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Results for “Tonometry, Ocular”

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At least 37 records · Page 2Linked to original sources
PubMed1976

[Intraocular pressure measurements on soft contact lenses (author's transl)].

The pneumotonograph was evaluated for its capability to record and measure intraocular pressure through soft contact lenses. In a series of patients with chronic corneal diseases treated with soft contact lenses, good pressure and intraocular pulsations were recorded both with and without the soft lenses. Areas of scarred cornea give incorrect values, whereas areas of corneal edema give values similar to those obtained in the presence of a soft lens and are believed to reflect accurate and reliable pressure readings. In normal eyes, it has been found that the presence of a plain soft lens does not modify the accuracy of pressure measurement. High values do occur, however, when the refraction of the lens exceeds eight diopters.

Contact Lenses, Hydrophilic↗
PubMed1989

The effect of increased intraocular pressure on visual acuity and corneal curvature after radial keratotomy.

To detect the effect of increased intraocular pressure on visual acuity and corneal curvature after radial keratotomy, we measured these variables in the sitting and inverted positions in 18 patients who underwent radial keratotomy (Group 1) and compared their results with those from the unoperated on eyes of seven patients (Group 2). We also compared the results before and after inversion within each group. Intraocular pressure increased to approximately two times normal in each group. Significant improvement in visual acuity and reduction in central keratometry were noted only in Group 1. By multiple regression analysis, visual improvement correlated with the number of incisions but not the time since surgery. Our study provides evidence that increased intraocular pressure may account for transient changes in vision and corneal curvature after radial keratotomy.

Adult↗
PubMed1995

[Are we measuring the right intraocular pressure after excimer laser photorefractive laser keratoplasty in myopia?].

BACKGROUND: It is possible that the traditional method to determine the intraocular pressure after excimer-laser PRK is inaccurate. Measuring the pressure in the temporal part of the cornea might give the true values. METHODS: Intraocular pressure was measured with a Goldmann Applanation Tonometer and with the Tonopen, before and after PRK for myopia in the central and in the temporal parts of the cornea. The paired student t-test was used for statistical analysis. RESULTS: The results of central and temporal measurements before treatment were identical with both instruments. After PRK, central values were 2 to 3 mm Hg lower than temporal values when measured with a Goldmann Tonometer, and about 2 mm lower when measured with the Tonopen. The differences were highly significant (p < 0.0001 and p = 0.004 respectively). CONCLUSIONS: The intraocular pressure measured in the usual manner after excimer-laser PRK is lower than the temporally measured pressure. These differences could be caused by absence of the Bowman's membrane, thinning of the cornea and/or change of its topography.

Cornea↗
PubMed2002

Phenotype of DFNA11: a nonsyndromic hearing loss caused by a myosin VIIA mutation.

OBJECTIVES/HYPOTHESIS: To characterize the audiovestibular phenotype of DFNA11, an autosomal dominant nonsyndromic hearing impairment caused by a mutation in the myosin VIIA gene (MYO7A), including whether DFNA11-affected subjects have retinal degeneration as is characteristic of Usher syndrome type 1B, caused by different MYO7A mutations. STUDY DESIGN: Retrospective study of audiovestibular and ophthalmological data in a Japanese family linked to DFNA11. METHODS: Otoscopic examination and pure-tone audiometry were performed in all participants in the family. Selected subjects underwent additional examinations including speech discrimination scoring, acoustic reflex measurements, Békésy audiometry, evoked and distortion-product otoacoustic emissions, auditory brainstem responses, and bithermal caloric testing; visual acuity, ocular tonometry, slit-lamp examination, ophthalmoscopy, and electroretinography; and computed tomography of the temporal bone. RESULTS: Most affected individuals had moderate cochlear hearing loss beginning in the second decade and progressing at all frequencies. Variable degrees of asymptomatic vestibular dysfunction were present. Computed tomography showed normal inner and middle ear structures. No evidence suggested retinitis pigmentosa. CONCLUSIONS: The phenotype of DFNA11 is postlingual, nonsyndromic sensorineural hearing loss with gradual progression. Showing moderate hearing loss with asymptomatic variable vestibular dysfunction and no retinal degeneration, the DFNA11 phenotype is mildest among phenotypes caused by MYO7A mutations.

Adaptor Proteins, Signal Transducing↗
PubMed2005

Underestimate of tonometric readings after photorefractive keratectomy increases at higher intraocular pressure levels.

PURPOSE: To determine whether tonometric readings of increases in intraocular pressure (IOP) during the water-drinking test (WDT) are affected by variations in central corneal thickness (CCT) induced by photorefractive keratectomy (PRK). METHODS: Data from 30 randomly selected eyes of 30 patients (18 men and 12 women; mean age, +/- SD: 33.9 +/- 7.6 years) undergoing bilateral PRK for myopia (-6.57 +/- 2.39 D) were obtained. Objective refraction, anterior radius of corneal curvature (R), CCT, and IOP measurements at baseline and at different time intervals after ingestion of 1 L of water within 5 minutes, were performed before and 6 months after PRK. All measured IOPs were recalculated by a correction factor for R and CCT and expressed as corrected intraocular pressure (IOPC) measurements. RESULTS: The mean R +/- SD was 7.84 +/- 0.20 and 8.76 +/- 0.34 mm, and the mean CCT was 544.83 +/- 19.69 and 453.97 +/- 29.95 microm, before and after PRK, respectively. The mean IOP at baseline was 15.05 +/- 2.78 and 9.83 +/- 2.56 mm Hg, and during WDT was 18.32 +/- 3.42 and 11.42 +/- 3.10 mm Hg at 10 minutes, 18.59 +/- 2.99 and 11.54 +/- 2.54 mm Hg at 20 minutes, 17.80 +/- 2.85 and 10.87 +/- 2.22 mm Hg at 30 minutes, 16.35 +/- 3.02 and 10.26 +/- 2.21 mm Hg at 45 minutes, and 14.90 +/- 2.52 and 9.81 +/- 2.32 mm Hg at 60 minutes, before and after PRK, respectively. The mean IOPC at baseline was 13.64 +/- 2.33 and 13.05 +/- 2.98 mm Hg, and during WDT was 16.61 +/- 2.77 and 15.08 +/- 3.59 mm Hg at 10 minutes, 16.96 +/- 2.69 and 15.33 +/- 2.96 mm Hg at 20 minutes, 16.10 +/- 2.50 and 14.42 +/- 2.60 mm Hg at 30 minutes, 14.92 +/- 2.72 and 13.62 +/- 2.65 mm Hg at 45 minutes, 13.82 +/- 2.27 and 13.05 +/- 2.55 mm Hg at 60 minutes, before and after excimer laser treatment, respectively. Pre- and postoperative IOPs and percentages of IOP increase differed significantly (P < 0.05), in particular at the peak, as did IOPCs but not the percentages of increase in IOPC, apart from the highest values. CONCLUSIONS: Corneal changes after PRK for myopia may induce an uneven underestimate of the IOP increases. The inadequacy of a correction factor to compensate for CCT and R at high IOP levels indicates that other biomechanical factors may play a role when the cornea is subjected to dynamic actual IOP variation. Such increase of the well-known underestimate of IOP after PRK at higher actual IOPs may have significant clinical implications in tonometric assessment of subjects at risk of glaucomatous damage.

Adult↗
PubMedDate not supplied

Distribution and determinants of intraocular pressure in a normal pediatric population.

PURPOSE: To examine the intraocular pressure (IOP) of a normal pediatric population under topical anesthesia without sedation and its correlation with other ocular parameters. SUBJECTS AND METHODS: The IOP of 810 eyes of 405 patients with ages ranging from 0 to 12 years was measured using the Perkins applanation tonometer. Cooperative patients also underwent pachymetry, refraction, and biometry measurements. RESULTS: The mean (+/- standard deviation) age was 6.68 (+/- 3.28) years, with a mean (+/- standard deviation) IOP of 12.02 (+/- 3.74) mm Hg. IOP showed an increasing trend with age (correlation coefficieit [r] = 0.49) and tended to approach adult levels by 12 years of age. The IOP correlated directly with refraction (r = 0.69) and pachymetry (r = 0.39) and inversely with axial length (r = -0.1). CONCLUSIONS: The IOP in children is much lower than that in adults. It was noted to increase with age, hyperopia, and corneal thickness and was inversely proportional to axial length.

Age Factors↗