Is gaze-dependent tonometry a useful tool in the differential diagnosis of Graves ophthalmopathy?
GROUND: A rise in intraocular pressure (IOP) in upgaze is regarded as a diagnostic sign in Graves’ ophthalmopathy (GO). However, the question of erroneous IOP measurement due to applanation carried out on the peripheral cornea has never been addressed. METHODS: In 22 healthy volunteers, as well as in 51 GO patients, applanation tonometry was performed in the primary position of gaze and at 20 degrees of upgaze. In addition, applanation tonometry was repeated using a flexible chin rest to incline the head and produce 20 degrees upgaze. This enabled applanation on the central cornea. RESULTS: In healthy controls, mean IOP in conventional upgaze showed a significant rise compared to primary position (p < 0.0001). IOP measurements in 20 degrees upgaze/head inclination were significantly lower compared to conventional upgaze tonometry (p < 0.0001) and comparable to mean IOP in primary position (p = 0.7930). Mean IOP in GO patients was also significantly higher in conventional upgaze compare
In 22 healthy volunteers, as well as in 51 GO patients, applanation tonometry was performed in the primary position of gaze and at 20 degrees of upgaze. In addition, applanation tonometry was repeated using a flexible chin rest to incline the head and produce 20 degrees upgaze. This enabled applanation on the central cornea.
