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A clinical evaluation of proview pressure phosphene tonometry in children
Ida Chung1, Amelia Bartolone, William H Swanson
1Department of Clinical Sciences, State University of New York, State College of Optometry, New York, New York, USA.
Insights
Proview pressure phosphene tonometry (PPPT) is a noninvasive method for measuring intraocular pressure (IOP) in children. While generally repeatable, PPPT showed significant variability and is not comparable to Goldmann tonometry (GT).
Area of Science:
- Ophthalmology
- Optometry
- Biomedical Engineering
Background:
- Intraocular pressure (IOP) measurement is crucial for diagnosing and managing glaucoma.
- Current methods like Goldmann tonometry (GT) require eye drops and direct corneal contact.
- Noninvasive tonometry methods are sought for improved patient comfort and accessibility, especially in pediatric populations.
Purpose of the Study:
- To compare intraocular pressure (IOP) measurements obtained in children using Proview pressure phosphene tonometry (PPPT) and Goldmann tonometry (GT).
- To assess the reliability, validity, and patient preference for PPPT compared to GT in a pediatric cohort.
Main Methods:
- A study involving 104 children aged 5-12 years at the University Optometric Center/SUNY College of Optometry.
- Participants were randomized to undergo either PPPT or GT first, with two measurements attempted per eye using each instrument.
- A subgroup of 41 participants indicated their preference between the two tonometry methods.
Main Results:
- PPPT had a higher coefficient of repeatability (3-4 mm Hg) compared to GT (1 mm Hg).
- Mean IOP measurements were 4 mm Hg higher with PPPT than GT, with increasing discrepancies at higher IOPs.
- 56% of surveyed children preferred PPPT, 24% had no preference, and 20% preferred GT.
Conclusions:
- PPPT measurements are repeatable within a few mm Hg for most children, but substantial variability exists for some.
- The mean difference of 4 mm Hg and wide confidence intervals indicate PPPT is not comparable to GT for IOP measurement.
- Despite comparability issues, PPPT's noninvasive nature and pediatric preference suggest potential as a portable screening tool, warranting further investigation in diverse patient groups.
Purpose:
The Proview tonometer measures intraocular pressure by inducing a pressure phosphene through the eyelid and, if reliable and valid, may offer a quick, nonthreatening and noninvasive alternative method of obtaining intraocular pressures (IOPs) without the use of eye drops. This study compares the IOP measurements obtained in children using Proview pressure phosphene tonometry (PPPT) and Goldmann tonometry (GT).
Methods:
One hundred four 5- to 12-year-old patients of the University Optometric Center/SUNY College of Optometry participated in the study. Subjects were randomized to receive, by different investigators, either PPPT or GT first. Two measurements with each instrument were attempted on each eye of all subjects. A subgroup of 41 subjects was asked which of the two methods was preferred.
Results:
Seven percent of the subjects did not report a pressure phosphene response compared with 12% of the subjects on whom the investigators were unable to perform GT. The remaining 85 subjects completed the subject protocol. Of the 41 subjects asked, 56% preferred PPPT, 24% had no preference, and 20% preferred GT. The coefficient of repeatability between the two readings was higher for PPPT (3-4 mm Hg) than for GT (1 mm Hg). Mean IOP was 4 mm Hg higher for PPPT than GT with the difference in readings between the two instruments increasing with higher IOPs (r >19%, p < 0.005).
Conclusions:
In our study of healthy young subjects, PPPT measurements of IOP appear to be repeatable within a few millimeters of mercury in most children, but for some children, variability in repeat measurements can be substantial. Our data showed a mean difference in readings of 4 mm Hg with a 95% confidence interval that the PPPT reading was between 12 mm Hg above GT and 4 mm Hg below GT. This wide range of values indicates that PPPT is not comparable to GT. However, because our study found that children can appreciate pressure phosphenes and most prefer PPPT over GT, the Proview monitor may have value as a noninvasive, portable screener in pediatric patients. To fully evaluate this potential, further studies are needed that include patients with high IOPs.
