Objective

To measure the effect of cataract extraction and lens implantation on elderly persons' health-related quality of life and on their ability to perform visual activities.

Design

Evaluations of health status were conducted preoperatively and at 3 and 12 months after surgery on patients scheduled for cataract extraction.

Setting

Patients were enrolled from the General Eye Service of the Massachusetts Eye and Ear Infirmary and 33 Boston practices.

Patients

The cohort consisted of 464 patients aged 65 years or older who were identified from the surgical schedule of the Massachusetts Eye and Ear Infirmary. At 3 to 12 months after surgery, 458 (99%) of the participants were successfully contacted. Health-related quality of life data were available for 419 (90%) to assess changes after surgery.

Main outcome measures

Ophthalmologic examinations were performed preoperatively and during the follow-up period. The Activities of Daily Vision Scale (ADVS) and the Medical Outcomes Study 36-item short from (SF-36) were administered before surgery and at 3 and 12 months postoperatively to assess changes in health status.

Results

At 12 months after surgery, 95% of patients had improved Snellen visual acuity, 80% had improved ADVS scores, but only 36% had improved SF-36 physical functioning. Average scores on seven of eight SF-36 subscales worsened at 12 months. Patients with improved ADVS scores had significantly smaller declines across all SF-36 dimensions except for role limitations due to emotional problems.

Conclusion

Improved visual function after cataract surgery was associated with better health-related quality of life, suggesting that age-related declines in health may be attenuated by improvements in visual function.

Objective

To develop a model to predict visual functional improvement after cataract extraction with intraocular lens implantation based on preoperative data.

Design

A prospective study with serial evaluations of visual function preoperatively and at 3 and 12 months after surgery.

Setting

The General Eye Service of the Massachusetts Eye and Ear Infirmary. Boston, Mass, and 33 ophthalmology practices in Boston.

Patients

Patients (N = 426; ages, > or = 65 years) who were undergoing cataract surgery.

Methods

Twelve-month improvement in visual function was measured by using the Activities of Daily Vision Scale (ADVS). Ordinal logistic regression was used to identify correlates of improved ADVS scores in 281 patients (derivative set). Potential factors included the preoperative visual acuity, preoperative ADVS score, four chronic ocular diseases, eight medical conditions, and demographic characteristics. Five predictors were identified and used to construct a prediction rule. The accuracy of the prediction rule was evaluated in an independent group of 145 patients (validation set).

Results

Postoperatively, 40% of the 281 patients in the derivative set had substantial improvement in their ADVS scores, and 53 (19%) had some improvement. Predictors of improvement included younger age (P < .001), a poorer preoperative ADVS score (P < .001), posterior subcapsular cataract (P = .09), and absence of age-related cataract (P = .09), and absence of age-related macular degeneration (P = .07) and/or diabetes (P = .006). When applied to the independent sample of 145 patients, these five characteristics classified the patients into three groups in which the probabilities of substantial improvement were 85%, 34%, and 3%, thus verifying the discriminatory power of the prediction rule.

Conclusions

Preoperative data can identify patients who are likely to have improvements in visual function after cataract surgery. Such findings may be useful in the selection of patients for this high-volume procedure.

Global tropospheric ozone distributions, budgets, and radiative forcings from an ensemble of 26 state-of-the-art atmospheric chemistry models have been intercompared and synthesized as part of a wider study into both the air quality and climate roles of ozone. Results from three 2030 emissions scenarios, broadly representing "optimistic," "likely," and "pessimistic" options, are compared to a base year 2000 simulation. This base case realistically represents the current global distribution of tropospheric ozone. A further set of simulations considers the influence of climate change over the same time period by forcing the central emissions scenario with a surface warming of around 0.7K. The use of a large multimodel ensemble allows us to identify key areas of uncertainty and improves the robustness of the results. Ensemble mean changes in tropospheric ozone burden between 2000 and 2030 for the 3 scenarios range from a 5% decrease, through a 6% increase, to a 15% increase. The intermodel uncertainty (±1 standard deviation) associated with these values is about ±25%. Model outliers have no significant influence on the ensemble mean results. Combining ozone and methane changes, the three scenarios produce radiative forcings of -50, 180, and 300 mW m^-2, compared to a CO2 forcing over the same time period of 800-1100 mW m^-2. These values indicate the importance of air pollution emissions in short- to medium-term climate forcing and the potential for stringent/lax control measures to improve/worsen future climate forcing. The model sensitivity of ozone to imposed climate change varies between models but modulates zonal mean mixing ratios by ±5 ppbv via a variety of feedback mechanisms, in particular those involving water vapor and stratosphere-troposphere exchange. This level of climate change also reduces the methane lifetime by around 4%. The ensemble mean year 2000 tropospheric ozone budget indicates chemical production, chemical destruction, dry deposition and stratospheric input fluxes of 5100, 4650, 1000 and 550 Tg(O3) yr^-1, respectively. These values are significantly different to the mean budget documented by the Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report (TAR). The mean ozone burden (340 Tg(O3)) is 10% larger than the IPCC TAR estimate, while the mean ozone lifetime (22 days) is 10% shorter. Results from individual models show a correlation between ozone burden and lifetime, and each model's ozone burden and lifetime respond in similar ways across the emissions scenarios. The response to climate change is much less consistent. Models show more variability in the tropics compared to midlatitudes. Some of the most uncertain areas of the models include treatments of deep tropical convection, including lightning NOx production; isoprene emissions from vegetation and isoprene's degradation chemistry; stratosphere-troposphere exchange; biomass burning; and water vapor concentrations. Copyright 2006 by the American Geophysical Union.

Air quality transcends all scales with in the atmosphere from the local to the global with handovers and feedbacks at each scale interaction. Air quality has manifold effects on health, ecosystems, heritage and climate. In this review the state of scientific understanding in relation to global and regional air quality is outlined. The review discusses air quality, in terms of emissions, processing and transport of trace gases and aerosols. New insights into the characterization of both natural and anthropogenic emissions are reviewed looking at both natural (e.g. dust and lightning) as well as plant emissions. Trends in anthropogenic emissions both by region and globally are discussed as well as biomass burning emissions. In terms of chemical processing the major air quality elements of ozone, non-methane hydrocarbons, nitrogen oxides and aerosols are covered. A number of topics are presented as a way of integrating the process view into the atmospheric context; these include the atmospheric oxidation efficiency, halogen and HOx chemistry, nighttime chemistry, tropical chemistry, heat waves, megacities, biomass burning and the regional hot spot of the Mediterranean. New findings with respect to the transport of pollutants across the scales are discussed, in particular the move to quantify the impact of long-range transport on regional air quality. Gaps and research questions that remain intractable are identified. The review concludes with a focus of research and policy questions for the coming decade. In particular, the policy challenges for concerted air quality and climate change policy (co-benefit) are discussed. © 2009 Elsevier Ltd.