Oxidative stress and antioxidants in cataract development.

PURPOSE OF REVIEW: Oxidative stress plays a central role in cataract pathogenesis, a leading cause of global blindness. This review delves into the role of oxidative stress in cataract development and key biomarkers - glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), and 4-hydroxynonenal (4-HNE) - to clarify their functions and potential applications in predictive diagnostics and therapies. RECENT FINDINGS: Antioxidants serve as pivotal markers in cataract pathogenesis. GSH affects the central lens due to factors such as enzyme depletion and altered connexin expression, impairing GSH diffusion. Age-related oxidative stress may hinder GSH transport via connexin channels or an internal microcirculation system. N-acetylcysteine, a GSH precursor, shows promise in mitigating lens opacity when applied topically. Additionally, SOD, particularly SOD1, correlates with increased cataract development and gel formulations have exhibited protective effects against posterior subscapular cataracts. Lastly, markers of lipid peroxidation, MDA and 4-HNE, have been shown to reflect disease severity. Studies suggest a potential link between 4-HNE and connexin channel modification, possibly contributing to reduced GSH levels. SUMMARY: Oxidative stress is a significant contributor to cataract development, underscoring the importance of antioxidants in diagnosis and treatment. Notably, GSH depletion, SOD decline, and lipid peroxidation markers are pivotal factors in cataract pathogenesis, offering promising avenues for both diagnosis and therapeutic intervention.

Intracameral antibiotics during cataract surgery: efficacy, safety, and cost-benefit considerations.

PURPOSE OF REVIEW: We summarize evidence-based considerations regarding the use of intracameral antibiotics during cataract surgery. RECENT FINDINGS: The use of intraoperative intracameral antibiotics reduced the incidence of postcataract surgery endophthalmitis 3.5-fold, with an odds ratio ranging from 0.14 to 0.19. A survey of the American Society of Cataract and Refractive Surgery showed usage of intracameral injections of antibiotics increased by 16% in the United States between 2014 and 2021. The frequency of vancomycin usage has sharply dropped to 6%, while moxifloxacin is now the dominant choice at 83% among respondents. One analysis showed that 2500 patients need to be treated with intracameral antibiotics to prevent one case of endophthalmitis. A 500 µg intracameral moxifloxacin at $22 dollars per dose is cost-effective, including for patients with posterior capsular rupture (PCR). SUMMARY: Studies substantiate the safety and efficacy of intracameral antibiotics for endophthalmitis prophylaxis. Intracameral moxifloxacin and cefuroxime are the most common choices. While vancomycin shows potential for efficacy, further studies evaluating clinical outcomes are needed. Adverse events are rare and commonly due to errors in preparation. Topical antibiotics do not provide additional prophylactic benefits to intracameral regimens. Intracameral antibiotics given alone are cost-effective.

Light adjustable intraocular lenses in cataract surgery: considerations.

PURPOSE OF REVIEW: Light adjustable intraocular lens (LAL) is a promising concept in cataract surgery. This review explores considerations for the use of LALs. RECENT FINDINGS: Through updates, the safety of LALs and light delivery devices have been enhanced, enabling more efficient treatment with lower ultraviolet (UV) energy. Preoperative topography and aberration are essential for understanding indications for LALs. Furthermore, when determining intraocular lens power, it is crucial to factor in potential postoperative myopia or hyperopic adjustments. This is achieved by establishing a proper postimplantation refractive target and considering potential wavefront changes. Postoperative adjustments for defocus and astigmatism have demonstrated excellent outcomes. Monovision strategy by adjustable blended vision of LALs revealed distance vision of 20/20 along with near vision of J2 in 96% of patients. However, the results of clinical studies on postrefractive cataract surgery showed contrasting outcomes at distance, indicating the need for further research results regarding its effectiveness. A new postoperative workflow needs to be designed to enable a systematic follow-up process. SUMMARY: LALs are safe and demonstrate promising refractive outcomes. To achieve appropriate results, understanding the changes in optical characteristics associated with adjustment and constructing a new postoperative workflow are necessary.

Axial length and pharmacologic pupillary dilation in highly myopic patients.

PURPOSE: To determine how high myopia impacts pharmacological pupillary dilation, and to evaluate the relationship between the extent of pharmacologic pupillary dilation and axial length. METHODS: Patients were grouped into high myopes, defined as one or both eyes having a refractive error greater than - 6 diopters, and controls (between - 2 and + 2 diopters). Dilation was achieved with 1 drop each of tropicamide 1% and phenylephrine 2.5%. Pupil size was measured at full and dim light prior to dilation, then 15 and 30 min after dilation. Biometry was measured for each patient. Statistical analyses were performed using the Mann-Whitney-Wilcoxon tests, two-sample Welch's t-tests, and linear mixed effect models and generalized estimating equations models accounting for inter-eye correlation. RESULTS: Forty patients (20 high myopes and 20 controls, 80 eyes total) participated in the study. High myopes had larger pupils at baseline and achieved significantly greater pupillary size (7.08 mm, 95% CI: 6.97 to 7.19 mm) than controls (6.23 mm, 95% CI: 5.94 to 6.52 mm) after 30 min of dilation (P < .0005). Fully dilated pupil size at 30 min was significantly correlated with both refractive error (r = - 0.57, P < .0005) and axial length (r = 0.47, P < .0005). Generalized estimating equations and linear mixed effect models identified other predictive variables of pupil size after dilation including age and white-to-white diameter. CONCLUSIONS: Highly myopic patients dilate to a larger pupillary size compared to other patients. Predicting dilation based on extent of myopia could facilitate intraocular surgery planning and reduce clinic wait times for myopic patients.

Advances in drug therapy and delivery for cataract treatment.

PURPOSE OF REVIEW: Cataract is one of the leading causes of blindness worldwide and surgery is the only available treatment. Pharmacological therapy has emerged as a potential approach to combat the global shortage of surgery due to a lack of access and resources. This review summarizes recent findings in pharmacological treatment and delivery, focusing on drugs that target oxidative stress and the aggregation of crystallins. RECENT FINDINGS: Antioxidants and oxysterols have been shown to improve or reverse lens opacity in cataract models. N-acetylcysteine amide and N-acetylcarnosine are two compounds that have increased bioavailability over their precursors, alleviating the challenges that have come with topical administration. Studies have shown promising results, with topical N-acetylcarnosine clinically decreasing lens opacity. Furthermore, lanosterol, and more recently 5-cholesten-3b,25-diol (VP1-001), have been reported to combat the aggregation of crystallins in vivo and ex vivo . Delivery has improved with the use of nanotechnology, but further research is needed to solidify these compounds' therapeutic effects on cataracts and improve delivery methods to the lens. SUMMARY: Although further research in drug dosage, delivery, and mechanisms will need to be conducted, pharmacologic therapies have provided new strategies and treatments for the reversal of cataracts.

Evaluating the accuracy of a cataract surgery simulation video in depicting patient experiences under conscious anesthesia.

PURPOSE: To evaluate the accuracy of a point-of-view cataract surgery simulation video in representing different subjective experiences of patients undergoing the procedure. METHODS: One hundred consecutive post-cataract-surgery patients were shown a short simulation video of the surgery obtained through a porcine eye model during the first postoperative week. Patients then answered a multiple-choice questionnaire regarding their visual and tactile intraoperative experiences and how those experiences matched the simulation. RESULTS: Of the patients surveyed (n = 100), 78% (n = 78) recalled visual experiences during surgery, 11% recalled pain (n = 11), and 6.4% (n = 5) recalled frightening experiences. Thirty-six percent of patients (n = 36) were interviewed after their second cataract surgery; there was no statistically significant difference between anxiety scores reported before the first eye surgery and second eye surgery (p = 0.147). Among all patients who recalled visual experiences (n = 78), nearly half (47.4%) reported that the video was the same/similar to their experience. Forty-eight percent of the patients recommended future patients to watch the video before their procedures, and more than a third (36%) agreed that watching the video before surgery would have helped them to relax. CONCLUSIONS: Our model reflects the wide range of subjective patient experiences during and after surgery. The high percentage of patients who found the video accurate in different ways suggests that, with more development, point-of-view cataract simulation videos could prove useful for educational or clinical use. Further research may be done to confirm the simulation's utility, by screening the video for subjects before operations.

Advancements in intraocular lens power calculation formulas.

PURPOSE OF REVIEW: We review recent studies comparing intraocular lens (IOL) formulas with an emphasis on selection of the highest performing formulas based on patient axial length, age, and history of previous corneal refractive surgery. RECENT FINDINGS: The Barrett Universal II formula based on a theoretical model has consistently demonstrated high accuracy. The Olsen four-factor formula using ray tracing optics and the Hill-RBF calculator using artificial intelligence have also demonstrated good prediction results after being updated. Notably, the Kane formula, incorporating artificial intelligence, has overall shown the best performance for all axial lengths. Although newly developed and updated IOL formulas have improved refractive prediction in patients with short or long axial length eyes or prior history of corneal refractive surgery, these challenging cases still require special consideration. The Barrett True-K formula has shown accurate results regardless of preoperative data in eyes with previous myopic refractive surgery. SUMMARY: Advancements in optical biometry and IOL calculation formulas continue to improve refractive outcomes. The clinician can optimize refractive outcomes in the majority of patients with the use of formulas that have shown consistent results and accuracy in several large studies.

Efficient use of ultrasound in cataract surgery.

PURPOSE OF REVIEW: Modern phacoemulsification machines apply ultrasound through a variety of settings and parameters to remove a cataract. Using these new technologies efficiently is critical for both reducing surgical times and improving postoperative outcomes. The present article reviews recent findings in phacodynamics to explore the optimum use of ultrasound in cataract surgery. RECENT FINDINGS: In studies seeking to determine the optimum parameters in both fluidics and power, increased power and aspiration does not necessarily equate to more efficiency. New developments, such as torsional ultrasound, micropulse, and burst mode have shown increased efficiency in randomized control trials and in-vitro compared with conventional ultrasound. Regarding vacuums, the venturi pump has demonstrated greater efficiency compared with the peristaltic pump. We also explore other parameters, such as chamber pressure and tip selection. Meta-analyses on femtosecond-laser assisted cataract surgery (FLACS) have shown similar long-term visual outcomes compared to conventional cataract surgery. SUMMARY: Though conventional cataract surgery remains highly effective, surgeons have increasing options for customizing their ultrasound settings and phacoemulsification techniques.

Recent developments in anterior capsulotomy for cataract surgery.

PURPOSE OF REVIEW: Successful anterior capsulotomy is an important step in cataract surgery. This article reviews the various anterior capsulotomy techniques available to surgeons to optimize the step, including those that have become available since the introduction of femtosecond-laser-assisted cataract surgery (FLACS). Studies comparing the relative advantages of each technique will be emphasized. RECENT FINDINGS: Manual continuous curvilinear capsulorhexis (CCC) and FLACS remain the two most widely studied techniques for achieving anterior capsulotomy. Each technique has been shown to be effective for a wide range of patients and cataract surgery complications. Meta-analyses have shown that FLACS provides similar results to manual CCC for long-term cataract surgery outcomes. Several alternative methods for anterior capsulotomy have been described, which aim to provide some of the advantages of laser capsulotomy at a lower cost; among these, precision pulse capsulotomy (PPC) and selective laser capsulotomy (SLC) have been investigated the most in the literature so far. SUMMARY: Cataract surgeons have an increasing number of techniques for anterior capsulotomy available. Manual CCC and FLACS remain the most widely used, and most well studied. The latest techniques, PPC and SLC, have shown promise in the few studies performed since they were introduced.

Cataract and systemic disease: A review.

We review the current literature regarding the risk factors for cataract and the association between cataract and systemic disease. Numerous epidemiologic studies have found that the risk factors for age-related cataract formation include age, sex, race and myopia. Modifiable risk factors include smoking, socioeconomic status and ultra-violet light exposure. Alcohol intake and nutritional status may play a role in cataract formation. Cataract has been associated with many systemic diseases mainly diabetes mellitus, hypertension, obesity, chronic kidney disease and autoimmune disease. Cataract is also a hallmark of many metabolic disorders and syndromes. These findings are important to help implement risk factor and lifestyle-modification strategies that can hopefully decrease the burden of global cataract blindness.

Topical Recombinant Human Nerve Growth Factor (Cenegermin) for Neurotrophic Keratopathy: A Multicenter Randomized Vehicle-Controlled Pivotal Trial.

PURPOSE: To evaluate the efficacy and safety of topical cenegermin (recombinant human nerve growth factor) in patients with neurotrophic keratopathy. DESIGN: Multicenter, randomized, double-masked, vehicle-controlled trial. PARTICIPANTS: Patients with neurotrophic persistent epithelial defect with or without stromal thinning. METHODS: The NGF0214 trial, conducted among 11 sites in the United States, randomized 48 patients 1:1 to cenegermin 20 µg/ml or vehicle eye drops, 6 drops daily for 8 weeks of masked treatment. Follow-up was 24 weeks. Safety was assessed in all patients who received study drug. Efficacy was assessed by intention to treat. MAIN OUTCOME MEASURES: The primary end point was healing of the neurotrophic lesion (persistent epithelial defect or corneal ulcer) after 8 weeks of masked treatment. Masked central readers measured neurotrophic lesions in randomized clinical pictures, then assessed healing status conventionally (<0.5 mm of fluorescein staining in the greatest dimension of the lesion area) and conservatively (0-mm lesion staining and no other residual staining). Secondary variables included corneal healing at 4 weeks of masked treatment (key secondary end point), overall changes in lesion size, rates of disease progression, and changes in visual acuity and corneal sensitivity from baseline to week 8. RESULTS: Conventional assessment of corneal healing showed statistically significant differences at week 8: compared to 7 of 24 vehicle-treated patients (29.2%), 16 of 23 cenegermin-treated patients (69.6%) achieved less than 0.5 mm of lesion staining (+40.4%; 95% confidence interval [CI], 14.2%-66.6%; P = 0.006). Conservative assessment of corneal healing also reached statistical significance at week 8: compared to 4 of 24 vehicle-treated patients (16.7%), 15 of 23 cenegermin-treated patients (65.2%) achieved 0 mm of lesion staining and no other residual staining (+48.6%; 95% CI, 24.0%-73.1%; P < 0.001). Moreover, the conservative measure of corneal healing showed statistical significance at week 4 (key secondary end point). Compared to vehicle, cenegermin-treated patients showed statistically significant reductions in lesion size and disease progression rates during masked treatment. Cenegermin was well tolerated; adverse effects were mostly local, mild, and transient. CONCLUSIONS: Cenegermin treatment showed higher rates of corneal healing than vehicle in neurotrophic keratopathy associated with nonhealing corneal defects.

The quest for homeopathic and nonsurgical cataract treatment.

PURPOSE OF REVIEW: Age-related cataract occurs when crystallin proteins in the lens partially unfold and subsequently aggregate. Physicians and traditional healers alike have been exploring pharmacologic cataract treatment for hundreds of years. Currently, surgery is the only effective treatment. However, there are an abundance of homeopathic and alternative remedies that have been suggested as treatment for cataract. This article reviews the current understanding of cataract development and discusses several homeopathic remedies purported to treat age-related cataract. Additionally, we will present an overview of evidence regarding the development of pharmacologic cataract reversal therapies. RECENT FINDINGS: Some homeopathic therapies have been shown to prevent cataract development in experimental models. More studies are required to elucidate the potential medicinal and toxic properties of the various alternative therapies. However, in recent years, scientists have begun to investigate substances that address cataract by reversing lens protein aggregation. One such compound, lanosterol, was reported to reverse cataract opacity in vitro and in animal models. Subsequently, 25-hydroxycholesterol and rosmarinic acid were identified as having similar properties. SUMMARY: Although challenges and uncertainties remain, further research has the potential to lead to the development of a nonsurgical therapeutic option for age-related cataract.

Iris reconstruction suturing techniques.

PURPOSE OF REVIEW: When patients have large iris defects, they may experience debilitating glare, halos, and unfavorable cosmetic appearance. Surgical iris reconstruction can alleviate these symptoms. This article will review current suturing techniques for iris reconstruction, as well as the benefits and drawbacks to various suturing methods. Alternative reconstructive methods are also discussed. RECENT FINDINGS: One of the earliest iris suturing methods described was the McCannel technique. This technique allows direct suturing of the iris using three incisions. The Siepser slipknot is another method used in closed chamber iris suturing techniques. This knot, and its recent modifications, utilizes a sliding knot, which is created outside the eye and slid into place atop the iris defect. The cerclage iris suture, in which small bites are taken around the pupillary circumference, is especially useful when treating a mydriatic pupil. Recently, a number of surgeons have adapted these techniques and developed novel suturing strategies to address complex ocular conditions. SUMMARY: The various iris suturing methods, as well as alternative techniques including cautery, corneal tattooing, and iris prosthetics, each have unique benefits, providing surgeons with a wide array of tools for iris reconstruction.

Hand hygiene and instrument sanitization in ophthalmology clinics.

PURPOSE OF REVIEW: This article reviews the various challenges in infection control in eye clinics and successful measures taken to prevent nosocomial infections. RECENT FINDINGS: The Center for Disease Control recommends hand-washing when hands are visibly soiled, and after direct contact with patients, and inanimate objects such as medical equipment. Published studies have identified poor hygiene in clinical settings as a major cause of nosocomial outbreaks, particularly in cases of epidemic keratoconjunctivitis (EKC). Some studies of EKC outbreaks are able to support direct observation of hygiene lapses with molecular analysis that can match viral strains on particular instruments to those found in infected patients. Although most studies are about adenoviral infection and tonometer use, researchers have found viral and bacterial loads on other common surfaces, indicating a need for further research. SUMMARY: Proper hygiene in eye clinics requires special attention because of the potential to examine many patients at a time and because multiple instruments are often used during a single exam. Studies reinforce the link between hygiene and outbreak prevention, and more research can be done to determine the specific links between certain instruments and nosocomial infections.

Chronic Conjunctivitis From a Retained Contact Lens.

PURPOSE: To help clinicians diagnose and manage unilateral recalcitrant chronic bacterial conjunctivitis secondary to a retained soft contact lens and describe the first report of Gram-negative bacteria causing this condition. METHODS: Chart review of successive cases presenting with unilateral chronic conjunctivitis with positive cultures and a retained contact lens. RESULTS: Three cases were identified and described. Culturing of the retained contact lenses grew Pseudomonas aeruginosa in the first case, Achromobacter xylosoxidans in the second, and Staphylococcus epidermidis in the third. All three patients were successfully treated with removal of the retained lens and targeted antibiotic eyedrop therapy. CONCLUSIONS: Unilateral chronic recurrent or recalcitrant purulent papillary conjunctivitis is rare, and a retained contact lens should be suspected in patients with a history of wearing contact lenses. Careful examination with double eversion of the upper eyelid and sweeping of the fornices can recover the offending lens. Although only Gram-positive organisms have been isolated in previous reports, two of our three cultures grew Gram-negative organisms, highlighting the importance of broad-spectrum antibiotic usage for these cases.

Nutritional effect on age-related cataract formation and progression.

PURPOSE OF REVIEW: To provide a comprehensive summary of the latest evidence-based data on nutrients linked to the pathogenesis of cataract formation and progression. RECENT FINDINGS: This summary of peer-reviewed publications emphasizes the ongoing effort to modulate the cataractogenous process through nutrition, and points at an only weak evidence for the contribution of a specific nutrient to this process. Although observational studies successfully demonstrated a positive correlation between specific nutrients intake and age-related cataract, such evidence was usually lacking in following interventional studies. Three metanalyses point towards a beneficial effect of high intake of vitamin C, vitamin E and vitamin A on the risk of age-related cataract. New studies point at a protective effect of a high intake of vitamin K1 and vitamin D but negate the influence of Mediterranean diet or an overall high dairy consumption on the progression of cataract in a subgroup of patients. Sterols are candidate nutrients for future investigation. SUMMARY: Nutrition rich in fruits and vegetables, and a high dietary intake of vitamins A, C, D, E and K1 may be inversely associated with the risk of age-related cataract. More studies involving patients in a wide range of nutritional status are required to establish the long-term benefit of nutritional supplements.

Cataract grading systems: a review of past and present.

PURPOSE OF REVIEW: To provide a comprehensive summary of past cataract grading systems, how they have shaped current grading systems, and the developing technologies that are being used to assess and grade cataracts. RECENT FINDINGS: This summary of cataract grading systems examines the development and limitations that existed in past grading systems and how they have shaped the grading systems of present time. The Lens Opacities Classification System III (LOCS III) system is currently used both clinically and for research purposes. Recent advancements in imaging technologies have allowed researchers to create automatic systems that can locate lens landmarks and provide cataract grading scores that correlate well with LOCS III clinical grades. Utilizing existing technologies, researchers demonstrate that fundus photography and optical coherence tomography can be used as cataract grading tools. Lastly, deep learning has proved to be a powerful tool that can provide objective and reproducible cataract grading scores. SUMMARY: Cataract grading schemes have provided ophthalmologists with a way to communicate clinical findings and to compare new developments in diagnostic technologies. As technologies advance, cataract grading can become more objective and standardized, allowing for improved patient care.

Video recording and light intensity change analysis during cataract surgery using an animal model.

PURPOSE: To estimate light exposure changes during cataract surgery through intraoperative images simulated from the "patient's perspective" using an animal model. METHODS: In this experimental study, a 3-mm maculostomy was performed through the posterior globe's surface of 15 porcine eyes. Eyes were fixated to a glass slide and placed over an iPad camera. Video footage of a cataract surgery was obtained through the maculostomy for each eye, keeping light exposure parameters and focus constant. Seventy-five images, five from each eye, were extracted at pre-determined points, and mean gray value (MGV), a light intensity measure, was calculated. Differences in MGV between discrete surgical steps were evaluated using multiple one-sample t-tests. RESULTS: This technique allowed for the capture of a full-length cataract surgery through a 3-mm maculostomy. MGV range was 14.21-132.51. Light intensity was similar across surgeries and varied greatly through each procedure. A 24% decrease in MGV between post-hydrodissection and post-phacoemulsification stages was noted (difference - 18.36; 95% CI - 30.50 to - 6.22; p value = 0.006). A 22.4% decrease in light intensity was noted after phacoemulsification in comparison to the starting image (MGV difference - 16.78; 95% CI - 32.45 to - 1.12; p value: 0.0375). Light intensity was similar at the start and end of surgery (difference - 7.15; 95% CI - 19.35 to + 5.05; p value = 0.229). CONCLUSIONS: Light intensity changes through different steps of cataract surgery and may be minimal after phacoemulsification completion. This video and data may serve as informational and educational tools for surgeons and patients.