Two studies in this month’s issue of Ophthalmology suggest that communicating with patients using cap color exclusively could lead to confusion and harm, especially when treating patients with more advanced disease who often have decreased or impaired visual acuity, contrast sensitivity and color perception.
In 1983 an informal agreement among the pharmaceutical industry, the American Academy of Ophthalmology and the U.S. Food and Drug Administration led to the packaging of ophthalmic medications with loosely standardized colors on bottle caps and labels to represent different classes of medications. A yellow cap usually represents a beta-blocker, a teal cap represents a prostaglandin analogue, a pink (or white) cap represents a steroid, etc.
However new research illustrate the problems that can occur if you depend on color alone to communicate with your patients about their medication regimen.
Dave and colleagues asked 100 glaucoma patients to provide color descriptions of 11 distinct medication bottle caps. Patients produced 102 unique color descriptors to describe the 11 bottle caps. Three physicians then matched each color descriptor to the medication they thought the patient had described. Mean physician-patient medication agreement was just 55.5%, with 4 medications showing less than 15% agreement. The odds of agreement decreased in patients with more severe visual field or color vision loss.
The other study from Marando and colleagues surveyed a convenience sample of 126 patients and found that 65% use cap color to keep their glaucoma medications straight; far more than printed material such as medication name (18%) or information printed on the box. Most supplemented cap color with other indicators such as bottle shape (48%) or even stored medications in different locations to distinguish among them.
This problem will only get worse as new classes of topical agents are introduced in the coming years, along with new combination products, and as patents expire, there will be more generic versions manufactured by companies not part of the informal color cap agreement between the Academy and FDA.
Dr. James Brandt penned an editorial accompanying the 2 studies, calling on patients, physicians, regulators, and industry to work together through the International Organization for Standardization (ISO) process to develop a global standard for how ophthalmic drugs are packaged and labeled; a standard designed with the visually impaired and confused end user in mind.
For example, different classes of topical medications could have caps with tactile clues based on the class or frequency of dosing, Dr. Brandt writes. “A once-daily medication could have a round cap, a thrice-daily medication could have a triangular-shaped cap, and so on. This standardized iconography (shape, color) would appear prominently on the label and box. The same shape would be debossed (raised) on the bottle so that the patient can feel the cap and bottle to be reassured that he is using the correct medication correctly even if he cannot read the label or if the label has rubbed off.
Because cap switching is common, he writes that caps for different classes of medications could each be threaded in a unique, standardized manner so that the cap for a topical steroid cannot be screwed onto a bottle containing a prostaglandin analogue.
Dr. Brandt asks his patients to bring their medications with them to every visit so that they are “always on the same page.” Similarly, he urges physicians, regulators and industry to get on the same page and develop a global standard for how ophthalmic drugs are packaged and labeled.