March 1, 2013 | POSTED BY | Clinical Pearls

Most students would agree that performing Goldmann Applanation Tonometry (GAT) on routine patients is fairly easy. However, what do you do if you have to measure the intraocular pressure (IOP) of a patient using GAT who constantly blinks, has a ptosis or dermatochalasis? Let’s see here, most students and/or clinicians would use their fingers to open the patient’s eyelids to obtain an IOP reading when using GAT. There are some problems when you utilize this method. First of all, you may be pressing your finger against the patient’s eyeball, and indirectly raising his/her IOP, and thus resulting in an artificially higher IOP. Secondly, your finger could be stuck against the light source of the slit lamp while pushing the slit lamp forward towards your patient’s eye. Finally, your finger against your patient’s eye makes the patient uneasy and/or uncomfortable, and he/she blinks even more. So, what other choices do you have to obtain an IOP reading now? Do you give up, and ask your preceptor to perform the GAT for you?

Here’s an easy and simple way using the Q-tip method for GAT. All you have to do is to have the patient look down or close his/her eyelid while you use a Q-tip to push the upper eyelid up against the orbital rim. Then, have your patient look forward, and ask him/her to blink and you will notice that they won’t be able to blink. The Q-tip will help you better stabilize the patient’s eyelids than using the finger method. Now, using your free hand to control the joystick of the slit lamp, you can move probe of the GAT forward to measure IOP with ease. Since the Q-tip is thinner than your finger, you will be able to move the probe of the GAT closer towards the patient’s cornea. If you’re measuring the patient’s right eye, then I would hold the Q-tip with my left hand. So, next time when you have a difficult patient, try this method out, and you will be pleasantly surprised how easy it will be for both you and your patient.

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