In search of disambiguation: development of eye drop bottle sleeves to aid in identification and survey among possible users. A cross-sectional study

BACKGROUND: Considerable numbers of individuals present low vision, blindness, illiteracy and other conditions that could possibly impair their identification of medications, such as eye drops. Through helping these individuals to identify their eye drops, they can achieve greater autonomy. Misidentification can be avoided through use of multisensory sleeves that can be adapted to most eye drop bottles. Correct use of eye drops is important for preventing progression of diseases like glaucoma that could potentially lead to blindness. OBJECTIVE: To develop bottle sleeves to aid in identification of eye drops and then interview a group of possible users to evaluate the acceptance of the solution. DESIGN AND SETTING: Cross-sectional survey performed at an ophthalmological clinic in São Paulo (SP), Brazil. METHODS: We describe the development of multisensory sleeves to assist in identification of eye drops. To assess the acceptance of this solution, we interviewed 18 patients who were currently using three or more types of eye drops. RESULTS: We developed four prototypes for eye drop bottle sleeves and conducted an acceptance test on them. Most of the patients who answered the survey about the sleeves were elderly. Most (95%) reported believing that the sleeves would help reduce the risk of mixing up eye drops with other medications that also dispense drops. They also believed that these would increase their autonomy in using eye drops. CONCLUSION: The solution presented was well accepted and may help increase safety in using eye drops through preventing misidentification.

Incorrect use of eye drops at home is very common, since most users, even those with experience in using eye drops, have the perception that they are using these drops correctly and do not recognize that they are making mistakes during this process. Some groups of people are at greater risk of using medications incorrectly: not only ocular but also systemic medications. Among these groups, the following can be highlighted: visually impaired individuals, 15 users with low literacy, 16 users of multiple types of eye drops, 6,7 elderly people 17,18 and disabled people with cognitive impairments such as dementia. 19,20 The sense of vision is the most common way to interact with the environment and, therefore, the most common means for guiding decision-making regarding the chosen medication. Temporary or permanent visual loss increases the risk of misidentification, due to difficulty in reading the labels of eye drop bottles. 6,7,21 According to the World Health Organization, there are 39 million blind people worldwide and 246 million people with low vision. 22 Chronic eye conditions such as glaucoma may require the use of more than one type of eye drop for many years, or even for life. Glaucoma is the leading cause of irreversible blindness in the world, and its prevalence is increasing. 23 The use of multiple types of eye drops may indicate greater severity of the condition under treatment, and this is also common in postoperative states. In both scenarios, correct use is critical. However, there is a greater risk of mix-up between medications due to the possible temporary visual changes and the increased number of medications to be used.
All over the world, the elderly population is increasing, and the prevalence of ophthalmic diseases is higher in this group. 24 Advanced age is also usually accompanied by cognitive and visual impairment, which can affect the use of medications. One study showed that 66.3% of the individuals over 77 years old presented one or more limitations with regard to using their medications and, among these individuals, 31.8% were living alone and did not get help from others. 25 Low literacy also limits the reading of labels and packaging. 16 According In the present study, we detail the idealization and development of multisensory sleeves and evaluation of the acceptance of this new method to help reduce the risk of confusion between eye medications. Misuse of ocular medications is a subject that has only been poorly explored so far, but it is of great importance and needs to be addressed so that more solutions are proposed for increasing the safety of users. Specifically, we address eye drops that have extremely similar bottles and are, therefore, more prone to misidentification.

OBJECTIVE
To develop eye drop bottle sleeves to aid in identification of eye drops and prevent mix-ups and misuse, and to interview a group of possible users to evaluate their acceptance of the solution.

Study setting and design
We describe the idealization and development of four multisen- The investigator applied the survey to patients who had spontaneously sought emergency ophthalmological care for any eye problem and also to patients who were regularly scheduled for routine appointments at the ophthalmology service.

Data source and patient characteristics
The survey was applied to individuals who were using three or more types of eye drops, regardless of the length of time for which they had been using these medications. The following exclusion criteria were applied: refusal to participate, presence of dementia that could be observed in the initial conversation, or use of less than three types of eye drops. The survey is shown in Table 1.
The researcher gave the participants four bottles of eye drops produced by the same company, each with a different ophthalmological solution and wrapped in a sleeve with a different texture and odor (Figure 1). The participant was able to hold, test and analyze each eye drop bottle for as long as they wished, even during or after the questions in the survey.

RESULTS
Four prototypes were produced from the orange silicone rubber material. This material had a thickness of 2 millimeters and was cut into strips of different widths. The ends of these strips  (Figure 1).
Eighteen individuals without any profile of dementia who were using three or more types of eye drops analyzed these eye drop bottles with the sleeves and answered the survey verbally.
The demographic data on the interviewees are shown in Table 2, The answers to the questions in the survey are shown in Table 3.
Only three individuals (17%) declared that they needed someone else to help them use eye drops, and all of these individuals    When expressing an opinion on the preference for attributes on the sleeve, one individual (5%) stated that they did not prefer any, eight (45%) preferred only the texture, two (10%) preferred only the odor and seven (40%) preferred both the texture and the odor ( Table 3).

DISCUSSION
The idealization and development of these prototypes for eye The acceptance test conducted was a type of usability test, which does not require a large sample to provide useful conclusions.
The inclusion of individuals who were using three or more types of eye drops was essential, give that they are aware of the difficulties in dealing with multiple medications.
There have been reports in the literature regarding misidentification of ophthalmic medications in relation to substances that are not suitable for ocular use, even in the absence of use of multiple medications. [11][12][13] In addition to having an impact on quality of life, 33 use of multiple medications increases the risk of misidentification. 34 Incorrect identification of medications is an underestimated problem that is not clearly apparent, due to the subtle effects of most misused eye drops.
Personal factors can also contribute to increased risk of misidentification. Among these factors, low levels of literacy, 16  in response to the odor. 38 In addition, olfactory changes are common among the elderly, with a prevalence of 60-75% in those over 80 years old, 39,40 which may limit the utility of this characteristic for more advanced age groups.
Tactile acuity also suffers age-related decline, but it has been observed that this acuity is preserved in congenitally blind individuals and those undergoing intense tactile training. 41,42 Healthcare professionals involved in patient care need to be able to identify which individuals are most at risk of using their Which feature is more helpful? ** -Texture alone 8 (45%) -Odor alone 2 (10%) -Both texture and odor together 7 (40%) * One patient (5%) could not remember whether the wrong drop had ever been used; ** One patient (5%) said that neither feature was helpful.
medications incorrectly and should seek solutions to assist them.
A study showed that women over 75 years old and elderly people with diabetes, hypertension and sequelae of stroke are at greater risk of developing limitations in activities of daily living. These patients need to be carefully evaluated and assisted in their use of medication. 43 It was important to do the acceptance test among potential users of this solution, so that problems could be identified and changes made in order to improve the sleeves in accordance with the needs of some of the possible users.
The use of identification aids is a creative way to reduce the risk of errors in using eye drops. This may also help in improving adherence to treatment and the safety of the treatment, especially among patients who are most susceptible to error, such as the elderly and people with visual impairments, who represent a considerable portion of the population.

Strengths and limitations of the study
Among the limitations of this study, we can mention the fact that a convenience sample was used and the fact that the component involving memory and cognition was not evaluated. More detailed studies with different populations of eye drop users could clarify which groups could gain greater benefit through use of these sleeves. Such studies could also promote greater adherence and enable assessment of possible clinical impacts.
Sleeves are a simple option that can be produced with flexible silicone material that is adaptable to most eye drop bottles.
The idea of sleeves could be extrapolated to systemic medication bottles as well. In the United States, where prescription medication bottles are standardized, sleeves with a larger diameter could be useful for differentiating between bottles, especially in cases of polypharmacy, which is common in old age.

CONCLUSION
Most of the patients using three or more types of eye drops who we interviewed (95%) believed that the sleeves could improve their autonomy in using the drops, and that the sleeves could reduce the risk of misidentification between bottles.
These multisensory sleeves for helping in eye drop identification were a well-accepted solution and may help increase safety in using eye drops.