Effects of Auricular Acupressure on Dry Eye Syndrome, Stress, and Depressive Symptoms in Older Adults: A Single-blind, Randomized Controlled Trial

Article information

J Korean Acad Fundam Nurs. 2024;31(2):243-253

Publication date (electronic) : 2024 May 31

doi : https://doi.org/10.7739/jkafn.2024.31.2.243

Hyeongyeong Yoon^1),

¹⁾Assistant Professor, Department of Nursing, Eulji University, Seongnam, Korea

Corresponding author: Yoon, Hyeongyeong Department of Nursing, Eulji University 553 Sanseong-daero, Sujeong-gu, Seongnam 13135, Korea Tel: +82-31-740-7521, Fax: +82-31-740-7359, E-mail: hkyoon@eulji.ac.kr

Received 2024 April 2; Revised 2024 May 7; Accepted 2024 May 16.

Abstract

INTRODUCTION

Worldwide, populations are rapidly aging; in particular, the size and proportion of the elderly population are increasing [1]. Generally, the elderly experience various factors that cause stress, such as a decline in physical function due to aging, decline in economic power, an increased risk of chronic diseases, death of acquaintances, job loss due to retirement, and a complex health condition called geriatric syndrome [2,3].

One component of geriatric syndrome is dry eye syndrome, one of the most common eye diseases worldwide. In 2020, 2.438 million patients were treated for dry eye disease, of which 37.6% were over 60 years of age [4]. Dry eye syndrome refers to a disease in which symptoms of irritation, foreign body sensation, itching, and dryness occur because of damage to the ocular surface due to a lack of tears [5]. The causes of dry eye syndrome include the increased use of electronic devices, excessive fatigue, ultraviolet rays, and aging; for the elderly, this can be caused by a decrease in tear secretion due to aging [2]. Dry eye syndrome manifests with symptoms such as foreign body sensation, itching, and fatigue, impacting dai-ly life [4]. A close relationship exists between dry eye syndrome and psychiatric conditions [6-8]. Meta-analyses in the literature demonstrated that depressive symptoms were more prevalent in patients with dry eye syndrome [7,8]; other studies have shown that these individuals experienced more psychological stress [6], and dry eye syndrome treatments were found to be effective in re-ducing depressive symptoms [8]. As high stress in the elderly increases their mortality risk, and depressive symptoms have a low survival rate [3], interventions are needed to manage dry eye syndrome, stress, and depressive symptoms in the elderly. Acupuncture, a complementary and alternative therapy, has been used in China to treat various diseases for thousands of years [9]. Auricular acupressure (AA) treatments derived from ear acupuncture therapy use seeds, magnets, and stones instead of needles to stimulate a unique reaction area in the ear by applying pressure to the corresponding area to continuously stimulate it. This reaction point is considered to be connected to the body's internal organs [9,10]. In 1990, the World Health Organization recognized 91 specific response points in the ear as an international standard, and these have been widely used [10]. Studies applying AA to the elderly include research on relieving the symptoms of chronic lower back pain [11]; general pain, shoulder pain, and range of motion in shoulder joints among the elderly with knee arthritis [12]; the effects of sleep on the elderly [13,14]; and depressive symptoms and anxiety among the elderly living in nursing homes [15].

Similar studies have been conducted on dry eye syndrome among the elderly; in one study, although the selection criterion was those aged 40 years or older, the aver-age age of the registered experimental group was 59.8 years old [16], which is less than the traditional elderly threshold age of 65 years. Additionally, in a prior eight-week experiment, AA was applied only to an experimental group and no intervention was applied to the control group, which could affect the external validity of the findings. There is a claim that 35% of the treatment outcomes are due to the placebo effect, which is based on the natural healing mechanisms of humans [17], so comparative studies to control for the placebo effect are necessary when de-signing research. Another study reviewed dry eye syndrome in college students using aural pressure therapy, but the cause of dry eye syndrome in the elderly differed according to age [2]; further, this study was limited, in that the placebo effect could not be controlled because there was no intervention for the control group [18]. In another study, a male patient with dry eye syndrome was given ear acupuncture twice a week for three weeks, which was found to be effective for dry eye syndrome [19], but effectiveness is difficult to generalize based on a case report. AA is used for various diseases and symptom relief, with a treatment period typically lasting 4 to 5 days, followed by 1 to 2 days of rest before resuming compression [10]. Therapies involving AA are widely used because they are inexpensive yet effective, with few side effects [9], and AA provides a complementary, alternative therapy that can be easily applied by the elderly at home.

As, to our knowledge, no study has confirmed the psychological effects of dry eye syndrome, such as stress and depressive symptoms, among the elderly, it is necessary to supplement previous studies to increase the number of subjects and prove AA effectiveness through study de-signs to reduce the placebo effect. Therefore, this study specifically aimed to examine the differences between experimental and control groups in terms of: (a) dry eye syndrome, (b) perceived stress, (c) the level of electrodermal activity (EDA), (d) cortisol levels in saliva, and (e) depressive symptoms.

METHODS

2. Participants

The study period spanned December 2022 to February 2023, with participants among the elderly people registered at the Seongnam senior complex who met the selection criteria and voluntarily agreed to participate in the study. The Seongnam senior complex supports the use, experience, and research of various products for the elderly. Participants in this study were those who had signed a consent form in advance to receive information about the research via mobile phone. A recruitment notice was sent to 300 elderly people registered at the senior center through a cell phone text message; if they met the selection criteria and wanted to participate, they were asked to visit the senior center. The inclusion criteria were those aged 65 years or older with an Ocular Surface Disease Index (OSDI) score of 13 or higher, stress, and an absence of inflammatory lesions or wounds in the ear. As an exclusion criterion, those who were receiving other complementary and alternative therapies using acupuncture or auricular pressure were also excluded. Participants were randomly assigned to the experimental and control groups. The G*Power program version 3.1.9 was used to calculate the sample size. The number of target subjects was calculated using a t-test. As a result of this calculation, the number of study subjects was determined to be 20 in each of the experimental and control groups. By calculating a dropout rate of 15%, 23 people in each of the experimental and control groups were set as the target subjects. A random number table generated by Random Allocation Software Version 2.0.0 was used to assign participants to one of the two groups. To prevent spread in the experiment, the experimental group visited the center at 9:00 am, and the control group visited the center at 10:00 am. To prevent the Hawthorne effect, participants were single-blinded and did not know which group they belonged to.

In this study, 175 of 300 people did not meet the selection criteria, and 79 refused to participate; therefore, 254 people were excluded. Of those remaining, 46 and 23 were assigned to the experimental and control groups, respectively. However, one person in the experimental group was eliminated on the second day of the visit because of insufficient questionnaires, one person in the control group did not visit on the second day of the study, and one person voluntarily withdrew from the study. One person was subsequently omitted due to missing cortisol measurements, leaving 42 participants whose data were included in the final analysis (22 and 20 in the experimental and control groups, respectively; see also Figure 1).

Figure 1.

CONSORT diagram: flow of participants through the study.

7. Intervention

The following six AA points in this study were selected based on a review of domestic and international literature and a consultation with two auricular therapy experts: the shenmen, liver, heart, endocrine, anterior lobe, eye points (Figure 2). One expert with 30 years of experience directly performed the AA therapy. As the seeds stimulated the ear reaction points, the control group dotted the patch from which the seeds were removed with a green pen. Blind patches were applied to the hip, cervical vertebrae, lumbar vertebrae, and shoulders (Figure 2).

Figure 2.

Acupressure zones: experimental and control groups.

RESULTS

1. Homogeneity Testing for the General Characteristics of the Subjects and the Dependent Variables

Table 1 displays the participants’ general characteristics and homogeneity test results, with no statistically significant difference observed in the homogeneity test according to the general characteristics between the experimental and control groups. The subjects’ age distribution ranged from 65 to 84 years; the mean of the experimental group was 75.40±4.94 years and the control group was 73.40±4.76 years. Table 2 presents the homogeneity test results for the dependent variables: the degree of dry eye syndrome (t=0.770, p=.446), PSS score (t=1.127, p=.266), salivary cortisol score (z=-1.360, p=.174), and EDA score (t=0.880, p=.384). No significant difference was observed between the two groups regarding the degrees of depressive symptoms (t=0.352, p=.462), ensuring the groups’ homogeneity.

Table 1.

General Sample Characteristics (N=42)

Table 2.

Homogeneity of Dependent Variables between Groups (N=42)

2 The effects of AA on dry eye syndrome, stress, and depressive symptom in the elderly

Table 3 illustrates the AA effects, including the results for dry eye syndrome (t=3.442, p=.002), PSS (t=3.455, p= .001), salivary cortisol (z=-3.703, p＜.001), and depressive symptoms (t=2.113, p=.043), which significantly differed between the two groups. The mean scores in the experimental group for dry eye syndrome decreased from 35.81 to 19.36, and the stress score decreased from 18.27 to 13.68. Additionally, the mean scores for salivary cortisol levels in the experimental group decreased from 0.285 to 0.218. The mean depressive symptoms score in the experimental group decreased from 4.77 to 2.09. However, the EDA measured using the Fitbit revealed no statistically significant difference (t=-1.081, p=.043).

Table 3.

Comparisons of Scores for Stress, Dry Eye Syndrome, and Depressive Symptoms between Groups (N=42)

DISCUSSION

This study applied AA to the control group for three weeks in a scientific study designed to control the placebo effect by applying placebo-based pressure therapy to elderly people with dry eye syndrome, stress, and depressive symptoms. In this study, dry eye syndrome was noted as severe with a score of 33 points or more before the intervention in both the experimental and control groups; how-ever, the symptoms in the experimental group became mild after the intervention, with a decrease of 16.45 points. This study supported similar findings to those of Choi et al.[16], who conducted an 8-week study targeting mid-dle-aged and old adults. In the experimental group, applying pressure to the tubercle, liver, and eye regions resulted in a decrease from 44.68 points to 30.90 points at week 4 and further decreased to 25.93 points at week 8, approximately an 18-point reduction. Similarly, Park et al.'s study [19] found a 14-point reduction in university students with dry eye syndrome after applying acupressure therapy to the tubercle, liver, eye, and shenmen regions for 2 weeks, from 38.4 points to 24.07 points. The acupressure therapy is maintained for 6 days with 1-2 days of rest intervals, following the protocol of Lee et al. [10]. However, there are no specific duration criteria for symptom im-provement. The acupressure points for the eye and liver were commonly used in previous studies and have been proven effective for dry eye syndrome. Additionally, this study targeted 65-year-old male seniors, accounting for 28.5% of the sample. However, a limitation arises from the preponderance of female seniors in previous studies con-firming dry eye syndrome in middle-aged and elderly individuals, with only 2 out of 56 participants being male seniors, representing a mere 3.5%. Moreover, given that dry eye syndrome has the highest prevalence among seniors in their 60s, this study holds significance in demonstrating the effectiveness of health promotion for the elderly. However, Choi et al.'s study [16] had the disadvantage that it was difficult to observe the effect of auricular pressure therapy alone by teaching group education and ear massage before auricular pressure therapy.

In Park et al.'s study [19], the control group did not apply pressure, and the placebo effect in the experimental group could not be controlled due to the unequal control before and after the design, rather than using a single-blind design. Another study examined the effects on 43 patients who were diagnosed with dry eye syndrome and received acupuncture treatment at an Oriental medical fa-cility [32]. Consequently, the OSDI score in that study decreased by 18.09 points, from 59.22 to 41.13. This is similar to the current study's results, in which the OSDI score decreased by 16.45 points by applying AA for three weeks, indicating that AA and acupuncture have similar ther-apeutic effects. In research by Lee, Lee et al. [32], participants were registered for 20 minutes a day three to four times a week, and 24 acupuncture treatments were registered in 12 blood sites around the ears, hands, eyes, and eyebrows. However, this AA is considered to have a continuous treatment effect because the attached seeds con-stantly stimulate the response point. This study provided effects through continuous stimulation for three weeks each week. However, unlike acupuncture treatment, which involved 24 sessions [25], it did not set a range for the duration of application. Moreover, the study lacked a control group and compared treatment effects only within a single group, thereby failing to control for placebo effects.

Patients diagnosed with dry eye syndrome were more likely to experience psychological problems, such as stress, depressive symptoms, and anxiety [7], with a 40% higher prevalence and 1.81 times higher incidence of depressive symptoms [7]. Therefore, participants with dry eye syndrome and stress were selected to verify the degrees of im-provement in both stress and depressive symptoms. In the present study, the perceived stress level decreased by 4.59 points in the experimental group, or from 18.27 to 13.68, but did not change in the control group. Eight weeks of AA on the shenmen, kidney, heart, adrenal gland, and oc-ciput areas reduced the stress effect in adults aged 18 to under 65 from 17.78 to 15.44 [14]. This is similar to the results of a study [13] in which both physical and psychological stress decreased as a result of applying AA to the sympathetic, shenmen, adrenal, endocrine, and subcor-tical areas of middle-aged women for two weeks. Although the current study spanned three weeks, stress was reduced to a greater degree than in Lee and Park [14], where the intervention was performed for eight weeks. Cha et al.'s study [13] included middle-aged women between the ages of 40 and 60, with only an age criterion and none for stress. Additionally, it is significant that the time difference between the participants’ visits and the different AA locations were controlled to prevent the AA therapy's spread.

The autonomic nervous system is important in maintaining the body's homeostasis, and cortisol in particular is the primary biomarker secreted from the HPA axis during stress and depressive symptoms [24,25]. In this study, the salivary cortisol level decreased by 0.066 in the experimental group; moreover, the depressive symptoms score decreased from 4.77 points in the experimental group to 2.09 points, and increased by 0.35 points in the control group, indicating a statistically significant difference. As a result of applying acupressure to middle-aged women's sympathetic, shenmen, adrenal, endocrine, and subcortex areas for two weeks, the blood cortisol level decreased by 2.04 [13]. As a result of auricular acupuncture on the shenmen, kidney, liver, lung, and sympathetic areas of participants with major depressive symptoms, salivary cortisol decreased [33], supporting this study. However, cortisol is rapidly secreted approximately once an hour due to an ul-tra-radian rhythm, and significantly varies depending on individual personality characteristics [34]; thus, it is necessary to control psychological and environmental factors and check for differences in cortisol by shortening the time interval. Further, depressive symptoms decreased by 2.68 points in the experimental group, demonstrating that, when AA was applied only to the shenmen area for two weeks among the elderly living in a nursing home, depressive symptoms scores decreased from 8.71 to 5.35 points [15], supporting this study.

The AA therapy was performed each time by selecting between four and six auricular points [10] and, following previous studies, applying pressure for five to six days, resting for one to two days, and applying acupressure again [14,16,18]. In this study, six acupoints were pressed, including the shenmen; the patch was removed after six days, and the acupressure was maintained for six days in a one-week cycle. In a study by Tseng et al.[15] tape with magnetic beads attached only stimulated one shenmen area-applied to the right ear for 7 days and the left for 7 days-and stimulation continued for 14 days without a break of 1 to 2 days. In this study, after six days of acupressure, a one-day rest period occurred, with no side ef-fects; the EDA score was measured once before and after using the Fitbit to measure stress, but without a statistically significant difference. The EDA is highly accurate in detecting stress [26], based on signal data with a 10-Hz res-olution and measured in tenths of a second [35]. Since the EDA score evaluates electrothermal activity at a very short period of time, it is noted that this study did not produce significant results using only one measurement; hence, future studies must check continuous data changes by measuring at least twice.

In summary, a three-week AA was effective in treating dry eye syndrome, stress, and depressive symptoms in the elderly, and the effect was verified as a physiological in-dicator given the reduced cortisol levels. The changes in dry eye were similar to the effects of acupuncture, but unlike acupuncture, AA has the significant advantage of being non-invasive, painless, simple, safe, fast, and low cost, so it was confirmed to be a cost-effective intervention to be applied in nursing. This study is significant in that the placebo effect was controlled by treating the elderly with dry eye syndrome and stress with a placebo AA in the control group; this was verified through a scientific design with increased internal validity in a single-blind, randomized experiment. This study's results proved that auricular pressure therapy is effective even with physiological indicators, and is a cost-effective intervention method with a short time requirement. Thus, it is meaningful to establish a scientific basis that can generalize AA as a non-pharma-cological nursing intervention for the nursing manage-ment of dry eye syndrome, stress, and depressive symptoms in the community-dwelling elderly.

However, despite this study's strengths, the general-izability of its results is limited because this study re-cruited participants from only one region-Bundang in Korea-with a small sample size; therefore, the effects of AA should be verified by expanding the number of participants in a multicenter study to increase the sample's representativeness. As this study applied AA for three weeks, a comparative study should verify the effects according to the application cycle.

CONCLUSION

This study's findings confirm that AA can be an effective nursing intervention for alleviating complex dry eye symptoms, lowering stress and cortisol levels, and re-ducing depressive symptoms in the elderly. Therefore, it can be used as a self-care mechanism for the elderly in the community.

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