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| ID | Type | Description | Link |
|---|---|---|---|
| 2025-A02953-46 | Other Identifier | ID RCB number |
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| Name | Class |
|---|---|
| URC-CIC Paris Descartes Necker Cochin | OTHER |
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In orthoptics, fusional vergence (FV) measurement is one of the key tests used to assess fusion ability. These amplitudes are generally reduced in individuals with convergence insufficiency. Fusional vergence are quantified by placing a prism bar randomly in front of one eye-first for distance vision and then for near vision. Rehabilitation exercises using the prism bar are also performed in the same manner.
Depending on orthoptic practice, the prism bar is placed in front of the left eye or the right eye, in a dogmatic manner, or in front of the right eye, in a conventional manner, without any study providing any justification. However, some practitioners report interocular differences when measuring fusion amplitudes depending on which eye is prismed, while others do not.
The hypothesis put forward is that, in individuals with an interocular difference in fusional vergence, ocular dominance (sensory and motor) could be the cause of this measurement discrepancy.
The objective is therefore to compare the difference in fusional vergence depending on whether the dominant or non-dominant eye is tested, using a randomized order of eyes and tests.
If this hypothesis is confirmed (greater fusional vergence when tested on the dominant eye), this would: (1) enhance our understanding of fusion mechanisms, (2) provide more targeted insights for the assessment, quantification, and rehabilitation of fusional vergence to improve the effectiveness of orthoptic intervention.
In orthoptics, fusional vergence (FV) measurement is one of the key tests used to assess fusion ability. These amplitudes are generally reduced in individuals with convergence insufficiency. Fusional vergence are quantified by placing a prism bar randomly in front of one eye-first for distance vision and then for near vision. Rehabilitation exercises using the prism bar are also performed in the same manner.
Depending on orthoptic practice, the prism bar is placed in front of the left eye or the right eye, in a dogmatic manner, or in front of the right eye, in a conventional manner, without any study providing any justification. However, some practitioners report interocular differences when measuring fusion amplitudes depending on which eye is prismed, while others do not.
The hypothesis put forward is that, in individuals with an interocular difference in fusional vergence, ocular dominance (sensory and motor) could be the cause of this measurement discrepancy.
The objective is therefore to compare the difference in fusional vergence depending on whether the dominant or non-dominant eye is tested, using a randomized order of eyes and tests.
If this hypothesis is confirmed (greater fusional vergence when tested on the dominant eye), this would: (1) enhance our understanding of fusion mechanisms, (2) provide more targeted insights for the assessment, quantification, and rehabilitation of fusional vergence to improve the effectiveness of orthoptic intervention.
The study consists of one-hour eye examinations of healthy individuals with no visual or oculomotor disorders.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Healthy individual | Individuals with no visual or oculomotor disorders. |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Fusional Vergence assessment | Other | Measurement of sensorimotor fusional vergence in the right and left eyes, in divergence and convergence, first for distance vision and then for near vision. A random draw will determine which eye is tested first for distance vision, followed by a second draw for near vision, in order to minimize training bias. Prior to this, a stereoscopic acuity test will be performed to confirm the presence of binocular vision. |
| Measure | Description | Time Frame |
|---|---|---|
| Amplitude of fusional vergence | Values of horizontal fusional vergence measured using a horizontal Berens prism bar in divergence and convergence, for distance and near vision, in the right eye and the left eye and reported in prism diopters. | Day 0 |
| Laterality ocular dominance | Assessment of ocular dominance for:
| Day 0 |
| Lateralization quotient value (LQ) | Determination of the lateralization quotient value by the mean of previous responses of the ocular dominance tests. | Day 0 |
| Measure | Description | Time Frame |
|---|---|---|
| Assessment of the degree of agreement among the various tests for ocular dominance | Compilation of responses to ocular dominance tests (sensorial and motor dominant eye, target eye and preferred eye) and lateralization quotient. | Day 0 |
| Agreeement between the bilateral prismatic test (new test for oculomotor dominance laterality determination and standard ocular dominance tests |
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Inclusion Criteria:
Exclusion Criteria:
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Any individual between the ages of 18 and 35, inclusive, with no organic ophthalmological disorders or oculomotor disorders.
| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Maxence Rateaux, PhD | Contact | 01 44 49 53 62 | +33 | maxence.rateaux@aphp.fr |
| Hélène Morel | Contact | 01 44 38 16 53 | +33 | helene.morel@aphp.fr |
| Name | Affiliation | Role |
|---|---|---|
| Maxence Rateaux, PhD | Assistance Publique - Hôpitaux de Paris | Principal Investigator |
| Dominique MD, PhD BREMOND-GIGNAC | Assistance Publique - Hôpitaux de Paris | Study Director |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Hôpital Necker-Enfants Malades | Paris | 75015 | France |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 37141181 | Background | Rovira-Gay C, Mestre C, Argiles M, Vinuela-Navarro V, Pujol J. Feasibility of measuring fusional vergence amplitudes objectively. PLoS One. 2023 May 4;18(5):e0284552. doi: 10.1371/journal.pone.0284552. eCollection 2023. | |
| 20521879 | Background | Rowe FJ. Fusional vergence measures and their significance in clinical assessment. Strabismus. 2010 Jun;18(2):48-57. doi: 10.3109/09273971003758412. |
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| Ocular dominance evaluation | Other | Assessment of ocular dominance for:
|
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| Complete Orthoptic | Other | Conducting an orthoptic evaluation to verify that patients meet the study's inclusion criteria:
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Evaluation of a new test (bilateral prismatic test for oculomotor dominance) and comparison to usually ocular dominance test. All tests classify the ocular dominance into 3 categories : Left, Right, None. This part tends to evaluation the efficacity and the utility of a new test for ocular dominance. |
| Day 0 |
| Assessment of the difference in fusional vergence measurements between the right and left eyes and the laterality quotient | Assessment of the difference in fusional vergence measurements between the right and left eyes and the laterality quotient. | Day 0 |
| Correlation between inter-pupillary distance measurements and differences in fusion amplitude measurements between the right and left eyes | Measurements of interpupillary distance and overall fusion ability, for distance vision and near vision. | Day 0 |
| 30292725 | Background | Bossi M, Hamm LM, Dahlmann-Noor A, Dakin SC. A comparison of tests for quantifying sensory eye dominance. Vision Res. 2018 Dec;153:60-69. doi: 10.1016/j.visres.2018.09.006. Epub 2018 Oct 22. |
| 30821611 | Background | Lanca CC, Rowe FJ. Measurement of fusional vergence: a systematic review. Strabismus. 2019 Jun;27(2):88-113. doi: 10.1080/09273972.2019.1583675. Epub 2019 Mar 1. |
| 24141750 | Background | Fray KJ. Fusional amplitudes: exploring where fusion falters. Am Orthopt J. 2013;63:41-54. doi: 10.3368/aoj.63.1.41. |
| 28759298 | Background | Fray KJ. Fusional Amplitudes: Developing Testing Standards. Strabismus. 2017 Sep;25(3):145-155. doi: 10.1080/09273972.2017.1349814. Epub 2017 Jul 31. |
| 24319677 | Background | Lopes-Ferreira D, Neves H, Queiros A, Faria-Ribeiro M, Peixoto-de-Matos SC, Gonzalez-Meijome JM. Ocular dominance and visual function testing. Biomed Res Int. 2013;2013:238943. doi: 10.1155/2013/238943. Epub 2013 Nov 11. |
| 29090482 | Background | Ho R, Thompson B, Babu RJ, Dalton K. Sighting ocular dominance magnitude varies with test distance. Clin Exp Optom. 2018 Mar;101(2):276-280. doi: 10.1111/cxo.12627. Epub 2017 Oct 31. |
| 12742109 | Background | Kommerell G, Schmitt C, Kromeier M, Bach M. Ocular prevalence versus ocular dominance. Vision Res. 2003 Jun;43(12):1397-403. doi: 10.1016/s0042-6989(03)00121-4. |
| 31069044 | Background | Garcia-Perez MA, Peli E. Psychophysical Tests Do Not Identify Ocular Dominance Consistently. Iperception. 2019 Apr 29;10(2):2041669519841397. doi: 10.1177/2041669519841397. eCollection 2019 Mar-Apr. |