iCare vs Goldmann Applanation Tonometry: What Eye-Care Professionals Need to Know

Whether it’s monitoring glaucoma risk, refining treatment plans, or providing reassurance during routine checks, measuring intraocular pressure (IOP) is an integral part of daily practice. Yet how we capture this vital data is evolving.

We’re all familiar with the gold standard – Goldmann applanation tonometry. As the most established form of contact tonometry, it’s long been the go-to, with little else coming close in terms of accuracy.

However, newer rebound devices, such as iCare’s IC100 and IC200 tonometers, are reshaping expectations around comfort, portability and access. For today’s clinicians, there is now a reliable alternative to Goldmann, one backed up by a wide variety of studies. 

Does it completely replace Goldmann? No, not at all. Instead, rebound tonometers offer a convenient alternative that is portable, accurate and, most importantly, more comfortable for patients. 

Accuracy and agreement with Goldmann

The strength of Goldmann lies in its repeatability when used correctly. Numerous studies confirm it remains the “gold standard”, which is why it underpins referral thresholds. But head-to-head studies with modern rebound devices show that iCare has matured into a robust clinical alternative in many scenarios.

For example, a 2016 study comparing the IC100, its predecessor TA01i, and GAT in patients with and without glaucoma found that IC100 typically read slightly lower than Goldmann, with mean differences of around −4 mmHg and limits of agreement between −10 and +2 mmHg. Importantly, differences were influenced by central corneal thickness and curvature, highlighting the need to interpret results in the context of pachymetry and corneal biomechanics.

Follow-up work on the IC100 has reinforced its reliability. A study of healthy and post-LASIK eyes found excellent repeatability (intraclass correlation coefficients >0.9) and good agreement with GAT (ICC ~0.8), suggesting that even in surgically altered corneas, the device performs consistently. Other comparative studies show broadly similar patterns: good overall correlation, but wider variability at very high or very low pressures.

Data confirms that, while Goldmann remains the definitive tool, modern rebound tonometers provide readings close enough for confident use in most clinical contexts, provided clinicians remain aware of corneal and IOP-range effects.

Patient comfort and clinical workflow

For patients, the distinction between applanation and rebound is often stark. Goldmann requires anaesthetic and fluorescein (which nobody enjoys). By contrast, the iCare devices require no drops and involve only a virtually undetectable tap of the probe.

In practical terms, this difference improves tolerance in children, anxious patients and those seen at home. Clinical studies with the IC200 in paediatric cohorts have shown reliable readings with far greater acceptability than applanation, making IOP assessment feasible in children who would otherwise be untestable. 

Patients are often less reluctant and quicker to process when using iCare tonometers, making it easier to manage workflow efficiency in busy practices. 

Clinical applications

The choice between Goldmann and rebound tonometry is not black and white. 

In hospital glaucoma clinics, Goldmann (or Perkins) continues to be essential for diagnosis, progression analysis and medico-legal purposes. In community optometry, domiciliary care and paediatrics, however, IC100 and IC200 offer clear advantages: they are fast, well-tolerated, and portable.

The IC200 in particular opens up additional clinical applications. Its ability to measure patients accurately in both upright and supine positions has been shown to reveal posture-related IOP changes, useful in research and in complex glaucoma cases where diurnal or positional variation may drive disease progression. 

Devices such as the iCare Home2, which share the same rebound principle, also provide opportunities for home monitoring, allowing clinicians to capture diurnal IOP profiles that Goldmann alone cannot provide.

A side-by-side comparison 

As a quick overview:

• iC100 is ideal for seated or standing patients
• iC200 is also used for supine patients in wards or theatres
• iCare Home2 is offered for self-monitoring between clinic visits

And, to help you compare the two, we’ve created a quick reference:

What’s right for your clinic?

Goldmann applanation tonometry remains the gold standard, but it no longer needs to stand alone. 

The latest generation of rebound tonometers show how innovation can complement tradition rather than replace it. iCare devices widen access to reliable IOP data, supporting early detection and long-term monitoring in settings where conventional applanation may be impractical.

For clinicians balancing patient comfort and accuracy, combining GAT with rebound technology offers the best of both worlds.

If you’d like guidance on how iCare systems can enhance IOP assessment in your clinic, we’re here to help.

Contact us at [email protected] or call 0121 458 6800 to discuss what iCare rebound tonometry can offer to your clinic.