The influence of changes in the intraocular circulation on the intraocular pressure / by E.E. Henderson and E.H. Starling.

  • Henderson, Edward Erskine, 1870-1929.
Date:
1904
Catalogue details

Licence: In copyright

Credit: The influence of changes in the intraocular circulation on the intraocular pressure / by E.E. Henderson and E.H. Starling. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    15/18 (page 317)
    results obtained by previous observers relating to the rise of intraocular pressure following stimulation of the 5th nerve were due either to the stimulation of the sympathetic fibres running in this nerve, and there- fore to contraction of the orbital muscle, or to faulty experimentation and the escape of current to adjacent portions of the brain, causing a reflex rise of blood-pressure and consequent passive rise of intraocular pressure. It is interesting to note that the path for the external unstriated muscles of the eyeball is similar to that of the dilator fibres, to the pupil, and differs from that for the vaso-constrictor nerves to the vessels of the eyeball. (Compare Fr. Franck(10).) The action of drugs on intraocular pressure. We have investigated by the same method the action of two drugs, namely, nicotin and adrenalin, on the intraocular pressure. As these drugs raise the general blood-pressure and constrict the peripheral arterioles, it is evident that we have to deal with the resultant of these two effects in measuring the intraocular pressure. It is there- fore not surprising to find that the actual effect on the intraocular pressure will vary with the individual. Thus the local effect may predominate, neutralize, or be overpowered by the general rise of blood-pressure. Thus Parsons'6* states that the intraocular pressure runs parallel to the general blood-pressure. He however employed much larger doses than we have done. We have employed for the adrenalin Parke Davis’s OT°/0 solution in doses of about 0'12c.c. (2 minims). To ensure the condition of the drug, we have employed the small tubes put up by Mart indale. The nicotin we employed was a 2% solution and we have used doses of about 0'06 c.c. (1 minim). The drug was introduced intravenously, the femoral vein being usually selected, and in every case the drug was washed in with a subsequent syringeful of normal saline solution. Cats only were employed and the blood-pressure was measured in the aorta. Four experiments were made on intact animals, three on animals in whom the superior cervical ganglion on one side had been removed immediately prior to the observation, and one on an animal in which this had been done four weeks previously. Of the first four in two the local effect predominated with both drugs. The blood-pressure rose while the intraocular pressure fell. In one the two effects nearly counterbalanced one another, the rise of blood-pressure being accompanied by a very slight rise of intraocular pressure. In the fourth, the intraocular rise appeared to be entirely passive.