Question: Does reading a computer monitor for an hour and feeling eye strain raise your IOP?
My Answer: The question of computer use and intraocular pressure is a common topic. Many people report that using the computer (even for several hours) for relaxing activities does not raise intraocular pressure. I have found this to be true for myself as well.
However, when a feeling of eye strain or psychological stress is involved, it is a different issue in my opinion.
You would actually have to check your intraocualr pressure (via self-tonometry) to know for sure.
The people in our self-tonometry group who have several years of experience with frequent (i.e., mutliple daily eye pressure measurements almost every single day) eye pressure monitoring can tune in to the subtle physiological symptoms that often accompany elevated intraocular pressure readings. The relationship can be complex, but it is also something one can learn. I can summarize it by saying that any time there is dis-ease (discomfort, etc.) in the body or mind, there is a good chance one's intraocular pressure will be higher than it would be otherwise.
If you have a tonometer and you have the skill to immediately let go of the dis-ease (e.g. psychological stress, etc.), you can often measure an immediate reduction in intraocular pressure. Some people have reported (as per multiple, careful measurements with high quality tonometers) drops in eye pressure of 5 mmHg in less than 5 minutues.
A couple weeks ago I found myself with slightly elevated intraocular pressure. I used the opportunity to apply the techniques I teach others. I dropped my IOP 5 mmHg in about 2 minutes. Then I used a second technique and dropped my IOP another 4 mmHg in another 2 minutes. So that is a total reduction in intraocular pressure of 9 mmHg in about 5 minutes. I measured it with the iCare tonometer and I confirmed each reading (before and after) with multiple measurements. In total I took 36 individual measurements per eye for this little test, so I am very confident in the values I'm reporting. (Furthermore, I have validated the iCare values against my Pascal Dynamic Contour tonometer, which is arguably the world's most accurate tonometer.)
I try to avoid doing anything that produces a feeling of eye strain (or any other strain in the body or mind). To help with the computer issue In my own case I purchased dual 24" monitors and a super high quality digital (DVI) graphics card for my computer so I can read my monitor without strain. However, there are still certain computer-related activities that will raise my IOP. I've gotten better at not getting myself into those situations. I simply pay attention to any hint of any type of strain. If there is any strain, I adjust as required so that I let go of the strain. Managing IOP is almost that simple. However, in my experience, it requires self-tonometry. Without self-tonometry, most of us do not seem to be able to make the connection between the subtle symptoms and intraocular pressure.