Laser Eye Surgery Research Articles

A Detailed Review of Lenticule-based Refractive Procedures – Kerato-refractive Lenticule Extraction Procedures

Kerato-refractive lenticule extraction (KLEx) is a modern laser eye surgery technique that utilizes a femtosecond laser to create and extract a lenticule from the cornea, correcting refractive errors. Compared to LASIK, KLEx offers advantages such as reduced dry eye symptoms, faster corneal sensation recovery, and potentially better biomechanical strength. However, it also presents the challenges such as a steeper learning curve for surgeons and a higher incidence of intraoperative complications in the initial learning phase. PubMed was searched for lenticule-based refractive procedures with the latest review articles, original articles, and research papers sorted up top and these were used as references for the data in this review. This review explores the procedure, its advantages and disadvantages and compares it to LASIK. It also discusses various KLEx techniques available commercially, including small incision lenticule extraction, cornea lenticule extraction for advanced refractive, SMART SIGHT, and smooth incision lenticular keratomileusis, and their unique features. Various techniques employed for lenticule extraction are discussed too. In addition, the review highlights intraoperative complications associated with KLEx, such as suction loss, black spots, cap lenticular adhesions, and epithelial defects. Overall, KLEx is a viable option for refractive error correction, offering distinct benefits over LASIK. However, careful consideration of the procedure’s risks, benefits, and potential complications is essential for patients and surgeons alike.

Xenon for preoperative management in laser eye surgery: clinical cases

Xenon for preoperative management in laser eye surgery: clinical cases

A modified model for laser-cornea interaction following the ablation effect in the laser eye-surgery

BackgroundLaser corneal reshaping is a successful treatment of many refraction disorders. However, some physical demonstrations for the laser interaction with cornea are not fully explained. In the current paper, we present a modified model to precisely investigate the ablation threshold, the ablation rate and the physical/chemical mechanisms in that action.ResultsThe model discusses the possible photochemical reaction between the incident photons and various components of the cornea. Such photochemical reaction may end by photo-ablation or just molecular electronic excitation. The ablation threshold is also produced by other chemical reaction. Finally another chemical reaction creates out-site fragments. Moreover, the effect of applying different laser wavelengths, namely the common excimer-laser (193-nm), and the solid-state lasers (213-nm & 266-nm) has been investigated.ConclusionDespite the success and ubiquity of the Argon Fluoride “ArF” laser, our results reveal that a carefully designed 213-nm laser gives the same outcomes with the potential of possible lower operational drawbacks related with heat generation and diffusion.

Evaluating Access to Laser Eye Surgery by Driving Times Using Medicare Data and Geographical Mapping

Recently, several states have granted optometrists privileges to perform select laser procedures (laser peripheral iridotomy, selective laser trabeculoplasty, and YAG laser capsulotomy) with the aim of increasing access. However, whether these changes are associated with increased access to these procedures among each state's Medicare population has not been evaluated. To compare patient access to laser surgery eye care by estimated travel time and 30-minute proximity to an optometrist or ophthalmologist. This retrospective cohort database study used Medicare Part B claims data from 2016 through 2020 for patients accessing new patient or laser eye care (laser peripheral iridotomy, selective laser trabeculoplasty, YAG) from optometrists or ophthalmologists in Oklahoma, Kentucky, Louisiana, Arkansas, and Missouri. Analysis took place between December 2021 and March 2023. Percentage of each state's Medicare population within a 30-minute travel time (isochrone) of an optometrist or ophthalmologist based on US census block group population and estimated travel time from patient to health care professional. The analytic cohort consisted of 1 564 307 individual claims. Isochrones show that optometrists performing laser eye surgery cover a geographic area similar to that covered by ophthalmologists. Less than 5% of the population had only optometrists (no ophthalmologists) within a 30-minute drive in every state except for Oklahoma for YAG (301 470 [7.6%]) and selective laser trabeculoplasty (371 097 [9.4%]). Patients had a longer travel time to receive all laser procedures from optometrists than ophthalmologists in Kentucky: the shortest median (IQR) drive time for an optometrist-performed procedure was 49.0 (18.4-71.7) minutes for YAG, and the the longest median (IQR) drive time for an ophthalmologist-performed procedure was 22.8 (12.1-41.4) minutes, also for YAG. The median (IQR) driving time for YAG in Oklahoma was 26.6 (12.2-56.9) for optometrists vs 22.0 (11.2-40.8) minutes for ophthalmologists, and in Arkansas it was 90.0 (16.2-93.2) for optometrists vs 26.5 (11.8-51.6) minutes for ophthalmologists. In Louisiana, the longest median (IQR) travel time to receive laser procedures from optometrists was for YAG at 18.5 (7.6-32.6) minutes and the shortest drive to receive procedures from ophthalmologists was for YAG at 20.5 (11.7-39.7) minutes. Although this study did not assess impact on quality of care, expansion of laser eye surgery privileges to optometrists was not found to lead to shorter travel times to receive care or to a meaningful increase in the percentage of the population with nearby health care professionals.

Single-pulse, reference-free, spatiospectral measurement of ultrashort pulse-beams

High-intensity pulse-beams are ubiquitous in scientific investigations and industrial applications ranging from the generation of secondary radiation sources (e.g., high harmonic generation, electrons) to material processing (e.g., micromachining, laser-eye surgery). Crucially, pulse-beams can only be controlled to the degree to which they are characterized, necessitating sophisticated measurement techniques. We present a reference-free, full-field, single-shot spatiospectral measurement technique called broadband single-shot ptychography (BBSSP). BBSSP provides the complex wavefront for each spectral and polarization component in an ultrafast pulse-beam and should be applicable across the electromagnetic spectrum. BBSSP will dramatically improve the application and mitigation of spatiospectral pulse-beam structure.

Factor analysis of the risk of developing primary open-angle glaucoma

To assess the significance of risk factors in POAG development based on multivariate analysis of variance. The study included 348 patients (348 eyes) with stages I-IV POAG aged 45 to 87 years, who underwent a comprehensive ophthalmological and genetic examination. The control group consisted of 48 individuals (48 eyes) without glaucoma, matched with POAG patients in terms of gender and age. Ophthalmological examination of patients was carried out in 2013-2019 at the «Optimed» Laser Eye Surgery Center in Ufa, molecular genetic research - at the Institute of Biochemistry and Genetics of the Ufa Federal Research Center of the Russian Academy of Sciences. The results were statistically processed using the IBM SPSS Statistics v.21 program. The multivariate analysis employed the principal component method. Correlations between patient parameters and main factors were calculated using the method of rotation - varimax. The significance level was taken equal to 0.05 when testing statistical hypotheses. Factor analysis was used to rank the factors associated with POAG development, the following variables were attributed to the most significant indicators of high risk (16.75% of the total variance) of developing the disease: age, comorbidity index, cataract, pseudoexfoliative syndrome, pigmentation intensity in the anterior chamber angle. Factor analysis is a multivariate method of mathematical analysis that allows studying the role of the risk factors for POAG development and their association with the disease, which contributes to early diagnosis and identification of clinical and functional features of the disease.

Sweet Potato Leaves Contain Beta Carotene and Lutein for Eye Health

This article discusses the benefits of sweet potato leaves containing beta carotene and lutein for eye health. There are some problems of eyes namely Conjunctivitis, Dry Eyes , Cataract, Glaucoma and Refractive errors (blurred vision). Treatment options include surgery, including laser and traditional eye surgery. Sweet potatoes are high in beta-carotene and anthocyanins, which are powerful antioxidants that can help prevent eyesight loss and support eye health. Beta carotene (provitamin A) and vitamin C are plentiful in yellow sweet potato. The beta carotene and lutein content is beneficial for eye health.

Surgeries and Diagnostic Procedures in Hemophilia Patients on Concizumab Prophylaxis: Results from the Phase 2 Explorer4 and Explorer5 Trials

Surgeries and Diagnostic Procedures in Hemophilia Patients on Concizumab Prophylaxis: Results from the Phase 2 Explorer4 and Explorer5 Trials

ReLEx® SMILE® – the third generation of laser eye surgery

ReLEx® (Refractive lenticule extraction) SMILE® (SMall Incision Lenticula Extraction) is the third generation of laser eye surgery, which is a follow-on to PRK (the first generation) and LASIK (the second generation). This technology has expanded the possibilities for the comfort and safety of the procedure, reduced the requirements for the thickness of the cornea, and made it extremely comfortable for the patient. SMILE® method helps improve vision in case of myopia, myopic and mixed astigmatism. The article analyzes the advantages and disadvantages of this technology, its possible risks and side effects. The data represented in this article was obtained by analyzing scientific publications and practical expertise.

The Impact of Eye Exercises on High Myopia and Visual Acuity in Patients Aged (15-30) Years

High myopia is a state in which the spherical equivalent objective refractive error is ≤ -5.00 Diopters (D) in either eye. Currently, there are several treatment options to correct high myopia including laser eye surgery, refractive lens exchange, pharmaceutical treatment, and others. This study focuses on physiotherapy treatment and aims to evaluate the potential advantage of applying new physical exercises for the eyes of patients aged between 15-30 years, was applied on 50 patients with a known case of high myopia who were recruited through criteria based purposive sampling, they visit the optical clinic routinely at the Medical Technical University. The optometrist assessed the refractive errors and visual acuity of subjects using a Snellen’s chart and an auto refractometer, then the eye exercises treatment was done by the specialist physician. The effect of physical exercises on the eyes was determined by comparing the visual acuity of patients before and after the treatment through the SPSS program, and the result was found to be significant with a P-value = 0.0281<0.05. Therefore, eye exercises provide an enhancement in visual acuity, ocular health, and correct the refractive error of high myopia resulting in better vision.

Pressure wave focusing effects following laser medical procedures in human eyes

Comparative analysis of pressure wave propagation, following laser-induced ablation of the human cornea, was performed. Evolution of the pressure field as well as temporal and spatial dependencies of the transient pressure amplitudes created at various input laser parameters, corresponding to different typical procedures of laser eye surgery, is presented comprehensively. The computations were performed with the next generation of the acoustic eye model, previously validated against existing measurements. The analysis allows the assessment of potentially problematic regions within the eye where the resultant positive and/or negative pressure may exceed values which are considered safe for the patient.

Коррекция состояния глазной поверхности у пациентов с синдромом «сухого глаза» на этапе подготовки к кераторефракционной операции

Aim: to analyze the prevalence of dry eye disease (DED) among adult patients with ametropias and the efficacy of its complex treatment when preparing the ocular surface for corneal refractive surgery.Patients and Methods: 1,762 patients with ametropias were examined. In addition to all of the standard eye checks, vital conjunctival and corneal staining, Scheimpflug corneal topography, and anterior segment OCT as well as patient survey were performed. Standard preservative-free tear substitutes with or without a short course of steroids, lubricants, 0.05% anionic cyclosporine emulsion (twice daily), and long-term punctal plugs were prescribed for DED.Results: mild DED was diagnosed in 1,021 patients (57.9%). Of them, corneal lesion was reported in 362 patients (35.4%) and asymptomatic DED in 250 patients (25.5%). Corneal topographic indices of one or both eyes were abnormal (as a result of DED) in 147 patients (14.4%). Significant (p≤0.05) increase in corneal epithelial thickness of one or both eyes was reported in 564 patients (55.2%). Ocular surface treatment in DED patients allowed for uncomplicated corneal refractive procedures while target refraction was achieved in 1,006 patients (98.5%). Conclusion: a complex diagnostic approach to DED involving specific tests, patient survey, corneal topography, and OCT provides the diagnosis of both manifest and latent DED. Combined treatment for conjunctival and corneal xerosis that includes tear substitutes, topical cyclosporine, and punctal plugs, improves ocular surface health in DED thus enlarging the list of indications and the safety of laser eye surgery in these patients.Keywords: dry eye disease, laser eye surgery, corneal refractive procedures, anionic cyclosporine emulsion, punctal plugs, corneal epithelium.For citation: Klokova O.A., Damashauskas R.O., Geidenrich M.S. Ocular surface treatment in dry eye patients before corneal refractive surgery. Russian Journal of Clinical Ophthalmology. 2020;20(4):180–186. DOI: 10.32364/2311-7729-2020-20-4-180-186.

An Analysis of YouTube Videos as Educational Resources for Patients About Refractive Surgery.

The aim of the study was to assess the quality of videos on YouTube as educational resources about refractive surgery. This is a retrospective, cross-sectional, register-based study. A search of YouTube was performed for the term "refractive surgery" without any changes to the Web site's standard search preferences. The first 160 videos were recorded. Additional videos from the search engine were also searched for the other common terms "LASIK," "PRK," and "laser eye surgery." The first 50 videos for each additional term were evaluated. A total of 310 videos were evaluated regarding DISCERN score (min-max: 16-75), Journal of the American Medical Association score (min-max: 0-4), and Global Quality score (min-max: 0-5). Once 135 videos that did not meet the inclusion criteria were excluded from the sample, the remaining 175 videos were analyzed. The mean DISCERN, Journal of the American Medical Association, and Global Quality scores were 33.25 ± 15.34 (poor quality), 0.74 ± 0.82 (lowest quality), and 1.74 ± 0.81 (poor quality), respectively. Of the 175 videos, 77 (42%) had been uploaded by physicians, 67 (38.2%) by health channels, 16 (9.1%) by patients, and another 15 (8.5%) by medical organizations. Although some of the analyzed online videos contain beneficial information, YouTube videos do not generally seem to be useful as educational resources for patients about refractive surgery. Nevertheless, health care professionals should continue to assess the reliability and usefulness of medical information provided by online resources from the viewpoint of patients.

Refrakcyjna wymiana soczewki z wszczepieniem soczewki trójogniskowej Alcon AcrySof® IQ PanOptix® – kontrowersja czy standard

Refractive lens exchange is still relatively new and slightly controversial method of correcting the refractive errors. The surgery consists of extracting the patient’s own lens using phacoemulsification technique in non-existent or irrelevant for sight opacifications in lens and implant of artificial intraocular lens. With modern surgery technique improvements and higher multifocal intraocular lens availability allowing the wide spectrum of acute vision, this technique becomes an attractive alternative to laser vision correction, especially in societies with higher presbyopia rates. The study included 7 patients (11 eyes) operated solely for refractive errors and/or presbyopia with Alcon AcrySof® IQ PanOptix® implant. In examination we evaluated refractive errors, both corrected and uncorrected visual acuity for distance and near, and improved quality of life and patient satisfaction after surgery. Refractive lens exchange is an effective alternative to laser eye surgery, at the same time being free from laser limitations such as high myopia or hyperopia, cornea thickness or dry eye syndrome.

Trends in narcotics and sedative use during mechanical ventilation of preterm infants in Canadian neonatal intensive care units

ObjectiveMechanical ventilation (MV) in preterm infants (PTI) causes discomfort. Whether it causes pain is controversial. Meta analysis reviews of published work on PTI during MV have shown no clinically significant impact of opioids on pain scales, and hence not recommended for routine use in neonatal intensive care units (NICUs). Similarly regular use of sedative midazolam is also not recommended. Therefore we hypothesized a downward trend in narcotics and sedatives used in MV of PTI in NICUs. This study aimed to assess trends of sedatives and narcotics use during MV of PTI in Canadian NICUs during 2004-2009. MethodsPTI born at gestational age (GA) of 24 hours were identified retrospectively from the Canadian Neonatal Network database for 2004-2009. PTI were excluded if moribund on admission, had major congenital anomalies, surgery (except laser eye surgery), necrotizing enterocolitis, chest tube or history of maternal narcotic abuse. PTI were classified according to whether they received any narcotics (morphine, fentanyl, methadone, sufentanyl, meperidine, alfentynl and codiene) or sedatives (chloral hydrate, midazolam, lorazepam, phenobarbital, pentobarbital, ketamine and propofol) for > 24 consecutive hours during MV. Trends of narcotics and sedatives were assessed using the Cochrane-Armitage Trend test separately for PTI born at <29 and 29-34 weeks of GA. ResultsAmong 5 638 study subjects, 2 169 (38.5%) received narcotics and 897 (15.9%) received sedatives. The most common narcotics were morphine (62.2%) and fentanyl (63.8%) and sedatives were phenobarbital (44.9%) and chloral hydrate (44.2%). A significant decreasing trend (P <0.01) in the use of any sedatives during MV was observed in PTI <29 and 29-34 weeks of GA. However, the use of any narcotics during MV increased significantly (P=0.03) among PTI <29 weeks of GA, and no change in trend was detected for PTI born at 29-34 weeks of GA. ConclusionsThe use of sedatives during MV in PTI born at <35 weeks of GA was positively affected, however the narcotics use during MV remained constant for PTI born at 29-34 weeks, and increased in extremely low GA group (less than 29 weeks) suggesting evidence based practice change was not observed during the study period.

Eyesight: a study of the staff of a dental school

Objectives/Aims:The aim was to investigate the vision of all 90 dentally qualified staff at a dental school.Materials and Methods:Ethical approval was obtained and a questionnaire-based survey conducted. Data were screened and analysed using Stata 13.1. The χ2 and Fisher’s Exact tests were used to test for significance with an alpha level of 0.05.Results:The participation rate was 95.6%. Most of the teachers (92%) considered their eyesight was satisfactory to practice dentistry. Of the 97% who had been tested at some stage, 15% had their eye examination due to sight deterioration with 22% needing correction. Almost two-thirds were myopic and a third were hyperopic. Forty-nine per cent wore spectacles only, with about a quarter of this group alternating between spectacles and contact lenses. Of those with corrected vision, 80% followed their optometrist’s recall advice. Four participants reported that they were colour blind. While 4% had had laser-eye surgery, a further 27% were interested in this. Magnification was used by 72% with no significant differences between genders, age of staff member, place of qualification or registration status. Most of the staff (81%) thought that screening of dental student’s eyesight should be mandatory, and regular eye examinations as a condition of dental practice was supported by 67%.Discussion:The number of teachers reporting recent vision tests was encouraging; nevertheless, a worrying 8% surveyed were unsure if their eyesight was satisfactory for work. The commonest vision problem was myopia, with almost half of the teachers wearing spectacles. It is clear that visual standards for dentistry would be helpful. Magnification use was high, with many non-users indicating their intention to buy loupes.Conclusions:Within the limits of this study the teachers were conscientious regarding their eye care, irrespective of their training and age. There was strong support for the mandatory testing of vision for all dentists and especially dental students.

Vibration isolation of large fan array air handling units in healthcare

A new hospital facility constructed in Denver, CO, has all the mechanical equipment that is typically on the roof of the building located directly over all the Operating Rooms (ORs). Many of the ORs are used for procedures involving equipment found in new facilities like high powered microscopes for laser eye surgery or neurosurgery, ceiling mounted high-definition video displays and robotic surgical systems using high resolution cameras. All of which are vibration sensitive. Also, in the future the client wanted flexibility in how the operating rooms are used as the equipment and procedures will change. Because “fan array” mechanical units, produce less vibration than traditional air handling units, they were selected by the design team. The air handling units varied in size from medium with six supply and six return fans to very large with 22 supply and 16 return fans. Because of their size and location in the building, the units were loaded into the facility in multiple modular sections that were then bolted together. This required the development of a vibration isolation solution that allowed for the easy assembly of the mechanical units on site. The rational for the location of the mechanical rooms above the operating rooms will be discussed along with the vibration criteria, analysis, and details of the isolation system. This includes vibration measurements of the final results.

Individual Differences in Scotopic Visual Acuity and Contrast Sensitivity: Genetic and Non-Genetic Influences.

Despite the large amount of variation found in the night (scotopic) vision capabilities of healthy volunteers, little effort has been made to characterize this variation and factors, genetic and non-genetic, that influence it. In the largest population of healthy observers measured for scotopic visual acuity (VA) and contrast sensitivity (CS) to date, we quantified the effect of a range of variables on visual performance. We found that young volunteers with excellent photopic vision exhibit great variation in their scotopic VA and CS, and this variation is reliable from one testing session to the next. We additionally identified that factors such as Circadian preference, iris color, astigmatism, depression, sex and education have no significant impact on scotopic visual function. We confirmed previous work showing that the amount of time spent on the vision test influences performance and that laser eye surgery results in worse scotopic vision. We also showed a significant effect of intelligence and photopic visual performance on scotopic VA and CS, but all of these variables collectively explain <30% of the variation in scotopic vision. The wide variation seen in young healthy volunteers with excellent photopic vision, the high test-retest agreement, and the vast majority of the variation in scotopic vision remaining unexplained by obvious non-genetic factors suggests a strong genetic component. Our preliminary genome-wide association study (GWAS) of 106 participants ruled out any common genetic variants of very large effect and paves the way for future, larger genetic studies of scotopic vision.

ESPRESSO: A novel device for laser-assisted surgery of the anterior eye segment

Introduction: Merging robotics with laser eye surgery could enhance precision, repeatability and automation. During some eye laser procedures the patient is awake, thus eye stabilization is desired to avoid movements that could affect the treatment. Material and methods: The ESPRESSO platform has a two-stage actuation system to position a stabilization tool on the eye, a proximity sensing unit to monitor the stabilization tool position, and a sensing unit to monitor the pressure exerted on the eye. The platform is tested in-vitro and ex-vivo with clinicians. A maximum pressure to be exerted on the eye is defined with expert ophthalmic surgeons to be 22 mmHg: physiological intraocular pressure (IOP) range is 10-21 mmHg. This pressure corresponds to a force of 0.3 N. Results: The necessary contact force to have eye fixation (according to the clinicians' feedback) is evaluated: maximum values resulted always below 0.3 N. A maximum IOP increase of 4.67 mmHg is observed, that is a slight variation with respect to the performance of other platforms (IOP elevations up to 328 mmHg). Conclusion: Design and initial assessment of the platform is presented. Eye stabilization is performed without exceeding the critical contact force value and causing large/sudden IOP increases.

PO-0441 Oxygen Reduction Initiative That Decreased Incidence And Severity Of Retinopathy Of Prematurity Results In Favourable Neuropsychological Outcomes At Age Three

Background and aims High oxygen exposure has adverse long-term medical consequences in premature infants. We hypothesised that a quality improvement initiative decreasing oxygen saturation limits in NICU-admitted infants would affect neuropsychological outcomes at age 3. Methods We studied 83 NICU-admitted participants born at 23–27 weeks; n = 37 (b.2009–2010) with targeted supplemental oxygen rates of 83–93% until 32 weeks, 85–95% until 35 weeks, and >95% after 35 weeks (O 2 Reduced); 8% laser eye surgery; 65% ROP compared with n = 46 (b.2007–2008) with higher target rates (89–100%; O 2 Higher); 28% laser eye surgery; 83% ROP. Group mortality rates ( 2 (n = 83, df=1)= 0.16, p = 0.900. ANCOVAs and regressions were conducted for 19 neuropsychological outcomes. Results O 2 Reduced performed significantly better than O 2 Higher in visual attention, controlling GA (p = 0.042; d= .47); O 2 Reduced was significantly correlated with visual attention (r = 0.288, p 5); ROP was not (r=-0.183, p > 0.05). 18/19 outcome scores favoured O 2 Reduced, low-to-moderate effect sizes ( d range:12–0.47). GA was positively related to all outcomes. A meaningful interaction effect between GA and O 2 Reduced for auditory attention and manual dexterity explained 3%-4% unique variance, respectively. Interaction showed O 2 Reduced’s effect on attention was greatest at 23–24 weeks, and at 27 weeks for manual dexterity. Conclusions Systematic reduction of saturation parameters that decreased retinopathy and laser surgery rates in infancy resulted in favourable three-year-old outcomes suggesting cognitive as well as medical advantages for O 2 Reduced. Moderate effect sizes demonstrated important associations between reduced oxygen saturation rates and 18/19 sensitive performance-based measures. Lowered targeted oxygen saturation rate had favourable yet differential effects across GA in extremely premature survivors.