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A comparison of Icare PRO and Tono-Pen XL tonometers in anesthetized children
Elliot C McKee1, Amanda L Ely1, Jared E Duncan1
1Duke Eye Center, Durham, North Carolina.
Insights
The Icare PRO measured lower intraocular pressure (IOP) than the Tono-Pen in anesthetized children. This difference was more pronounced with corneal edema, suggesting Icare PRO as a valuable tool for pediatric glaucoma evaluation.
Area of Science:
- Ophthalmology
- Pediatric Medicine
- Medical Devices
Background:
- Tonometry is crucial for evaluating pediatric glaucoma but is limited by device capabilities for supine measurements.
- The Icare PRO offers intraocular pressure (IOP) measurement in both sitting and supine positions.
- Current tonometry methods for anesthetized children often require supine recording capabilities.
Purpose of the Study:
- To compare the Icare PRO and Tono-Pen for IOP measurement in supine children undergoing examination under anesthesia.
- To evaluate the devices' performance in eyes with normal findings, glaucoma, and corneal pathology.
Main Methods:
- A prospective study involved 100 eyes of 50 children undergoing examination under anesthesia.
- Intraocular pressure was measured using both Icare PRO and Tono-Pen immediately after anesthesia induction.
- The order of instrument use was randomized to minimize bias.
Main Results:
- The Tono-Pen measured a mean IOP 2.2 mm Hg higher than the Icare PRO (P < 0.001).
- Eyes with corneal edema showed significantly higher IOP measurements with the Tono-Pen compared to the Icare PRO (mean difference of 8.4 mm Hg).
- No correlation was found between central corneal thickness and IOP difference when corneal edema was absent.
Conclusions:
- The Tono-Pen consistently yielded higher IOP readings than the Icare PRO in supine, anesthetized children.
- The discrepancy in IOP measurements was amplified in the presence of corneal edema.
- The Icare PRO shows potential as a valuable tool for pediatric tonometry, with a recommendation for confirmatory testing in cases of corneal edema.
Background:
Tonometry in the anesthetized child, vital for evaluating known or suspected glaucoma, remains limited to tonometers capable of supine recording. The Icare PRO measures intraocular pressure (IOP) in the sitting or supine patient. The purpose of this study was to compare Icare PRO and Tono-Pen tonometry during examination under anesthesia in eyes of supine children with normal eyes and glaucoma and/or corneal pathology.
Methods:
In this prospective study of children undergoing examination under anesthesia, IOP was recorded in both eyes with Icare PRO and Tono-Pen immediately after mask anesthesia induction, with instrument order randomized.
Results:
A total of 100 eyes of 50 children (median age, 58 months) were included. IOP range was 6-50 mm Hg by Icare PRO and 6-53 mm Hg by Tono-Pen. Mean IOP measured by Tono-Pen (18.9 ± 7.5) was higher than that measured by Icare PRO (16.7 ± 7.1 mm Hg) by 2.2 mm Hg (P < 0.001). The presence of corneal edema was associated with IOP measurements higher by Tono-Pen than by Icare PRO (mean difference, 8.4 mm Hg). When eyes with corneal edema were excluded from analysis, there was no correlation between central corneal thickness and the difference in IOP between the two instruments.
Conclusions:
IOP in eyes of supine children under anesthesia measured approximately 2 mm Hg higher by Tono-Pen than Icare PRO and this difference was greater in eyes with frank corneal edema. Icare PRO may become a valuable tool for tonometry in supine infants and children, but a confirmatory test should be considered in eyes with corneal edema.
