Objective: To develop and validate scales measuring common concerns of patients with choroidal melanoma: perception of appearance, concern about cancer recurrence, and difficulty with vision-dependent activities requiring stereopsis or binocularity.
Design: Cross-sectional study within a randomized multicenter clinical trial.
Methods: Eight-hundred forty-two of 1317 patients with choroidal melanoma enrolled in the Collaborative Ocular Melanoma Study (COMS) for medium-sized tumors and randomized to receive iodine 125 brachytherapy or enucleation were interviewed. Scale reliability was evaluated using Cronbach's alpha, and validity was investigated through correlation with existing scales and with data collected during COMS clinical examinations.
Results: All 3 proposed scales had good internal consistency reliability. The appearance and recurrence scales had low to moderate correlation with the 36-Item Short-Form Health Survey mental health scale (r = 0.26 and 0.31, respectively) and with the the Hospital Anxiety and Depression Scale depression (r = -0.22 and -0.19) and anxiety (r = -0.27 and -0.42) scales. Appearance scores were significantly associated with occurrence of appearance-altering complications and conditions, recurrence scores were associated with recent removal of the brachytherapy-treated eye, and stereopsis/binocularity scores were higher in patients with good visual acuity in both eyes than in those with good visual acuity in one eye and an enucleated fellow eye.
Conclusions: All 3 proposed scales have good internal consistency, range, and SDs of measurement in the tested population. Based on clinical data, there is evidence of good construct validity for all 3 scales, although there also is evidence that the stereopsis/binocularity scale is sensitive to other aspects of vision in addition to stereopsis and binocularity. The appearance and recurrence scales capture clinically relevant information not available from standard mental health scales.