Phacoemulsification and modern cataract surgery

The argument for two-handed cataract surgery in veterinary ophthalmology

Despite access to contemporary phacoemulsification technology and the strong shift to two-handed nucleofractis techniques in human medicine, a one-handed, single incision approach has persisted among Diplomates of the American College of Veterinary Ophthalmologists. The perpetuation of techniques such as bowl-sculpting one-handed phacoemulsification in veterinary medicine is multifactorial; it is likely associated with the lack of two-handed training in residency programs, the challenges of learning on complex cases, the ease of teaching one-handed versus two-handed techniques to a resident, and the lack of specific instrumentation available designed for larger lens size, among other factors. Additionally, variation in globe and palpebral fissure size in veterinary patients complicates the training of cataract surgery. Finally, many mentors or mentors' mentors, were trained alongside previous generations of MD surgeons who performed bowl sculpting techniques during the transition from extracapsular cataract extraction to phacoemulsification, and understandably, are not comfortable teaching a two-handed technique consistently. The authors have observed an unwillingness to convert from one-handed to two-handed technique in the post-residency career for most veterinary ophthalmologists; this could be due to the high expectations becoming a specialist, especially when the stakes are as high as in phacoemulsification. Therefore, the authors advocate for hands-on training in multiple nucleofractis techniques, including two-handed methods during residency training. Simply put, if residents are not trained and comfortable with two-handed techniques by the end of residency, they are less likely to make further changes later in their career. In this article, we aim to explore the proposed rates of one-handed versus two-handed mentors currently teaching veterinary phacoemulsification, the history of cataract surgery, and to discuss the benefits of two-handed nucleofractis techniques. The authors will also illustrate and provide videos as well as some tools for veterinary ophthalmologists wishing to learn two-handed techniques.

BCLA CLEAR presbyopia: Management with intraocular lenses

Cataract surgery including intraocular lens (IOL) insertion, has been refined extensively since the first such procedure by Sir Harold Ridley in 1949. The intentional creation of monovision with IOLs using monofocal IOL designs has been reported since 1984. The first reported implantation of multifocal IOLs was published in 1987. Since then, various refractive and or diffractive multifocal IOLs have been commercialised. Most are concentric, but segmented IOLs are also available. The most popular are trifocal designs (overlaying two diffractive patterns to achieve additional focal planes at intermediate and near distances) and extended depth of focus designs which leave the patient largely spectacle independent with the reduced risk of bothersome contrast reduction and glare. As well as mini-monovision, surgical strategies to minimise the impact of presbyopia with IOLs includes mixing and matching lenses between the eyes and using IOLs whose power can be adjusted post-implantation. Various IOL designs to mimic the accommodative process have been tried including hinge optics, dual optics, lateral shifts lenses with cubic-type surfaces, lens refilling and curvature changing approaches, but issues in maintaining the active mechanism with post-surgical fibrosis, without causing ocular inflammation, remain a challenge. With careful patient selection, satisfaction rates with IOLs to manage presbyopia are high and anatomical or physiological complications rates are no higher than with monofocal IOLs.

Phaco-Chop versus Divide-and-Conquer in Patients Who Underwent Cataract Surgery: A Systematic Review and Meta-Analysis

Background

Cataract surgery is one of the most frequently performed eye surgeries worldwide, and among several techniques, phacoemulsification has become the standard of care due to its safety and efficiency. We evaluated the advantages and disadvantages of two phacoemulsification techniques: phaco-chop and divide-and-conquer.

Methods

PubMed, Cochrane, Embase, and Web of Science databases were queried for randomized controlled trial (RCT), prospective and retrospective studies that compared the phaco-chop technique over the divide-and-conquer technique and reported the outcomes of (1) Endothelial cell count change (ECC); (2) Ultrasound time (UST); (3) Cumulated dissipated energy (CDE); (4) Surgery time; and (5) Phacoemulsification time (PT). Heterogeneity was examined with I2 statistics. A random-effects model was used for outcomes with high heterogeneity.

Results

Nine final studies, (6 prospective RCTs and 3 observational), comprising 837 patients undergoing phacoemulsification. 435 (51.9%) underwent the phaco-chop technique, and 405 (48.1%) underwent divide-and-conquer. Overall, the phaco-chop technique was associated with several advantages: a significant difference in ECC change postoperatively (Mean Difference [MD] -221.67 Cell/mm2; 95% Confidence Interval [CI] -401.68 to -41.66; p < 0.02; I2=73%); a shorter UST (MD -51.16 sec; 95% CI -99.4 to -2.79; p = 0.04; I2=98%); reduced CDE (MD -8.68 units; 95% CI -12.76 to -4.60; p < 0.01; I2=84%); a lower PT (MD -55.09 sec; 95% CI -99.29 to -12.90; p = 0.01; I2=100). There were no significant differences in surgery time (MD -3.86 min; 95% CI -9.55 to 1.83; p = 0.18; I2=99%).

Conclusion

The phaco-chop technique proved to cause fewer hazards to the corneal endothelium, with less delivered intraocular ultrasound energy when compared to the divide-and-conquer technique.

A randomized controlled trial to assess safety and efficacy between terminal chop, stop and chop, and direct chop

PURPOSE

The goal in developing new techniques of cataract surgery is to provide a safer, more efficient surgical experience with the lowest complication rate and endothelial cell loss. We compared the efficiency and safety of stop-and-chop, direct chop, and the novel terminal chop techniques of nuclear fragmentation for cataracts grade II-V.

METHODS

We conducted a prospective randomized clinical trial comparing three different techniques of phacoemulsification, namely, stop-and-chop, direct chop, and terminal chop to assess any differences between them and to establish whether any one method was superior to the others. The pre- and postoperative parameters studied, included central corneal thickness (CCT), ultrasonic time (UST), endothelial cell density (CD), cell loss and effective phacoemulsification time (EPT), average cumulative dissipative energy (CDE), and best-corrected visual acuity, among others.

RESULTS

307 eyes were recruited to the study, 102 were recruited to the stop-and-chop group, 103 to the direct chop group, and 102 to the terminal chop group. Statistical differences were found between the techniques with regard to postoperative CCT among NS II (P. 0001) and NS IV cataracts (P = .005) with the lowest values in the terminal chop group among NS II, NS III, and NS IV cataracts. Endothelial cell loss was minimum with a terminal chop in NS II (P = .018) and NS IV cataracts (P = .245). CDE was minimum in terminal chop across different cataract densities.

CONCLUSION

Terminal chop showed improvement over the other two techniques in terms of CDE and was comparable to them with regard to other parameters.

Principles of Ophthalmic Ultrasound

Introduction

Ultrasound imaging of the eye was introduced over 50 years ago. While the physical principles of ultrasound imaging have not changed, technology has undergone tremendous and ongoing development.

Areas covered

The fundamentals of ultrasound physics, biometry (A-scan), structural imaging (B-scan) and blood-flow imaging and measurement (Doppler) will be described. Emphasis will be placed on technological development and potential future advances.

Expert opinion

While A- and B-scan ultrasound of the eye has traditionally been performed with focused single-element transducers, the introduction of annular and linear arrays has enhanced clinical utility. Future advances, especially in multielement arrays, and point-of-care systems promise amazing new capabilities for diagnostic imaging of the eye and orbit.

Anterior Segment Biometry in a Caucasian Population with Cataracts

PURPOSE

To investigate biometric factors of the anterior segment of phakic eyes with cataracts.

METHODS

This population-based study included Caucasian patients with cataracts in the University Eye Hospital, Goethe University Frankfurt, Germany. Biometric parameters were measured using the swept-source optical coherence tomography method. Patients were grouped into intermediate stages based on decades of life.

RESULTS

In total, 6289 eyes of 3615 patients (age: 70.67 ± 8.42 years) were included. Age-related reductions in the anterior chamber depth (mean ± standard deviation) decreased from 3.26 ± 0.42 mm (group A: 55-59 years) to 2.94 ± 0.4 mm (group G: 85-89 years), and those in the axial length decreased from 24.37 ± 1.87 mm (group A) to 23.39 ± 1.07 mm (group G). Likewise, the white-to-white distance decreased from 12.12 ± 0.48 mm (group A) to 11.96 ± 0.47 mm (group G). Lens thickness tended to increase accordingly from 4.39 ± 0.36 µm (group A) to 4.9 ± 0.40 µm (group G). A comparison of the eyes showed no detectable lateral difference regarding the biometric parameters between the groups (axial length: p = 0.26, Rosenthal effect size = 0.03; lens thickness: p = 0.12, R = 0.03; anterior chamber depth: p = 0.63, Rosenthal effect size = 0.01). The axial length and anterior chamber depth differed significantly between sexes (r = 0.22, p < 0.0001 and r = 0.16, p < 0.0001, respectively). Multiple regression analysis of the anterior chamber depth as a function of biometry parameters as well as age and sex additionally indicated a positive correlation of anterior chamber depth with white-to-white distance (b = 0.32, p = 10-5), axial length (b = 0.10, p = 10-5), keratometry (b = 0.07, p = 10-5), and lens thickness (b=-0.05, p = 10-5) with a high effect size (Cohen f2=1.866, p = 10-5) and strong multiple correlation coefficient (Rosenthal effect size = 0.80, p = 10-5).

CONCLUSIONS

In the anterior segment, there are age- and sex-dependent changes in biometric parameters. In addition, changes in anterior chamber depth were noted in relation to white-to-white distance, axial length, keratometry, and lens thickness. These data should be considered in lens calculation formulas.

How Cultural Behaviors and Superstitions Associate the Willingness to Undergo Cataract Surgery in Taiwan: A Nationwide Survey

Background and Objectives: Cultural beliefs influence the conceptualization, adaptation, and coping strategies for diseases. This study aimed to investigate the impact of cultural beliefs and customs on the willingness to undergo cataract surgery in Taiwan. Materials and Methods: The data were retrospectively retrieved from the national Longitudinal Health Insurance Database 2000 (LHID2000). From the national database, we enrolled patients that were diagnosed with cataracts and underwent cataract surgery from 2001 to 2010. All the patients were stratified according to their gender and living area. Gender was categorized as male or female, and the living area was classified as urban or rural. We compared the difference in the number of surgeries between stratified patient groups in each Chinese lunar month. Results: The number of cataract surgeries decreased significantly in the seventh and twelfth lunar months for both genders. There was a significant reduction in cataract surgeries in both the urban and rural groups during the seventh lunar month. Interestingly, only the seventh lunar month had an association with sex in different living areas, which meant that in the seventh month, there was a gender-specific difference in the surgical numbers. Conclusions: The Taiwanese population holds a belief that surgical procedures, including cataract surgery, during the lunar ghost month is inauspicious. Citizens tend to avoid elective surgery due to cultural practice, resulting in a decrease in surgical numbers during the period of the Chinese New Year. The authorities should consider these cultural behaviors when developing medical policies and allocating resources. Healthcare providers should be aware of these superstitions and take them into account when providing medical care and advice to patients.

Evaluation of the Corneal Endothelium Following Cataract Surgery in Diabetic and Non-Diabetic Patients

The aim of this study was to evaluate the influence of phacoemulsification cataract surgery on the state of the corneal endothelium in diabetic versus non-diabetic patients. We compared the corneal cell morphology in 48 diabetics with good glycemic control and 72 non-diabetic patients before and after uneventful phacoemulsification. Corneal cell density, central corneal thickness, and hexagonality were measured preoperatively and post-surgery (at 1 and 4 weeks) by specular microscopy. The effect of age, gender, axial length, and anterior chamber depth on the parameters of the corneal endothelium were evaluated. We noticed a drop in the endothelial density in both groups postoperatively: a mean endothelial cell loss of 472.7 ± 369.1 in the diabetic group was recorded versus 165.7 ± 214.6 mean loss in the non-diabetic group after the first week. A significant increase in central corneal thickness was also noticed in both groups one week after phacoemulsification, but no statistical significance after 4 weeks in the diabetic group. In terms of cell hexagonality, statistically significant differences were noticed after 4 weeks in both groups. Overall, a significant difference between diabetic and non-diabetic population was noticed in terms of corneal endothelial cell loss after uneventful phacoemulsification cataract surgery. Routine specular microscopy and HbA1c evaluation is recommended before cataract surgery, while intraoperative precautions and high monitorisation in terms of pacho power intensity and ultrasound energy, along with a proper application of the dispersive viscoelastic substances are essential to reduce the risk of endothelial damage.

Remote follow-up after cataract surgery (CORE-RCT): study protocol of a randomized controlled trial

BACKGROUND

Cataract surgery has become one of the most performed surgical procedures worldwide. Postoperative management consists of routine clinical examinations to assess post-operative visual function and detect possible adverse events. Due to the low incidence of complications, the majority of clinic visits after cataract surgery are uneventful. Nonetheless, valuable time and hospital resources are consumed. We hypothesize that remote post-operative follow-up involving teleconsultations and self-assessments of visual function and health status, could be a valid alternative to face-to-face clinical examinations in selected patient groups. The practice of remote follow-up after cataract surgery has not yet been evaluated. The aim of this study is to investigate the validity, safety and cost-effectiveness of remote cataract surgery follow-up, and to report on the patients' experiences with remotely self-assessing visual function.

METHODS

This study is a multicenter, open-label, randomized controlled trial. Patients planned for cataract surgery on both eyes, without ocular comorbidities, are eligible for participation. Participants will be allocated (1:1) into one of the two study groups: 'telemonitoring' or 'usual care'. Participants in the 'telemonitoring' group will perform in-home assessments after cataract surgery (remote web-based eye exams and digital questionnaires on their own devices). Participants in the 'usual care' group will have regular post-operative consultations, according to the study site's regular practice. Outcome measures include accuracy of the web-based eye exam for assessing visual acuity and refraction, patient-reported outcome measures (visual function and quality of life), adverse events, and cost aspects.

DISCUSSION

Investigating remote follow-up after cataract surgery fits the current trends of digitization of health care. We believe that remote self-care can be a promising avenue to comply with the increasing demands of cataract care. This randomized controlled trial provides scientific evidence on this unmet need and delivers the desired insights on (cost)effectiveness of remote follow-up after cataract surgery.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04809402. Date of registration: March 22, 2021.

Feasibility assessment of the Eye Scan Ultrasound System for cataract characterization and optimal phacoemulsification energy estimation: protocol for a pilot, nonblinded and monocentre study

Background

Cataracts are lens opacifications that are responsible for more than half of blindness cases worldwide, and the only treatment is surgical intervention. Phacoemulsification surgery, the most frequently performed cataract surgery in developed countries, has associated risks, some of which are related to excessive phacoemulsification energy levels and times. The protocol proposed in herein will be used to evaluate the feasibility of a new experimental medical device, the Eye Scan Ultrasound System (ESUS), for the automatic classification of cataract type and severity and quantitative estimation of the optimal phacoemulsification energy.

Methods

The pilot study protocol will be used to evaluate the feasibility and safety of the ESUS in clinical practice. The study will be conducted in subjects with age-related cataracts and on healthy subjects as controls. The procedures include data acquisition with the experimental ESUS, classification based on the Lens Opacity Classification System III (LOCS III, comparator) using a slit lamp, contrast sensitivity test, optical coherence tomography, specular microscopy and surgical parameters.

ESUS works in A-scan pulse-echo mode, with a central frequency of 20 MHz. From the collected signals, acoustic parameters will be extracted and used for automatic cataract characterization and optimal phacoemulsification energy estimation.

The study includes two phases. The data collected in the first phase (40 patients, 2 eyes per patient) will be used to train the ESUS algorithms, while the data collected in the second phase (10 patients, 2 eyes per patient) will be used to assess the classification performance. System safety will be monitored during the study.

Discussion

The present pilot study protocol will evaluate the feasibility and safety of the ESUS for use in clinical practice, and the results will support a larger clinical study for the efficacy assessment of the ESUS as a diagnostic tool. Ultimately, the ESUS is expected to represent a valuable tool for surgical planning by reducing complications associated with excessive levels of phacoemulsification energy and surgical times, which will have a positive impact on healthcare systems and society. The study is not yet recruiting.

Trial registration

ClinicalTrials.gov identifier NCT04461912, registered on July 8, 2020.

A Systematic Review of the Effects of Second-Eye Cataract Surgery on Motor Function

Cataract removal surgery is one of the most commonly performed surgical procedure in developed countries. The financial and staff resource cost that first-eye cataract surgery incurs, leads to restricted access to second-eye cataract surgery (SES) in some areas, including the United Kingdom. These restrictions have been imposed despite a lack of knowledge about the impact of not performing SES on visuo-motor function. To this end, a systematic literature review was carried out, with the aim of synthesising our present understanding of the effects of SES on motor function. Key terms were searched across four databases, PsycINFO, Medline, Web of Science, and CINAHL. Of the screened studies (K = 499) 13 met the eligibility criteria. The homogeneity between participants, study-design and outcome measures across these studies was not sufficient for meta-analyses and a narrative synthesis was carried out. The evidence from objective sources indicates a positive effect of SES on both mobility and fall rates, however, when considering self-report measures, the reduction in falls associated with SES becomes negligible. The evidence for any positive effect of SES on driving is also mixed, whereby SES was associated with improvements in simulated driving performance but was not associated with changes in driving behaviours measured through in vehicle monitoring. Self-report measures of driving performance also returned inconsistent results. Whilst SES appears to be associated with a general trend towards improved motor function, more evidence is needed to reach any firm conclusions and to best advise policy regarding access to SES in an ageing population.

Systematic Review Registration:https://osf.io/7hne6/, identifier INPLASY2020100042.

Corneal Endothelial Cell Loss After Endocapsular and Supracapsular Phacoemulsification: The PERCEPOLIS Randomized Clinical Trial

PURPOSE

Subluxation techniques are superior to divide-and-conquer in procedure duration, pain, and ultrasound quantity, but their safety in endothelial cell loss (ECL) is unclear. This randomized single-blind noninferiority clinical trial aimed to determine whether subluxation supracapsular phacoemulsification techniques are inferior to a reference endocapsular technique (divide-and-conquer) regarding postoperative corneal ECL.

METHODS

Patients (aged18 years or older) with greater than +0.2 logarithm of the minimum angle of resolution best spectacle-corrected visual acuity and normal to severe density cataract were randomized to subluxation or divide-and-conquer phacoemulsification in 2015 to 2016. Follow-up with ophthalmic tests was conducted on day 4 and months 1, 3, and 12. The primary study outcome was ECL at all time points. Secondary study end points were operative variables, including effective phaco time and procedure duration. A clinically relevant noninferiority ECL limit was established on the basis of the literature.

RESULTS

In total, 292 patients (mean age, 73 yrs; 59% female) were randomized and underwent subluxation (n = 148) or divide-and-conquer (n = 144). Day 4 and month 1, 3, and 12 data were available for 243, 270, 275, and 198 patients, respectively. The unexpectedly high dropout at 12 months meant that the 12-month ECL data could only be assessed qualitatively. Surgery was successful in all patients. Subluxation was noninferior to divide-and-conquer in ECL. Effective phaco times were similar, but subluxation associated with shorter procedure duration.

CONCLUSIONS

The subluxation technique was noninferior to divide-and-conquer regarding postoperative ECL, at least in the first 3 months, and associated with reduced intervention time. Subluxation techniques may be suitable alternatives to endocapsular techniques.Clinical Trial Registration-URL: ClinicalTrials.gov. Unique identifier: NCT02535819.

Eye-Related Factors That Can Be Associated With the Plane of Phacoemulsification

Purpose: To evaluate the effect of eye-related factors such as biometric and surgical parameters, nuclear sclerosis (NS) grade, and pupil and capsulorhexis diameters on the plane of phacoemulsification (PP).

Material and Methods: This prospective study included 328 eyes of 328 patients who underwent phacoemulsification surgery. The phaco-chop technique was performed in all patients and changes in PP that occurred during surgery were recorded. Patients were grouped as follows: Group 1, > 75% of lens nucleus emulsified in the capsular bag; Group 2, > 75% of lens nucleus emulsified at the pupillary plane; and Group 3, > 50% of lens nucleus emulsified in the anterior chamber. The association between PP and eye-related factors was evaluated.

Results: There were 153 patients (46.7 %) in Group 1, 104 patients (31.7 %) in Group 2 and 71 patients (21.6 %) in Group 3. The factors associated with PP were anterior chamber depth (ACD) (p = 0.020) and NS grade (p = 0.028). No significant relationship was detected between PP and age, surgical parameters or other biometric values. Moreover, PP was found to be more anterior in patients with soft cataracts and deeper ACD values (p values were 0.002 and 0.036, respectively).

Conclusion: The present study has reported that PP may move to more anterior, as softer cataracts may increase the fear of posterior capsule rent. Moreover, PP may move to more posterior due to shallow anterior chambers or high-grade cataracts that could potentially increase the fear of endothelial injury.

The Association Between Glycaemic Control, Renal Function and Post-operative Ophthalmic Complications in People With Diabetes Undergoing Cataract Surgery-A Single-Centre Retrospective Analysis

INTRODUCTION

In general surgery, it has been shown that poor peri-operative diabetes control, as measured by glycated haemoglobin (HbA_1c), is associated with adverse post-operative outcomes. National data for the UK suggest that the post-operative complication rate for cataract surgery is 2.8%. It is unknown whether people with diabetes who undergo cataract surgery are also at increased risk.

METHODS

This single-centre retrospective study looked at the association of peri-operative HbA_1c and estimated glomerular filtration rate (eGFR) with the risk of post-operative complications in people undergoing phacoemulsification and intraocular lens implantation under local anaesthesia during 2016.

RESULTS

4401 individuals had cataract surgery. Of these, 34.6% (1525) had diabetes. Of those with diabetes, 114 (7.5%) developed a post-operative ophthalmological complication (as defined by the Royal College of Ophthalmologists) necessitating at least one eye clinic appointment. Mean HbA_1c did not differ between those who did and those who did not develop complications (52 vs 50 mmol/mol, p = 0.12). After adjustment, HbA_1c was not a significant risk (OR 1.00; 95% CI: 0.99-1.05; p = 0.85). However, eGFR had a small but statistically significant effect on outcome (OR 0.99; 95% CI: 0.98-1.00; p = 0.02).

CONCLUSIONS

This study has shown that more people who undergo cataract surgery have diabetes than previously reported. Also, people with diabetes are at higher risk of developing complications than previously reported. HbA_1c concentration was not a factor in these adverse post-operative outcomes. However, eGFR was a predictor of risk. More focus should be placed on pre-operatively optimising co-morbidities than diabetes control in those undergoing cataract surgery.

Clinical Outcomes of Applying Therapeutic Contact Lenses and Eye Drops after Cataract Surgery

Purpose: To investigate the safety of applying therapeutic contact lenses and eye drops after cataract surgery.Methods: Immediately after cataract surgery, 947 eyes (group 1) used therapeutic contact lenses and eye drops and 914 (group 2) applied antibiotic ointment and wore a gauze eye patch for the first postoperative day. Clinical outcomes including best corrected visual acuity (BCVA), IOP, degree of anterior chamber inflammation, wound leakage, and postoperative endophthalmitis were compared in the two groups 1 day, 1 week, and 1 month after surgery.Results: There were no significant differences in the mean pre- and postoperative BCVA and IOP at 1 day, 1 week, and 1 month between groups 1 and 2. There was no difference in anterior chamber inflammation between the two groups at 1 day (p = 0.302), 1 week (p = 0.437), or 1 month (p = 0.960) after surgery. On the first postoperative day, 10 eyes in group 1 and nine eyes in group 2 had wound leakage (p = 1.000). There was no endophthalmitis in either group.Conclusions: The risk of postoperative complications in group 1 was not higher than in group 2. Therefore, wearing therapeutic contact lenses and using eye drops is a relatively safe management method after cataract surgery.

Trends in cataract surgical treatment within the Brazilian national public health system over a 20-year period: Implications for Universal Eye Health as a global public health goal

Cataract is a highly prevalent, treatable, and sight threatening condition considered one of the main focuses of public health policies addressing visual impairment and blindness towards Universal Eye Health. We aimed to investigate the trends on number of cataract surgical procedures performed through the Brazilian national health system (SUS) from 2000 to 2019 while also evaluating costs associated with it. The Brazilian Public Health System Information Database (DATASUS) was used as the primary data source for procedures including extracapsular cataract extraction (ECCE) and phacoemulsification. Trends along the years were evaluated through generalized linear models. A total of 8,424,521 cataract procedures were performed from 2000 to 2019, with a significant increase along the years from 228,145 in 2000 to 663,186 in 2019 (p<0.001), a cataract surgical procedure rate change from 13.15 to 32.28 procedures per 10,000 people. It was observed a significant increase on the number of phacoemulsification (p<0.001) and a significant decrease on the number of ECCE (p<0.001). A shift on the predominant technique has occurred between 2007 and 2008 with phacoemulsification increasing its percentual representativity from 34.3% to 69.7% of all procedures, reaching 96.1% in 2019. Phacoemulsification costs per procedure increased 30.5% from from USD$119.00 to USD$155.33 (p = 0.007) and the ECCE costs per procedure increased 29.1% from USD$78.57 to USD$101.43 (p = 0.001). There is an increasing trend of procedures related to cataract treatment performed through SUS along the 20-years period and a switch on the technique predominance from ECCE to phacoemulsification was observed after 2007. The costs associated with both techniques have increased but have not followed the country's overall inflation. Data derived from DATASUS is important to understand the overall panorama of ocular health offered by the national health system and to provide information to guide healthcare leaders on management and planning of public health policies within the system.

Cataract Surgery Numbers in U.S. Ophthalmology Residency Programs: An ACGME Case Log Analysis

PURPOSE

To describe and assess the cataract experience of ophthalmology residents throughout the United States (U.S.).

METHODS

Cataract procedures logged by graduating ophthalmology residents nationwide and published by the Accreditation Council for Graduate Medical Education (ACGME) from 2009 to 2020 were analyzed using linear regression on log-transformed response variables with robust variance.

RESULTS

As primary surgeon, average numbers logged for phacoemulsification increased yearly by an average of 4.1% prior to 2019 and then decreased by 22.1% in 2019 for an overall average yearly increase of 2.9% (95% CI: 0.5, 5.4%, p = .03), non-phacoemulsification extracapsular extraction decreased yearly by an average of 4.6% (95% CI: -7.7, -1.5%, p = .01), other cataract/intraocular lens surgeries decreased yearly by an average of 8.4% (95% CI: -10.1, -6.6%, p < .001), anterior vitrectomies decreased yearly by an average of 12.5% (95% CI: -14.9, -10.1%, p < .001), and laser capsulotomies increased yearly by an average of 6.0% prior to 2019 and then decreased by 3.0% for an overall average yearly increase of 5.3% (95% CI: 4.5, 6.2%, p < .001). As assistant, average numbers logged in all ACGME minimum categories showed decreasing trends.

CONCLUSIONS

Over the last decade, the average numbers of phacoemulsification and laser capsulotomies logged by residents as primary surgeon increased while other ACGME cataract minimum procedures decreased. Surgical volume in 2019-20 was lower due to the coronavirus disease-19 pandemic but higher than from 2009 to 2013.

Phacoemulsification: Proposals for Improvement in Its Application

A cataract is defined as opacity of the crystalline lens. It is currently one of the most prevalent ocular pathologies and is generally associated with aging. The most common treatment for cataracts is surgery. Cataract surgery is a quick and painless process, is very effective, and has few risks. The operation consists of removing the opacified lens and replacing it with an intraocular lens. The most common intraocular lens removal procedure that is currently used is phacoemulsification. The energy applied in this process is generated by ultrasonic waves, which are mechanical waves with a frequency higher than 20 kHz. A great deal of research on the different ways to perform the stages of this surgical procedure and the analysis of the possible side effects of the operation has been published, but there is little information on the technical characteristics, the intensities applied, and the use of ultrasound-emitting (U/S) equipment for cataract removal. More studies on the method and depth of absorption of ultrasonic waves in our visual system when performing the phacoemulsification procedure are needed. It would be advisable for health authorities and medical professionals to develop guidelines for the handling and use of ultrasonic wave-emitting equipment, such as those that exist for ultrasound and physiotherapy. This could help us to reduce undesirable effects after the operation.

Cataract inhibitors: Present needs and future challenges

Cataracts result from opacification of the ocular lens and represent the leading cause of blindness worldwide. After surgical removal of the diseased lens material and implantation of an artificial intraocular lens, up to 50% of cataract patients develop a secondary lens defect called posterior capsular opacification (PCO). While vision can be restored in PCO patients by a laser-mediated capsulotomy, novel therapies involving inhibition of aldose reductase are now being developed to prevent PCO development and complications of laser capsulotomy. A question we wished to address was whether cataract surgeons believe there is an unmet need for a preventative PCO therapy, whether they would prescribe such a therapy were it available, and to assess their perceptions regarding the benefits of and obstacles to adopting novel PCO therapies in the place of laser capsulotomy. We gathered perspectives from adult, pediatric, and veterinary cataract surgeons using an online questionnaire. From 161 surgeon responses, we found that the majority of adult, pediatric, and veterinary cataract surgeons (78% n = 35, 88% n = 37, and 96% n = 71 respectively) believed there is an unmet need for preventative PCO therapy, with more than 95% expressing interest in incorporating such therapy into surgical protocols. Perceived benefits included optimizing visual outcomes, avoiding the need for additional procedures, eliminating complications related to neodymium:yttrium-aluminum-garnet laser, preserving the posterior capsule particularly in patients receiving multifocal intraocular lens implants, providing a viable solution for PCO in animals, and using it in developing countries that lack access to neodymium:yttrium-aluminum-garnet lasers. Perceived obstacles included potential lack of reimbursement by insurance companies, and the need for strong efficacy and safety profiles. Among adult surgeons, 70% (n = 31) indicated that preventative PCO therapy could add value to premium intraocular lens packages. Our studies revealed that cataract surgeons overwhelmingly support the development of preventative PCO therapy, and that clinical trials will play a critical role to test the safety and efficacy of specific therapeutic agents.

Fill levels, cost comparisons and expulsion force requirements of commonly used topical ophthalmic steroids

PURPOSE

To determine volume fill levels, estimated costs, and force expulsion requirements per bottle of topical ophthalmic steroids commonly used in the United States.

SETTING

Tertiary care academic referral center.

DESIGN

Prospective laboratory investigation.

METHODS

Eight commercially available medications were tested: loteprednol 0.5%, loteprednol gel 0.5%, loteprednol gel 0.38%, difluprednate 0.05%, generic fluorometholone 0.1%, branded fluorometholone 0.1%, generic prednisolone 1.0%, and branded prednisolone 1.0%. Ten bottles of each medication were tested. A double-blinded method was used to measure actual bottle-fill volume and number of drops dispensed per bottle. The total perioperative cost per drop was calculated for each medication using average cash price. Force requirements were measured using a customized force gauge apparatus. Formulations were compared using Kruskal-Wallis one-way ANOVAs.

RESULTS

All formulations were able to cover postoperative periods commensurate with commonly used dosing regimens for cataract surgery. All medications had greater than sticker volume. Loteprednol 0.5% suspension and branded fluorometholone had the highest and lowest number of drops among the medications tested, respectively. Loteprednol 0.38% gel was the most expensive medication, while generic prednisolone 1.0% was the least expensive. Gel and branded formulations of ophthalmic steroids required less expulsion force compared to other tested formulations.

CONCLUSIONS

Volume fill levels, patient-incurred costs and expulsion force requirements per bottle of topical steroid medications vary widely. Clinicians may wish to consider these findings when determining their perioperative prescribing regimens.

Incidence and complications of retained lens fragment in the anterior chamber after uneventful cataract surgery in a United Kingdom tertiary center

PURPOSE

To analyze the outcomes of retained lens fragment (RLF) in the anterior chamber after uneventful cataract surgery.

SETTING

Moorfields Eye Hospital, NHS Foundation Trust, London, United Kingdom.

DESIGN

Retrospective, observational cross-sectional study.

METHODS

A single-center, retrospective review was performed to identify patients who underwent RLF removal after uneventful phacoemulsification surgery between October 2012 and November 2018; 122 eyes from 121 patients were identified. Patient characteristics, clinical findings, visual outcomes, and need for subsequent surgical procedure were recorded. Main outcomes were change in corrected distance visual acuity (CDVA), and number and risk factors associated with additional surgery following RLF removal.

RESULTS

One hundred twenty-two RLF over a total of 98 467 uneventful phacoemulsification surgeries were identified, with an incidence of 1 (0.124%) in 807 operations. The mean CDVA improved significantly after RLF removal from 0.32 to 0.26 logMAR (SD 0.26) (P = .001). Six eyes (4.9%) had persistent corneal edema that required endothelial keratoplasty (EK) after a mean of 13 months after RLF removal (SD 12 months; median 8; range 4 to 35). Risk factors for EK include α-receptor blocker use (odds ratio [OR], 6.75; 95% CI, 1.069, 42.63), increased interval (month) between cataract surgery and diagnosis of RLF (OR, 1.29; CI: 1.080, 1.541), increased interval between cataract surgery and RLF washout (OR, 1.28; CI, 1.075, 1.522), and RLF diagnosis on gonioscopy (OR, 10.60; CI, 1.885, 59.59).

CONCLUSIONS

RLF is a rare complication of uneventful cataract surgery and appears more frequently in challenging cataract cases and myopic eyes. CDVA improved significantly after RLF removal, but approximately 1 in 20 eyes needed additional surgery-mainly EK for corneal decompensation.

Pharmacologic interventions for mydriasis in cataract surgery

BACKGROUND

Cataract surgery is one of the most common surgical procedures performed worldwide. Achieving appropriate intraoperative mydriasis is one of the critical factors associated with the safety and performance of the surgery. Inadequate pupillary dilation or constriction of the pupil during cataract surgery can impair the surgeon's field of view and make it difficult to maneuver instruments.

OBJECTIVES

To evaluate the relative effectiveness of achieving pupillary dilation during phacoemulsification for cataract extraction using three methods of pupillary dilation: topical mydriatics, intracameral mydriatics, or depot delivery systems. We also planned to document and compare the risk of intraoperative and postoperative complications following phacoemulsification for cataract extraction, as well as the cost-effectiveness of these methods for pupillary dilation.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Eyes and Vision Trials Register) (2021, Issue 1); Ovid MEDLINE; Embase.com; PubMed; Latin American and Caribbean Health Sciences Literature Database (LILACS); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 22 January 2021.

SELECTION CRITERIA

We included only randomized controlled trial (RCTs) in which participants underwent phacoemulsification for cataract extraction.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology.

MAIN RESULTS

We included a total of 14 RCTs (1670 eyes of 1652 participants) in this review. Of the 14 trials, 7 compared topical versus intracameral mydriatics, 6 compared topical mydriatics versus depot delivery systems, and 1 compared all three methods. We were unable to calculate overall estimates of comparative effectiveness for most outcomes due to statistical heterogeneity among the estimates from individual studies or because outcome data were available from only a single study. Furthermore, the certainty of evidence for most outcomes was low or very low, due primarily to imprecision and risk of bias. Comparison 1: topical mydriatics versus intracameral mydriatics Four RCTs (739 participants, 757 eyes) of the 8 RCTs that had compared these two methods reported mean pupillary diameters at the time surgeons had performed capsulorhexis; all favored topical mydriatics, but heterogeneity was high (I2 = 95%). After omitting 1 RCT that used a paired-eyes design, evidence from three RCTs (721 participants and eyes) suggests that mean pupil diameter at the time of capsulorhexis may be greater with topical mydriatics than with intracameral mydriatics, but the evidence is of low certainty (mean difference 1.06 mm, 95% confidence interval (CI) 0.81 mm to 1.31 mm; I2 = 49%). Four RCTs (224 participants, 242 eyes) reported mean pupillary diameter at the beginning of cataract surgery; the effect estimates from all trials favored topical mydriatics, with very low-certainty evidence. Five RCTs (799 participants, 817 eyes) reported mean pupillary diameter at the end of cataract surgery. Data for this outcome from the largest RCT (549 participants and eyes) provided evidence of a small difference in favor of intracameral mydriasis. On the other hand, 2 small RCTs (78 participants, 96 eyes) favored topical mydriatics, and the remaining 2 RCTs (172 participants) found no meaningful difference between the two methods, with very low-certainty evidence. Five RCTs (799 participants, 817 eyes) reported total intraoperative surgical time. The largest RCT (549 participants and eyes) reported decreased total intraoperative time with intracameral mydriatics, whereas 1 RCT (18 participants, 36 eyes) favored topical mydriatics, and the remaining 3 RCTs (232 participants) found no difference between the two methods, with very low-certainty evidence. Comparison 2: topical mydriatics versus depot delivery systems Of the 7 RCTs that compared these two methods, none reported mean pupillary diameter at the time surgeons performed capsulorhexis. Six RCTs (434 participants) reported mean pupillary diameter at the beginning of cataract surgery. After omitting 1 RCT suspected to be responsible for high heterogeneity (I2 = 80%), meta-analysis of the other 5 RCTs (324 participants and eyes) found no evidence of a meaningful difference between the two methods, with very low-certainty evidence. Three RCTs (210 participants) reported mean pupillary diameter at the end of cataract surgery, with high heterogeneity among effect estimates for this outcome. Estimates of mean differences and confidence intervals from these three RCTs were consistent with no difference between the two methods. A fourth RCT reported only means for this outcome, with low-certainty evidence. Two small RCTs (118 participants) reported total intraoperative time. Surgical times were lower when depot delivery was used, but the confidence interval estimated from one trial was consistent with no difference, and only mean times were reported from the other trial, with very low-certainty evidence. Comparison 3: Intracameral mydriatics versus depot delivery systems Only one RCT (60 participants) compared intracameral mydriatics versus depot delivery system. Mean pupillary diameter at the time the surgeon performed capsulorhexis, phacoemulsification time, and cost outcomes were not reported. Mean pupil diameter at the beginning and end of cataract surgery favored the depot delivery system, with very low-certainty evidence. Adverse events Evidence from one RCT (555 participants and eyes) comparing topical mydriatics versus intracameral mydriatics suggests that ocular discomfort may be greater with topical mydriatics than with intracameral mydriatics at one week (risk ratio (RR) 10.57, 95% CI 1.37 to 81.34) and one month (RR 2.51, 95% CI 1.36 to 4.65) after cataract surgery, with moderate-certainty evidence at both time points. Another RCT (30 participants) reported iris-related complications in 11 participants in the intracameral mydriatics group versus no complications in the depot delivery system group, with very low-certainty evidence. Cardiovascular related adverse events were rarely mentioned.

AUTHORS' CONCLUSIONS

Data from 14 completed RCTs were inadequate to establish the superiority of any of three methods to achieve mydriasis for cataract surgery, based on pupillary dilation at different times during the surgery or on time required for surgery. Only one trial had a sample size adequate to yield a robust effect estimate. Larger, well-designed trials are needed to provide robust estimates for the comparison of mydriasis approaches for beneficial and adverse effects.

Phacoemulsification and IOL-Implantation without Using Viscoelastics: Combined Modeling of Thermo Fluid Dynamics, Clinical Outcomes, and Endothelial Cell Density

Phacoemulsification is a widely used surgical method in cataract surgery with a high energy ultrasound source. The viscoelastic is considered to be tissue protective. The aim of this study is to investigate during surgery the impact of using viscoelastic versus no viscoelastic on clinical outcomes, potential complications and effect on endothelial cell density. The study group included 64 patients, who were subjected to phacoemulsification using balanced salt solution (BSS). Control group consisted of 62 patients, who underwent phacoemulsification using Hyaloronic acid 1% Healon 1%. Student’s t-test was applied for statistical analysis. The simulations of temperature changes during phacoemulsification were performed by COMSOL Multiphysics software. In the BSS group, a mean endothelial cell loss (ECL) of 4.5% was measured one month postoperatively, while in the Healon group ECL was 5.3%. Data analysis showed no significant difference in ECL between the groups (Student’s t-test, p = 0.8). No significant difference was observed in endothelial cell morphology and IOP between the two groups pre- and postoperatively (all p > 0.05). The modeling of thermo fluid dynamics showed that the heating of the cornea is slightly less when Healon was used as irrigation fluid. The phacoemulsification technique can be performed by an experienced surgeon with viscoelastics or continuous anterior chamber (AC) irrigation on the same level of safety regarding endothelial cell damage, providing equally satisfying clinical outcomes.

Efficacy of Nepafenac versus Flurbiprofen in Maintaining Intraoperative Mydriasis During Phacoemulsification: A Comparative Study

Purpose

To compare the efficacy of topical nepafenac (0.1%) with flurbiprofen (0.03%) in maintaining intra-operative mydriasis during phacoemulsification surgery.

Patients and Methods

This study comprised of 160 patients, who were divided into two arms of 80 each (arms A and B) after randomisation. Pre-operatively, all patients received one drop of tropicamide 0.8% and phenylephrine 5% (combination), 4 times, at an interval of 15 minutes on the day of surgery. Thereafter, Nepafenac drop in arm A/Flurbiprofen drop in arm B was administered 4 times, at an interval of 15 minutes keeping a gap of 10 minutes between tropicamide-phenylephrine and any of the experimental drugs. Phacoemulsification was performed one hour after the administration of last drop. Both vertical and horizontal pupillary diameter were measured at three steps; immediately before the surgical incision (baseline), at the end of emulsification of nucleus (before irrigation and aspiration) and at the end of surgery (after stromal hydration).

Results

The difference in pupillary diameter between two groups, was statistically insignificant for vertical diameter (P = 0.08) and horizontal diameter (P = 0.28) at the start of surgery. On the other hand, pupillary diameter difference was statistically significant after emulsification of nucleus and at the end of surgery as well when both vertical (P < 0.05) and horizontal diameter (P < 0.05) were considered. The total reduction in pupillary diameter (both vertically and horizontally) was significantly less in the Nepafenac as compared to Flurbiprofen group (P < 0.05). Analysis of mean cumulative dissipated energy did not document any appreciable difference between the two groups. Phacoemulsification time analysis yielded statistically significant results (P = 0.004) between the Nepafenac and Flurbiprofen group.

Conclusion

In the present study, topical Nepafenac (0.1%) proved to be more efficacious in maintaining intra-operative mydriasis during phacoemulsification surgery as compared to topical Flurbiprofen (0.03%).

One-Handed Rotational Phacoemulsification Technique

Introduction

We described a one-handed rotational phacoemulsification technique to decrease phaco time and power, and surgical stress on the cornea in eyes with different types of cataract.

Methods

In this technique a single sutureless corneal incision was made without any side-port incision. After hydrodissection and hydrodelamination were performed, a phaco tip was positioned in contact with the nucleus beside the capsulorhexis edge. By using a peristaltic pump, phacoemulsification was started with high levels of vacuum to keep the probe tip on the edge of the lens and to ensure the rotation of the nucleus, and with low ultrasound energy. The torsional mode used required less occlusion time and volume of fluid. The inclination of the tip was modified to 45-degree, directing it toward the lens center. So the nucleus was aspirated from the periphery toward the center by a rotational movement.

Results

The eye in the technical video had a NC4-NO4 cataract. The preoperative vision in this eye was 20/100 with no improvement with refraction. On postoperative day 1, visual acuity had improved to 20/20. We recorded low intraoperative parameters including ultrasound time (21.4 sec), phacoemulsification power (73%), balanced salt solution used (31 mL) and cumulative dissipated energy (7.27) at the conclusion of the case. After 1 month, Central Corneal Thickness changed from 504 µm to 516 µm, and Endothelial Cell Loss was 1.15%.

Conclusion

This technique uses a single clear corneal incision, high vacuum and low ultrasound power to reduce the exposition to excessive surgical maneuvers, fluid turbulence and ultrasound energy.

Modified manual small incision cataract surgery technique for phacoemulsification-trained surgeons

Purpose:

To present the technique and outcomes of a modified manual small incision cataract surgery designed for the phacoemulsification surgeons who are learning to perform manual small incision cataract surgery.

Methods:

This was a retrospective, single-centred, comparative study. We included all the patients who underwent the modified manual small incision cataract surgery for visually significant cataract at Singapore National Eye Centre. All surgeries were performed by either a senior phaco-trained surgeon (M.A.) who had performed more than 500 manual small incision cataract surgery or a junior phaco-trained surgeon (D.C.) who had performed around 500 phacoemulsification but never performed any manual small incision cataract surgery. The main modification of this technique lies in the creation of an additional phaco-like main wound at 90° to the scleral tunnel wound, with most surgical steps performed through this additional wound. The outcomes were analysed and compared between the senior and junior surgeons. The main outcome measures were visual outcome and major intraoperative complications such as posterior capsular rupture and zonular dialysis.

Results:

A total of 132 cases were included; 102 (77.3%) and 30 (22.7%) cases were performed by the senior and junior surgeons, respectively. Pre-operatively, 85.6% eyes had best-corrected visual acuity of counting fingers or worse. Postoperatively, the visual outcome at 1 month was similar between the senior and junior surgeons, with 68.7% eyes achieving a best-corrected visual acuity of ⩾6/12 (p = 0.17). No posterior capsular rupture, zonular dialysis or endophthalmitis was observed during the study period.

Conclusions:

This modified technique may serve as a useful transition technique for the phaco-trained surgeons to develop skills in manual small incision cataract surgery, with demonstrable good visual outcome and safety.

Comparison of semicircular and bent tips regarding regional differences in oscillation amplitude under various torsional power settings

PURPOSE

To analyze the difference between the behavior of semicircular (balanced) and bent (mini) tips at 20 incremental torsional power settings.

SETTING

Tsukazaki Hospital, Himeji, Japan.

DESIGN

Experimental study.

METHODS

Using an ultra-high-speed video camera HPV-X2, the 2 tips during torsional oscillation were recorded, comparing tip behavior at power settings from 5% to 100% by tracking points 1 to 5 (tip end and at 1325, 2650, 3975, and 5035 μm from the tip end).

RESULTS

Both tips increased their amplitude widths, drawing an S-curve at all points as the torsional power setting was increased, reaching their upper limits from 70% to 90% torsional power. At all 20 power settings, both tips showed significantly different amplitudes (all P < .01), and the difference of the amplitude increased as the power setting increased. Although, at points 1 and 3, the balanced tip amplitude was nearly 1.5 times larger than the mini tip amplitude, the amplitude difference was 10 μm or less at points 2 and 4. At point 5, the mini tip amplitude was at least 3 times more than the balanced tip amplitude.

CONCLUSIONS

The amplitude does not increase proportionally and varies markedly with the tip shape on reaching the upper limit, suggesting that a higher power setting might not contribute greatly to nuclear fragmentation. The balanced tip might cause greater damage to surrounding tissues if it is inserted at approximately 3 mm from the wound site. To obtain maximum shaft stability using the balanced tip, it is important to insert at least 5 mm.

[What will cataract surgery look like in the future? Alternatives in the pipeline]

Phacoemulsification is the most frequently performed surgery in the world. Over the past few years, this surgery seems to have reached a plateau with no further innovative breakthroughs. In this paper, we focus on alternatives techniques, the latest innovations, and the research and development pipeline in this field.

Difluprednate 0.05% versus Prednisolone Acetate Post-Phacoemulsification for Inflammation and Pain: An Efficacy and Safety Clinical Trial

Background

The purpose of this study was to compare the efficacy and safety of difluprednate 0.05% (PRO-145) versus prednisolone acetate 1% (Prednefrin^® SF), for management of postoperative inflammation and pain, after cataract surgery.

Methods

This was a Phase III, multicenter, prospective, double-blind, clinical trial. Intent-to-treat population included 178 post-phacoemulsification patients that were assigned to receive either PRO-145, or prednisolone. One day after unilateral eye surgery, patients instilled a drop 4 times a day for 14 days (then tapering the dose downward for 14 days). The primary efficacy endpoints were anterior chamber (AC) cell grade and flare. Other parameters measured included: retinal central thickness (measured via OCT), conjunctival hyperemia, edema, pain and photophobia. Tolerability and safety were assessed through burning, itching, foreign body sensation, visual acuity (VA), intraocular pressure (IOP) and incidence of adverse events (AE).

Results

A total of 171 subjects were randomized (1:1) and completed the study. Compared to day 1, there was a significant improvement in the AC cell count and flare in both groups by the final visit (80.2% vs 88.4%, p=1.000). Conjunctival hyperemia improved in a similar fashion (81.2% vs 79%, p=0.234) in both PRO-145 and prednisolone groups, without differences between them. This was also observed for edema (82.4% vs 82.5%, p=0.246), pain (15.3% vs 7%, p=0.497) and photophobia (16.4% vs 15.1%, p=0.246), respectively. There was no significant difference between treatments for any tolerability parameter studied. Finally, at the 4-week postoperative visit, there were no significant differences between treatments for VA, IOP and AE results (p-values; 0.095, 0.053 and 0.099, respectively).

Conclusion

The results of this study suggest that PRO-145 is as effective and safe as prednisolone acetate in treating postoperative inflammation and pain in patients undergoing phacoemulsification. The study was registered at ClinicalTrials.gov as NCT03693989.

Scoop and chop - A modified phaco-chop technique for pseudoexfoliation and cataract

PURPOSE

The purpose is to evaluate the results of the modified direct phaco-chop technique of cataract surgery in eyes with pseudoexfoliation.

METHODS

All patients with pseudoexfoliation and visually significant cataract with normal intraocular pressure (IOP) and optic nerve that underwent cataract surgery by the same surgeon using Infiniti^®, OZil^® Torsional handpiece (Alcon Labs), were included for this retrospective hospital-based study. Direct vertical or horizontal chop technique was used in all cases with parameters set as required for quadrant removal with high vacuum after the initial cleanup of cortex under the capsulorhexis. To allow better visualization of the hardness of the nucleus core, the sides of the lens were scooped out a central well with vacuum with maximum chopping done centrally within the rhexis as the first step to enable better assessment of the depth of burying the chopper for direct chop. Intraoperative details recorded and analyzed included ultrasound time and cumulative dissipated energy. The mean visual acuity and IOP before and after surgery were recorded at 1 day, 1 week, and 1 month. Complications during or after surgery were noted.

RESULTS

A total of 138 patients with a mean age of 62 ± 6.7 years underwent phachop technique of phacoemulsification for nuclear cataract grades of nuclear sclerosis 2-4 with significant improvement in visual acuity from baseline (0.26) to 3 months (0.82), P < 0.001. The mean ultrasound torsional amplitude and cumulative dissipated energy (CDE) were greater for brown cataract of grading >3, P = 0.02. A total of 8 patients had intraoperative zonular dialysis in 1 quadrant (none in >1 quadrant), which was not associated with intraoperative vitreous prolapse in 6 eyes.

CONCLUSIONS

Direct modified phaco-chop technique may be a safe technique in pseudoexfoliation due to minimal zonular stress with successful outcomes and reduced complications.

Comparison of power-free-chop and phaco-chop techniques for moderate nuclei

Background

To compare the intraoperative and postoperative effects of power-free-chop and phaco-chop techniques for moderate nuclei in phacoemulsification surgery.

Methods

Sixty patients were evaluated in 2 groups. The power-free-chop technique was performed in Group 1 (30 eyes), and the phaco-chop technique was performed in Group 2 (30 eyes). There were no significant differences between these 2 groups. The cumulative dissipated energy (CDE), time to achieve maximum vision, corneal thickness variation, and time to return to the preoperative values were collected. All parameters were statistically compared in these 2 groups by using the chi-square test and the independent-sample t-test.

Results

The CDE was 5.53 ± 1.92 J in Group 1 and 7.02 ± 1.77 J in Group 2. After the operation, the mean time to recover to the maximum vision was 2.80 ± 1.42 days in Group 1 and 3.80 ± 1.92 days in Group 2. The mean postoperative corneal thickness increased 36.9 ± 14.74 μm in Group 1 and 46.20 ± 20.67 μm in Group 2. The mean time to return to preoperative pachymetry values was 3.73 ± 1.70 days and 4.83 ± 2.11 days in Group 1 and Group 2, respectively. There were significant differences in these parameters between the groups.

Conclusions

The power-free-chop technique had fewer negative effects on the corneal endothelium, as less ultrasound power was used for moderate nucleus cases. This can accelerate the functional healing process and the return to preoperative physiologic values.

Tilt-and-crush: A safe, effective and energy-saving technique for soft cataract removal

BACKGROUND AND OBJECTIVE

The tilt and crush technique is a modified chopping technique developed mainly to maximize safety and effectiveness in emulsifying soft cataracts.

MATERIAL AND METHODS

After clear corneal incision and continuous curvilinear capsulorhexis, the hydro-dissection cannula is introduced under the anterior capsule about 90 degrees to the axis of the main wound and injection of fluid is continued until the distal pole of the nucleus prolapses out of the capsulorhexis rim into the anterior chamber. The centre of the nucleus is then engaged with the phacoemulsification tip using high vacuum and tilted vertically in the anterior chamber. The second instrument is passed behind the full length of the vertically tilted nucleus to crush it against the phacoemulsification tip.

RESULTS

This technique was successfully performed in 517 eyes by a single experienced surgeon. The mean effective phaco time was 0.11 ± 0.32 s, and it was zero in 382 (73.9%) eyes. The mean total phaco time was 4.79 ± 10.71 s. In 322 (62.3%) eyes, no phaco energy was utilized to remove cataract. None of the eyes experienced any complication during or after the surgery.

CONCLUSION

This safe and reliable technique is significantly more energy-efficient compared to other traditional techniques like divide-and-conquer and phaco-chop. Unlike, some widely known pre-chopping techniques, it can be taught easily with good reproducibility.

Nox4-mediated ROS production is involved, but not essential for TGFβ-induced lens EMT leading to cataract

The reactive oxygen species (ROS) producing enzyme, NADPH oxidase 4 (Nox4), is upregulated in response to TGFβ in lens epithelial cells in vitro, and its selective inhibition was shown to block aspects of TGFβ-induced epithelial-mesenchymal transition (EMT). In the present in situ study we validate the role(s) of Nox4 in TGFβ-induced lens EMT leading to anterior subcapsular cataract (ASC) formation. Mice overexpressing TGFβ in the lens, that develop ASC, were crossed to Nox4-deficient mice. When comparing mice overexpressing TGFβ in lens, to mice that were also deficient for Nox4, we see the delayed onset of cataract, along with a delay in EMT protein markers normally associated with TGFβ-induced fibrotic cataracts. In the absence of Nox4, we also see elevated levels of ERK1/2 activity that was shown to be required for TGFβ/Smad2/3-signaling. qRT-PCR revealed upregulation of Nox2 and its regulatory subunit in TGFβ-overexpressing lens epithelial cells devoid of Nox4. Taken together, these findings provide an improved platform to delineate putative Nox4 (and ROS) interactions with Smad2/3 and/or ERK1/2, in particular in the development of fibrotic diseases, such as specific forms of cataract.

Effect of Uncomplicated Cataract Surgery on Central Macular Thickness in Diabetic and Non-diabetic Subjects

Purpose

To assess the quantitative changes of macula in diabetic and non-diabetic eyes after uncomplicated cataract surgery.

Methods

In this prospective interventional study being performed in a tertiary healthcare hospital, a total of 660 eyes were divided into two groups. Group 1 included 330 eyes from healthy subjects and group 2 included 330 eyes from well-controlled diabetic subjects with no diabetic retinopathy planned for phacoemulsification with foldable IOL implantation by the same surgeon under similar settings. Optical Coherence Tomography (Heidelberg Spectralis SD-OCT) was used to assess preoperative and postoperative central macular thickness (CMT) at weeks 1 and 6.

Results

The mean CMT in group 1 preoperatively, at postoperative week 1, and at post-operative week 6 was 257.03 ± 20.904, 262.82 ± 17.010, and 265.15 ± 20.078 µm, respectively. The corresponding values in group 2 were 255.36 ± 17.852, 259.15 ± 16.644, and 266.09 ± 18.844 µm, respectively. There was no significant difference in the mean CMT values between the two groups on any of the three occasions when the CMT was measured (P = 0.374 and P = 0.313 at weeks 1 and 6, respectively).

Conclusion

There was no statistically significant difference in CMT between normal subjects and diabetic subjects without diabetic retinopathy preoperatively and in early postoperative period after uncomplicated phacoemulsification surgery.

Improving clinical refractive results of cataract surgery by machine learning

AIM

To evaluate the potential of the Support Vector Machine Regression model (SVM-RM) and Multilayer Neural Network Ensemble model (MLNN-EM) to improve the intraocular lens (IOL) power calculation for clinical workflow.

BACKGROUND

Current IOL power calculation methods are limited in their accuracy with the possibility of decreased accuracy especially in eyes with an unusual ocular dimension. In case of an improperly calculated power of the IOL in cataract or refractive lens replacement surgery there is a risk of re-operation or further refractive correction. This may create potential complications and discomfort for the patient.

METHODS

A dataset containing information about 2,194 eyes was obtained using data mining process from the Electronic Health Record (EHR) system database of the Gemini Eye Clinic. The dataset was optimized and split into the selection set (used in the design for models and training), and the verification set (used in the evaluation). The set of mean prediction errors (PEs) and the distribution of predicted refractive errors were evaluated for both models and clinical results (CR).

RESULTS

Both models performed significantly better for the majority of the evaluated parameters compared with the CR. There was no significant difference between both evaluated models. In the ±0.50 D PE category both SVM-RM and MLNN-EM were slightly better than the Barrett Universal II formula, which is often presented as the most accurate calculation formula.

CONCLUSION

In comparison to the current clinical method, both SVM-RM and MLNN-EM have achieved significantly better results in IOL calculations and therefore have a strong potential to improve clinical cataract refractive outcomes.

Cataract in diabetes mellitus

Diabetes mellitus (DM) is a chronic systemic disease that has increases in prevalence over time. DM can affect all ocular structures, with cataract being the most common ocular complication. Cataract is the leading cause of blindness worldwide. Due to several mechanisms, there is an increased incidence of cataract formation in the diabetic population. Advancements in technology have now made cataract surgery a common and safe procedure. However, the diabetic population is still at risk of vision-threatening complications, such as diabetic macular edema (ME), postoperative ME, diabetic retinopathy progression, and posterior capsular opacification.

Comparison of two popular nuclear disassembly techniques for cataract surgeons in training: divide and conquer versus stop and chop

PURPOSE

To compare two common phacoemulsification techniques in the learning curve phase, and their effect on ultrasound energy dissipation.

METHODS

One hundred and ten consecutive patients scheduled for cataract surgery with the same surgeon in training were prospectively enrolled. Study was divided in two parts. In the first one, 60 patients were stratified for cataract grade [nuclear opalescence (NO) grade 2-4] and divided in two groups receiving surgery with the divide-and-conquer technique (Group-1) and with the stop-and-chop technique (Group-2). In the second part, 50 patients were stratified according to cataract grade (NO2-6), and the surgeon had to choose one of the two techniques according to personal preference. The primary outcome was the cumulative dissipated energy (CDE).

RESULTS

Significant differences of CDE were observed between the NO3 and NO4 cataracts in Group-1. In Group-2, this difference was not significant, suggesting that with more advanced cataracts, the stop-and-chop technique allows less ultrasound use. In the second part of the study, the stop and chop was most frequently used for more advanced cataracts. When considering harder cataracts (NO5-NO6), patients receiving surgery with the divide-and-conquer technique had higher CDE values compared to stop and chop.

CONCLUSIONS

Both divide-and-conquer and stop-and-chop techniques are efficient in the learning curve. Stop and chop dissipates less energy in harder nuclei. Once surgeons reach sufficient experience with both techniques, they should switch to a stop-and-chop technique, allowing lower levels of ultrasound energy.

Using continuous intraoperative optical coherence tomography to classify swirling lens fragments during cataract surgery and to predict their impact on corneal endothelial cell damage

PURPOSE

To quantify and classify swirling lens fragments during cataract surgery and record their impact on the corneal endothelium using continuous intraoperative optical coherence tomography (OCT).

SETTING

Vienna Institute for Ocular Surgery, Hanusch Hospital, Vienna, Austria.

DESIGN

Prospective case series.

METHODS

Patients scheduled for cataract surgery without other ophthalmologic comorbidities were included. During surgery, continuous OCT recordings were performed to measure and score swirling lens fragments that came into contact with the corneal endothelium. Endothelial cell density (ECD) was measured preoperatively and 1 month postoperatively. In addition, the central corneal thickness and aqueous flare were measured preoperatively and 1 hour, 1 day, and 1 month postoperatively.

RESULTS

Continuous intraoperative OCT video recordings showed 104 swirling lens fragments in 40 eyes that came into contact with the corneal endothelium. A mean of 2.6 lens fragments (range 0 to 6) that came into contact were observed per eye. Small fragments and fragments touching the center of the endothelium had a significantly greater effect on postoperative ECD than other fragment parameters. The predictive power of the fragment score on ECD was found to be moderate (r(2) = 0.6).

CONCLUSIONS

Small swirling lens fragments touching the center of the corneal endothelium had a significant influence on ECD. With the newly developed fragment score, it was possible to predict the operative endothelial cell loss.

FINANCIAL DISCLOSURE

None of the authors has a financial or proprietary interest in any material or method mentioned.

Efficacy of Preoperative Administration of Acetaminophen and Melatonin on Retrobulbar Block Associated Pain in Cataract Surgery

Background

Retrobulbar block is one of the chosen methods for local anesthesia in cataract surgery. Since it is a painful procedure, using analgesic and sedative drugs is recommended. Current medications have side effects and evaluating of new drugs or new uses of existing safer drugs is necessary.

Objectives

The aim of this study was to compare the administration of melatonin and acetaminophen on pain and hemodynamic changes during retrobulbar block.

Methods

In a double-blinded randomized trial, 180 patients undergoing cataract surgery were randomly divided into three groups: Melatonin group (received melatonin 6 mg), acetaminophen group (received acetaminophen 500 mg), and control group (received placebo). All drugs were administered orally 60 min before arrival to the operating room by nurses blinded to the drugs administered. All patients received fentanyl 0.5 μg/kg before retrobulbar block intravenously. Hemodynamic variables and pain score in each patient were evaluated on arrival in the operating room, during retrobulbar block, during surgery, 20 min after operation, at the end of surgery, and in the recovery room. In case of pain score more than three, additional fentanyl was administered. All data were recorded in structured data sheets.

Results

Data analysis indicated no significant differences among the groups at baseline on any of the demographic variables. Both acetaminophen and melatonin reduced the pain score significantly compared with control during retrobulbar block (P < 0.05 and P < 0.01, respectively). Administration of additional fentanyl was significantly lower in the melatonin group than the control group (P < 0.05). Hemodynamic changes were not significantly different among all groups.

Conclusions

For the first time, as far as we have studied, the analgesic effect of acetaminophen on the retrobulbar block was indicated. We also showed that melatonin can reduce pain during retrobulbar block leading to reduction of additional fentanyl during operation. It seems that both melatonin and acetaminophen may have a beneficial effect on pain control in the retrobulbar block.

Numerical stress analysis of the iris tissue induced by pupil expansion: Comparison of commercial devices

Purpose

(1) To use finite element (FE) modelling to estimate local iris stresses (i.e. internal forces) as a result of mechanical pupil expansion; and to (2) compare such stresses as generated from several commercially available expanders (Iris hooks, APX dilator and Malyugin ring) to determine which design and deployment method are most likely to cause iris damage.

Methods

We used a biofidelic 3-part iris FE model that consisted of the stroma, sphincter and dilator muscles. Our FE model simulated expansion of the pupil from 3 mm to a maximum of 6 mm using the aforementioned pupil expanders, with uniform circular expansion used for baseline comparison. FE-derived stresses, resultant forces and area of final pupil opening were compared across devices for analysis.

Results

Our FE models demonstrated that the APX dilator generated the highest stresses on the sphincter muscles, (max: 6.446 MPa; average: 5.112 MPa), followed by the iris hooks (max: 5.680 MPa; average: 5.219 MPa), and the Malyugin ring (max: 2.144 MPa; average: 1.575 MPa). Uniform expansion generated the lowest stresses (max: 0.435MPa; average: 0.377 MPa). For pupil expansion, the APX dilator required the highest force (41.22 mN), followed by iris hooks (40.82 mN) and the Malyugin ring (18.56 mN).

Conclusion

Our study predicted that current pupil expanders exert significantly higher amount of stresses and forces than required during pupil expansion. Our work may serve as a guide for the development and design of next-generation pupil expanders.