SUMMARY
Purpose:
To compare the mean ophthalmic artery pressure (Pm ophth) and the ocular perfusion pressure (PP) of individuais submitted to physical effort with the mean brachial pressure (Pm brach), with the purpose of obtaining a better understanding of the autoregulation of the blood flow in the eyeball under physical stress.
Method:
The authors examined 36 volunteers submitted to physical effort by mean of an ergometric test. The ophthalmic artery pressure (P ophth) and the intraocular pressure (IOP) were measured at three phases: basal, effort and recuperation. The results were compared with the Pm brach.
Results:
During the basal phase, the Pm ophth corresponded to 71.12% of the Pm brach value. During the phase of maximum effort, the Pm brach increased 36.13% and the Pm ophth, 8.37%. Thus the relation between them decreased from 71.12% to 56.62%, i.e., it dropped from 0.71 mmHg to 0.56 mmHg, which represents a decrease of 2 1 . 1 2 %. Yet, in the effort phase, the PP underwent an increase of 17.4% ar 9.43 mmHg.
Conclusions:
This study would like to demonstrate the existence of an auto regulatiory mechanism that controls the blood flow to the eye even when Pm ophth does not increase in the sarne proportion as the Pm brach, and, also, that there would exist an increase of the PP responsible for a greater oxygen supply to the optic disc, during physical effort.
Keywords:
Ophthalmic artery pressure; Ocular perfusion pressure; Cycloergometry; Ophthalmodynamometry