Light therapy is applied to older people with dementia as a treatment to reset the biological clock, to improve the cognitive functioning, and to reduce behavioral symptoms. Although the methodological quality of light therapy studies is essential, many aspects concerning the description of the lighting applied are missing. This study reviewed light therapy studies concerning the effects on people with dementia as a way to check the methodological quality of the description of light from a light engineering perspective. Twelve studies meeting the inclusion criteria were chosen for further analysis. Each study was scored on a list of aspects relevant to a proper description of lighting aspects. The overview demonstrates that the overall quality of the methodologies is poor. The studies describe the lighting insufficiently and not in the correct metrics. The robustness of light therapy studies can be improved by involving a light engineer or specialist.