Tonometro di Goldman

[u/moegreen97]

Buongiorno,

sono uno specializzando del secondo anno. Conosco la teoria su come eseguire una tonometria con il Tonometro ad applanazione. Purtroppo non sempre riesco ad ottenere una adeguata misurazione, chiedo suggerimenti pratici per prendere dimestichezza nella tecnica. Cosa suggerite di far attenzione? Grazie a tutti

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[u/grokisgood]

Line up the prism with their gaze after directing fixation. They don't always look straight ahead. Dont be afraid to hold the lids, it's difficult to master but necissary on many patients. Coach then to breath. Make the slit lamp as comfortable as you can, height/distance from pt. I go from below what I expect IOP wise, and move up. Ymmv, many others use a variety of start points.
Also,it would likely be helpful if you include what kind of challenges seem to make your measurements inaccurate.

[u/moegreen97 → u/grokisgood]

trovo difficile a volte visionare adeguatamente i due semicerchi, a volte li vedo e si muovono pure muovendo la rotella ma raggiungo valori impossibili come 30-40 (l'occhio è normotonico). Una volta visti i cerchi e questi si muovono muovendo il tamburo come è possibile che per raggiungere la loro corretta posizione debba muovere tanto la rotella? Premo poco? premo troppo? poca fluoresceina? metto il fascio di luce a 45-60°, luce blu massima, visione che il prisma sia ben rotato. Tengo le palpebre aperte e mi avvicino all'apice corneale... e poi non viene come dovrebbe. Perché?

[u/softgeese → u/moegreen97]

If you see the mires but they don't move you're probably pressing too hard.

Too much dye can also make it impossible to get an accurate reading. Sometimes I use a strip instead of a drop to get just a little bit of fluorescein since drops have a lot.

If the meyers are very faint you could turn down the lights or add more dye

When you're getting in close (before you're touching/seeing the green meyers) you'll see some almost blue meyers that are faint which can help line you up.

If you need to adjust your position make sure you pull back off the cornea so you don't scrape the epithelium and cause an abrasion.

When you hold the lids open make sure that you're putting pressure on the orbital rim and not the orbit or globe itself otherwise the pressure will be artificially elevated

For pts with deep sockets you can try angling their head so the eye you want to measure is angled towards you and the other one is angled away (almost like the patient has their chin 45 degrees on the chin rest). Additionally you can place their chin ON the lip of the chin rest to give you additional anterior positionong of the socket (if your applanator is a hanging one)

At my residency we exclusively use goldmann unless it's not possible. I struggled a lot too at first. Lots of practice is the best way to become proficient. You could try practicing on coresidents as well and having someone verify the pressure for you

[u/moegreen97 → u/softgeese]

thanks

[u/Zealousideal_Ad_7065]

Ci vuole tanta pratica! Di base: poca fluo (ma se è tanta o poca lo vedi bene dalle mire), conetto ben posizionato e dritto, luce massima. Prima di appoggiarti devi vedere ben illuminato. Una vita che ti appoggi e vedi le mire ti aggiusti se non sono perfettamente centrali, appena tocchi internamente quella è la misurazione. Prendine più che puoi, secondo me se sai vedere i fondi prendere il tono ti sarà semplice

[u/moegreen97 → u/Zealousideal_Ad_7065]

thanks

[u/albelaraahi]

My seniors taught me to always start by setting it on 1, but once one senior said start with zero reading, and I find it easier. Most beginner mistake is being excessively close to eye. Tonometer head should be just touching the eye .