Biomedical subjects
Publications and source records attributed to S W Hyams.
The prevalence of glaucoma in a rural population of 6232 people over the age of 40 years, including patients with previously diagnosed glaucoma, was found to be 1.21%. There were 41 cases of open-angle glaucoma compared to 32 cases of angle-closure glaucoma. The prevalence of glaucoma among subjects over the age of 60 years was 3.07%.
The use of a data retrieval system for patients' ophthalmic records is described. Input is by using simple forms and output is in batch. The system is adaptable for on-line use as soon as a terminal is established in the clinic. To date there are over 6000 patients on file, of whom about one half have no other form of ophthalmic medical record.
The programmed system of a data retrieval system for the eye clinic is described. The system uses an IBM 370/168 computer, involves programmes to minimize the possibility of entering errors and a magnetic tape back-up system to reduce the cost of storing rarely required material and as a safeguard against the accidental erasion of material on disc.
Diagnostic techniques using radioactive isotopes can be used for the investigation of cerebral, orbital and intraocular tumours and for the dynamic study of tear flow. The value of such techniques in the study of obstruction of the nasolacrymal system (particularly partial and functional obstructions) has been established and the possibility of using Tc99m clearance for the investigation of dry eyes is being investigated.
Two hundred and sixty-seven eyes which underwent peripheral iridectomy for presumed angle-closure glaucoma were investigated. The diagnosis of angle-closure glaucoma was confirmed postoperatively in 258 eyes, in 201 of which the intraocular pressure became normal without further treatment and in 57 of which the postiridectomy IOP was elevated because of visible damage to the anterior chamber angle. Three eyes had open-angle glaucoma with a narrow angle. Six eyes had possible mixed (combined mechanism) glaucoma (2-2%). Mixed glaucoma is a rare, fortuitous combination of open-angle and angle-closure glaucoma rather than a distinct entity, and it might be advisable to avoid the term, which tends to be used for primary glaucomas of uncertain classification.
The prevalence of refractive errors was studied in an adult rural population. Of the 8102 eyes studied 18-4% were myopic, 57-1% were emmetropic, and 24-5% were hypermetropic. Mild myopia was commoner in males than in females, and mild hypermetropia was commoner in females than in males. There was increasing hypermetropia with increasing age, probably due to unmasked, latent hypermetropia up to the age of 70 years and to a true shift toward hypermetropia after the age of 70 years.
Expulsive hemorrhage occurring during cataract extraction was successfully treated by immediate wound closure, without evacuation of blood through the sclera. Only two such cases have been reported previously. Modern micro-surgical techniques are not ideal for the management of this condition.
Paralysis of the right third and fourth cranial nerves, lasting for about six weeks, occurred in a patient following the injection of procaine hydrochloride in the area of the right superior alveolar artery. Ocular complications of dental anesthesia are rare and are probably caused by intra-arterial injection of anesthetic that reaches the orbit via an anastomosis between the middle meningeal and ophthalmic arteries. Such complications include transient oculomotor palsies and permanent or transient loss of vision.
Nine cases are presented, six of them in detail, which suggest that there is a high risk of bullous keratopathy developing when the lens is removed for the treatment of acute glaucoma due to an intumescent cataract. In some cases the keratopathy is due to detachment of Descemet's membrane from the cornea. Acute glaucoma due to an intumescent cataract should be treated medically or by peripheral iridectomy. The lens should be removed only after the intraocular pressure has been normal and the cornea free of edema for at least 6 weeks.
118 consecutive patients with angle-closure glaucoma (ACG) were investigated. The primarily affected eye presented with acute ACG in 71 patients, with intermittent or chronic ACG in 41, and with acute ACG secondary to intumescent cataract in six. ACG was demonstrated in the fellow eye in 85 of the 118 patients (72 per cent.), including 72, 71, and 83 per cent. respectively of the three groups distinguished above. In 27 fellow eyes, ACG was demonstrable only by provocative testing. Eleven patients failed to return for follow-up investigation. A routine prophylactic peripheral iridectomy in the fellow eye is justified in patients who are unlikely to attend for follow-up examinations,, but may be avoided in about 23 per cent. of patients who attend regularly.
Retinal detachment after cataract extraction occurred in nine out of 136 eyes with myopia of 6 or more dioptress (6-7 per cent), during a follow-up period of 1 1/2-9 1/2 years. Five of the nine detachments occurred within 3 months of cataract extraction. All patients with retinal detachment were under the age of 63 years. Relatively young patients with high myopia bear a special risk of developing retinal detachment after lens extraction. The possible reason for this is discussed.
Biomicroscopical examination of the vitreous and peripheral retina was performed on 103 aphakic eyes with myopia of at least -6-0 dioptres. Retinal breaks were found in 19 eyes (18-4 per cent). Posterior vitreous detachment was present in all but one of the eyes. The high prevalence of retinal breaks in aphakic eyes with high myopia is compatible with the high incidence of retinal detachment in such eyes.
A patient suffering from open angle glaucoma was treated with topical phospholine iodide and epinephrine. Before treatment the anterior chamber was deep and the angle wide open in both eyes. Two weeks after beginning treatment there was an acute elevation of pressure to 52 mm hg in the right eye accompanied by myopia, shallowing of the anterior chamber and closure of the angle. These findings were dramatically reversed by the instillation of one drop of tropicamide and one drop of cyclopentolate. Simultaneous contraction of the dilator and sphincter muscles of the iris in this case probably caused pupillary block and closure of the anterior chamber angle, in spite of the initially wide open angle. Phospholine iodide may also have caused a spasm of the ciliary muscle and a forward movement of the lens, in a manner similar to that thought to occur in malignant glaucoma. Strong miotics together with epinephrine should be used cautiously in the treatment of glaucoma even when the initial examination shows a wide open angle.
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