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Comparison of Aqueous Outflow Facility Measurement by Pneumatonography and Digital Schiøtz Tonography
- Source :
- Investigative Ophthalmology & Visual Science
- Publication Year :
- 2017
-
Abstract
- Purpose It is not known if outflow facilities measured by pneumatonography and Schiotz tonography are interchangeable. In this study we compared outflow facility measured by pneumatonography to outflow facility measured by digital Schiotz tonography. Methods Fifty-six eyes from 28 healthy participants, ages 41 to 68 years, were included. Intraocular pressure (IOP) was measured in the sitting and supine positions with a pneumatonometer. With the subject in the supine position, IOP was recorded for 2 minutes by using a pneumatonometer with a 10-g weight and for 4 minutes by using a custom digital Schiotz tonometer. Outflow facility was determined from the changes in pressure and intraocular volume and a standard assumed ocular rigidity coefficient for each instrument, respectively, and by using an ocular rigidity coefficient calculated by measuring pressure without and with a weight added to the pneumatonometer tip. Results The outflow facility was 0.29 ± 0.09 μL/min/mm Hg by Schiotz tonography and 0.24 ± 0.08 μL/min/mm Hg by pneumatonography (P < 0.001) when using the standard assumed constant ocular rigidity coefficient. Mean calculated ocular rigidity coefficient was 0.028 ± 0.01 μL-1, and outflow facility determined by using this coefficient was 0.23 ± 0.08 μL/min/mm Hg by Schiotz tonography and 0.21 ± 0.07 μL/min/mm Hg by pneumatonography (P = 0.003). Outflow facilities measured by the two devices were correlated when the ocular rigidity was assumed (r = 0.60, P < 0.001) or calculated (r = 0.70, P < 0.001). Conclusions Outflow facilities measured by pneumatonography were correlated with those measured by Schiotz tonography, but Schiotz tonography reported approximately 10% to 20% higher facilities when using the standard method. When ocular rigidity was determined for each eye, differences were smaller. Measurements from these devices cannot be compared directly.
- Subjects :
- Aqueous outflow
Adult
Male
medicine.medical_specialty
Intraocular pressure
Materials science
Supine position
Schiøtz tonometer
Posture
Aqueous humor
tonography
Body weight
Aqueous Humor
03 medical and health sciences
Tonometry, Ocular
0302 clinical medicine
Ophthalmology
medicine
Humans
Intraocular Pressure
Aged
tonometry
Reproducibility of Results
aqueous outflow facility
Ocular rigidity
Glaucoma
Equipment Design
Middle Aged
Healthy Volunteers
Surgery
Nomograms
030221 ophthalmology & optometry
Outflow
Female
ocular rigidity
030217 neurology & neurosurgery
Subjects
Details
- ISSN :
- 15525783
- Volume :
- 58
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- Investigative ophthalmologyvisual science
- Accession number :
- edsair.doi.dedup.....cd42fe6bf5a8f443edca11c3a6e64df6