Comparison of Three Methods of Tonometry in Patients with Inactive Thyroid-Associated Orbitopathy

Area of Science:

• Ophthalmology
• Endocrinology
• Medical Devices

Background:

• Intraocular pressure (IOP) measurement in thyroid-associated orbitopathy (TAO) patients can be difficult and misleading.
• TAO patients may present with subtle eye deviations or motility disorders impacting IOP readings.
• Accurate IOP assessment is crucial for managing glaucoma risk in TAO patients.

Purpose of the Study:

• To evaluate the accuracy of IOP measurement using rebound tonometer (iCARE), Goldmann applanation tonometer (GAT), and non-contact airpuff tonometer (NCT).
• To compare the performance of these tonometers in patients with inactive TAO.
• To determine the most reliable tonometer for IOP assessment in this specific patient group.

Main Methods:

• A total of 98 eyes from 49 adult patients with inactive TAO were included.
• IOP was measured using NCT, iCARE, and GAT in all participants.
• Bland-Altman analysis was used to compare measurements between the three tonometers.

Main Results:

• The iCARE rebound tonometer showed no significant difference compared to the Goldmann applanation tonometer (GAT) (p = 1.000).
• The non-contact airpuff tonometer (NCT) significantly overestimated IOP values compared to both GAT (p < 0.0001) and iCARE (p < 0.0001).
• Mean IOP measurements were 18.1 ± 2.4 mmHg (GAT), 22.3 ± 5.0 mmHg (NCT), and 18.0 ± 2.4 mmHg (iCARE).

Conclusions:

• The iCARE rebound tonometer provides IOP measurements comparable to the gold standard GAT in patients with inactive TAO.
• The non-contact airpuff tonometer (NCT) significantly overestimates IOP in this patient population.
• iCARE is a reliable alternative for IOP measurement in TAO patients, even those without apparent motility disorders.