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At least 19 recordsLinked to original sources
PubMed1976

Ocular tonometry in the child under general anesthesia with IM ketamine.

In the young child, the ocular tension cannot be taken without general anesthesia. Most of the anesthetic drugs lower the ocular tension which may give false low results in glaucoma. Ketamine is the only practical drug elevating the ocular tension. To determine the amount of the change in ocular tension under ketamine, the ocular tension was measured under I.M. ketamine 5 to 10 mg/kg in 30 children without ocular disease. The ocular tension before the anesthesia has not been measured. As soon as the child fell asleep, the ocular tension was recorded between 15 to 20 minutes. We noticed that the ocular tension remains stable in the beginning, but that it tends to rise after eight minutes of narcosis. So the ocular tension must be measured as soon as possible after induction, as soon as the child does not react to stimuli. Abnormal ocular tensions under ketamine are discussed. The ocular tensions under two different types of anesthesia (ketamine and methohexital + Thalamonal) are compared. Some examples of ocular tensions in glaucoma under ketamine are presented.

Anesthesia, General↗
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↗
PubMed1976

Prognostic factors in glaucomatous visual field loss.

A retrospective review was conducted of 31 patients with bilateral elevations of intraocular pressure and unilateral glaucomatous visual field loss. Nine (29%) of the fellow eyes developed visual field loss during a three- to seven-year follow-up period. Of the 13 fellow eyes that had an initial intraocular pressure greater than 26 mm Hg, eight (62%) developed visual field loss, as opposed to one (6%) of the 18 eyes that had lower intraocular pressures. Of the 11 fellow eyes whose intraocular pressures exceeded 24 mm Hg, either treated or untreated, on more than 50% of the measurements, seven (64%) lost visual field, whereas in the 20 eyes whose intraocular pressures were lower, only two )10%) lost visual field.

Female↗
PubMed1975

[A contribution to the study of the correlation between the depth of the anterior chamber and the coefficient of aqueous humor outflow (author's transl)].

The depth of the anterior chamber was measured and the coefficient of the aqueous humor outflow was ascertained by means of tonography in 88 normal eyes. The mean value of the depth of the anterior chamber established was 2095+/-0.42 and the median value of the outflow coefficient of the aqueous humor was found to be 0.27+/-0.07. Both values showed a regular distribution. A statistically significant correlation was established between the two values. Expressed through a correlation coefficient this would mean in practice that the coefficient of aqueous humor outflow is affected up to 10 percent by the value of the depth of the anterior chamber.

Adolescent↗
PubMed1977

Calibration of the Schiøtz tonometer for the normal canine eye.

The Schiøtz tonometer with 5.5-, 7.5-, and 10-g weights was calibrated for the normal canine eye, using a transducer with open and closed reservoir systems. The line of best fit for the observations was determined, and the equation of this line was utilized to derive a calibration table for the conversion of tonometer scale readings to mm of Hg intraocular pressure.

Animals↗
PubMed1976

Fluorophotometry and the rate of aqueous flow in man. I. Instrumentation and normal values.

A new objective fluorophotometer, based on a previous model but with changes in electronic circuitry, was designed and built. The fluorometric method was applied to 38 normal eyes to obtain the aqueous outflow rate and fluorescein decay constant. Aqueous outflow rate has a direct correlation with the anterior chamber depth and an inverse correlation with age. The aqueous flow rate is higher in whites than in blacks, but in our sample, mean pressure was lower in whites. Acetazolamide decreases the aqueous flow rate and the fluorescein constant; the mean decrease in 10 eyes of 5 patients was approximately 38% and 22%, respectively. Fluorophotometry gives a higher value for the aqueous outflow rate than that calculated by tonography.

Acetazolamide↗
PubMed1992

Deterioration in the accuracy of the pulsair non-contact tonometer with use: need for regular calibration.

The Pulsair non-contact tonometer (Keeler Pulsair: Keeler UK) has been shown to be a versatile instrument particularly suitable for screening for raised intraocular pressure. Although demonstrated to be accurate initially when compared to the Goldmann applanation tonometer no study has examined its long-term accuracy. Comparisons of three Pulsair tonometers with different degrees of usage with the Goldmann tonometer are described. Measurements were obtained from 64, 116, and 223 eyes in three separate comparative studies. Correlation coefficients of between 0.78 and 0.90 were obtained, the least used instrument being significantly more accurate than the two more extensively used instruments. Taking the Goldmann tonometer as the standard tonometer, and the aim to detect intraocular pressures of greater than 21 mmHg, sensitivities of 40%, 48%, and 85% for the three Pulsair tonometers respectively were shown. The Pulsair tonometer appears liable to a long-term drift in accuracy with use, and we suggest that provision is made for the regular re-calibration of the instrument.

Calibration↗
PubMed1975

Influence of body position on the intraocular pressure of normal and glaucomatous eyes.

In 77 normal and 65 glaucomatous eyes the influence of body position on the intraocular pressure was studied, using the pneumatonograph. The pressure increment when changing from the seated to the supine position averaged 2.9 mm Hg in normal eyes and 3.9 mm Hg in glaucomatous eyes. The pressure increase occurred immediately upon lying down and was reversible after returning to the seated position. Comparative measurements with the Goldman tonometer in the seated position showed good agreement with the results obtained by the pneumatonograph. The Schiotz tonometer did not reliably reveal the true supine intraocular pressure. The postural response (seated to supine) showed considerable variation in individual normal and glaucomatous eyes, and it did not correlate consistently with the intraocular pressure in the seated position. It should be taken into account that the results in the glaucomatous eyes were obtained while the patients were on glaucoma medication. In a series of six lowtension glaucomatous eyes the postural response was significant as a probable pathogenetic factor in that disease, because the intraocular pressure could rise from a normal to a glaucomatous level upon changing from the seated to the supine position.

Adult↗
PubMed1977

[The diagnostic and prognostic significance of increase intra-ocular pressure (author's transl)].

A single tonometry observation is not very relevant due to considerable interobserver variations which are also found in applanation tonometry. Furthermore, the intraocular decreases by repeated applanation tonometry and intra-ocular pressure that change for as much as 8 mm Hg in 1 minute has been found in continous pressure recordings. There are in addition diurnal pressure variations and pressure alterations with the position of the body. Therefore, the diurnal pressure curve is much more important than the single tonometric value. The prognosis and also the decision to start medical treatment depends upon the height of the pressure, the family history diabetes, vasoclerosis, low blood pressure, heart insufficiency, age, disease of the carotid artery, anemia, the size of the excavation, the condition of the visual field, the reliability of the patient and the pressure lowering effects of pilocarpine, which can be very different individually. Rarely pressures of 26 mm Hg or more can be left untreated. If unfavourable factors are combined, even in pressures of 20 mm Hg it should be tested if pilocarpin lowers the intra-ocular pressure considerably. There is no magic number of pressure where treatment has to be started.

Adult↗
PubMed1992

Ocular pulsation correlates with ocular tension: the choroid as piston for an aqueous pump?

In 26 random out-patients, including 13 treated glaucoma patients and ocular hypertensives, the higher the ocular tension, the greater the pulse amplitude, by Alcon pneumotonometry, at a statistically significant level. In a single untreated hypertensive, when 2-hourly pneumotonometry was done for 24 h, the correlation was similar and significant. The higher the diastolic blood pressure, the higher the ocular pulsation, also significantly. Pulsation is suggested to be a pump, the choroid being the piston, contributing (1) to an increase in the outflow of aqueous humour and (2) to a homeostatic mechanism contributing to normalization of the intra-ocular pressure, wherein pulsation increases or decreases, as the intraocular pressure increases or decreases, respectively.

Aqueous Humor↗
PubMed1977

Comparative evaluation of two new applanation tonometers-preliminary study.

Three separate intra-ocular pressure assessment preliminary studies utilising the Goldmann, E.M.T. 20 and the Digilab Model 30R pneumatonometer were carried out on a total of 114 eyes with glaucoma, and in 184 normal eyes in 162 patients. In general the E.M.T 20 gave a lower result that the Goldmann but both compared well within the normal intra-ocular pressure range. Within the normal intra-ocular pressure range the pneumatonometer generally gave a 1-3 mm Hg higher reading than the Goldmann but in the glaucomatous eyes this difference became much less and readings tended to be similar with both tonometers. The fixed calibration of the E.M.T. 20 and its accuracy for pressures in the 20 mm Hg range make it an ideal instrument for screening for glaucoma but it is not suitable for the accurate stabilization of glaucoma patients under treatment. The accuracy of the pneumatonometer in the range of intra-ocular pressure above 22 mm Hg render it the instrument of choice for the diagnosis and control of glaucoma patients. Added advantages of the pneumatonometer were the resilience of the probe to accidental damage and the ability to record the ocular pulse.

Glaucoma↗