Daytime profile of the intraocular pressure and tear production in normal dog

Giannetto, Claudia; Piccione, Giuseppe; Giudice, Elisabetta

doi:10.1111/j.1463-5224.2009.00717.x

Cited by 67 publications

(87 citation statements)

References 19 publications

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“…50 This effect of cross-linking deficiency may partially explain the decreased mechanical damping properties (i.e., tan [d]) in the affected canine sclera, because the decreased intrafibril sliding in the lesser cross-linked group effectively would reduce the relative amount of energy dissipated by the fibrils. The measurements before euthanasia showed that all IOP values (11-17 mm Hg) were well within the normal range of IOPs seen in clinically healthy dogs, [51][52][53] confirming that the young affected dogs still were normotensive. Although not statistically significant, the mean IOP at euthanasia was slightly higher in the young affected dogs compared to that in the young carrier dogs (16.0 6 1.4 vs. 13.5 6 2.1 mm Hg), prompting a consideration of whether this IOP could have confounded the outcome of the genotype comparisons reported in our study.…”

Section: Discussionmentioning

confidence: 92%

Biomechanical Properties and Correlation With Collagen Solubility Profile in the Posterior Sclera of Canine Eyes With anADAMTS10Mutation

Palko

Iwabe

Pan

et al. 2013

Invest. Ophthalmol. Vis. Sci.

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Citation: Palko JR, Iwabe S, Pan X, Agarwal G, Komáromy AM, Liu J. Biomechanical properties and correlation with collagen solubility profile in the posterior sclera of canine eyes with an ADAMTS10 mutation. Invest Ophthalmol Vis Sci. 2013;54:268554: -269554: . DOI:10.1167 PURPOSE. We examined the biomechanical properties and correlation with the collagen solubility profile of the posterior sclera in a canine model of primary open-angle glaucoma caused by the G661R missense mutation in the ADAMTS10 gene. METHODS.Scleral strips from ADAMTS10-mutant (affected) dogs and age-matched controls were collected. Viscoelastic properties (i.e., complex modulus and tan[d]) were measured using dynamic mechanical analysis (DMA) with a 0.15% sinusoidal strain at different frequencies superimposed upon different preloads. A tensile ramp was performed following DMA. The collagen solubility profile was examined using a colorimetric hydroxyproline assay to determine the amount of soluble and insoluble collagen. The viscoelastic properties were compared between groups using linear mixed models for repeated measures at different preloads and frequencies. The correlation between the biomechanical properties and collagen content were evaluated using Pearson correlations. RESULTS.Complex modulus and tan(d) were significantly lower in the affected group (P < 0.001), and the differences were consistent at different preloads and frequencies. The B value from the tensile ramp test also was significantly lower in the affected group (P ¼ 0.02). The insoluble collagen was significantly lower in the affected group (P < 0.05) and correlated positively with the complex modulus (R ¼ 0.88, P < 0.005).CONCLUSIONS. An inherently weaker and biochemically distinct posterior sclera was observed in dogs with the G661R missense mutation in ADAMTS10 before clinical indications of optic nerve damage. It remains to be shown whether and how the altered scleral biomechanics may affect the rate of glaucoma progression following intraocular pressure elevation.

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Section: Discussionmentioning

confidence: 92%

Biomechanical Properties and Correlation With Collagen Solubility Profile in the Posterior Sclera of Canine Eyes With anADAMTS10Mutation

Palko

Iwabe

Pan

et al. 2013

Invest. Ophthalmol. Vis. Sci.

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“…Horizontal pupil diameter was measured with Jameson calipers under fixed light conditions every five minutes as described above. All measurements were done at approximately same time of day (9.00-11.00 am) because of the effects of light conditions at different times of day on the IOP and the HPD (Gelatt et al, 1981;Giannetto et al, 2009).…”

Section: Datamentioning

confidence: 99%

Changes in intraocular pressure and horizontal pupil diameter during use of topical mydriatics in the canine eye

Kovaļčuka¹,

Ilgazs²,

Bandere³

et al. 2017

Open Vet J.

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The objective of this study was to determine the effects of topical 0.5% tropicamide, 1% atropine sulphate and 10% phenylephrine hydrochloride ophthalmic solutions on intraocular pressure (IOP) and horizontal pupil diameter (HPD) in the dog during the first hour after treatment. Forty clinically and ophthalmologically normal canine patients (between the ages of 2 and 6 years) of varying breed and sex were used in this study. Animals were randomly divided into four groups of ten and given one drop of tropicamide, atropine, phenylephrine or saline into one eye. IOP and HPD were measured in both eyes every 5 minutes for 60 minutes. Tropicamide increased IOP by 8.8±4.0 mmHg 35 minutes post-treatment compared to pre-treatment (P<0.01) only in treated eye. IOP in the contralateral eye did not increase. With atropine the maximum increase in IOP was 2.6±2.8 mmHg at 20 minutes post treatment in the treated eye (P<0.01). IOP in the contralateral eye did not increase. Phenylephrine increased IOP by 2.3±2.1 mmHg (P<0.05) 10 minutes after treatment. Also in the untreated eye IOP increased by 2.3±2.1 mmHg, 20 minutes post-treatment. Maximum HPD in eyes treated with tropicamide occurred at 55 minutes and with atropine at 60 minutes. There were no HPD changes in the contralateral, untreated eye. Topical 10% phenylephrine showed maximal pupil dilation 60 minutes after treatment, but the HPD of the -untreated eye slightly decreased at 15 minutes, but this change only reached statistical significance at 40 min post-treatment (P<0.05). Normal saline showed no influence on IOP or HPD. The drugs investigated here show a significant increase in IOP after mydriatics.

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“…Ulcer depth was entered as an ordinal variable from 0 (no ulcer) to 3 (deep ulcer), with STT and IOP as covariates. Given the mean value of 20±3 mm/min from normal dogs in one paper from the senior author's research group (Hartley et al, 2006) and 20±1 mm/min in a paper from another group (Giannetto et al, 2009) a power calculation showed that detecting a 3mm/min difference between ulcerated and control eyes with a statistical power of 0.8 and significance at 0.05 would require 30 cases. Similarly detecting a difference of 5mmHg in dogs with a mean and standard deviation of 19±6 mmHg, a figure derived from a previous published large sample of normal dogs (Giannetto et al, 2009), would require a sample size of 36 dogs.…”

Section: Introductionmentioning

confidence: 99%

“…There were no significant differences between eyes with signs of mild inflammation, as noted above, and those without. The study makes the assumption that there is no significant difference in STT or IOP between the right and left eyes, this based on the fact that previous studies have not shown a difference between STT values of left and right eyes in normal dogs (Wyman et al, 1995), and similarly IOP values have not been shown to differ between eyes (Giannetto et al, 2009) so we feel confident that differences between ulcerated and control eyes here are highly likely to be related to the ulceration and not a random difference between eyes. One limitation of this study was to only perform the Schirmer I test which measures both basal and reflex tear production.…”

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confidence: 99%

Tear production and intraocular pressure in canine eyes with corneal ulceration

Williams¹,

Burg²

2017

Open Vet J.

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This study aimed to evaluate changes in lacrimation and intraocular pressure (IOP) in dogs with unilateral corneal ulceration using the Schirmer tear test (STT) and rebound (TonoVet®) tonometry. IOP and STT values were recorded in both ulcerated and non-ulcerated (control) eyes of 100 dogs diagnosed with unilateral corneal ulceration. Dogs presented with other ocular conditions as their primary complaint were excluded from this study. The mean ± standard deviation for STT values in the ulcerated and control eyes were 20.2±4.6 mm/min and 16.7±3.5 mm/min respectively. The mean ± standard deviation for IOP in the ulcerated and control eyes were 11.9±3.1 mmHg and 16.7±2.6 mmHg respectively. STT values were significantly higher (p<0.000001) in the ulcerated eye compared to the control eye while IOP was significantly lower (p<0.0001). There is an increase in lacrimation and a decrease in IOP in canine eyes with corneal ulceration. The higher tear production in ulcerated eyes shows the importance of measuring STT in both eyes in cases of corneal ulceration, since this increased lacrimation may mask an underlying keratoconjunctivitis sicca only evident in the contralateral eye. The lower IOP in ulcerated eyes is likely to relate to mild uveitic change in the ulcerated eye with a concomitant increase in uveoscleral aqueous drainage. While these changes in tear production and IOP in ulcerated eyes are widely recognised in both human and veterinary ophthalmology, it appears that this is the first controlled documented report of these changes in a large number of individuals.

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Daytime profile of the intraocular pressure and tear production in normal dog

Abstract: This study has demonstrated circadian rhythms in both IOP and STT I.

Cited by 67 publications

References 19 publications

Biomechanical Properties and Correlation With Collagen Solubility Profile in the Posterior Sclera of Canine Eyes With anADAMTS10Mutation

Biomechanical Properties and Correlation With Collagen Solubility Profile in the Posterior Sclera of Canine Eyes With anADAMTS10Mutation

Changes in intraocular pressure and horizontal pupil diameter during use of topical mydriatics in the canine eye

Tear production and intraocular pressure in canine eyes with corneal ulceration

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