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Biomedical subjects

R A Moses

Publications and source records attributed to R A Moses.

11 recordsLinked to original sources
PubMed1979

The pneumatonograph. A laboratory study.

The scale reading of the pneumatonograph (PTG) is dependent on the force of application to the cornea. Since this force is relatively greater at low intraocular pressure, the scale is compressed, yielding an overestimate of intraocular pressure in physiologic range. When the PTG is held vertically, the weight of the plunger is added to the gas propulsion force and the compression of the scale is accentuated. When a 10-g plunger load is added, as is advocated for tonography, the scale compression is further accentuated. We conclude that the PTG scale is compressed, the PTG is position-sensitive, and that the PTG is totally unsuited to tonography. The PTG is not an applanation tonometer and should not be confused with applanation tonometers.

False Positive Reactions↗
PubMed1979

Blood reflux in Schlemm's canal. I. Normal findings.

Blood may be refluxed into Schlemm's canal in the normal eye by occlusion of recipient veins in a sector of the conjunctiva and episclera. The blood makes the anterior margin of the canal distinct near the midportion of the trabecular mesh at the same place in which it is seen after hypotony. Circumferential flow in segments of the canal is possible when a pressure head exists to promote such flow. Evidence was found that the canal is not partially collapsed in the normal eye.

Adolescent↗
PubMed1979

Circumferential flow in Schlemm's canal.

A model of Schlemm's canal was designed and analyzed mathematically. The effect of canal width on intraocular pressure was examined, and the pressure and flow distribution in the canal were calculated.

Aqueous Humor↗
PubMed1979

A standard large wound of the corneal epithelium in the rabbit.

A method of iodine vapor cautery was applied to rabbit eyes. The cautery produces an approximately circular area denuded of epithelium of uniform size. The eye is not inflamed, and the very rapid mean healing rate of 1.42 mm2hr-1 was observed.

Burns, Chemical↗
PubMed1978

Increased corneal thickness simulating elevated intraocular pressure.

A 17-year-old girl had intraocular pressure readings of 30 to 40 mm Hg in both eyes, with normal visual fields and optic nerve heads. Medical treatment was unsuccessful in lowering the IOP measurements substantially. The central corneal thickness was 0.90 mm in each eye in the absence of corneal edema. Cannulation of the left anterior chamber revealed an IOP of 11 mm Hg, while the Perkins' and Schiŏtz' tonometers gave readings of 35 and 34 mm Hg, respectively. Previously, elevated tonometry readings had been obtained by Goldmann's, Perkins', Schiŏtz', MacKay and Marg's, pneumatic tonometer and air puff tonometer. This suggested that measurement of central corneal thickness be performed in cases in which IOP recordings do not correspond to other clinical findings.

Adolescent↗
PubMed1977

Corneal penetration of rifampin.

We tested the corneal penetration of rifampin in four vehicles: dimethylsulfoxide, polyethylene glycol, an ocular lubricant, and as rifampin ointment. We measured drug concentrations in the aqueous humor in rabbits after topical instillation of 1 and 2.5% rifampin according to two dosage schedules. Drug concentrations in the aqueous humor were bactericidal to Mycobacterium leprae. Since leprosy of the cornea, iris, and ciliary body may develop despite standard systemic bacteriostatic treatment, treatment of leprotic involvement of the anterior eye may be enhanced by intensive topical application of rifampin.

Administration, Topical↗
PubMed1977

The scleral spur and scleral roll.

The scleral spur and scleral roll together form a fibrous hoop which may be detached from adjacent structures as a unit. Tensile tests of the spur-roll resemble reported data on sclera. It is proposed that the circular structure of the spur-roll prevents action of the meridional portion of the ciliary muscle on the trabecular meshwork from collapsing the canal of Schlemm.

Aged↗
PubMed1977

Choroid tension and facility of aqueous outflow.

Tension of the choroid of enucleated eyes was adjusted by incising the sclera and lengthening the eye. The facility of outflow increased in direct proportion to choroid stretch. The present results are compared with reported results of anterior chamber deepening and lens depression in vitro and with accommodation and goniospasis in vivo. Choroid stretch in the enucleated eye is less efficient in increasing outflow facility than is equivalent choroid movement in accommodation. Anterior chamber deepening and lens depression also appear to be relatively inefficient means of enhancing outflow facility, although goniospasis appears to be relatively efficient. The suggestion is made that traction of the ciliary body on the trabecular mesh in an axipetal direction is more efficient in enhancing outflow facility than is traction in the meridional direction.

Accommodation, Ocular↗
PubMedDate not supplied

The effect of intraocular pressure on resistance to outflow.

As intraocular pressure is increased, facility of aqueous outflow decreases. For many years this fact was obscured by the often used procedure of experimental perfusion into the anterior chamber. Anterior chamber perfusion deepens the anterior chamber; retrodisplacement of the iris-lens diaphragm tenses the trabecular mesh with resulting facility increase and obscuration of the facility-reducing effect of pressure. The probable mechanism of facility reduction under experimental conditions is apposition of the inner wall of Schlemm's canal to the outer wall. Since facility of aqueous outflow is not constant at different intraocular pressures, application of poiseuille's law to the eye must be restricted to each pressure investigated.

Animals↗