Hydration StatusHYDRI-EYENCT07177131
Hydration Status and Ocular Parameters Study
A study testing Relative Dehydration Protocol and Hyperhydration Protocol in people with Hydration Status and Macular Thickness, run by Ante Kreso.
Trial summary
This study will examine how hydration status (drinking a large amount of water or avoiding water for a short period of time) affects the eye. Healthy adult volunteers will participate in two sessions: one after mild dehydration (no water for 12 hours) and one after drinking 2 liters of water within 4 hours. Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Hydration Status, Macular Thickness, Ocular Biometry
- What is being tested?
- Relative Dehydration Protocol and Hyperhydration Protocol
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 60 participants
- Where
- No sites listed yet
- Study dates
- 25 Sep 2025to 1 Dec 2025
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Healthy adult volunteers aged 18 to 65 years
- Normal ophthalmological findings
- Best corrected visual acuity (BCVA) ≥ 1.0 (decimal)
- Willingness to participate and provide written informed consent
Who cannot join
- Known ocular diseases (e.g., glaucoma, keratoconus, retinal pathology)
- History of ocular surgery
- Systemic diseases affecting hydration status (e.g., diabetes mellitus, kidney disease)
- Any condition that, in the investigator's opinion, could interfere with study participation or data quality
- Refusal to participate
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Prospective, Randomized Cross-over Within-subject Study on the Effects of Dehydration and Hyperhydration on Macular Thickness, Corneal Morphology, and Ocular Biometric Parameters Measured by OCT, Pentacam and Optical Biometer
This study will examine how hydration status (drinking a large amount of water or avoiding water for a short period of time) affects the eye. Healthy adult volunteers will participate in two sessions: one after mild dehydration (no water for 12 hours) and one after drinking 2 liters of water within 4 hours. At each session, detailed eye measurements will be taken, including scans of the retina and optic nerve using optical coherence tomography (OCT), corneal imaging with Pentacam, and eye length measurements with an optical biometer. The results from the two conditions will be compared within the same participants.
The main goal is to determine whether hydration influences the thickness of the retina (macula). Secondary goals include assessing changes in the optic nerve, cornea, and other biometric eye parameters. The study involves only non-invasive tests and minimal risk. Findings may help improve understanding of how hydration affects the eye and may be important for clinical practice, such as planning cataract or refractive surgery.
- Conditions
- Hydration Status, Macular Thickness, Ocular Biometry
- Being tested
- Relative Dehydration Protocol, Hyperhydration Protocol
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Relative Dehydration ProtocolBehavioural
Participants will abstain from water intake for 12 hours prior to the study visit. Food is allowed, but fluid intake is limited to a maximum of 250 ml until 20:00 h on the previous evening. Eye measurements will be performed in the morning (8-10 h).
Hyperhydration ProtocolBehavioural
Participants will consume 2 liters of water within 4 hours prior to the study visit. Eye measurements will be performed in the morning (8-10 h).
| Study group | Role | What they receive |
|---|---|---|
| Relative Dehydration | Experimental | 12-hour fluid restriction (≤250 ml fluids until 20h previous day) Receives: Behavioral: Relative Dehydration Protocol |
| Hyperhydration | Experimental | 2 liters of water within 4 hours before testing Receives: Behavioral: Hyperhydration Protocol |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in macular thickness between dehydration and hyperhydration states
Macular thickness (central subfield, parafoveal, and perifoveal regions) will be measured using Zeiss Cirrus HD-OCT. Each participant will undergo measurements in both hydration states, and paired comparisons will be performed.
Measured: Within 1 week (cross-over design with ≥7-day washout period)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Sep 2025
- Study start25 Sep 2025 (estimated)
- Primary completion1 Nov 2025 (estimated)
- Study completion1 Dec 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Hydration StatusStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Ante Kreso
- Sponsor type
- University, hospital or other
- Collaborators
- University Hospital of Split, University of Split, School of Medicine
- Responsible party
- Sponsor-investigator, Ante Kreso, University Hospital of Split
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07177131
- Sponsor's protocol ID
- JC092025
- Acronym
- HYDRI-EYE
- Status last verified
- Sep 2025
- First submitted
- 9 Sep 2025
- Last updated
- 22 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 22 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Prospective, Randomized Cross-over Within-subject Study on the Effects of Dehydration and Hyperhydration on Macular Thickness, Corneal Morphology, and Ocular Biometric Parameters Measured by OCT, Pentacam and Optical Biometer
- ClinicalTrials.gov ID
- NCT07177131
- Acronym / sponsor ID
- HYDRI-EYE / JC092025
- Conditions
- Hydration Status, Macular Thickness, Ocular Biometry
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- Ante KresoUniversity, hospital or other
- Collaborators
- University Hospital of Split, University of Split, School of Medicine
- Study start
- 25 Sep 2025 (estimated)
- Primary completion
- 1 Nov 2025 (estimated)
- Study completion
- 1 Dec 2025 (estimated)
- First posted
- 16 Sep 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study will examine how hydration status (drinking a large amount of water or avoiding water for a short period of time) affects the eye. Healthy adult volunteers will participate in two sessions: one after mild dehydration (no water for 12 hours) and one after drinking 2 liters of water within 4 hours. At each session, detailed eye measurements will be taken, including scans of the retina and optic nerve using optical coherence tomography (OCT), corneal imaging with Pentacam, and eye length measurements with an optical biometer. The results from the two conditions will be compared within the same participants.
The main goal is to determine whether hydration influences the thickness of the retina (macula). Secondary goals include assessing changes in the optic nerve, cornea, and other biometric eye parameters. The study involves only non-invasive tests and minimal risk. Findings may help improve understanding of how hydration affects the eye and may be important for clinical practice, such as planning cataract or refractive surgery.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Relative Dehydration | Experimental | Behavioral: Relative Dehydration Protocol12-hour fluid restriction (≤250 ml fluids until 20h previous day) |
| Hyperhydration | Experimental | Behavioral: Hyperhydration Protocol2 liters of water within 4 hours before testing |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Healthy adult volunteers aged 18 to 65 years
- Normal ophthalmological findings
- Best corrected visual acuity (BCVA) ≥ 1.0 (decimal)
- Willingness to participate and provide written informed consent
Key exclusion criteria (5 listed)
- Known ocular diseases (e.g., glaucoma, keratoconus, retinal pathology)
- History of ocular surgery
- Systemic diseases affecting hydration status (e.g., diabetes mellitus, kidney disease)
- Any condition that, in the investigator's opinion, could interfere with study participation or data quality
- Refusal to participate
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Relative Dehydration ProtocolParticipants will abstain from water intake for 12 hours prior to the study visit. Food is allowed, but fluid intake is limited to a maximum of 250 ml until 20:00 h on the previous evening. Eye measurements will be performed in the morning (8-10 h). | Behavioural | Relative Dehydration |
| Hyperhydration ProtocolParticipants will consume 2 liters of water within 4 hours prior to the study visit. Eye measurements will be performed in the morning (8-10 h). | Behavioural | Hyperhydration |
Primary outcome
Change in macular thickness between dehydration and hyperhydration states
Time frame: Within 1 week (cross-over design with ≥7-day washout period)
Macular thickness (central subfield, parafoveal, and perifoveal regions) will be measured using Zeiss Cirrus HD-OCT. Each participant will undergo measurements in both hydration states, and paired comparisons will be performed.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Sep 2025.
- Individual participant dataSharing planned: Undecided
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Hydration Status
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Questions about this trial
What is this clinical trial studying?
A study testing Relative Dehydration Protocol and Hyperhydration Protocol in people with Hydration Status and Macular Thickness, run by Ante Kreso.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 22 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Ante Krešo, MD (+385 21 556 402, ante.kreso@mefst.hr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in macular thickness between dehydration and hyperhydration states (time frame: Within 1 week (cross-over design with ≥7-day washout period)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Sep 2025; AzTrials last refreshed its copy on 28 Oct 2026.