Abstract

Studies on accommodation in monkeys suggest that accommodation is caused by a pressure differential between the anterior and vitreous chambers of the eye. Our subjects were six adult male pigtail monkeys. This animal was chosen because it has strong eye-contact behavior to control his accommodation. Each subject had a radiosonde pressure transducer implanted in the vitreous chamber of one eye. The transdicer was activated by a radio-frequency source taped to the skull above the eye. The unit was calibrated by putting the unit (attached to the monkey) into a pressure chamber and elevating the pressure. The first two monkeys were restrained in a chair and were alert because no drugs were used. The other four were not familiar with a restraining chair. For this reason we used ketamine anesthesia, along with eserine, to induce accommodation. At 20 ft (6.1 m) from the monkey's eyes the caretaker developed eye contact with the monkey. The caretaker then slowly walked to within 1 ft (30.6 cm) of the monkey's eyes while the pressure steadily increased. The caretaker then backed away to 20 ft (6.1 m) and the signal returned to its starting point. The results on the four monkeys under anesthesia and eserine support the findings from the first group.

© 1990 Optical Society of America