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Intraocular accommodative movements in monkeys; relationship to presbyopia.
Mary Ann Croft1, T Michael Nork1, Gregg Heatley1
1Department of Ophthalmology and Visual Sciences, Madison, WI, 53792, USA.
Experimental Eye Research
|March 14, 2022
Summary
Age-related changes in primate eye accommodation show that vitreous and aqueous humor movements decline with age. These dynamic accommodative movements are crucial for lens thickening and may impact presbyopia development.
Area of Science:
- Ophthalmology
- Biomechanics
- Primate Eye Research
Background:
- Accommodation involves dynamic changes in intraocular structures.
- Understanding age-related decline in accommodation is key to addressing visual impairments like presbyopia.
- Previous studies have not fully quantified dynamic vitreous and aqueous humor movements during accommodation in primates.
Purpose of the Study:
- To quantify age-related changes in dynamic accommodative movements of vitreous and aqueous humor.
- To investigate these movements in various ocular conditions: iridic, aniridic, phakic, and aphakic primate eyes.
- To explore the implications of these movements for lens thickening and presbyopia.
Main Methods:
- Used rhesus monkeys (6-25 years old) with induced accommodation via midbrain stimulation.
- Employed specialized imaging techniques and contrast agents to visualize intraocular structures.
- Measured accommodative responses using a Hartinger coincidence refractometer.
Main Results:
- Accommodation caused posterior bowing of the anterior hyaloid membrane and lens capsule.
- Central vitreous fluid and structures moved posteriorly, while peripheral vitreous moved anteriorly.
- Accommodative movements and fluid flow between chambers occurred in all eyes but declined with age.
Conclusions:
- Statistically significant accommodative movements of intravitreal structures occur and diminish with age.
- Fluid displacement facilitates lens thickening during accommodation.
- Findings suggest a potential mechanism for presbyopia related to age-dependent accommodative changes.
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