The intraocular pressure (IOP) is a central parameter in the diagnosis and monitoring of glaucoma. However, not all measurement methods yield the same values, and each has its own particularities.
Many patients become concerned when different devices produce different results. As an ophthalmologist, I explain the differences between Goldmann applanation tonometry, non-contact tonometry (“air-puff measurement”) and iCare – and how reliable these methods really are in everyday clinical practice.
An increased intraocular pressure is the most important modifiable risk factor in glaucoma. The aim of every treatment is to achieve the individual target pressure and maintain it long-term to protect the optic nerve.
However, intraocular pressure fluctuates throughout the day and is affected by various factors. This makes reliable measurement all the more important.
The IOP measurement determines treatment decisions: Should treatment begin with eye drops? Is laser treatment required? Is surgery necessary?
The success of treatment is also judged by changes in pressure. Therefore, an exact, reproducible measurement is essential.
This method is considered the reference standard. After administering a topical anesthetic drop, the cornea is gently flattened with a small measuring probe. The force required for applanation is expressed in mmHg. Advantages:
Disadvantages: The method requires rest, cooperation, and a well-hydrated cornea. In cases of pronounced corneal astigmatism or thickness, the measured value may vary.
At Bányai Augenheilkunde, the Goldmann measurement is used specifically for complex or critical cases.
In addition, our diagnostics take into account the central corneal thickness (pachymetry), which can affect the measurement. This enables us to detect and correctly interpret falsely high or low values.
This method uses a short air pulse to flatten the cornea. It is fast, hygienic, and comfortable — but somewhat less precise:
However, it is susceptible to interference from an unsteady gaze, a dry ocular surface, or excessive eyelid activity.
Values tend to be slightly higher than with Goldmann. Therefore, it is usually not used alone for follow-up examinations or treatment decisions.
In screening situations, however, it can help quickly identify patients with abnormalities — for example, during occupational health screenings or in nursing facilities.
The iCare device uses a small probe that briefly touches the eye—no anesthesia required. Ideal for use at home, on the go, or with children and elderly patients. Advantages:
The values are reliable but may vary slightly depending on the application. Proper handling is crucial.
For patients with normal-tension glaucoma or markedly fluctuating pressure measurements throughout the day, iCare provides a valuable complement — especially when other methods are difficult to perform.
| Situation | Recommended method |
| Standard preventive care | Non-contact or iCare |
| Monitoring during therapy | Goldmann |
| Suspected glaucoma attack | Goldmann |
| Measurements for children or at home | iCare |
| Assessment of tendency at first contact | Combination of multiple methods |
Differences between methods often cause uncertainty. It is important to know that no single measurement determines a diagnosis or treatment.
Ophthalmologists always assess the overall situation – including the optic nerve, visual field, OCT, and the personal circumstances of female patients.
At Bányai Augenheilkunde, you will receive a detailed assessment of your pressure measurements – taking into account all relevant factors. This allows individual fluctuations to be properly interpreted.
Especially with glaucoma symptoms such as a sensation of pressure or reduced vision, the choice of measurement method is crucial.
Reliable measurements are the foundation of any successful glaucoma treatment.
Depending on the method, patient group and stage of the disease, different procedures are used—often in combination.
Modern practices such as Bányai Augenheilkunde rely on tailored diagnostics to support optimal treatment decisions.
Because technology, contact method, and measurement conditions vary – especially with corneal thickness or dry eye.
There is no absolute “right” pressure reading – what matters is the trend over time and the patient’s individual target.
Yes – with devices such as iCare HOME, if the application is performed correctly and is medically appropriate.
Depending on the type and course of glaucoma – usually every 3–6 months, more frequently in unstable cases.
Not necessarily – the decisive factor is whether the optic nerve is damaged or whether the pressure is permanently elevated.
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