Effect of Dry Eye Treatment on Corneal Astigmatism Measurements (NCT07657858) | Clinical Trial Compass
RecruitingNot Applicable
Effect of Dry Eye Treatment on Corneal Astigmatism Measurements
China400 participantsStarted 2026-01-01
Plain-language summary
This prospective single-center study evaluates the effect of dry eye disease and short-term ocular surface treatment on the agreement and repeatability of corneal astigmatism measurements in patients with age-related cataract. Participants undergoing preoperative cataract evaluation are classified into a control group or a dry eye disease group according to ocular surface symptoms and objective tear film findings.
All participants undergo ocular surface assessment and repeated corneal measurements using three commonly used devices: IOLMaster 700, Pentacam AXL, and iTrace Prime. Measurements include keratometric corneal astigmatism, total corneal astigmatism, and vector components of astigmatism. Patients with dry eye disease receive 0.3% sodium hyaluronate eye drops four times daily for 2 weeks, after which ocular surface assessment and device measurements are repeated.
The primary objective is to determine whether dry eye disease reduces interdevice agreement and test-retest repeatability of corneal astigmatism measurements, and whether short-term ocular surface treatment improves measurement stability. Interdevice agreement is assessed using Bland-Altman analysis, and repeatability is evaluated using within-subject standard deviation, test-retest repeatability, and intraclass correlation coefficient.
Who can participate
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria:
* Patients with age-related cataract undergoing preoperative ocular examination.
* Ability to complete ocular surface evaluation, including the Ocular Surface
* Disease Index questionnaire, non-invasive tear film break-up time, tear meniscus height, Schirmer test, and ocular surface staining.
* Ability to complete repeated corneal astigmatism measurements using IOLMaster 700, Pentacam AXL, and iTrace Prime.
* Ability to maintain stable fixation during device measurements. Provision of written informed consent.
Exclusion Criteria:
* Previous ocular surgery or ocular trauma.
* Corneal degeneration, corneal dystrophy, or other corneal diseases that could affect corneal measurements.
* Active corneal or conjunctival infection.
* Uveitis.
* Use of any topical eye drops within 24 hours before examination.
* Use of antiglaucoma medications.
* Contact lens wear within 1 month before examination.
* Previous or ongoing treatment for dry eye disease.
* Poor fixation during device measurements.
* Poor-quality measurements from any study device
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Since this trial is studying how dry eye treatment affects the accuracy of corneal astigmatism measurements before cataract surgery, could participating help ensure my own pre-surgical measurements are more reliable?
2This study seems to be focused on measurement accuracy rather than testing a new drug or procedure — what exactly would I be asked to do as a participant, and how many visits would that involve?
3Because this trial is listed as 'Phase NA,' meaning it's not testing a new treatment but rather comparing measurement devices and techniques, are there any risks to my eyes or vision from the measurement procedures involved?
4If I have both dry eye and cataract, could my dry eye be affecting the accuracy of the astigmatism measurements my doctor is already taking, and is treating the dry eye first something I should consider regardless of this trial?
5Are there standard dry eye treatments my doctor would recommend before my cataract surgery measurements anyway, and how does participating in this study compare to just going that route on my own timeline?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Interdevice Agreement of Corneal Astigmatism Measurements
Timeframe: Baseline and 2 weeks after ocular surface treatment in the dry eye disease arm.
2
Test-Retest Repeatability of Corneal Astigmatism Measurements
Timeframe: Baseline and 2 weeks after ocular surface treatment in the dry eye disease arm.