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The mechanism of accommodation in primates
1College of Optometry, University of Houston, Texas 77004, USA.
Ophthalmology
|May 18, 1999
Summary
This study investigated primate accommodation, finding that the ciliary body and lens equator move outward during accommodation, supporting the classic Helmholtz theory.
Area of Science:
- Ophthalmology
- Neuroscience
- Physiology
Background:
- The mechanism of accommodation in primates is debated.
- A novel theory and surgical procedure for presbyopia reversal have been proposed.
Purpose of the Study:
- To investigate the accommodative mechanism in primates.
- To evaluate the proposed novel accommodative mechanism and its relation to presbyopia reversal surgery.
Main Methods:
- Experimental study involving monkeys.
- Accommodation induced via midbrain electrical stimulation and muscarinic agonists.
- Disaccommodation induced via muscarinic antagonist.
- Ultrasound biomicroscopy and goniovideography used to image ciliary body and lens equator movements.
Main Results:
- Both electrical and pharmacological stimulation resulted in outward movement of the ciliary body and lens equator away from the sclera during accommodation.
- Eye movements varied with stimulation type but the accommodative structure movement was consistent.
Conclusions:
- Observed movements of accommodative structures align with the traditional Helmholtz theory of accommodation.
- Findings contradict the recently proposed Schachar accommodative mechanism.