Simon Read, Heather Waterman, James E Morgan, Robert A Harper, Anne Fiona Spencer, Penelope Stanford

"She wouldn't remember. Even when I go through, and she's decided to go to bed, I'll say I'll come and do her drops. If I didn't say that, they wouldn't be done." Dementia is widely considered as a key factor in whether patients take their medication as prescribed. However, few studies have examined the effect of dementia on medication management strategies for glaucoma including how patient and carer needs impact adherence and long-term prognosis. We report findings from a qualitative grounded theory study incorporating the views of patients, carers, and healthcare professionals. Eighty-three semistructured interviews were conducted with 35 patients, 22 lay carers, and nine healthcare professionals across sites in Wales and Scotland. These explored understanding of eye drop regimens, barriers, and facilitators to drop administration, as well as attitudes toward glaucoma, dementia, and other comorbidities. Using Pound's synthesis of adherence behavior, we identified categories of active and passive acceptance of medicines, alongside modification or rejection of eye drop regimens. In relation to dementia, participants highlighted transitions between such categories, with a shift from active to passive acceptance commonly reported. This loss of self-medicating capability was referred to as the precipice of care, where entwinement of multiple conditions (eg, heart disease, glaucoma, and dementia) and sociocultural influences (eg, living alone) contributed to accelerated health declines. That said, numerous factors mitigated this, with a key role being the lay carer. Spouses and family members often acted as the monitor of eye drops for patients, seeking intervention when any behavioral changes influenced their administration. Though dementia was associated with progression toward the precipice of care, factors such as communication with healthcare professionals appeared to affect patient adherence. Recommendations for healthcare practice include better recording of dementia diagnoses and integrating eye drops into preexisting routines.