Refractive error

About: Refractive error is a research topic. Over the lifetime, 5047 publications have been published within this topic receiving 156603 citations. The topic is also known as: disorder of refraction & eye refraction disorder.

Development of the 25-item National Eye Institute Visual Function Questionnaire.

Abstract: Objective To develop and test the psychometric properties of a 25-list-item version of the National Eye Institute Visual Function Questionnaire (NEI VFQ-25). Design Prospective observational cohort study of persons with 1 of 5 chronic eye diseases or low vision who were scheduled for nonurgent visits in ophthalmology practices and a reference sample of persons without eye disease. Setting Eleven university-based ophthalmology practices and the NEI Clinical Center. Patients Eligible participants had to have 1 of the following eye conditions: age-related cataracts, age-related macular degeneration, diabetic retinopathy, primary open-angle glaucoma, cytomegalovirus retinitis, or low vision from any cause. Seven of the 12 sites also enrolled persons in a reference sample. Reference sample participants had no evidence of underlying eye disease but were scheduled for either screening eye examinations or correction of refractive error. All eligible persons had to be 21 years or older, English speaking, and cognitively able to give informed consent and participate in a health status interview. Measurements and Main Results To provide the data needed to create the NEI VFQ-25, all subjects completed an interview that included the 51-list-item NEI VFQ. Estimates of internal consistency indicate that the subscales of the NEI VFQ-25 are reliable. The validity of the NEI VFQ-25 is supported by high correlations between the short- and long-form versions of the measure, observed between-group differences in scores for persons with different eye diseases of varying severity, and the moderate-to-high correlations between the NEI VFQ-25 subscales that have the most to do with central vision and measured visual acuity. Conclusions The reliability and validity of the NEI VFQ-25 are comparable to those of the 51-list-item NEI VFQ field test version of the survey. This shorter version will be more feasible in settings such as clinical trials where interview length is a critical consideration. In addition, preliminary analyses indicate that the psychometric properties of the NEI VFQ-25 are robust for the eye conditions studied; this suggests that the measure will provide reproducible and valid data when used across multiple conditions of varying severity.

Global magnitude of visual impairment caused by uncorrected refractive errors in 2004.

Abstract: Estimates of the prevalence of visual impairment caused by uncorrected refractive errors in 2004 have been determined at regional and global levels for people aged 5 years and over from recent published and unpublished surveys. The estimates were based on the prevalence of visual acuity of less than 6/18 in the better eye with the currently available refractive correction that could be improved to equal to or better than 6/18 by refraction or pinhole. A total of 153 million people (range of uncertainty: 123 million to 184 million) are estimated to be visually impaired from uncorrected refractive errors, of whom eight million are blind. This cause of visual impairment has been overlooked in previous estimates that were based on best-corrected vision. Combined with the 161 million people visually impaired estimated in 2002 according to best-corrected vision, 314 million people are visually impaired from all causes: uncorrected refractive errors become the main cause of low vision and the second cause of blindness. Uncorrected refractive errors can hamper performance at school, reduce employability and productivity, and generally impair quality of life. Yet the correction of refractive errors with appropriate spectacles is among the most cost-effective interventions in eye health care. The results presented in this paper help to unearth a formerly hidden problem of public health dimensions and promote policy development and implementation, programmatic decision-making and corrective interventions, as well as stimulate research.

Psychometric properties of the National Eye Institute Visual Function Questionnaire (NEI-VFQ). NEI-VFQ Field Test Investigators

Abstract: Objective To test the reliability and validity of the 51-item Field Test Version of the National Eye Institute Visual Function Questionnaire (NEI-VFQ) across 5 common chronic eye conditions. Design Prospective observational cohort study of persons with 1 of 5 chronic eye diseases who were scheduled for nonurgent visits in ophthalmology practices or had low vision from any cause, and a reference sample of persons without eye disease. Setting Six university-based ophthalmology practices and the National Eye Institute Clinical Center, Bethesda, Md. Patients Eligible participants had to have 1 of the following eye conditions: age-related cataracts, age-related macular degeneration, diabetic retinopathy, primary open-angle glaucoma, cytomegalovirus retinitis, or low vision from any cause. Each of the 7 sites also enrolled persons in a reference sample. Reference sample participants had no evidence of underlying eye disease but were scheduled for either screening eye examinations or correction of refractive error. All eligible persons had to be aged 21 years or older, English speaking, and cognitively able to give informed consent and participate in a health status interview. Measurements and Main Results To provide the data needed to assess the reliability and validity of the 51-item NEI-VFQ, all subjects completed an interview that consisted of the 51-item NEI-VFQ, the Medical Outcomes Study 36-Item Short-Form Health Survey, and at least 1 measure of vision-targeted functional status. Estimates of internal consistency and test-retest reproducibility indicate that the 51-item NEI-VFQ is reliable. Tests of association with other scales and clinical variables support the construct validity of the survey. Conclusions In this cross-sectional study, the 51-item NEI-VFQ seems to be reliable and valid and should be a useful tool for group-level comparisons of vision-targeted, health-related quality of life in clinical research. Additionally, the psychometric properties of the NEI-VFQ were not influenced by the type or severity of the underlying eye disease, suggesting that the measure will provide reproducible and valid data when used across multiple eye conditions.