Measuring visual symptoms in British cataract patients: the cataract symptom scale.

AIMS To develop and validate a scale for the measurement of visual symptoms and functional disability due to cataract in older UK residents. METHODS In depth semistructured interviews were undertaken with 44 consecutive patients awaiting cataract surgery. Patients were asked to describe visual symptoms and problems with social functioning which were then incorporated into a questionnaire, the cataract symptom scale (CSS). The CSS was further examined in a cohort of 118 consecutive cataract patients awaiting surgery. Further assessments in these patients included visual acuity, visual function using an existing scale (the VF-14), activities of daily living, perceived health status, anxiety and depression, and a global assessment of how much patients felt their visual symptoms affected their daily life. RESULTS A 15 item scale was derived which was simple to administer to older patients and had a high internal consistency. The test-retest correlation coefficient for the total instrument score was r = 0.91 (p<0.0001). The CSS correlated well with the VF-14 and to a lesser extent with visual acuity in the better eye, activities of daily living, perceived health status, anxiety and depression, and the patients' global assessment of visual symptoms. CONCLUSION The CSS provides information regarding the symptomatic and functional status of older cataract patients resident in the UK which cannot be obtained by measurement of visual acuity alone.