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Biomedical subjects

E S Perkins

Publications and source records attributed to E S Perkins.

At least 37 records · Page 2Linked to original sources
PubMed1981

The ocular pulse.

A recording applanation tonometer was used to examine the ocular pulse in normal subjects and patients with ocular hypertension, open angle glaucoma and low tension glaucoma. The mean pulse amplitude of right eyes of normal subjects was 2.84 mm Hg +/- 1.16 and 2.83 mm Hg +/- 1.18 for left eyes. Only 2% of subjects showed an interocular difference in pulse amplitude of more than 0.5 mm Hg. There were significant differences in pulse amplitude with refractive errors. Hypermetropic eyes had the largest pulse amplitude and myopic eyes the smallest. There was no significant correlation between pulse amplitude and intraocular pressure or age in normal subjects. The mean pulse amplitude of eyes with open angle glaucoma was significantly higher than that of normals. The mean pulse amplitude of a small number of eyes with ocular hypertension was significantly higher and eyes with low tension glaucoma had significantly lower pulse amplitudes than normal subjects.

Female↗
PubMed1981

Hereditary and congenital factors in inflammations of the uveal tract.

The discovery of associations between HLA antigens and particular diseases has provided an explanation for some racial differences in the incidence of uveitis. Acute anterior uveitis is strongly associated with HLA B27 and this hereditary influence has been substantiated by evidence of familial cases. HLA B5 occurs more frequently in Japanese patients with Behçet's disease and HLA BW22J and HLA DWa are associated with the Vogt-Koyanagi-Harada disease. HLA B7 and HLA DRW2 occur more frequently in patients with presumed ocular histoplasmosis. Some possible explanations for these associations are discussed. Syphilis, cytomegalic inclusion disease, and toxoplasmosis can all produce a congenital form of uveitis.

Acute Disease↗
PubMed1979

Single treatment laser iridotomy.

A technique is described for producing an iridotomy in the treatment of closed-angle and secondary glaucoma using a single pulse from a dye laser. It was successful in 28 out of 32 eyes treated, and no significant complications were encountered.

Coumarins↗
PubMed1979

Survey of ophthalmic conditions in a Labrador community. I. Refractive errors.

Of the 745 available members of the population of Nain in Labrador 650 (87%) were screened for refractive errors and ocular disease. Refraction by retinoscopy was done in 553 and axial length measured by an optical method in 514. The results showed that the incidence of low degrees of myopia was higher in Inuit (Eskimos) and those of Mixed Inuit-Caucasian blood in the age groups 10 to 40 than in those over 40. 75% of the myopes came from 20 families in which myopia was present in 2 or more generations. Although there was no significant correlation between the refraction of parents and offspring, there were significant correlations between them for axial length. The axial lenths of the myopic eyes of the Inuit and Mixed populations were significantly longer than emmetropic and hypermetropic eyes. The younger memebers of the population were taller than their parents, and except in female Caucasians axial length showed a significant positive correlation with height. More myopes than emmetropes and hypermetropes achieved grade 8 or more in school. It is suggested that the increased incidence of myopia in the younger age groups might be due to environmental factors interfering with the process of emmetropisation in eyes with a genetic predisposition to myopia by virtue of inheriting a slightlt longer eye. Better nutrition resulting in an increase in stature may also have had some influence.

Adolescent↗
PubMed1977

Comparison of ultrasonic and photographic methods of axial length measurements of the eye.

The axial length of 25 eyes was measured by the photographic method and by ultrasonography. The photographic measurements were consistently larger than the ultrasonic, but analysis gave a correlation coefficient of r = 0-8483. The results suggest that the centre of rotation of the eye lies posterior to the anatomical centre of the globe. Using an empirical method of calculation and allowing for an error of +/-0-3 mm in the ultrasonic measurement, the photographic results were within +/-0-5 mm in 13 eyes and +/-1-0 mm in 7 eyes. The photographic method may be helpful as a guide to the power of intraocular lens implants and for comparing axial lengths in population studies.

Anthropometry↗
PubMed1977

Prostaglandins and ocular trauma.

Laser irradiation of the iris in rabbits causes miosis, a rise in intraocular pressure and an increase in the protein content of the aqueous humour. These effects on intraocular pressure and the blood-aqueous barrier are partly due to the release of prostaglandins of the E type and can be very much reduced by pretreatment with prostaglandin synthetase inhibitors such as indomethacin. The miosis and part of the rise in intraocular pressure and breakdown of the blood-aqueous barrier may be due to antidromic stimulation of sensory nerves, and they are reduced by nerve-blocking drugs. A combination of indomethacin and local anaesthetic can block the miosis and rise in intraocular pressure and greatly reduce the increase in protein content of the aqueous humour. It is probable that the human eye reacts in a similar way to laser irradiation of the iris, but so far the rise in intraocular pressure has not had serious results clinically in the treatment of glaucomatous eyes.

Animals↗
PubMed1976

Simple method of determining the axial length of the eye.

By photographing the corneal reflex in two positions of gaze and measuring the radius of curvature of the cornea it is possible to calculate the radius of rotation of the eye. The measurements obtained in this way showed a high correlation with refraction in a series of 80 eyes. The axial length obtained by this method was about 3 mm greater than that obtained by ultrasonographic or x-ray methods, and the reasons for the discrepancy are discussed.

Anthropometry↗
PubMed1975

Plasma vitamin A and beta-carotene in retinitis pigmentosa.

Plasma levels of vitamin A and beta-carotene were measured by spectrophotometry in 39 patients with genetically determined retinitis pigmentosa, No difference was found between the levels in these patients and the levels in a control group.

Adolescent↗
PubMed1975

Prostaglandins and the eye.

Prostaglandins are present in the iris and cilliary body and are synthesized in these tissues. Prostaglandins are released into the aqueous following a variety of insults to the eye, and the results of such trauma can be reproduced by the application of prostaglandins to the eye. Prostaglandins have been detected in the aqueous of patients suffering from endogenous uveitis and it is probable that the anti-inflammatory effects of drugs such as aspirin and indomethacin are due to their prostaglandin antagonistic actions. little is known yet concerning the physiological role of prostaglandins in the eye, but their association with adrenergic mechanisms, which is now being studied, may produce some clarification. The relationship between prostaglandins and antidromic stimulation of sensory nerves and the so-called axon reflex is still obscure and it would be ironic if the miosis following stimulation of the Vth nerve, which was the starting-point for the discovery of irin and its subsequent identification with prostaglandins, is not in fact due to prostaglandin but to some other chemical mediator.

Animals↗