, and 50 mL/min and at bottle heights of 60, 80, and 100 cm. Pressures were recorded after the foot pedal was depressed to vacuum setting (second position), and the pressure was allowed to stabilize. Subsequently, it was compared to the pressure value displayed by the machine. Results: Externally measured vacuum pressure was on average 13.02% greater (39.05 mmHg) than displayed vacuum pressure at 300 mmHg (P < 0.005) and 8.60% greater (42.98 mmHg) than displayed vacuum at 500 mmHg (P < 0.005). The average difference between displayed and measured pressure increased with increasing bottle heights. Conclusion: On average, the vacuum pressure generated in the Oertli was found to be significantly higher than the machine's reading when the machine was set at 300 mmHg and 500 mmHg. Adjusting vacuum had variable effects on the measured versus displayed pressure readings.

Optimization of Phacoemulsification Tip Gauge on the Oertli CataRhex3 in an in vitro Setting.

Purpose: To evaluate the effect of each of the tip sizes available for the Oertli CataRhex3® phacoemulsification machine on efficiency. Methods: Porcine lenses were fixed in formalin for 2 hours, then cut into 3.0 mm cubes. We studied three Oertli tips, all of which had a 30-degree bevel: easyTip 2.2 mm (20G), easyTip 2.8 mm (19G), and CO-MICS (21G). For the 19G and 20G tips, vacuum was set at 600 mmHg, irrigation rate at 50 mL/min, continuous power 70%, and bottle height 85 cm. For the 21G tip, vacuum was set at 450 mmHg; irrigation and power settings were identical to those used for the easyTip tips. We measured time to removal and chatter events to determine efficiency. Results: Results from 20 trials for each tip showed that the larger the gauge size, the more quickly lens fragments were removed. Chatter events demonstrated an increasing trend with smaller tip gauge. The 19G tip used an average time to fragment removal of 2.8 seconds; the 20G, 3.2 seconds; and the 21G, 4.6 seconds. Increasing tip diameter from 21G to 20G decreased emulsification time by 33% (P = 0.02). Increasing the diameter from 21G to 19G further decreased time to emulsification by 42% (P = 0.003). The 21G tip had a mean 1.4 events/cube; 20G, 0.35 events; and 19G, 0.1 events. Differences in mean chatter events for each tip were each statistically significant. Conclusion: These data suggest that when evaluated by chatter events and emulsification time, the 2.8 mm (19G) easyTip proves to have greatest efficiency.

Utilizing a Professionalism Mentor to Address Sexual Harassment in Academic Ophthalmology.

Objective This study assesses a new departmental role-a professionalism mentor-who receives sexual harassment reporting, liaisons with campus resources, and organizes educational sessions. Study Design Multicenter randomized controlled survey study. Methods Academic ophthalmology departments in the United States were randomized to a professionalism mentor group ( n = 9) and a control group ( n = 7). Among both pre- and postsurveys, 605 faculty and trainee responses were received and 546 were complete. The intervention group was assigned a professionalism mentor with educational session for a 6- to 10-month period. Sexual harassment and reporting rate change over time were compared between the two groups. Results Among 546 anonymous responses, 16% experienced workplace sexual harassment during the prior 10 months. Location in the South or Midwest was a risk factor ( p < 0.001). Victims were mostly women (76%), including residents/fellows (46%) and academic attendings (49%); perpetrators included patients (35%) and academic attendings (35%). Departments with and without a professionalism mentor had stable harassment from pre- to postsurvey ( p = 0.95 comparing change). The professionalism mentor group had an increase in reporting to an authority from pre- to postsurvey (7-23%), whereas the control group had a decrease (27-12%; p = 0.07 comparing change). Most faculty and trainees in the interventional arm of this study recommended instituting a professionalism mentor with educational session (66% presurvey and 68% postsurvey), compared with educational session alone (25% presurvey and 23% postsurvey), or neither (9% presurvey and 9% postsurvey). Residency program directors in the professionalism mentor group even more strongly supported instituting both a professionalism mentor and educational program (100% presurvey and 100% postsurvey) as opposed to educational program alone (0% presurvey and 0% postsurvey) or neither (0% presurvey and 0% postsurvey). Conclusion This study identified a high sexual harassment rate in academic ophthalmology departments over a brief period. The presence of a professionalism mentor was viewed favorably and may lead to increased reporting.

Effects on phacoemulsification efficiency and chatter at variable longitudinal ultrasound settings when combined with constant torsional energy.

PURPOSE: To evaluate longitudinal power settings for optimally efficient lens fragment removal, using the Centurion machine. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, USA. DESIGN: Experimental study. METHODS: Porcine lens nuclei were cut into 2.0 mm cubes. Experiments were conducted at 100% torsional power; vacuum set at 500 mm Hg, aspiration 50 mL/min, and intraocular pressure 110 mm Hg. A 20-degree tip with a 30-degree bevel was used. Longitudinal power was tested between 20% and 100%. Efficiency (time for fragment removal) and chatter (the number of times the fragment bounced from the tip) were measured. RESULTS: A linear increase in efficiency was observed from 20% to 100% longitudinal power (R = 0.9281, slope = -0.0271). An efficiency slope change occurred at 60% power, with the largest incremental change in efficiency between 20% and 60% (R = 0.9756, slope = -0.0394) and a lesser change between 60% and 100% (R = 0.9827, slope = -0.0121). Chatter analysis showed minimal events at 20% to 60%, but a significant increase at >80% (P = .005). This increase appeared to be incremental (R = 0.8929). CONCLUSIONS: Increasing longitudinal power, with all other settings constant, increased efficiency. Greatest efficiency gains were observed between 20% and 60%. At 80% and 100%, chatter events increased significantly. With a goal of recommending optimally efficient settings while minimizing excess energy and chatter, adding 60% of longitudinal power to 100% torsional power was shown to be the best setting to increase efficiency and avoid repulsion in these vacuum and aspiration settings.

Systemic Disease and Ocular Comorbidity Analysis of Geographically Isolated Federally Recognized American Indian Tribes of the Intermountain West.

BACKGROUND: The American Indian Navajo and Goshute peoples are underserved patient populations residing in the Four Corners area of the United States and Ibupah, Utah, respectively. METHODS: We conducted a cross-sectional study of epidemiological factors and lipid biomarkers that may be associated with type II diabetes, hypertension and retinal manifestations in tribal and non-tribal members in the study areas (n = 146 participants). We performed multivariate analyses to determine which, if any, risk factors were unique at the tribal level. Fundus photos and epidemiological data through standardized questionnaires were collected. Blood samples were collected to analyze lipid biomarkers. Univariate analyses were conducted and statistically significant factors at p < 0.10 were entered into a multivariate regression. RESULTS: Of 51 participants for whom phenotyping was available, from the Four Corners region, 31 had type II diabetes (DM), 26 had hypertension and 6 had diabetic retinopathy (DR). Of the 64 participants from Ibupah with phenotyping available, 20 had diabetes, 19 had hypertension and 6 had DR. Navajo participants were less likely to have any type of retinopathy as compared to Goshute participants (odds ratio (OR) = 0.059; 95% confidence interval (CI) = 0.016-0.223; p < 0.001). Associations were found between diabetes and hypertension in both populations. Older age was associated with hypertension in the Four Corners, and the Navajo that reside there on the reservation, but not within the Goshute and Ibupah populations. Combining both the Ibupah, Utah and Four Corners study populations, being American Indian (p = 0.022), residing in the Four Corners (p = 0.027) and having hypertension (p < 0.001) increased the risk of DM. DM (p < 0.001) and age (p = 0.002) were significantly associated with hypertension in both populations examined. When retinopathy was evaluated for both populations combined, hypertension (p = 0.037) and living in Ibupah (p < 0.001) were associated with greater risk of retinopathy. When combining both American Indian populations from the Four Corners and Ibupah, those with hypertension were more likely to have DM (p < 0.001). No lipid biomarkers were found to be significantly associated with any disease state. CONCLUSIONS: We found different comorbid factors with retinal disease outcome between the two tribes that reside within the Intermountain West. This is indicated by the association of tribe and with the type of retinopathy outcome when we combined the populations of American Indians. Overall, the Navajo peoples and the Four Corners had a higher prevalence of chronic disease that included diabetes and hypertension than the Goshutes and Ibupah. To the best of our knowledge, this is the first study to conduct an analysis for disease outcomes exclusively including the Navajo and Goshute tribe of the Intermountain West.

High vacuum and aspiration on phacoemulsification efficiency and chatter for Centurion.

OBJECTIVE: To compare relative efficiency and chatter of high aspiration and vacuum settings. DESIGN: In vitro laboratory study. METHODS: The John A. Moran Eye Center Laboratories, University of Utah, Salt Lake City, Utah, was the study setting. Porcine nuclei were fixed in formalin and cut into 2.0 mm cubes. Lens cubes were phacoemulsified with Balanced tips at 50 and 60 mL/min aspiration with 500, 600, and 700 mm Hg vacuum with monitored forced infusion. Experiments were conducted at constant torsional power, longitudinal power, and intraocular pressure. RESULTS: No significant change was observed in average chatter across each tested setting. Increasing aspiration rate did not increase efficiency. Increasing vacuum up to 600 mm Hg from 500 mm Hg did not change efficiency. However, increasing vacuum to 700 mm Hg decreased efficiency (p = 0.008 for 500 mm Hg vs 700 mm Hg and p = 0.05 for 600 mm Hg vs 700 mm Hg). Increasing aspiration and increasing vacuum did not significantly improve chatter. CONCLUSIONS: Increasing aspiration above 50 mL/min did not improve phacoemulsification efficiency. Increasing vacuum settings to 700 mm Hg decreases efficiency. Chatter did not significantly change with increasing aspiration and vacuum settings.

Phacoemulsification in review: Optimization of cataract removal in an in vitro setting.

Phacoemulsification, initially used in the late 1960s, continues to be the standard of care for cataract removal. An animal model was developed so that, in a controlled research setting, all the various machines, handpieces, tips, and settings could be investigated. As a general rule, the higher power, vacuum, and aspiration settings lead to optimally efficient phacoemulsification. In addition, both new phacoemulsification platforms and newly developed devices have been shown to improve efficiency. As a result, we recommend that the integration of these recent developments should be considered in future investigations.