No Eye DisorderEPOLAFNCT05613517
Study of the Angle Lambda and Ocular Dominance
An observational study of No Eye Disorder, run by Assistance Publique - Hôpitaux de Paris at 1 site in France.
Trial summary
Anatomical ophthalmological connections and their dynamics are still debated in the scientific community. However, their considering is essential in many surgeries (strabismus, cataract, refractive...) or in clinical practice. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- No Eye Disorder
- What is being tested?
- Eye examination
- How many people
- 76 participants
- Where
- 1 siteFrance
- Study dates
- 25 Nov 2022to 28 Feb 2024
- Phase
- Observational
- Are there results?
- None posted in the registry
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 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Healthy individuals without visual disorders
Who may be able to join
- Informed major subject not opposing to their participation in the study
Who cannot join
- Subject with strabismus or organic ophthalmologic pathology
- Or presenting a visual acuity lower than 10/10th
- Or with a history of eye surgery
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Study of the Correlations Between the Ocular Dominance Depth, the Angle Lambda and the Fixation Disparity in Healthy Individuals
Anatomical ophthalmological connections and their dynamics are still debated in the scientific community. However, their considering is essential in many surgeries (strabismus, cataract, refractive...) or in clinical practice.
The correlation between these biometric values would make it possible to refine the knowledge related to these landmarks and thus offer better ophthalmological management by integrating these variables into the clinical examination.
Read more
The aim of the study is to analyze the correlation between the angle lambda and the ocular dominance depth in healthy individuals without ophthalmologic disorder.
Then, seconds goals were defined as the study of the relation between the value of the angle lambda and the fixation disparity quantified with the Rousseau test.
Relation between ocular dominance measured with the Guillon's test and the Hole-in-car test will also studied.
Read the detailed description
The angle lambda corresponds to the angle formed by the pupillary axis (line passing through the center of the pupil and perpendicular to the cornea) and the line of sight (broken line between the fixation point and the fovea and passing through the center of the pupil entrance). The angle kappa corresponds to the angle between the visual axis (line between the point of fixation and the fovea: area of the retina allowing precise vision) and the pupillary axis.
The angle lambda and the angle kappa are very close, which is why the lambda angle is often equated with the kappa angle, both in practice and in the literature.
The literature reports a non-null angle kappa ranged between 1.91° ± 0.14° and 5.73° ± 0.10° in the general population. Also, studies have reported a significantly greater angle on the left eye compared to the right eye. Moreover - because of the interpupillary difference - each eye perceives the same image from a different angle, resulting in a fixation disparity, defined as the angle of the residual deviation of the visual axes when the subject fixes and binocularly merges an image. In some cases, too high a value of the disparity can lead to a fixation disorder requiring orthoptic treatment.
Anatomical ophthalmological connections and their dynamics are still debated in the scientific community. However, their considering is essential in many surgeries (strabismus, cataract, refractive...) or in clinical practice.
The correlation between these biometric values would make it possible to refine the knowledge related to these landmarks and thus offer better ophthalmological management by integrating these variables into the clinical examination.
The aim of the study is to analyze the correlation between the angle lambda and the ocular dominance depth and the fixation disparity in a healthy population without ophthalmologic disorder.
Then, seconds goals were defined as the study of the relation between the value of the angle lambda and the fixation disparity quantified with the Rousseau test.
Relation between ocular dominance measured with the Guillon's test and the Hole-in-car test will also studied.
- Conditions
- No Eye Disorder
- Being tested
- Eye examination
- Keywords
- Angle lambda, Ocular dominance, Fixation disparity, Pupillary axis, Line of sight
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Eye examinationOther
- orthoptic assessment (visual acuity, refraction, stereopsis test, Cover-test, evaluation of the disparity of fixation and ocular dominance, measurement of the inter-pupillary distance
- ocular biometry
- corneal topography
- monocular photographs in photopic condition
| Study group | Role | What they receive |
|---|---|---|
| Healthy individual | Healthy individual without eye disorder. Receives: Other: Eye examination |
What is being measured
The primary outcome is the main question the study is designed to answer.
Value of the angle lambda
Semi-automatic digital method of measurement by eye photograph.
Measured: Day 0
Ocular dominance depth
Guillon's and Hole-In-Card tests.
Measured: Day 0
Secondary outcomes (5)
Fixation disparity
Rousseau test.
Measured: Day 0
Ocular dominance measurements quantified by the Hole-in-the-card method
Ocular dominance.
Measured: Day 0
Guillon test
Ocular dominance.
Measured: Day 0
Semi-automatic method of measurement by ocular photography
Compare the values of the lambda angle obtained using the semi-automatic method of measurement by ocular photography and the method using corneal topography.
Measured: Day 0
Method using corneal topography
Compare the values of the lambda angle obtained using the semi-automatic method of measurement by ocular photography and the method using corneal topography.
Measured: Day 0
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Nov 2022
- Study start25 Nov 2022
- Primary completion28 Feb 2024
- Study completion28 Feb 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for No Eye DisorderStudies of the same condition, open and under way.
- More trials run by Assistance Publique - Hôpitaux de ParisThe sponsor's other registered studies.
- 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
- Observational
- Observational model
- Other
- Time perspective
- Prospective
- Enrolment
- 76 participants (actual)
Sponsor and investigators
- Lead sponsor
- Assistance Publique - Hôpitaux de Paris
- Sponsor type
- University, hospital or other
- Collaborators
- URC-CIC Paris Descartes Necker Cochin
- Responsible party
- Sponsor
- Investigators
- Maxence Rateaux, PhD, Principal investigator, Assistance Publique - Hôpitaux de ParisDominique Bremond-Gignac, MD, PhD, Study director, Assistance Publique - Hôpitaux de Paris
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05613517
- Sponsor's protocol ID
- APHP221023
- Other IDs
- 2022-A01045-38
- Acronym
- EPOLAF
- Status last verified
- Sep 2025
- First submitted
- 4 Nov 2022
- Last updated
- 12 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 12 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Study of the Correlations Between the Ocular Dominance Depth, the Angle Lambda and the Fixation Disparity in Healthy Individuals
- ClinicalTrials.gov ID
- NCT05613517
- Acronym / sponsor ID
- EPOLAF / APHP221023
- Conditions
- No Eye Disorder
- Keywords
- Angle lambda, Ocular dominance, Fixation disparity, Pupillary axis, Line of sight
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 76 participants (actual)
- Lead sponsor
- Assistance Publique - Hôpitaux de ParisUniversity, hospital or other
- Collaborators
- URC-CIC Paris Descartes Necker Cochin
- Study start
- 25 Nov 2022 (actual)
- Primary completion
- 28 Feb 2024 (actual)
- Study completion
- 28 Feb 2024 (actual)
- First posted
- 14 Nov 2022 (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.
Anatomical ophthalmological connections and their dynamics are still debated in the scientific community. However, their considering is essential in many surgeries (strabismus, cataract, refractive...) or in clinical practice.
The correlation between these biometric values would make it possible to refine the knowledge related to these landmarks and thus offer better ophthalmological management by integrating these variables into the clinical examination.
The aim of the study is to analyze the correlation between the angle lambda and the ocular dominance depth in healthy individuals without ophthalmologic disorder.
Then, seconds goals were defined as the study of the relation between the value of the angle lambda and the fixation disparity quantified with the Rousseau test.
Relation between ocular dominance measured with the Guillon's test and the Hole-in-car test will also studied.
Detailed description
The angle lambda corresponds to the angle formed by the pupillary axis (line passing through the center of the pupil and perpendicular to the cornea) and the line of sight (broken line between the fixation point and the fovea and passing through the center of the pupil entrance). The angle kappa corresponds to the angle between the visual axis (line between the point of fixation and the fovea: area of the retina allowing precise vision) and the pupillary axis.
The angle lambda and the angle kappa are very close, which is why the lambda angle is often equated with the kappa angle, both in practice and in the literature.
The literature reports a non-null angle kappa ranged between 1.91° ± 0.14° and 5.73° ± 0.10° in the general population. Also, studies have reported a significantly greater angle on the left eye compared to the right eye. Moreover - because of the interpupillary difference - each eye perceives the same image from a different angle, resulting in a fixation disparity, defined as the angle of the residual deviation of the visual axes when the subject fixes and binocularly merges an image. In some cases, too high a value of the disparity can lead to a fixation disorder requiring orthoptic treatment.
Anatomical ophthalmological connections and their dynamics are still debated in the scientific community. However, their considering is essential in many surgeries (strabismus, cataract, refractive...) or in clinical practice.
The correlation between these biometric values would make it possible to refine the knowledge related to these landmarks and thus offer better ophthalmological management by integrating these variables into the clinical examination.
The aim of the study is to analyze the correlation between the angle lambda and the ocular dominance depth and the fixation disparity in a healthy population without ophthalmologic disorder.
Then, seconds goals were defined as the study of the relation between the value of the angle lambda and the fixation disparity quantified with the Rousseau test.
Relation between ocular dominance measured with the Guillon's test and the Hole-in-car test will also studied.
Study design
- Observational model
- Other
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Healthy individual | – | Other: Eye examinationHealthy individual without eye disorder. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Healthy individuals without visual disorders
Key inclusion criteria (1 listed)
- Informed major subject not opposing to their participation in the study
Key exclusion criteria (3 listed)
- Subject with strabismus or organic ophthalmologic pathology
- Or presenting a visual acuity lower than 10/10th
- Or with a history of eye surgery
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 |
|---|---|---|
| Eye examination* orthoptic assessment (visual acuity, refraction, stereopsis test, Cover-test, evaluation of the disparity of fixation and ocular dominance, measurement of the inter-pupillary distance * ocular biometry * corneal topography * monocular photographs in photopic condition | Other | Healthy individual |
Primary outcome
Value of the angle lambda
Time frame: Day 0
Semi-automatic digital method of measurement by eye photograph.
Ocular dominance depth
Time frame: Day 0
Guillon's and Hole-In-Card tests.
5 secondary outcomes
Fixation disparity
Time frame: Day 0
Ocular dominance measurements quantified by the Hole-in-the-card method
Time frame: Day 0
Guillon test
Time frame: Day 0
Semi-automatic method of measurement by ocular photography
Time frame: Day 0
Method using corneal topography
Time frame: Day 0
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Sep 2025.
- Individual participant dataSharing planned: No
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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. This study is not recruiting at the moment.
Maxence Rateaux, PhD principal investigator
Assistance Publique - Hôpitaux de Paris
Dominique Bremond-Gignac, MD, PhD study director
Assistance Publique - Hôpitaux de Paris
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of No Eye Disorder, run by Assistance Publique - Hôpitaux de Paris at 1 site in France.
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 1 inclusion and 3 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: finished, as of the sponsor's last update on 12 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in France. Whether a site is taking part right now should be confirmed with that site. See every site.
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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Value of the angle lambda (time frame: Day 0). The study lists 2 primary outcomes in all. 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 12 Sep 2025.