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Choroidal thickness changes during altered eye growth and refractive state in a primate
D Troilo1, D L Nickla, C F Wildsoet
1Department of Biological Science and Disease, The New England College of Optometry, Boston, Massachusetts 02115, USA. troilod@ne-optometry.edu
Investigative Ophthalmology & Visual Science
|May 8, 2000
Summary
In marmosets, choroidal thickness changes with age and induced refractive errors. Thicker choroids correlate with hyperopic eyes, while thinner choroids correlate with myopic eyes, though changes are smaller than in chicks.
Area of Science:
- Ophthalmology
- Comparative physiology
- Animal models in vision research
Background:
- Choroidal thickness changes are known to compensate for experimentally induced defocus in chicks.
- This compensatory mechanism involves thickening in response to myopic defocus and thinning in response to hyperopic defocus.
Purpose of the Study:
- To investigate whether similar choroidal thickness changes occur in primate eyes.
- To determine the relationship between induced refractive errors and choroidal thickness in marmosets.
Main Methods:
- Thirty-three common marmosets were studied, with some eyes undergoing monocular lid suture to induce refractive changes.
- Refractive errors were measured using refractometry and retinoscopy.
- Axial ocular dimensions and choroidal thickness were assessed using high-frequency A-scan ultrasonography.
Main Results:
- Choroidal thickness naturally increases with age in marmosets.
- Monocular lid suture induced initial hyperopic and subsequent myopic shifts.
- Interocular differences in choroidal thickness correlated with refractive state: thicker in hyperopic eyes and thinner in myopic eyes.
Conclusions:
- Marmoset choroidal thickness increases during postnatal growth.
- Induced refractive errors lead to changes in choroidal thickness, correlated with eye size.
- These choroidal changes in marmosets are smaller than those in chicks and contribute minimally to refractive error correction.