The pressure phosphene tonometer--a clinical evaluation

Area of Science:

• Ophthalmology
• Medical Devices
• Diagnostic Techniques

Background:

• Intraocular pressure (IOP) measurement is crucial for diagnosing and managing glaucoma.
• Goldmann applanation tonometry is the established gold standard for IOP assessment.
• Pressure phosphene tonometry is a newer technique aiming to measure IOP by inducing a pressure phosphene.

Purpose of the Study:

• To compare the efficacy and accuracy of pressure phosphene tonometry with Goldmann applanation tonometry.
• To evaluate the success rate of obtaining readings with the Proview eye pressure monitor.

Main Methods:

• A randomized study involving 100 patients (196 readings) at a general ophthalmology clinic.
• Patients received either pressure phosphene tonometry (Proview) or Goldmann tonometry first, performed by different examiners.
• Intraocular pressure readings were compared between the two methods.

Main Results:

• Pressure phosphene tonometry readings were obtained in only 69% of eyes (136/196), while Goldmann tonometry achieved 100% success.
• The mean IOP measured by pressure phosphene tonometry was 18.5 mmHg, versus 16.0 mmHg with Goldmann tonometry.
• A mean difference of +2.43 mmHg was observed, with wide confidence intervals, indicating common large discrepancies.

Conclusions:

• 31% of patients could not perceive a pressure phosphene with the Proview device.
• Significant discrepancies between pressure phosphene tonometry and Goldmann tonometry readings were common among patients who could perceive the phosphene.
• The Proview eye pressure monitor demonstrated limitations in obtaining consistent and comparable IOP measurements to Goldmann tonometry.