Procedures and methods for the study of the central control of accommodation by electrical stimulation are presented. Positive accommodation (an increase in the dioptric power of the eye) and negative accommodation (a decrease in the dioptric power of the eye) were found by brainstem stimulation.
The frequency threshold for positive accommodation was about 4 cps; the frequency threshold for negative accommodation about 10 cps. Frequencies of 60 and 90 cps were more efficient in producing positive accommodation while negative accommodation varied directly with the frequency up to the 120 cps limiting frequency.
It is concluded that the central control of accommodation by the oculomotor nucleus depends somewhat on the stimulus frequency. Not all responses can be explained by frequency alone and a definitive theory must await further data analysis.
*Submitted on July 27, 1967, for publication in the September, 1968, issue of the American Journal of Optometry and Archives of American Academy of Optometry.
Submitted in partial fulfillment of the requirements for the Doctor of Philosophy degree in Physiological Optics, Indiana University, June, 1964.
The research reported in this paper was conducted by personnel of the USAF School of Aerospace, Medical Division, AFSC, United States Air Force, Brooks AFB, Texas. Further reproduction is authorized to satisfy the needs of the U.S. Government. These experiments were conducted according to the “Principles of Laboratory Animal Care” of the National Society for Medical Research.
†Optometrist, Ph.D., Major, U.S. Air Force. Fellow, American Academy of Optometry.
© 1968 American Academy of Optometry