Related Experiment Video
Updated: Jul 30, 2026
Trabecular Meshwork Response to Pressure Elevation in the Living Human Eye
Published on: June 20, 2015
[Intraocular pressure measurement using the Proview tonometer]
J Moreno Montañés1, L M Sádaba, H Heras
1Departamento de Oftalmología, Clínica Universitaria de Navarra, Pamplona, España. jmoreno@unav.es
Purpose:
To evaluate a new ocular tonometer (Proview) which functions by visualizing a phosphene after putting pressure on the upper eyelid. To ascertain its accuracy and reproducibility with respect to the Goldmann tonometer (GT).
Methods:
A study on both eyes of 110 non-selected patients was performed. One measurement with GT and three subsequent measurements with Proview were taken by the same investigator. The number of failed attempts to visualize the phosphene was recorded. We evaluated each eye separately to observe the possible learning effect.
Results:
The intraocular pressure (IOP) mean with Proview is 5 mm Hg higher than the GT (p < 0.001). The coefficient of correlation between both instruments is low (R = 0.67; R(2) = 0.45) in the right eye (RE). The difference between maximum and minimum values of the 3 measurements taken with the Proview was 3.21 (SD: 1.73) mm Hg in RE. The failed attempts to see the phosphene were 5.14 (SD: 2.39) in RE and 4.93 (SD: 2.78) in left eye (p > 0.05).
Conclusions:
The Proview(R) tonometer showed low accuracy and reproducibility in comparison with the GT. This tonometer requires a long learning process before phosphene visualization. The results demonstrated that this tonometer is not clinically useful, except in patients with serious corneal diseases which make measurement with GT very difficult.
