A new electromechanical method for measuring intraocular pressure

Kontiola, Antti

doi:10.1007/bf02569066

Cited by 125 publications

(103 citation statements)

References 11 publications

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“…16 The rebound tonometer used in this study is a relatively new device based on similar physical principles as the vibration tonometer. 22,23 Reports of rebound tonometer use in rats, 15,24 mice, 14,15,25 and human patients 26,27 demonstrated that this type of tonometer is convenient to use and yields reliable data.…”

Section: Discussionmentioning

confidence: 99%

Intraocular pressure measurement in mice: a comparison between Goldmann and rebound tonometry

Kim

Kuehn

Anderson

et al. 2006

Eye

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Purpose The development of mouse models of glaucoma requires methods to accurately measure the intraocular pressure (IOP) in this species. The aim of this study was to compare the accuracy of IOP measurements in mice between modified Goldmann and rebound tonometers. Methods IOP was measured either with a modified Goldmann or a rebound tonometer while simultaneously measuring the IOP using invasive manometry in enucleated eyes and in vivo. The level of IOP was controlled hydrostatically. The agreement and correlation between the IOP determined by invasive manometry and by either noninvasive method was evaluated. In addition, the IOP was determined by both noninvasive methods in a cohort of mice with laser-induced ocular hypertension (OHT), and the agreement and correlation between the two tonometry methods were evaluated. Results Measured IOP by either noninvasive tonometer correlated well with those recorded simultaneously by invasive manometry (r ¼ 0.98 for rebound and r ¼ 0.94 for Goldmann). In mice with OHT, the IOP correlation between rebound and modified Goldmann was moderate (r ¼ 0.71); the IOP measured by modified Goldmann tonometry was consistently higher than that by rebound by approximately 5 mmHg. However, the relative per cent increases in IOP were similar between the two methods. Conclusion Both noninvasive methods of IOP measurements in mice are suitable to detect changes in IOP although rebound tonometry correlated better with the invasive manometry readings. The results suggest that the relative, rather than absolute, IOP offers a more reliable means of correlating findings from studies using different tonometers.

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Section: Discussionmentioning

confidence: 99%

Intraocular pressure measurement in mice: a comparison between Goldmann and rebound tonometry

Kim

Kuehn

Anderson

et al. 2006

Eye

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“…Induction-based impact detection simplifies the construction of this kind of tonometer, compared with earlier methods using an acceleration sensor or an electrical contact (Dekking & Coster 1967;Kontiola 1997). This makes the tonometer more durable and easier to construct.…”

Section: Discussionmentioning

confidence: 99%

“…When the measurement is started, the probe is propelled against the eye, impacts it and rebounds from the eye. The impact duration or maximum deceleration is measured (Kontiola 1997). Though the speed of the probe is low, the measurement is faster than the corneal reflex.…”

mentioning

confidence: 99%

A new induction‐based impact method for measuring intraocular pressure

Kontiola

2000

Acta Ophthalmologica Scandinavica

190

183

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ABSTRACT.Purpose: An improved induction-based impact method for measuring intraocular pressure is presented. Methods: A light probe containing a permanent magnet is launched towards the eye using a solenoid. The probe hits the eye and bounces back. The same solenoid, inside which the probe moves, is used to detect the movement and impact of the probe, because the moving magnet induces voltage in the solenoid. In the clinical study, the Goldmann applanation tonometer was used as a standard. Handheld and fixed tonometers were also compared by means of measurements in pressurized pig eyes. Results: At a low intraocular pressure (IOP), there is a longer impact time than at a high IOP. A handheld tonometer causes more variation in impact times, especially at low intraocular pressure (IOP), than a fixed tonometer. Conclusions: The new induction-based impact method can be used to measure IOP. When a fixed tonometer is used, there is less variation in impact times.

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“…Their eyes are so small that applanation tonometers are too big for accurate readings. The rebound tonometer was found to be quite accurate in these animals despite constant movement (Danias et al, 2003;Goldblum et al, 2002: Kontiola, 1996 The rebound tonometer (RBT) is an assembly of two coils coaxial to a probe shaft that bounce a magnetized probe off the cornea and detect the deceleration of the probe caused by the eye. A moving magnet within a coil induces changes in the voltage at the two ends of the coil generating a magnetic field with a given voltage, which is detected by the tonometer sensor.…”

Section: Tonometers With Research and Clinical Utility 61 Rebound Tomentioning

confidence: 99%

“…Of all the variables linked to the probe's movement, the inverse of its deceleration speed seems to correlate best with IOP. (Kontiola, 1996) The probes used by the tonometer are disposable and are 24 mm long and weigh 11 mg. The probe tip has a 1-mm-diameter plastic cover, to minimize corneal damage.…”

Section: Tonometers With Research and Clinical Utility 61 Rebound Tomentioning

confidence: 99%