Related Experiment Video
Updated: Jun 6, 2026
05:46
Correction of Presbyopia by Monocular Bi-Aspheric Ablation Profile
Published on: September 20, 2024
Monofixation with eso-, exo-, or hypertropia: is there a difference?
The American Orthoptic Journal
|December 15, 2010
Summary
Small angle esotropia (micro-ET) is the most common and stable form of microtropia, offering excellent binocular vision. This stability is linked to superior sensory and motor fusion capabilities compared to exotropia or hypertropia.
Area of Science:
- Ophthalmology
- Neuroscience
- Vision Science
Background:
- Monofixation syndrome provides excellent binocular vision and alignment stability in small angle strabismus.
- Understanding the preference for specific strabismus types is crucial for predicting visual outcomes.
Purpose of the Study:
- To investigate potential anatomic or physiologic reasons for the visual system's preference for small angle esotropia over exotropia or hypertropia.
- To identify factors contributing to the stability of microtropia.
Main Methods:
- Retrospective analysis of 259 cases of strabismus with angles ≤10 prism diopters.
- Statistical association of stability with sensory fusion, motor fusion, stereopsis, and clinical signs.
- Comparison of esotropic, exotropic, and hypertropic microtropia characteristics.
Main Results:
- Esotropia was the most common and stable form of microtropia.
- Stability was significantly associated with sensory fusion, motor fusion, and stereopsis.
- Micro-esotropia cases demonstrated superior performance in sensory categories, especially motor fusion, compared to micro-exotropia and micro-hypertropia.
Conclusions:
- The visual system may favor esotropia due to more advantageous neural connections for maintaining binocular vision and stereopsis.
- Anatomic and physiologic disadvantages of temporal retinal input may contribute to the instability of exotropia and hypertropia.
- Factors like A/V patterns, oblique dysfunction, amblyopia, and refractive changes are linked to instability, particularly in micro-exotropia and micro-hypertropia.
Related Concept Videos
02:52Stereoisomerism
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
01:16Focusing of Light in the Eye
Light rays enter the eye through the cornea, a transparent dome-shaped tissue that is the eye's outermost layer. The cornea bends or refracts, light rays traveling to the pupil. The shape of the cornea determines how much of the light is bent and whether the image will be focused correctly on the retina at the back of the eye. Once the light has passed through both refraction layers, it converges into a single focal point onto a small area. This is where photoreceptors start transforming...
01:03¹H NMR Chemical Shift Equivalence: Homotopic and Heterotopic Protons
Protons in identical electronic environments within a molecule are chemically equivalent and have the same chemical shift. The replacement test is a useful tool to identify chemical equivalence and predict NMR spectra. A substituent replaces each of the protons being examined and the resulting molecules are compared. If the same molecule is obtained, the protons are equivalent or homotopic. Replacement of any hydrogens in ethane by chlorine yields chloroethane because all six protons are...
02:24Properties of Enantiomers and Optical Activity
It is essential to understand the difference between chiral and achiral interactions and the implications thereof in optical activity and their applications. Just as our feet, which are chiral, interact uniquely with chiral objects, such as a pair of shoes, but identically with achiral socks, enantiomers of a molecule exhibit different properties only when they interact with other chiral media. An example of a significant implication from this facet is the phenomenon known as optical activity,...
01:27Pharmaceutical Alternatives: Polymorphic Form-Related and Particle Size-Related Therapeutic Nonequivalence
Changes in polymorphic forms can significantly influence the bioavailability of poorly soluble drugs. Although the FDA defines pharmaceutical equivalence based on having the same active ingredient, dosage form, and route of administration, it does not automatically disqualify products with different polymorphic forms. This means two products with different polymorphs can still be deemed pharmaceutically equivalent. However, polymorphic differences can affect properties like wettability,...
01:30Geometry of Hyperbolas
A hyperbola consists of all points where the absolute difference of distances to two fixed points, called foci, remains constant. The standard equation isEach branch extends infinitely and approaches two asymptotes, which guide the curve’s behavior. The parameters a and b define key features: a measures the distance from the center to each vertex along the transverse axis, while b influences the slopes of the asymptotes. The asymptotes have equationsA rectangle centered at the origin with...