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Eye Pressure with Goldmanns


Why is there pressure in the eye?

For the eye to maintain its naturally firm structure, the eye is filled with a fluid and a jelly, which provide the eye with all the nutrients it requires.

There are areas within our eyes that produce this fluid and an area by where the fluid is drained out, therefore constantly replenishing the fluid.  These constant changes within in the production and drainage of fluids, causes changes to the pressure within the eye throughout the day.  This pressure is called the Intra-Ocular Pressure (IOP) and needs to be regularly monitored.

Why measure eye pressure?

The best way to understand Eye pressure is to think of Blood Pressure! ...We all have a blood pressure and it is regularly monitored by our GP and if it is too high or too low it is meditation.  It is the same for your opticians when it comes to IOP.   

An average IOP reading is usually somewhere between 10-19 mmHg but is likely to vary between individuals and increase with age.  Raised IOP is one of the causes of Glaucoma, therefore making it vital for regular examinations to monitor any changes, especially in patients over the age of 40.  Glaucoma is any eye disease that affects the Optic Nerve and it is also one of the most common eye health issues that if left untreated may lead to BLINDNESS. Please visit ‘eye conditions’ page for more information. 

How is eye pressure measured?

There are three different ways of measuring the IOP, which all vary in the levels of accuracy.

  • NON-CONTACT TONOMETRY is one of the most cost effective techniques used most commonly by most high street opticians.  It is described by many people as the ‘puff of air machine’ and is carried out by your optician approximately three times to then give you a average reading and therefore it is not the most accurate way to monitor pressures. 
  • GOLDMANN APPLANATION TONOMETRY gives a more accurate reading of IOP and is therefore used in most Eye Hospitals.  At West Malling Opticians, we will use this technique as a standard method for measuring IOP.  Goldmann Applanation Tonometry involves the instillation of a small eye drop, which is a lot less pain full and more comfortable that the ‘puff of air’ test for most of our patients.   Once the drops have been instilled, we then combine this technique and use a Pachymetry to give us the most accurate reading.
  • PACHYMETER gives us more specific and personalised information regarding the thickness of your cornea.  As individuals we all come in different shapes and sizes and in this same manner, out eyes are also different.  Each individual cornea is a different thickness to others and due to this it will affect the IOP.  If we were to use the above method only, Goldmann Applanation Tonometry, this will again give us an average of your corneal thickness, then again giving us approximate results for your IOP. 

This is why for most of our patients, we combine the two methods and use Goldmann Applanation Tonometry and Pachymetry to give us a accurate and true reading of your IOP.  As the tachymeter gives a true reading of your corneal thickness, this will substitute for the average reading that may be used.  It is almost imperative that all patients who have undergone Laser Eye Surgery have Pachymetry, since their cornea's are considerably thinner than average.