Are there any implications on undergoing LASIK if I have different eye pressure test results?

Doctor's Answers (3)

In short, yes definitely! Your eye pressure will affect whether or not you are suitable for LASIK.

Long answer:

Your eye pressure is an indication of your glaucoma risk.

Although everyone’s eye pressure fluctuates on a daily basis (it even varies depending on the time of day), a normal person’s eye pressure should be consistently within the range of 8 to 21.

If your eye pressure is ever recorded as higher than 21, you may need further tests to evaluate the possibility of glaucoma.

Having said that, it must be reiterated that not all eye pressure machines measure eye pressure in the same way, and hence there may be inaccuracies (or falsely high readings) sometimes.

Your eye doctor will be able to tell you which is the most accurate method to measure your eye pressure.

So why does eye pressure affect LASIK (and vice versa)?

Everyone’s eye pressure measurements are dependent on their eye cornea thickness. A thicker cornea gives a higher pressure reading and similarly, a thinner cornea yields a lower pressure reading.

In LASIK, the cornea is thinned out in order to correct the refractive power. This thin cornea will lead to an artificially lower eye pressure recording. So that effectively means that a person with glaucoma (high eye pressure) who had LASIK done, would be measured as having normal or low eye pressure, but falsely so.

This is potentially dangerous because post-LASIK patients with glaucoma could go undetected.

In my practice, I have come across many such post-LASIK patients who had their glaucoma diagnoses missed by other doctors due to their seemingly normal eye pressures.

After they sought a second opinion with me and taking into consideration their thin corneas, we were able to elicit that their true eye pressures were high. Unfortunately, many of them had already suffered irreversible vision loss since detection was too late.

LASIK does NOT increase your risk of glaucoma. LASIK does however make the detection and monitoring of glaucoma more difficult. Difficult, but not impossible.

It is thus necessary to rely on your trusted eye doctor to be astute at using better methods (other than eye pressure) to detect and monitor glaucoma effectively.

Hence, if there is any indication at all that you might be at risk of glaucoma, it would be prudent for your eye doctor to counsel adequately regarding your suitability for LASIK.

I hope that this was easy to understand and helpful to you!

I think in a case like this, where the measurements are very different when measured in 2 different settings – the question is: which one is the accurate one?

There are different ways of checking the eye pressure. One common way is using an ‘air puff’ machine:

Another way is a ‘Goldmann tonometer’:

There are still other ways, but suffice to say some methods are more accurate than others.

When using the airpuff, it is quite common to get a reading that is ‘too high’-higher than what the real pressure is. This can happen when someone has long eyelashes that point downwards, for example, and block the airpuff blown by the machine. The machine has to ‘blow harder’ to achieve a result, and it reads a higher eye pressure than the real pressure.

The best way (and most accurate way) is still considered the Goldmann tonometer currently.

In your case, I would get the eye pressure re-measured with a Goldmann tonometer, and

  1. if that reads something like 18, then I would say that is your real eye pressure, and that you would be OK for LASIK. On the other hand,
  2. if a Goldmann tonometer measures your eye pressure at 26, then you should have other tests done such as visual fields and OCT to check on the health of your optic nerve. A high eye pressure of eg 26 has other implications besides affecting your suitability for LASIK, and needs to be investigated further.

I hope this helps!

Dr David Chan

"Ophthalmologist with over 20 years of experience"

Certainly, having different test results from different centres can be disconcerting to say the least. In most eye clinics, an automated pressure measuring device known as an air-puff tonometry is used as a quick screening tool to check for eye pressure levels.

In the event a raised eye pressure is found, another pressure measuring technique which uses a contact lens is employed as a means of crosscheck. The concern regarding high pressure is related to an important blinding eye condition known as glaucoma. Part of the aims of a LASIK suitability assessment include identifying and treating any eye pathologies prior to any LASIK treatment.

In order to have a piece of mind, it might be best to have your pressure rechecked by your surgeon via the contact lens method.

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