The Proview Eye Pressure Monitor: influence of clinical factors on accuracy and agreement with the Goldmann tonometer

To investigate (i) the effect of probe position on the lid when using the Proview Eye Pressure Monitor (Proview) and (ii) the accuracy of the Proview and its agreement with the Goldmann applanation tonometer (GAT) in a normal population.

Intraocular pressure (IOP) measurements were performed on 107 control subjects (mean 25 years) using the Proview and the GAT. The Proview probe was applied to two locations on the eyelid (superior nasal and superior temporal). The IOPs measured with both instruments were compared.

A total of 4.6% of young normal eyes could not perceive the phosphene. The mean Proview reading using the recommended nasal lid position was significantly higher (+2.5 mmHg) than that measured using the GAT. The position of the probe application was significant, with temporal lid application giving statistically significantly higher IOP readings than the recommended nasal lid application. The repeatability of Proview measurements was lower than the GAT (coefficients of repeatability of GAT and Proview nasal were 0.96 and 4.21 mmHg respectively). The limit of agreement between the GAT and the Proview nasal was low at +/-7.95 mmHg.

This study shows that the position of probe application can influence the measurements taken using the Proview. Application of the probe to the nasal superior lid (as recommended) gives the more repeatable and accurate results. Overall however the data indicate that the Proview is neither sufficiently accurate nor repeatable to be used in the detection and management of glaucoma. More work is needed in developing this interesting product.