Identifying low vision rehabilitation priorities using a conjoint analysis approach

To identify the relative importance of a range of activities amongst patients with age-related macular degeneration (AMD) and to explore the visual function and clinical characteristics associated with the different priorities for low vision rehabilitation. A prospective sample of 122 patients with AMD attending the low vision clinics at Edinburgh Eye Hospital were given several tests including: binocular visual acuity (logMAR), binocular contrast sensitivity (Pelli-Robson), quality of life (QoL) NEI-VF 25 questionnaire and utilities were determined using a time trade-off task (TTO) and a conjoint analysis task. Clinical grading of AMD severity was according to the international classification system. The relative importance of five different activities, identified by factor analysis in a previous study, was assessed in a paired comparison paradigm using discrete-choice conjoint analysis. The activities were: reading, recognising faces, getting about outside, problems associated with glare, and difficulties associated with performing household tasks. Each activity was represented at three levels of difficulty (none, a few, and a lot). Utilities derived from conjoint analysis were compared with TTO utilities. A factor analysis showed that AMD severity and basic measures of visual function were only moderately related to TTO utilities but independent of conjoint utilities. Analyses of individual patient utilities showed two distinct patient clusters; those for whom reading was of greatest importance and those for whom getting about outside was of greatest importance. Conjoint analysis offers the potential of identifying individual patient priorities for low vision rehabilitation. © 2005.