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Biomedical subjects

I M Strachan

Publications and source records attributed to I M Strachan.

At least 19 recordsLinked to original sources
PubMed1992

Whiplash and its effect on the visual system.

Whiplash or indirect injuries to the neck as a consequence of motor vehicle collisions are a common occurrence in which the frequency of ocular complications is largely unknown. Ophthalmic and oculomotor function was investigated in a longitudinal study of 39 cases who had their initial ophthalmological assessment within one week of the whiplash injury. Ten of 39 cases had ocular symptoms and signs which developed shortly after the accident. The principal abnormality in 6 of these was decreased convergence and accommodation, superior oblique muscle paresis in 2, decreased stereoacuity in 1 and bilateral vitreous detachments in 1 patient. All but 2 had complete resolution of their symptoms within 9 months. Four other patients were asymptomatic but had ophthalmic signs which resolved within 3 months. Oculomotor abnormalities following whiplash injuries are generally mild, have a good prognosis, and would appear from this study to be commoner than hitherto expected.

Accidents, Traffic↗
PubMed1990

Orbital blowout fractures--the influence of age on surgical outcome.

We report the frequency of troublesome diplopia in 17 patients (11 patients less than or equal to 21 years) who underwent surgical repair of traumatic orbital blowout fractures. Thirteen patients had primary surgery performed within 21 days of injury, 2 patients at 4 and 6 weeks and 2 cases at 6 and 24 months. The latter continues to complain of diplopia. Contrary to previous studies, we found that young patients were no more likely to suffer from symptomatic post-operative residual diplopia than their adult counterparts.

Adolescent↗
PubMed1990

Convergence excess esotropia treated surgically with fadenoperation and medical rectus muscle recessions.

Convergence excess esotropia has been treated with bifocals, miotics, medial rectus recession(s), fadenoperation, or a combination of these. However, comparatively few studies on the sensory status of these patients exist. We present the sensory findings in 31 children treated surgically. Twenty-one had fadenoperations combined with bimedial rectus recessions, one had a fadenoperation alone, and nine had augmented bimedial rectus recessions. Five children (16%) achieved bifoveal fusion, 22 (71%) had varying degrees of peripheral fusion, and four (13%) had no detectable binocularity after a mean postoperative follow-up of 2.4 years.

Child↗
PubMed1989

Acquired Brown's syndrome associated with Hurler-Scheie's syndrome.

A 5-year-old Caucasian girl with known Hurler-Scheie's syndrome (mucopolysaccharidosis) developed a right Brown's syndrome while under orthoptic review. There was no evidence of trauma or inflammation of the superior oblique tendon, trochlea, or surrounding tissues. The Brown's syndrome in this case may be due to shortening of the superior oblique tendon, associated with the shortening of long tendons of the arms and feet, which is common in Hurler-Scheie's syndrome.

Child, Preschool↗
PubMed1986

Unilateral Kayser-Fleischer ring.

A patient is presented who had unrecognised Wilson's disease. He had developed a clinically obvious Kayser-Fleischer ring in only one eye. The eye without the corneal ring had been injured in childhood and had a low intraocular pressure. Possible mechanisms for formation of a Kayser-Fleischer ring are reviewed and the lack of Kayser-Fleischer ring in this case is discussed.

Cornea↗
PubMed1981

Meridional variation in visual acuity of hooded rats reared in a carpentered environment.

Resolution acuity in people is frequently better for horizontal and vertical gratings than for obliques. An animal model of this oblique effect might be of help in elucidating its underlying neural mechanisms. Rats were chosen because laboratory rats area reared in a 'carpentered environment' apparently similar to those proposed to cause the oblique effect in people, and because electrophysiological experiments suggest that orientation selective units in rats' visual cortex may prefer horizontal and vertical stimuli. The acuity of eight laboratory-reared hooded rats was measured with high-contrast horizontal, vertical, and oblique gratings. The animals learned to detect low-frequency square-wave gratings with slightly fewer errors if they were horizontal or vertical than if they were oblique, but the effects of grating orientation on acuity were not significant. Refraction of the rats' eyes gave no evidence of astigmatism. These results suggest that the rat may not be a good animal model for studying the mechanisms that underlie meridional variations in acuity in people, and raise questions concerning both the neural bases of resolution acuity, and the validity of the 'carpentered environment' hypothesis.

Animals↗
PubMed1981

Non-surgical factors in the correction of aphakia.

72 unselected patients wearing aphakic spectacle correction were examined more than 6 months postoperatively. Approximately one third had poor adaptation in spite of satisfactory acuity. No correlation with age was found in the 60-85 year range. Binocularity appeared to play no part in adaptation but a significant sex difference was found, females predominating in the non-adapted group. Tests of eye movements showed defects in vestibulo-ocular suppression, smooth pursuit, and saccadic accuracy in the non-adapted group. This may indicate floccular dysfunction as a reason for failure to adapt to aphakic spectacles. This suggests the possibility of a useful preoperative assessment test to predict adaptation difficulties.

Adaptation, Ocular↗
PubMed1975

New apparatus for measuring forces in strabismus.

An apparatus for measuring muscle forces in strabismus has been developed. The globe is fixed with a modified suction cup, force applied is measured by strain gauges, and the excursion of the globe is measured by a light pointer and tangent screen. The values of force generation tests for normal horizontal rectus muscles performing 30 degrees saccades lie mainly within the range of 60 to 80 G.

Eye Movements↗