UMIN-CTR Clinical Trial
| Unique ID issued by UMIN | UMIN000060945 |
|---|---|
| Receipt number | R000069745 |
| Scientific Title | Verification of the Effects of Bathing and Carbon Dioxide Bathing on Eye Strain and Dry Eye |
| Date of disclosure of the study information | 2026/03/16 |
| Last modified on | 2026/03/16 14:40:34 |
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Basic information
Public title
Effects of Bathing with Carbon Dioxide Bath Additives on Dry Eye Symptoms and Eye Strain
Acronym
Improvement of Dry Eye by CO2 Bathing
Scientific Title
Verification of the Effects of Bathing and Carbon Dioxide Bathing on Eye Strain and Dry Eye
Scientific Title:Acronym
Study on Dry Eye via Bathing and CO2 Bathing
Region
| Japan |
Condition
Condition
Dry eye, Eye strain
Classification by specialty
| Ophthalmology |
Classification by malignancy
Others
Genomic information
NO
Objectives
Narrative objectives1
To clarify the effects of bathing with inorganic salt-containing carbon dioxide bath additives on periocular blood flow, dry eye-related findings (tear dynamics, meibomian gland function), and subjective symptoms.
Basic objectives2
Efficacy
Basic objectives -Others
Trial characteristics_1
Exploratory
Trial characteristics_2
Explanatory
Developmental phase
Not applicable
Assessment
Primary outcomes
Change in eyelid blood flow before and after intervention (measured by laser speckle blood flow imager). Time points: After rest/acclimatization and 12 minutes after bathing.
Key secondary outcomes
Tear dynamics: Changes in tear meniscus height (TMH) and tear film break-up time (BUT).
Meibomian gland function: Changes in the meibomian gland plugging score.
Subjective symptoms: Changes in eye strain, dryness, and neck stiffness evaluated by Visual Analogue Scale (VAS).
(All measures assessed after acclimatization and 12 minutes after bathing.)
Base
Study type
Interventional
Study design
Basic design
Cross-over
Randomization
Randomized
Randomization unit
Individual
Blinding
Open -no one is blinded
Control
No treatment
Stratification
NO
Dynamic allocation
NO
Institution consideration
Institution is not considered as adjustment factor.
Blocking
NO
Concealment
Numbered container method
Intervention
No. of arms
2
Purpose of intervention
Treatment
Type of intervention
| Behavior,custom |
Interventions/Control_1
Carbonated bath: Whole-body bathing for 15 minutes in 39 degrees Celsius water containing inorganic salt-containing carbon dioxide bath additives. Single intervention.
Interventions/Control_2
Warm water bath (Control): Whole-body bathing for 15 minutes in 39 degrees Celsius plain tap water. Single intervention.
Interventions/Control_3
Interventions/Control_4
Interventions/Control_5
Interventions/Control_6
Interventions/Control_7
Interventions/Control_8
Interventions/Control_9
Interventions/Control_10
Eligibility
Age-lower limit
| 18 | years-old | <= |
Age-upper limit
| 60 | years-old | > |
Gender
Male and Female
Key inclusion criteria
1. Adults aged 18 to 59 years.
2. Participants with chronic dry eye symptoms (J-OSDI score >= 13).
3. Participants without a regular bathing habit (bathing in a tub < 4 times per week).
4. Participants who understand the study and provide written informed consent.
Key exclusion criteria
1. Participants currently receiving treatment for ocular diseases (e.g., infections, severe corneal disorders).
2. Participants with serious systemic diseases (e.g., severe heart disease, skin disease).
3. Pregnant or lactating women.
4. Others deemed inappropriate by the principal investigator.
Target sample size
10
Research contact person
Name of lead principal investigator
| 1st name | Genki |
| Middle name | |
| Last name | Hata |
Organization
Earth Corporation
Division name
Tsukuba Research Center
Zip code
305-0033
Address
29-9 Higashiarai, Tsukuba-shi, Ibaraki
TEL
08067255003
hata-genki@earth.jp
Public contact
Name of contact person
| 1st name | Genki |
| Middle name | |
| Last name | Hata |
Organization
Earth Corporation
Division name
Tsukuba Research Center
Zip code
305-0033
Address
29-9 Higashiarai, Tsukuba-shi, Ibaraki
TEL
08067255003
Homepage URL
hata-genki@earth.jp
Sponsor or person
Institute
Earth Corporation
Institute
Department
Personal name
Genki Hata
Funding Source
Organization
Earth Corporation
Organization
Division
Category of Funding Organization
Profit organization
Nationality of Funding Organization
Japan
Other related organizations
Co-sponsor
Lid and Meibomian Gland Working Group (LIME), Itoh Clinic
Name of secondary funder(s)
IRB Contact (For public release)
Organization
Shibukawa Chuo Hospital
Address
508-1 Ishihara, Shibukawa-shi, Gunma
Tel
0279251711
aoyama@oms-laboratory.co.jp
Secondary IDs
Secondary IDs
NO
Study ID_1
Org. issuing International ID_1
Study ID_2
Org. issuing International ID_2
IND to MHLW
Institutions
Institutions
Other administrative information
Date of disclosure of the study information
| 2026 | Year | 03 | Month | 16 | Day |
Related information
URL releasing protocol
Publication of results
Published
Result
URL related to results and publications
Number of participants that the trial has enrolled
10
Results
Carbonated bathing significantly increased eyelid blood flow compared with warm water bathing (p < 0.05). Significant improvements were also observed in TMH, meibomian gland plugging score, and BUT following carbonated bathing (all p < 0.05). Subjective symptoms, including ocular fatigue and dryness, were significantly improved.
Results date posted
| 2026 | Year | 03 | Month | 16 | Day |
Results Delayed
Results Delay Reason
Date of the first journal publication of results
Baseline Characteristics
Ten adults (20 eyes, mean age 38.4 plus minus 11.2 years, 5 males and 5 females) with chronic dry eye symptoms (J-OSDI score of 13 or more).
Participant flow
All 10 participants were randomized and completed both carbonated bathing and warm water bathing conditions in a crossover design.
Adverse events
No adverse events related to the interventions were observed in this study.
Outcome measures
Eyelid blood flow, tear meniscus height (TMH), meibomian gland plugging score, tear film break-up time (BUT), and subjective symptoms (VAS).
Plan to share IPD
No
IPD sharing Plan description
Data will be shared upon reasonable request at the discretion of the authors.
Progress
Recruitment status
Main results already published
Date of protocol fixation
| 2025 | Year | 01 | Month | 10 | Day |
Date of IRB
| 2025 | Year | 01 | Month | 17 | Day |
Anticipated trial start date
| 2025 | Year | 04 | Month | 01 | Day |
Last follow-up date
| 2025 | Year | 04 | Month | 30 | Day |
Date of closure to data entry
| 2025 | Year | 05 | Month | 30 | Day |
Date trial data considered complete
| 2025 | Year | 06 | Month | 30 | Day |
Date analysis concluded
| 2025 | Year | 10 | Month | 31 | Day |
Other
Other related information
This study was retrospectively registered because it was initially designed as a preliminary exploratory pilot study. The trial was conducted appropriately in accordance with the principles of the Declaration of Helsinki and with the approval of the Institutional Review Board.
Management information
Registered date
| 2026 | Year | 03 | Month | 16 | Day |
Last modified on
| 2026 | Year | 03 | Month | 16 | Day |
Link to view the page
Value
https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000069745
