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Biomedical subjects

A C Molteno

Publications and source records attributed to A C Molteno.

At least 19 recordsLinked to original sources
PubMed1992

A clinicopathological study of loop recession in strabismus.

This communication reports the histological structure of loop recessions of extraocular muscles from seven patients. In all cases the loops formed pseudotendons in which the typical histological structure was well established by four months. Subsequently, moulding of these pseudotendons occurred with improved alignment of collagen and decrease in vascularity. By three and a half years after the operation the pseudotendon had acquired a very close resemblance to true tendon.

Adolescent↗
PubMed1992

The development of fixing and focusing behaviour in normal human infants as observed with the Otago photoscreener.

The Otago photoscreener is an optical instrument which gives a very sensitive indication of the accuracy with which a subject's eyes are fixing and focusing. Early experience suggested that this instrument could be used effectively to screen for the presence of amblyogenic factors in pre-verbal infants. This communication describes the development of ocular fixation and focusing in 137 normal infants who were followed at regular intervals during the first year of life. Accurate fixation and focusing was found in 13% of three-month-old infants, in 68% of six-month-old infants and in 76% of one year olds. The levels of 'focusing' visual acuity obtained from the photoscreen data are considerably better than the levels of cortical acuity measured by the standard behavioral and electrophysiological methods. This suggests that human infants fix and focus accurately for a considerable period before they are able to perceive all the details obtained in their retinal images.

Amblyopia↗
PubMed1991

Characterization of the fundal reflectance of infants.

Pupillary images recorded by a linear knife-edge photoscreener for infants accommodating more or less within the bounds of chromatic aberration show three smooth offset pupillary irradiance ramps when analyzed with a color video camera and frame-grabbing hardware. Both the shape of the ramps and the lack of a second image in a shadowing experiment support the view that the retina acts as an angularly diffuse partial reflector in photorefraction. We propose a lateral image-spreading characteristic to account for observed color-dependent ramp heights and offsets and consider possible physical mechanisms for lateral spreading.

Child, Preschool↗
PubMed1991

Bone implants after enucleation.

A method of preparing antigen-free cancellous bone for use as an orbital implant is described together with the surgical technique for its use in enucleation. The results of 52 patients with follow-up spanning 10 years is reported. In the first four years, five implants had to be removed, all due to infection following breakdown of Tenon's capsule in the early postoperative period. However, with more careful closure of Tenon's capsule, there have been no extrusions during the last six years.

Adolescent↗
PubMed1990

Effectiveness and predictability of tendon lengthening procedures.

A retrospective study was performed on the results of surgery in infantile esotropia with the aim of comparing recessions with a loop (a procedure in which the effect of a recession is increased by attaching the muscle to the globe with an intervening loop of suture to lengthen the tendon) to standard recession operations. The results of surgery were examined in 188 cases, of which 41 had been treated using a loop alone and 38 using a loop combined with a recession. The loop or sling procedure was found to be as predictable as conventional surgery and effective in increasing the amount of correction obtained.

Child↗
PubMed1990

The dual chamber single plate implant--its use in neovascular glaucoma.

The insertion of an artificial draining implant consisting of a silicone tube, opening onto the upper surface of a circular episcleral plate, will provide long-term drainage in cases of neovascular glaucoma. A simple modification of the episcleral plate, the addition of a subsidiary pressure ridge, allows the episcleral tissues to function as a temporary pressure-sensitive valve which limits the escape of aqueous in the early postoperative period. The surgical technique used with this modified implant is described, together with the results in the first 24 eyes in which it has been used.

Anesthesia↗
PubMed1990

Pupillary irradiance distributions for light backscattered in the human eye.

An investigation of linear knife-edge photoscreening devices for detecting focusing errors, refractive defects and other optical artifacts in the human eye is described. Pupillary irradiance distributions calculated for a model eye are shown to agree qualitatively with distributions recorded experimentally using video frame grabbing equipment. The form of the pupillary irradiance distribution from a cyclopleged human eye supports a diffuse-like characterization for the reflection/scattering processes at the retina. The extreme sensitivity of the instruments enables real-time detection of refractive effects from tear films on the cornea and real-time tracking of floaters.

Eye Diseases↗
PubMed1988

Pedicle flaps for cicatricial ectropion.

A surgical procedure is described for the correction of cicatricial ectropion secondary to actinic skin damage. This involves the rotation of an upper lid skin and muscle flap to the lower lid, thereby reversing the cicatrising process. The procedure, its advantages and disadvantages, are outlined. The procedure was successful in 44 of the 48 lids reviewed.

Cicatrix↗
PubMed1986

Twenty-two cases of clear cornea trabeculectomy.

The essential feature of clear cornea trabeculectomy is the use of a corneal approach, to create an intrascleral cleft communicating freely with the anterior chamber, without disturbing Tenon's tissue and conjunctiva. In this small series the procedure produced diffuse thick walled blebs with normalisation of intraocular pressure without medication in 11 eyes. This relatively poor result may be due to lack of the specialised instruments used by Cairns. The technique deserves further investigation.

Aged↗
PubMed1986

The vicryl tie technique for inserting a draining implant in the treatment of secondary glaucoma.

We have previously described surgical techniques for draining severe cases of secondary glaucoma by means of an artificial implant. Wherever possible these implants have been inserted in two stages. The technique involved suturing the episcleral plates of the implant to the sclera without connecting them to the chamber as the first procedure. Following this procedure the presence of the plates cause the surrounding tissue to form a thin fibrous envelope called a preformed bleb cavity. After a suitable interval of between six and eight weeks the connecting tube of the implant was inserted into the anterio chamber so as to drain aqueous into this preformed bleb cavity. This manoeuvre drastically reduced the incidence of postoperative hypotony and has proved a safe and effective technique. This communication reports an improvement on this technique in which the connecting tube of the implant is occluded by a ligature of 5-0 vicryl before inserting the tube into the anterior chamber through a fine needle puncture, at the same time as the episcleral plates of the implant are sutured to the sclera. The effect of this procedure is thus to prevent any drainage of aqueous until three to five weeks after operation when the vicryl suture material dissolves, allowing aqueous to drain into the preformed bleb system lined by a thin layer of dense fibrous tissue. This technique provides the advantages of the previous two-stage technique without the need for a second operation. The surgical technique is described together with the results of treating a series of 20 eyes with severe secondary glaucoma.

Adolescent↗
PubMed1985

Clinical experience with the Otago Photoscreener.

The Otago Photoscreener provides a sensitive indication of whether or not an infant is able to fix and focus binocularly on nearby objects. This instrument was designed for mass screening to identify infants with strabismus and/or amblyopia who do not fix and focus binocularly. This communication reports the authors' experience with the machine in the diagnosis and treatment of strabismus and amblyopia.

Amblyopia↗
PubMed1985

The visual outcome in cases of neovascular glaucoma.

The visual outcome of cases of neovascular glaucoma treated by draining implants has improved from 12% to 32% of eyes achieving a vision of 6/60 or better. The main factor responsible for this improvement has been the recognition that, in neovascular glaucoma, the retinal blood vessels are not capable of autoregulation of calibre in response to changes in intraocular pressure and ophthalmic artery perfusion pressure. The consequences of this situation are discussed and the importance of early treatment of neovascular glaucoma by a combination of photocoagulation, insertion of a draining implant and medical measures to improve the circulation where possible is emphasized.

Adult↗