Abstract
Abstract: :
Purpose: To develop an instrument for the comprehensive measurement of the impact of refractive correction on quality of life in the pre-presbyopic age group. To design the questionnaire to be relevant to refractive correction by spectacles, contact lenses and refractive surgery such that it is suitable for comparison between correction mode and for studies of treatment outcome. Methods: The quality of life literature was reviewed to identify all domains of quality of life. These domains were discussed in a focus group of eye care professionals for reduction to those thought to be influenced by refractive correction. Items within these domains were selected from the scientific literature and from suggestions of professionals and lay people. The literature search included global quality of life instruments and those specific to vision and cosmetic surgery. Suggestions were sought from 63 clinicians and clinical staff working in optometry, contact lens fitting, optical dispensing, ophthalmology and refractive surgery. Six focus groups were used for item reduction: Three groups of professionals (psychology and eye care professionals experienced with spectacle, contact lens and refractive surgery patients) and three groups of lay public (one group of each correction mode). Questions and response scales were chosen following review of the questionnaire design literature and after feedback from the focus groups. The pilot version of the questionnaire was submitted to equal numbers of people using the three correction modes to minimise bias in favour of any correction type. Results: Seven domains of quality of life were selected. Within these, 647 items were selected as possibly being relevant (Physical function 176, Well-being 192, Convenience 85, Symptoms 97, Work/Economic issues 54, Health concerns 19, Cognitive issues 24). This number was reduced based on the responses of the focus groups to 115 items, which form a pilot questionnaire. This has been given to 225 subjects (75 spectacle wearers, contact lens wearers and people who have had refractive surgery). Conclusion: A 115-item pilot questionnaire has been produced via literature survey and input from professionals and focus groups. This methodological approach for item selection, item reduction, question construction and response scaling ensures construct validity. Further item reduction using Rasch analysis of data from 225 responses to the pilot questionnaire will result in the finalised questionnaire.
Keywords: 542 refraction • 536 quality of life • 350 clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology