Effects of head elevation on intraocular pressure in healthy subjects: raising bed head vs using multiple pillows

Dy, Yeon; C, Yoo; Te, Lee; Jh, Park; Yy, Kim

doi:10.1038/eye.2014.211

Cited by 20 publications

(19 citation statements)

References 29 publications

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“…The 109 eye clinical study indicated zero bias error between the CATS and GAT prisms. Low correlation coefficients are common in clinical IOP studies due to the multiple variables in measurement error [ 20 – 23 ]. The assumption made in statistical analysis examining correlation is that the biomechanical error relationships are linear when in fact there is evidence that they may be non-linear which may add to a lower correlation [ 24 ].…”

Section: Discussionmentioning

confidence: 99%

Goldmann and error correcting tonometry prisms compared to intracameral pressure

et al. 2018

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BackgroundCompare Goldmann applanation tonometer (GAT) prism and correcting applanation tonometry surface (CATS) prism to intracameral intraocular pressure (IOP), in vivo and in vitro.MethodsPressure transducer intracameral IOP was measured on fifty-eight (58) eyes undergoing cataract surgery and the IOP was modulated manometrically to 10, 20, and 40 mmHg. Simultaneously, IOP was measured using a Perkins tonometer with a standard GAT prism and a CATS prism at each of the intracameral pressures. Statistical comparison was made between true intracameral pressures and the two prism measurements. Differences between the two prism measurements were correlated to central corneal thickness (CCT) and corneal resistance factor (CRF). Human cadaver eyes were used to assess measurement repeatability.ResultsThe CATS tonometer prism measured closer to true intracameral IOP than the GAT prism by 1.7+/−2.7 mmHg across all pressures and corneal properties. The difference in CATS and GAT measurements was greater in thin CCT corneas (2.7+/−1.9 mmHg) and low resistance (CRF) corneas (2.8+/−2.1 mmHg). The difference in prisms was negligible at high CCT and CRF values. No difference was seen in measurement repeatability between the two prisms.ConclusionA CATS prism in Goldmann tonometer armatures significantly improve the accuracy of IOP measurement compared to true intracameral pressure across a physiologic range of IOP values. The CATS prism is significantly more accurate compared to the GAT prism in thin and less rigid corneas. The in vivo intracameral study validates mathematical models and clinical findings in IOP measurement between the GAT and CATS prisms.

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Section: Discussionmentioning

confidence: 99%

Goldmann and error correcting tonometry prisms compared to intracameral pressure

et al. 2018

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“…The supine position measurement adds significantly more error to the applanation IOP compared to the upright position. Several studies have examined the clinical differences in IOP measurement between upright and supine positions and have shown either the same or increased IOP when supine [ 20 – 22 ]. The critical difference in these studies and ours is found in the modulated control and of the intracameral pressure.…”

Section: Discussionmentioning

confidence: 99%

Goldmann applanation tonometry error relative to true intracameral intraocular pressure in vitro and in vivo

McCafferty¹,

Levine

Schwiegerling

et al. 2017

BMC Ophthalmol

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Background: Goldmann applanation tonometry (GAT) error relative to intracameral intraocular pressure (IOP) has not been examined comparatively in both human cadaver eyes and in live human eyes. Futhermore, correlations to biomechanical corneal properties and positional changes have not been examined directly to intracameral IOP and GAT IOP. Methods: Intracameral IOP was measured via pressure transducer on fifty-eight (58) eyes undergoing cataract surgery and the IOP was modulated manometrically on each patient alternately to 10, 20, and 40 mmHg. IOP was measured using a Perkins tonometer in the supine position on 58 eyes and upright on a subset of 8 eyes. Twenty one (21) fresh human cadaver globes were Intracamerally IOP adjusted and measured via pressure transducer. Intracameral IOP ranged between 5 and 60 mmHg. IOP was measured in the upright position with a Goldmann Applanation Tonometer (GAT) and supine position with a Perkins tonometer. Central corneal thickness (CCT) was also measured. Results: The Goldmann-type tonometer error measured on live human eyes was 5.2 +/−1.6 mmHg lower than intracameral IOP in the upright position and 7.9 +/− 2.3 mmHg lower in the supine position (p < .05). CCT also indicated a sloped correlation to error (correlation coeff. = 0.18). Cadaver eye IOP measurements were 3.1+/−2. 5 mmHg lower than intracameral IOP in the upright position and 5.4+/− 3.1 mmHg in the supine position (p < .05).

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“…The head elevation of 30° from the supine position was also shown to reduce nocturnal IOP significantly in normal subjects, but the same study did not find an IOP reduction when 2 pillows were used to elevate the head a similar amount ( P =0.061 OD, P =0.089 OS). 53 A 20% head only up position utilizing only a wedge pillow in OAG and normal patients found an almost significant reduction in nocturnal IOP in either group (95% confidence interval 0.99–2.04). 54 While a 3.2 mmHg IOP reduction overnight may not seem clinically significant, a millimeter of IOP reduction has been shown to reduce the risk of progression in OAG patients 10% 55 and one-third of our life is spent in a sleeping position.…”

Section: Discussionmentioning

confidence: 94%

Effects of different sleeping positions on intraocular pressure in secondary open-angle glaucoma and glaucoma suspect patients

Sedgewick

et al. 2018

OPTH

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PurposeThe aim of this study was to investigate the effects of different recumbent sleeping positions of the head and body on intraocular pressure (IOP) in secondary open-angle glaucoma and glaucoma suspect patients, specifically pigmentary dispersion (PD) as measured using the ICare rebound tonometer.Patients and methodsA total of 44 eyes of 24 patients with PD were selected in this study. The IOP of 44 eyes was measured in the initial seated position, in the 4 recumbent positions, and again in the sitting position between each of the recumbent positions.ResultsThe IOP of the right eyes and left eyes was higher in each of the 4 recumbent positions compared to its initial sitting position (all P<0.001). Dependent (D) vs nondependent (ND) comparisons failed to show a significant difference. All lateral vs prone comparisons showed a higher average IOP in the prone position than in the lateral position regardless of D vs ND status. The range of recumbent IOP changes was −4 to +17 mmHg or −17% to +142%. A total of 64% had at least a ≥33% IOP increase with 43% having a ≥50% increase.ConclusionLateral and prone sleeping positions usually do result in significant elevations of IOP in PD patients. Dependency status did not make a difference. A significantly larger IOP increase was seen in the prone position than in the lateral position. The presence of 3 clinical variables (disk hemorrhage [DH], notches, and BV changes) might increase the chances of developing a large recumbent increase in IOP. These patients and possibly all PD syndrome (PDS) or PD glaucoma (PDG) patients should consider sleeping in a bed that allows a head elevation of 30°.

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Effects of head elevation on intraocular pressure in healthy subjects: raising bed head vs using multiple pillows

Cited by 20 publications

References 29 publications

Goldmann and error correcting tonometry prisms compared to intracameral pressure

Goldmann and error correcting tonometry prisms compared to intracameral pressure

Goldmann applanation tonometry error relative to true intracameral intraocular pressure in vitro and in vivo

Effects of different sleeping positions on intraocular pressure in secondary open-angle glaucoma and glaucoma suspect patients

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