Binocular vision and refractive surgery.

Binocular status can have an effect on the outcome of refractive surgery. Some accommodative deviations and anisometropia can be managed effectively. Fully accommodative esotropia has been successfully treated in young patients but the outcome can be less predictable in older patients. High anisometropes are usually unaffected by the change in aniseikonia following refractive surgery but there are exceptions. Failure to recognise and appropriately classify a binocular vision anomaly pre-surgically can result in symptoms that are difficult to manage post-operatively. Refractive surgery producing a binocular vision anomaly where there was none pre-operatively is less common. I present a review of the literature discussing the relationship between binocular vision anomalies and refractive surgery, illustrating the findings with published reports of successful and unsuccessful binocular postoperative outcomes. I argue that predicting the binocular outcome should be considered pre-operatively for every refractive surgery patient.     

Factors influencing patient choice of refractive surgery or contact lenses and choice of centre.

PURPOSE: To explore patient demographics and motivations in choosing refractive surgery (RS) or contact lenses (CL) and factors influencing their choice of practice. METHODS: A questionnaire was presented to 212 RS and 115 CL patients at four RS centres and three CL centres, respectively. The authors, with consent from the clinics and patients, collected all data. No patient or clinic refused to participate in the study. RESULTS: There was no statistical difference between RS and CL groups for gender (p = 0.28), although in both groups more females presented than males. The mean age of RS patients was 39.2 +/- 10.6 years and for CL patients was 32.0 +/- 12.4 years (p < 0.0001). The occupational differences between RS and CL patients were found to be significant (p < 0.0001). Primary motivations for RS or CL were cosmesis and inconvenience of CL and spectacles. The main reason why RS patients did not choose CL was due to the inconvenience; there was little difference in this whether patients had previously worn CL or not. CL patients did not choose refractive surgery due to lack of information and apprehension. RS and CL patients selected their respective centres primarily due to reputation. CONCLUSIONS: Refractive surgery appears increasingly to be a lifestyle choice, possibly based on perceptions and psychological aspects that need to be investigated. The popularity of cosmesis as a highly popular factor for RS and CL patients, together with a few patients citing minor contact lens complications suggests that contact lens clinicians may be able to hold onto patients through better management.     

Medical device labeling and advertising: an overview

The Food and Drug Administration (FDA) has the authority under the Federal Food, Drug, and Cosmetic Act (FDCA) to regulate the labeling of all medical devices. This statement, however, is not as simple as it appears. The regulation of medical device labels and labeling, closely linked to the advertisement of medical devices, is a dynamic area, and FDA is struggling to address the new issues that arise daily in this area. This article seeks to: 1) provide the background necessary to understand the current law and FDA's regulation of medical devices; 2) summarize the law and regulations governing medical devices; 3) define "intended use" and explain its importance; and 4) discuss several areas that are of particular interest to FDA, including promotion of uncleared or unapproved devices and uses, Internet promotion, press releases, and comparative claims.     

Systematic review comparing penetrating keratoplasty and deep anterior lamellar keratoplasty for management of keratoconus

Aim

Perception of reduced incidence of graft rejection after deep anterior lamellar keratoplasty (DALK) has attracted many surgeons towards this technique in keratoconus. This review aims to compare the visual, refractive and graft outcomes after penetrating keratoplasty (PK) and DALK for keratoconus.

The use of the Ocular Response Analyser to determine corneal hysteresis in eyes before and after excimer laser refractive surgery

Purpose

To compare corneal biomechanical parameters and two measures of intraocular pressure (IOP) in eyes before and after excimer laser refractive surgery, with the Ocular Response Analyser (ORA).

Materials and methods

Eighty normal eyes of 41 patients undergoing excimer laser refractive surgery in Birmingham, U.K. were recruited into three groups: Laser Assisted-Epithelial Keratomileusis (LASEK) (Myopes), Laser Assisted in Situ Keratomileusis (LASIK) (myopes) and LASIK (hyperopes). The preop and 3 months postop Goldmann correlated IOP (IOPg), corneal compensated IOP (IOPcc), corneal hysteresis (CH), and corneal resistance factor (CRF) were measured by the ORA. Central corneal thickness (CCT) was measured using ultrasonic pachymeter. The differences of the changes in IOPg, IOPcc, CH, CRF and CCT between the three groups were estimated. A General Linear Model was selected to investigate the influence of gender, age, initial conditions (CH, CRF, CCT, IOPcc and IOPg) and changes in CCT on the measured IOP.

Results

The differences between the mean IOPg, CH and CRF after refractive surgery were statistically significant for all three groups. The hyperopic LASIK group had a significantly smaller change compared to the other groups (which had no statistical significance). The preop IOPg, preop CH and gender were significant predictors of the changes in measured pressure and biomechanical parameters after surgery in the myopic groups only.

Conclusion

CH and CRF were found to decrease after both myopic and hyperopic refractive surgery. CH and CRF measurement may prove important tools to clarify the role of corneal biomechanics for refractive surgery.     

Very long term success of pterygium surgery with conjunctival graft

Purpose

To examine to the very long term prognosis (16 years in average) of pterygium surgery with superior or inferior conjunctival graft.

卷烟工业企业品牌发展与原料供给矛盾的分析与建议

针对品牌发展与原料供给的矛盾,分析了近几年工业企业解决原料问题的主要做法,探讨了当前重点品牌优质原料供给面临的主要问题,提出为解决这一矛盾的建议:1)加强品牌风格特征规划管理;2)保障重点品牌烟叶供给数量;3)保障重点品牌核心原料供给;4)完善烟叶质量监管;5)强化基地单元建设支持力度;6)提升重点品牌原料技术支撑能力;7)提高原料保障应急防灾能力.     

Examination of ocular biomechanics with a new Scheimpflug technology after corneal refractive surgery

PurposeTo analyze the early results of a new device measuring ocular biomechanics after corneal refractive surgery.Patients and methodsThirty nine refractive surgery patients were enrolled in the study (age: 32.6 ± 9.9 years). Laser in situ keratomileusis (LASIK) was performed on 52 eyes of 26 patients and photorefractive keratectomy (PRK) was done on 26 eyes of 13 patients. Ten device-specific biomechanical parameters, intraocular pressure (IOP) and pachymetry were measured preoperatively and at day 1, week 1 and month 1 after the surgeries with a new technology based on Scheimpflug imaging (CorVis ST, Oculus).ResultsIn case of LASIK, the day after the procedure, radius values showed significant differences compared to preoperative data. One month after surgery, radius values, velocity of the second applanation and pachymetry showed significant differences compared to preoperative data. In case of PRK, the day after the procedure, significant differences in IOP, maximum amplitude at the apex, A1 time, A2 velocity and highest concavity time were measured. After 1 month of PRK, there were no differences in the parameters compared to preoperative data except pachymetry.ConclusionsWe observed that some specific biomechanical parameters changed measured with CorVis ST after LASIK and PRK, in the early postoperative time. However, most of these parameters remain unchanged after one month of LASIK and PRK compared to preoperative data.     

Efficacy,predictability and safety of long-term orthokeratology: An 18-year follow-up study

PurposeTo determine the efficacy, predictability and safety of long-term orthokeratology in children and adults.MethodsCase histories of 300 orthokeratology patients (596 eyes; 34.3% children; 65.7% adults) were reviewed to collect information on demographics, corneal and refractive parameters, visual acuity, residual refraction and adverse effects. Predictability was defined as the percentage of eyes with absolute values of spherical equivalent refraction ≤ 0.5 D of emmetropia, and efficacy as the ratio of post-orthokeratology uncorrected and pre-orthokeratology corrected distance visual acuity.ResultsMedian duration of treatment was 37 and 28.5 months in children and adults, respectively (p = 0.022). During the first year, 17.2% of children and 33% of adults ceased lens wear (p < 0.001). For children and adults with a successful ortho-k treatment of at least one year of duration, 88.7% and 95.9% of eyes had a predictable refractive outcome, and efficacy was 0.98 and 1.01, respectively. A larger percentage of children (65.7%) were free of complications than of adults (55.4%) (p = 0.015). One event of microbial keratitis occurred in adults (6.8 cases per 10,000 patient-years) and none in children. Corneal staining was the most frequent complication, with a higher incidence in adults (p = 0.007) and in higher myopia (p < 0.001), higher anterior corneal eccentricity (p = 0.019) and smaller anterior horizontal radius (p = 0.027).ConclusionOrthokeratology is a safe and predictable long-term procedure in children and adults, with a low incidence of serious adverse effects. Corneal staining episodes are relatively frequent throughout the course of the treatment, thus highlighting the relevance of education of experienced users.     

Tobacco industry litigation to deter local public health ordinances: the industry usually loses in court

Background: The tobacco industry uses claims of state preemption or violations of the US Constitution in litigation to overturn local tobacco control ordinances.

Methods: Collection of lawsuits filed or threatened against local governments in the USA; review of previously secret tobacco industry documents; interviews with key informants.

Results: The industry is most likely to prevail when a court holds that there is explicit preemption language by the state legislature to exclusively regulate tobacco. The industry has a much weaker record on claims of implied preemption and has lost all challenges brought under equal protection claims in the cases we located. Although the tobacco industry is willing to spend substantial amounts of money on these lawsuits, it never won on constitutional equal protection grounds and lost or dropped 60% (16/27) of the cases it brought claiming implied state preemption.

Conclusions: Municipalities should continue to pass ordinances and be prepared to defend them against claims of implied preemption or on constitutional grounds. If the ordinance is properly prepared they will likely prevail. Health advocates should be prepared to assist in this process.

     

Discontinuation of long term orthokeratology lens wear and subsequent refractive surgery outcome

Purpose

To report a case of lens discontinuation in a long term orthokeratology (OK) lens wearer and describe regression in refraction, corneal topography, and corneal thickness over 408 days after lens discontinuation. Furthermore, the outcome of subsequent LASIK treatment is also reported.

Eating Well with Canada's Food Guide: "A tool for the times".

This article outlines the processes undertaken to revise Canada's Food Guide and shares the updated science that underpins the dietary pattern. The Dietary Reference Intakes provide updated nutrient requirement values and better tools for dietary assessment and planning. Alignment with this updated science was an important component of defining and communicating accurate dietary guidance for Canada. Ensuring that stakeholders had access to the updated review of requirements led to the development of the text Dietary Reference Intakes: The Essential Guide to Nutrient Requirements. Equally important was ensuring that stakeholders were provided opportunity to influence the approach taken to giving dietary guidance, both content and the elements of the final package. A combination of research, consultation and expert advice guided the process to the release of Eating Well with Canada's Food Guide (2007).     

Issues in the substantiation process of health claims

Attempts are being made at the international level within the framework of the Codex Alimentarius to establish guidelines for health claims. An important issue that has to be addressed is the process of substantiating any health claim. Previous papers have addressed aspects relating to the development and regulatory control of functional foods and certain issues relating to claims. This paper addresses several issues concerning the substantiation of health claims through the examination of the regulations and guidelines in several countries. They include (1) importance of human- and product-based studies; (2) concept of scientific consensus; (3) authorization of claim wording; (4) availability of scientific evidence to public (confidentiality). The paper finally proposes a system based on generic and innovative health claims.     

Perceived relevance and foods with health-related claims

Although consumer perception of the health claims and nutrition information has been studied widely there is relatively little understanding about the motivational factors underpinning claim perception. The objective of this study is to investigate how levels of perceived relevance influence consumers’ responses to health claims that either promise to reduce a targeted disease risk or improve well-being in comparison to other types of health-related messages, and how attitudes towards nutritionally healthy eating, functional food and previous experience relating to products with health claims affect the consumers’ perceptions of nutrition and health claims. The data (N = 2385) were collected by paper and pencil surveys in Finland, the UK, Germany and Italy on a target group of consumers over 35 year old, solely or jointly responsible for the family’s food shopping. The results showed that relevance has a strong influence on perceptions of personal benefit and willingness to buy products with health claims. However the impact of relevance is much stronger when the health risks are relevant to self than when it is relevant to those close to oneself, especially when the claim promises a targeted risk reduction with detailed information about function and health outcome. Previous experience with products with health claims and interest in nutritionally healthy eating promoted the utility of all claims, regardless of whether they were health or nutrition claims. However, to be influenced by health claims consumers also need to have a positive attitude towards functional food products.     

Contact lens fitting post-laser-in situ keratomileusis (LASIK).

Despite recent advances in refractive surgical procedures a small proportion of patients still achieve sub-optimal results for a variety of reasons. In such cases, contact lenses may provide the only option for visual rehabilitation and restoration of binocular vision post-refractive surgery. The indications for contact lenses post-LASIK may be one, or a combination of the following: *Initial bandage lens for corneal protection. *Residual ametropia--over and under correction. *Irregular astigmatism. * Anisometropia. * Decentred ablation zones. In low powered corrections conventional soft lenses can be fitted in the normal way, giving good levels of acuity. Where there is astigmatism (>0.75 DC) then toric soft contact lenses may appropriate. Rigid lenses may prove to be the only viable option in a number of cases where visual correction is required post-refractive surgery, or in the presence of high levels of astigmatism. Fitting can be more complex however, since a conventional rigid lens cannot follow the shape of both the flattened central cornea and the relatively steeper periphery in higher corrections, as the amount of laser ablation increases. Reverse geometry lenses are indicated where there is a significant difference between the flat central ablated zone and the relatively steeper peripheral cornea. On rare occasions scleral lenses may also be indicated.     

Smoker and ex-smoker reactions to cigarettes claiming reduced risk

Context: The tobacco industry is introducing modified tobacco products claiming to reduce the risk of smoking (potential reduced exposure products, PREPs). If PREPs are perceived as safe, they may deter smokers from quitting and encourage re-initiation by smokers who have quit.

Objective: To assess smokers' and ex-smokers' perceptions of PREPs and the impact of PREP claims on interest in quitting (among smokers) or in resuming smoking (ex-smokers).

Design: A random-digit-dialled survey of US smokers and ex-smokers. We used Eclipse, a modified PREP cigarette, as an exemplar PREP. During the survey, the interviewer read risk reduction claims made for Eclipse by its manufacturer, assessing smokers' interest in quitting before and after the exposure.

Participants: 1000 current cigarette smokers and 499 ex-smokers (300 quit within the last two years), over 18 years old.

Main outcome measures: Perception of risk reduction from Eclipse; interest in using Eclipse; smokers' interest in quitting was assessed using a stage of change approach (pre- and post-exposure to claims).

Results: 91% of smokers thought Eclipse was safer than regular cigarettes. 24% believed Eclipse was completely safe. 57.4% of smokers were interested in using Eclipse; interest was greatest among smokers who were contemplating quitting. Exposure to Eclipse's claims was followed by reduced interest in quitting. Among all ex-smokers, interest in Eclipse was 6.2%, but interest was 15.2% among young adults (18–25 years) who had stopped smoking within two years.

Conclusions: There is substantial risk that smokers will overinterpret reduced risk claims made for modified tobacco products. PREPs appeal to smokers who are contemplating quitting and exposure to reduced risk product claims appears to reduce smokers' readiness to quit. PREPs also appealed to young adults who had recently stopped smoking. Thus, reduced risk tobacco product claims can undermine adult cessation and youth prevention, possibly resulting in increased harm even if the products are less toxic.

     

Early clinical outcomes after small incision lenticule extraction surgery (SMILE)

Purpose

Dry eye is known to impact on clinical outcomes after laser vision correction and the use of a newer ‘all femtosecond laser’ surgical approach may be associated with less impact on the ocular surface post-operatively. The purpose of this study was to evaluate the early clinical outcomes and tear instability after the first small incision lenticule extraction (SMILE) cases undertaken by three surgeons at a single site in the UK.

Risk, consent and public debate: some preliminary considerations for the ethics of food safety

Two conceptual frameworks for understanding ethical responsibility with respect to risk impinge on food safety. On the one hand, optimization or public health frameworks define responsibility in terms of outcomes – benefits and harms – that are the result of choosing a particular action or policy. Statistics and probability theory provide a way for advocates of this approach to cope with imperfect or indeterminate knowledge of future outcomes. Informed consent criteria, on the other hand, demand that riskbearers be provided with all available information about the risks to which they are being exposed, and that they have a viable option of nonparticipation – of withholding consent to being placed at risk. Both approaches have relevance to food safety. In application, the optimization approach has relied on scientific assessment of outcomes associated with food-borne pathogens, while the informed consent approach has sanctioned the view that each individual has a right to apply their own definitions and values with respect to which foods are safe. Thus, in practice, 'science' has prescribed a particular theory of moral action – one that promotes optimization, rather than informed consent. By common agreement, science should be neutral with respect to moral claims. Scientists should, thus, find a narrower basis on which to state their factual claims about food safety risk.     

Corneal morphology and visual outcomes in LASIK patients after orthokeratology: A pilot study

A statement of Significance

For the first time, this study shows that corneas that previous undergone orthokeratology treatment do not respond differently to LASIK compared with previous soft contact lens wear experience.

Availability and quality of hi-tech medical care: the multilevel analysis in the system "doctor-patient"

The feature contains the results of public opinion research on accessibility and quality of high-tech medical attendance. The received data, covering a wide range of issues of organization, accessibility, quality and effectiveness of cardiac care, interaction of estimates from the positions of different groups of respondents, which may serve as basis for targeted management decisions to improve the medical care of the population by high-tech medical care in modern conditions and in the near future.