No Eye DisorderEKAPSNCT04886219
Studies of the Angle Kappa and the Angle Alpha
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
- 70 participants
- Where
- 1 siteFrance
- Study dates
- 19 May 2021to 4 Oct 2021
- 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
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Studies of the Characteristics of the Angle Kappa and the Angle Alpha in the Healthy Individual. Studies of the Angle Kappa and the Angle Alpha
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 alpha and the angle kappa in a healthy individual without ophthalmologic disorder.
Read the detailed description
The angle kappa corresponds to the angle formed between the visual axis (line between the point of fixation and the fovea: area of the retina allowing precise vision) and the pupillary axis (line passing through the center of the pupil and perpendicular to the cornea). The angle alpha corresponds to the angle formed between the visual axis and the optical axis (line passing through the nodal point of the eye and corneal center).
In theory, the angle kappa and angle alpha are equal; but physiological corectopy in the nasal position induces a variation between these two angles; the angle kappa being generally less than the angle alpha without a correlation being established. Also, pupillary constriction causes a variation in the position of the center of the pupil. The angle kappa therefore exhibits a variation depending on the expansion.
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 alpha and the angle kappa in a healthy individual without an eye disorder.
- Conditions
- No Eye Disorder
- Being tested
- Eye examination
- Keywords
- Angle Kappa, Angle Alpha, Pupillary axis, Visual axis, Optical axis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Eye examinationOther
- Multimodal fundus imaging (color fundus photography, optical coherence tomography (OCT))
- orthoptic assessment (Visual acuity, Refraction, Cover test, Stereopsis evaluation
- ocular biometry
- corneal topography
- monocular photographs in photopic and scotopic condition
| Study group | Role | What they receive |
|---|---|---|
| Healthy individual | Healthy individual 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 Kappa
Semi-automatic digital method of measurement by eye photography
Measured: Day 0
Value of the angle Alpha
Semi-automatic digital method of measurement by eye photography
Measured: Day 0
Secondary outcomes (3)
Variation of the Kappa angle depending on the pupillary diameter
Variation in the same individual. Value of the Kappa angle using the semi-automatic method of measurement by ocular photography in photopic and scotopic conditions \& measurement of the pupillary diameter using the photographs obtained
Measured: Day 0
Correlation between the value of the angle Alpha and the Optic disc / fovea distance
Angle Alpha value using the semi-automatic method of measurement by eye photography and the distance between the optic disc and the fovea
Measured: Day 0
Correlation between the angle Kappa and the axial length
Value of the angle Kappa and Alpha using the semi-automatic method of measurement by eye photography and Value of the axial length measured by biometry IolMaster 500 (Carl Zeiss)
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 May 2021
- Study start19 May 2021
- Primary completion4 Oct 2021
- Study completion4 Oct 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- 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
- 70 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, Principal investigator, Assistance Publique - Hôpitaux de ParisDominique Brémond-Gignac, MD, PhD, Study director, Assistance Publique - Hôpitaux de Paris
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04886219
- Sponsor's protocol ID
- APHP210289
- Other IDs
- 2020-A03370-39
- Acronym
- EKAPS
- Status last verified
- Sep 2025
- First submitted
- 10 May 2021
- Last updated
- 19 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Rateaux M, Vienne-Jumeau A, Bremond-Gignac D, Robert MP. Fluctuations in angle lambda with the pupil diameter and correlations with biometric values in a healthy population. Ophthalmic Physiol Opt. 2025 Nov;45(7):1837-1844. doi: 10.1111/opo.70006. Epub 2025 Aug 14.
PubMed 40810703Rateaux M, Bremond-Gignac D, Robert MP. From monocular photograph to angle lambda: A new clinical approach for quantitative assessment. J Binocul Vis Ocul Motil. 2022 Jul-Sep;72(3):169-175. Epub 2022 Jun 22.
PubMed 35731900
Study at a glance
From the registry record, last updated by the sponsor on 19 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Studies of the Characteristics of the Angle Kappa and the Angle Alpha in the Healthy Individual. Studies of the Angle Kappa and the Angle Alpha
- ClinicalTrials.gov ID
- NCT04886219
- Acronym / sponsor ID
- EKAPS / APHP210289
- Conditions
- No Eye Disorder
- Keywords
- Angle Kappa, Angle Alpha, Pupillary axis, Visual axis, Optical axis
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 70 participants (actual)
- Lead sponsor
- Assistance Publique - Hôpitaux de ParisUniversity, hospital or other
- Collaborators
- URC-CIC Paris Descartes Necker Cochin
- Study start
- 19 May 2021 (actual)
- Primary completion
- 4 Oct 2021 (actual)
- Study completion
- 4 Oct 2021 (actual)
- First posted
- 14 May 2021 (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 alpha and the angle kappa in a healthy individual without ophthalmologic disorder.
Detailed description
The angle kappa corresponds to the angle formed between the visual axis (line between the point of fixation and the fovea: area of the retina allowing precise vision) and the pupillary axis (line passing through the center of the pupil and perpendicular to the cornea). The angle alpha corresponds to the angle formed between the visual axis and the optical axis (line passing through the nodal point of the eye and corneal center).
In theory, the angle kappa and angle alpha are equal; but physiological corectopy in the nasal position induces a variation between these two angles; the angle kappa being generally less than the angle alpha without a correlation being established. Also, pupillary constriction causes a variation in the position of the center of the pupil. The angle kappa therefore exhibits a variation depending on the expansion.
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 alpha and the angle kappa in a healthy individual without an eye disorder.
Study design
- Observational model
- Other
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Healthy individual | – | Other: Eye examinationHealthy individual |
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 (1 listed)
- Subject with strabismus or organic ophthalmologic pathology
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* Multimodal fundus imaging (color fundus photography, optical coherence tomography (OCT)) * orthoptic assessment (Visual acuity, Refraction, Cover test, Stereopsis evaluation * ocular biometry * corneal topography * monocular photographs in photopic and scotopic condition | Other | Healthy individual |
Primary outcome
Value of the angle Kappa
Time frame: Day 0
Semi-automatic digital method of measurement by eye photography
Value of the angle Alpha
Time frame: Day 0
Semi-automatic digital method of measurement by eye photography
3 secondary outcomes
Variation of the Kappa angle depending on the pupillary diameter
Time frame: Day 0
Correlation between the value of the angle Alpha and the Optic disc / fovea distance
Time frame: Day 0
Correlation between the angle Kappa and the axial length
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 19 Sep 2025.
- Results publication: PubMed 40810703Rateaux M, Vienne-Jumeau A, Bremond-Gignac D, Robert MP. Fluctuations in angle lambda with the pupil diameter and correlations with biometric values in a healthy population. Ophthalmic Physiol Opt. 2025 Nov;45(7):1837-1844. doi: 10.1111/opo.70006. Epub 2025 Aug 14.
- Results publication: PubMed 35731900Rateaux M, Bremond-Gignac D, Robert MP. From monocular photograph to angle lambda: A new clinical approach for quantitative assessment. J Binocul Vis Ocul Motil. 2022 Jul-Sep;72(3):169-175. Epub 2022 Jun 22.
- 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 principal investigator
Assistance Publique - Hôpitaux de Paris
Dominique Brémond-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 1 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 19 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 Kappa (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?
On the ClinicalTrials.gov record for NCT04886219, which also lists 2 linked publications.
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 19 Sep 2025.