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.