Improvement of Multiple Generations of Intraocular Lens Calculation Formulae with a Novel Approach Using Artificial Intelligence.

Purpose: Cataract surgery is the most common eye surgery. Appropriate optimization of intraocular lens (IOL) calculation formulae can result in improved patient outcomes. The purpose of this article is to describe a methodology of optimizing existing IOL formulae and develop hybrid formulae based on artificial intelligence (AI). Methods: Preoperative biometric and postoperative outcomes data were obtained from medical records at a single institution. A numeric computing environment was used to analyze these data and refine IOL formulae using supervised learning AI. The mean absolute error of each IOL formulae with and without AI enhancement was determined, as well as the number of eyes within 0.5 diopter of the predicted refraction. Results: AI algorithms improved the mean absolute error as well as number of eyes within 0.5 diopters of predicted refraction for each of the formulae tested (P < 0.05). Conclusions: A novel methodology is described that uses AI to improve existing IOL formulae. This methodology has the potential to improve clinical outcomes for cataract surgery patients. Translational Relevance: Artificial intelligence can be used to improve existing IOL formulae.

Twist and out intraocular lens removal.

Foldable acrylic posterior chamber intraocular lenses (PC IOLs) can be removed via a variety of methods. In this technique, the PC IOL is freed from its position in the capsular bag or sulcus space and raised into the anterior chamber. The IOL is manipulated such that a haptic is externalized through a 2.2 mm corneal incision. A spatula is inserted through a paracentesis incision and placed above the PC IOL. Straight forceps are inserted through the main incision and the haptic/optic junction closest to the paracentesis is grasped with the hand completely supinated. The hand is then pronated while rolling the PC IOL around the forceps using the spatula to guide the PC IOL and guard the cornea. The forceps are then retracted through the main wound, enveloped by the PC IOL, thereby removing an acrylic PC IOL in its entirety using standard intraocular instruments through a 2.2 mm incision.

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

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

Intraocular lens calculations in atypical eyes.

Cataract surgery is the most performed surgical procedure in the field of ophthalmology. The process of intraocular lens (IOL) calculations is a critical step to achieving successful outcomes. Many IOL formulae exist to guide surgeons through the difficult process of picking the most appropriate lens to achieve a certain target refraction. However, these formulae reach within 0.50 diopters of the target refraction only 75% of the time, leaving 25% of the eyes with a significant refractive surprise. A literature review was performed to investigate all the relevant published material on the history, progress, and recent advancements of IOL calculations. Based on this review, the appropriate history, evolution, progress, limitations, and recent advancements are analyzed and explained. Although the modern IOL formulae and biometric devices perform well for average eyes, they are suboptimal for eyes with atypical biometric parameters and also those that are postrefractive and keratoconic. There has not been a single, perfect formula that can resolve the complexities of this process. Various methods of formula optimization and newer generation of IOL formulae and devices may hold the key to improving outcomes in both typical and atypical eyes. These solutions minimize refractive error by introducing new input parameters and complex mathematical techniques to better estimate postoperative lens position.

Cataract surgery in the small eye.

UNLABELLED: The surgical management of cataract in the small eye presents the ophthalmic surgeon with numerous challenges. An understanding of the anatomic classification in addition to a thorough preoperative assessment will help individualize each case and enable the surgeon to better prepare for the obstacles that might be encountered during surgery. Small eyes are especially challenging in terms of intraocular lens (IOL) calculations and possible current limitations of available IOL powers, which could necessitate alternative means of achieving emmetropia. Surgical strategies for minimizing complications and maximizing good outcomes can be developed from knowledge of the anatomic differences between various small-eye conditions and the pathologies that may be associated with each. A thorough understanding of the challenges inherent in these cases and the management of intraoperative and postoperative complications will ensure that surgeons approaching the correction of these eyes will achieve the best possible surgical results. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

A 3-D "Super Surface" Combining Modern Intraocular Lens Formulas to Generate a "Super Formula" and Maximize Accuracy.

IMPORTANCE: Cataract surgery is the most common eye surgery. Calculating the most accurate power of the intraocular lens (IOL) is a critical factor in optimizing patient outcomes. OBJECTIVES: To develop a graphical method for displaying IOL calculation formulas in 3 dimensions, and to describe a method that uses the most accurate and current information on IOL formulas, adjustments, and lens design to create one "super surface" and develop an IOL "super formula." DESIGN, SETTING, AND PARTICIPANTS: A numerical computing environment was used to create 3-D surfaces of IOL formulas: Hoffer Q, Holladay I, Holladay I with Koch adjustment, Haigis, and SRK/T. The surfaces were then analyzed to determine where the IOL powers calculated by each formula differed by more than 0.5, 1.0, and 1.5 diopters (D) from each of the other formulas. Next, based on the current literature and empirical knowledge, a super surface was rendered that incorporated the ideal portions from 4 of the 5 formulas to generate a super formula. Last, IOL power values of a set of 100 eyes from consecutive patients at an eye institute were calculated using the 5 formulas and super formula. The study was performed from December 11, 2014, to April 20, 2015. Analysis was conducted from February 18 to May 6, 2015. MAIN OUTCOMES AND MEASURES: Intraocular lens power value in diopters and the magnitude of disparity between an existing individual IOL formula and our super formula. RESULTS: In the 100 eyes tested, the super formula localized to the correct portion of the super surface 100% of the time and thus chose the most appropriate IOL power value. The individual formulas deviated from the optimal super formula IOL power values by more than 0.5 D 30% of the time in Hoffer Q, 16% in Holladay I, 22% in Holladay I with Koch adjustment, 48% in Haigis, and 24% in SRK/T. CONCLUSIONS AND RELEVANCE: A novel method was developed to represent IOL formulas in 3 dimensions. An IOL super formula was formulated that incorporates the ideal segments from each of the existing formulas and uses the ideal IOL formula for an individual eye. The expectation is that this method will broaden the conceptual understanding of IOL calculations, improve clinical outcomes for patients, and stimulate further progress in IOL formula research.

Evaluating teaching methods: validation of an evaluation tool for hydrodissection and phacoemulsification portions of cataract surgery.

PURPOSE: To develop and assess the validity of an evaluation tool to assess quantitatively the hydrodissection and phacoemulsification portions of cataract surgery performed by residents. DESIGN: Case series. SETTING: Jules Stein Eye Institute, Olive View-UCLA Medical Center, and Veterans Administration Medical Center, Los Angeles, California, USA. METHODS: The UCLA ophthalmology faculty members were surveyed and the literature was reviewed to develop a grading tool consisting of 15 questions to evaluate surgical technique, including questions from the Global Rating Assessment of Skills in Intraocular Surgery and from the International Council of Ophthalmology's Ophthalmology Surgical Competency Assessment Rubric. Video clips of the hydrodissection and phacoemulsification portions of cataract surgery performed by 1 postgraduate year 2 (PGY2) resident, 1 PGY3 resident, 2 PGY4 residents, and an advanced surgeon were independently graded in a masked fashion by an 8-member faculty panel. RESULTS: Eleven of the 15 questions had a significant association with surgical experience level (P<.05, analysis of variance). Interobserver variability in grading yielded intraclass correlation coefficients between 0.28 and 0.72. The questions with the lowest interobserver variability were hydrodissection questions on instrument handling, flow of operation, and nucleus rotation. Nucleus cracking also had low variability. Less directly visible tasks, especially 3-dimensional tasks, had wider interobserver variability. CONCLUSIONS: Surgical performance can be validly measured using an evaluation tool. Improved videography and studies to identify the best questions for evaluating each step of cataract surgery may help ophthalmic educators more precisely measure training outcomes for improving teaching interventions. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Management of the subluxated crystalline lens.

The surgical management of ectopia lentis presents the ophthalmic surgeon with numerous challenges and options. From the clinical evaluation to the surgical approach, ectopia lentis patients require additional methodologies, techniques, and devices to ensure the best possible outcome. The continued refinement of surgical techniques and adjunctive prosthetic devices has led to incremental improvements in the ability to achieve successful in-the-bag placement and centration of intraocular lenses while reducing complications. A thorough understanding of the challenges inherent in ectopia lentis cases and the management of intraoperative complications will ensure that surgeons approaching the correction of these eyes will achieve the best possible surgical results.

Evaluating teaching methods of cataract surgery: validation of an evaluation tool for assessing surgical technique of capsulorhexis.

PURPOSE: To develop and assess the validity of an evaluation tool to quantitatively assess the capsulorhexis portion of cataract surgery performed by residents. SETTING: University of California at Los Angeles (UCLA), Department of Ophthalmology, Jules Stein Eye Institute, Los Angeles, California, USA. DESIGN: Masked prospective case series. METHODS: Ophthalmology faculty members at UCLA were surveyed and literature was reviewed to develop a grading tool comprising 12 questions to evaluate surgical technique, including 4 from the Global Rating Assessment of Skills in Intraocular Surgery and 2 from the International Council of Ophthalmology's Ophthalmology Surgical Competency Assessment Rubric. Video clips of continuous curvilinear capsulorhexis (CCC) performed by 2 postgraduate year (PGY) 3 residents, 2 PGY 4 residents, and 2 advanced surgeons were independently graded in a masked fashion by a 7-member faculty panel. RESULTS: Four questions had low interobserver variability and a significant correlation with surgical skill level (intraclass correlation coefficient >0.75; P<.05, analysis of variance; 42 observations). The 4 questions were visual Likert-scale questions grading flow of operation, set up for regrasp, commencement of flap and formation, and circular completion of the CCC. CONCLUSIONS: Surgical performance can be validly measured using an evaluation tool. However, not all evaluation questions produced reliable results. The reliability and accuracy of the measurements appear to depend on the form and content of the question. Studies to optimize assessment tools identifying the best questions for evaluating each step of cataract surgery may help ophthalmic educators more precisely measure outcomes for improving teaching interventions. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Methicillin resistance of Staphylococcus species among health care and nonhealth care workers undergoing cataract surgery.

PURPOSE: The purpose of this study is to characterize the bacterial flora of the ocular and periocular surface in cataract surgery patients and to determine the prevalence of methicillin resistance among staphylococcal isolates obtained from health care workers (HCWs) and non-HCWs. METHODS: In this prospective, multicenter, case series study, eyelid and conjunctival cultures were obtained from the nonoperative eye of 399 consecutive cataract patients on the day of surgery prior to application of topical anesthetics, antibiotics, or antiseptics. Speciation and susceptibility testing were performed at the Dean A. McGee Eye Institute. Logistic regression was utilized to evaluate whether any factors were significant in predicting the presence of methicillin-resistant staphylococcal isolates. RESULTS: Staphylococcus epidermidis (62.9%), followed by S. aureus (14.0%), was the most frequently isolated organism. Methicillin-resistant S. epidermidis accounted for 47.1% (178/378) of S. epidermidis isolates, and methicillin-resistant S. aureus accounted for 29.5% (26/88) of S. aureus isolates. Methicillin-resistant staphylococcal isolates were found in 157 of 399 (39.3%) patients, the majority (89.2%) of whom were non-HCWs. The likelihood of being colonized with methicillin-resistant organisms increased with age (odds ratio [OR], 1.27; 95% confidence interval [CI]: 1.02-1.58; P = 0.04) but decreased with diabetes (OR, 0.51; 95% CI: 0.29-0.89; P = 0.02). Being a HCW (OR, 1.25; 95% CI: 0.61-2.58; P = 0.54) was not a risk factor for colonization with methicillin-resistant organisms. CONCLUSION: Patients without exposure to health care environments are as likely as HCWs to be colonized with methicillin-resistant organisms. Increasing methicillin resistance with age may partially explain the increased risk of endophthalmitis reported with older age.

Use of triamcinolone acetonide particles to visualize aqueous outflow.

Using triamcinolone acetonide suspension within the anterior chamber allows visualization of fluid outflow for glaucoma surgeries where aqueous egress from the eye is desired for pressure control. Dilute non-preserved triamcinolone acetonide particles can be injected into the anterior chamber at the end of intraocular surgeries to assess fluid outflow and to provide an anti-inflammatory effect at the end-target tissue.

Surgical techniques in phacoemulsification.

PURPOSE OF REVIEW: Recent advances in cataract surgical techniques are described, focusing on the evolution towards less traumatic surgery. RECENT FINDINGS: Smaller incisions, split infusion, astigmatic management, and techniques of managing floppy iris syndrome are significant changes in the cataract surgical technique within the last 12-24 months. SUMMARY: Surgeons need to learn the new techniques and instrumentation as cataract surgery moves towards less invasive surgery, with smaller incisions, more precise refractive outcomes, and fewer complications.

Phaco fluidics and phaco ultrasound power modulations.

The most common surgical procedure in the United States is cataract surgery; most specifically, phacoemulsification. Understanding the fluidics and ultrasonic power fundamentals for phacoemulsification is instrumental for their safe and efficient use. Although phaco machines allow a few decades ago, the basic concepts have remained the same. Phaco machines allow ultrasonic-assisted aspiration of the cataract while maintaining the stability within the eye and minimizing the trauma of surgery to ocular structures. In this light, the two primary concepts are the fluidics of the lens aspiration and the application of the ultrasound power.