Due to a disease of my eyes I have to avoid
extreme pressure on my head for a while. This
means not lifting heavy objects and not bending
forward to pick something up (for example.)

Now I don't know, and neither the physicians do,
how much pressure I release by playing the horn.

For now I've canceled my lessons and rehearsals.
In the meantime I'm very curious about medical
issues that occur by playing the horn.

Good thinking.
Different people use different amounts of pressure when playing. A former principal player with the Los Angeles Phil has had to retire because of Apnea surgery. He uses a lot of air and pressure (esp in the high range). When he played after his surgery the tissue ripped out and had to be re-sutured. He waited more than 6 months after the second set of sutures and the same thing happened.

I know another player who had prolapsed discs in his neck.And sometimes if the disc are inflamed and more swollen than usual when he plays fluid transfer between the brain and spine ceases. When he stops playing the spinal fluis rushes past a barrier into the brain area cuasing him to incur a severe headache and then black out. He has to be careful not to do this as it can lead to death.

Depending on how a person plays you can close off blood flow to the brain. Blood pressure has been measured at increasing as much as 100% when playing Horn.I forget what the actual air pressure is in teh oral cavity, but it is relatively high.

I've heard it said that more Horn players die from stroke than other muscians; however, I have never actually seen any medical extract on that statement.

A fellow musician told me the same story about having the risk of a stroke but in his version oboe-players were vulnerable to this.

Monday I've to go back to the hospital for the second treatment ( of four ) and then I will ask further on the subject.
It seems a little weird
to me that I'm allowed to get on with sports after a week and should
get away from playing the horn !?

Well, with sports you are only increase volume of air and speed of circulation; well maybe a little circulatory pressure. When playing a wind instrument you are increasing pressure by a whole lot. Ten folds or more.

Thanks for your quick replies John. I will keep the people here informed about the matter. I'm not the only one who has to deal with health problems in combination with playing a wind-instrument.

In a short time I'm expecting that I'm allowed to pick up horn playing again. Since I haven't played or buzzed a single note since January 19 I'm wondering what to expect of my embouchure ?!
I'm sure that I'll have to build up things and would very much appreciate advice on how to take care of this !?

Take it slow, step by step. Concentrate on the low and middle register, the high range you had will come back by itself. Don't use too much pressure and stop if you notice that your embouchure muscles get too tired. If you've got a double horn, play on the F side mostly.
Most important though is to relax your shoulders, thereby relaxing your throat and avoiding too much head pressure to build up. Just let the air flow through you into the horn with as little resistance as possible. Don't go higher than you can play in that relaxed way.
Hope that will help,
mave

Blewit,
Glad to see you will be playing the horn again. I agree mostly with Mave, although I don't understand why you should stay away from the Bb side of the double horn. I might actually encourage you to use the Bb side more often. A lot of the lower notes will speak easier when played on Bb horn (although tuning and intonation may be sacrificed) they certainly will keep pressure to a minimum. And everyone should have at least one set of alternate fingerings under their belt.

Otherwise I totally agree with Mave. You want to start out slow and soft. It should be like riding a bike - although it may take a while to get your balance back. I would suggest keeping a daily journal, it doesn't need to be long or too detailed. If you have a standard warm up you can follow that will help. Play your scales and feel which notes are easiest to play. Make a note of when you start feeling pressure. Do this regularly and you will see your range increase and you will see how each week you get more and more notes that are easier. If you don't keep a journal or a check sheet you may not notice the improvement you are making.

There's my nickel's worth of advice.

Thanks to both of you !
Tomorrow they check my eyes again and the left eye will undergo a laser-treatment for the fourth time in order to stop the bleedings from the retinal blood vessels. Got that through Diabetes.

But back to playing the horn; it seems very usefull to start slowly and work my way up back ! I suppose the "A" on the staff will be proper as highest note for the first week !
And I'm sure going to keep track on my doing with the help of a scheme of what I do day by day !

I recently got over a serious infection that took me away from the horn for 4 weeks. When starting to play again, I did the scale exercices by Michael Hoeltzel (big scales up from the bottom end of the range, two pages for each key) on the f-horn alone up to g on top of the staff. I noticed that after having played mostly on the b side of the horn for 11 years, my embouchure built up quicker and more accurately playing on the f side. Also, I automatically played much more precisely, just because one has to aim better on the f side. Besides that, I can now play a lot of things on both sides of my horn. When switching back to my usual playing method to play the first Strauss concert, I noticed I had gained tremendous accuracy and good sound on the b side by practicing on the f side.

Mave, Ah, that's why. Very good idea. I can see why you are thinking that. I will agree with Mave on that point as well. The caveat being that if you feel too much pressure switch to the Bb side and see if the pressure goes away.

I have not seen or heard of the Hoeltzel book before.I looked it up and like the format it has. I think I'll pick it up. Thanks Mave.