Although patients often receive medical information in writing, many visually impaired patients are unable to read the instructions for their treatment, particularly on eye drop bottles, according to a new study in the British Journal of Ophthalmology. 

Researchers from Glasgow, Scotland, assessed the point at which patients were unable to readwithout magnificationthe manufacturers instructions on the side of a bottle of eye drops. They recruited 180 patients (mean age of 70) who had impaired eyesight in one or both eyes and grouped them according to the best line of Snellen acuity, from 6/9 to 6/60 (about 20/30 to 20/200). When comparing distance acuity and the ability to read the instructions on medications, the researchers found that patients whose visual acuity was 6/24 (20/80) or worse were significantly less able to read the instructions on bottles.

The researchers concluded that patients whose visual acuity was between 6/24 and 6/60 were able to read an Arial font size of 22. When asked, patients whose acuity was 6/24 or worse preferred 16-point type for the 6/24 group, 18-point type for the 6/36 (20/120) group and 22-point type for the 6/60 group.

The small number of patients whose visual acuity was 6/24 or less, and who were able to read the small writing, tended to be age 40 or less. Most of these patients suffered from  congenital conditions, and their young age presumably enabled them to adapt to their impairment.

The authors say this overlooked aspect of care is important, because patients need to be able to take the right and safe dose of medicine.

It is common for patients to leave a consultation without remembering what was discussed, including how to take their medication, they say, adding that the problems can be compounded for those who are hearing impaired or whose memory is impaired.

Drummond SR, Drummond RS, Dutton GN. Visual acuity and the ability of the visually impaired to read medication instructions. Br J Ophthalmol 2004 Dec;88(12):1541-2.