The nervous system
Peter Kopelman, Dame Jane Dacre in Handbook of Clinical Skills, 2019
Strabismus This is an abnormality of ocular movement such that the visual axes do not meet at the point of fixation (Fig. 6.40). Paralytic strabismus is due to weakness of one or more of the extraocular muscles. The following clinical features are seen in paralytic strabismus: Limitation of movement: a prominent feature is impairment of ocular movement in the direction of action of the muscles affected.False orientation of the field of vision: there is erroneous judgement by the patient of the position of the object in that portion of the field of vision towards which the paralysed muscles should usually move the eye. Patients point wide of an object if they close the unaffected eye.Diplopia: patients with paralytic strabismus complain of double vision.
What can eye muscle studies tell us about strabismus?
Jan-Tjeerd de Faber in 28th European Strabismological Association Meeting, 2020
It is not generally believed that concomitant strabismus is due to a primary abnormality of the eye muscles or the ocular motor system. The gross anatomy of EOM including the shape and position of the eye muscle pulleys was not changed in strabismus. The histology of the EOM fibers was also basically the same, but changes have been observed in the cellular and biochemical machinery of the fibers, most notably in the singly innervated orbital fibers. Functionally this was seen as slower contractions and reduced fatigue resistance of EOM in animals with strabismus and defects of binocular vision. Most likely the changes represented an adaptation to modified visual demands on the ocular motor control, due to the defects of binocular vision in strabismus from an early age. Adaptation of EOM function to visual demands could be seen also in the adult human ocular motor system, but here the effects can be reversed with treatment in some conditions. However, it is not known if the developmental modifications of EOM function seen in animals are reversible or represent an insurmountable obstacle to treatment of strabismus.
Accident and Emergency
Nagi Giumma Barakat in Get Through, 2006
Concomitant strabismus is most common in children. The angle of deviation will remain the same wherever the eye moves. There are many unknown causes of strabismus, but it is important in any refractory error or neurological problem. Incomitant strabismus is usually caused by neurological or mechanical problems, such as VIth nerve palsy or orbital trauma. Half of the patients referred for orthoptistic assessment for strabismus are normal. The covered-eye test can be performed. GPs can be trained to do this - it is very easy. A light is shined into the eyes, where one looks for the pupillary reflex. If it is centred in both eyes, this is normal. In case one is temporally situated, cover it centrally. If the abnormality becomes central, the child has strabismus. If the child is not yet 10 years of age, there could be a latent squint or an underlying neurological problem, and a full neurological examination is required.
Impact of visual impairment following stroke (IVIS study): a prospective clinical profile of central and peripheral visual deficits, eye movement abnormalities and visual perceptual deficits
Published in Disability and Rehabilitation, 2022
Fiona J. Rowe, Lauren R. Hepworth, Claire Howard, Kerry L. Hanna, Jim Currie
The profile of visual impairment following stroke has received little attention. Monocular or binocular vision loss can be an isolated presentation of stroke [9]. Reduced central vision has largely been attributed to spectacle need or eye disease but with less consideration to new onset low vision after stroke [3,10]. Homonymous hemianopia is the most common form of visual field loss due to stroke but less is reported on other types of visual field loss [11,12]. Strabismus is an ocular misalignment in which both eyes no longer coordinate as a pair and usually causes the symptoms of blurred/jumbled or double vision (diplopia). The misaligned eye may turn inwards, outwards, up, down or a combination [13]. Ocular motility abnormalities are varied following stroke and include ocular cranial nerve palsies, horizontal and vertical gaze palsies, nystagmus and deficits in saccadic, smooth pursuit and vergence eye movements. Resultant symptoms are often diplopia, oscillopsia, reading difficulty and altered vision [14].
The Management of Childhood Intracranial Tumours and the Role of the Ophthalmologist
Published in Neuro-Ophthalmology, 2019
G. Mole, R. Edminson, A Higham, C. Hopper, D. Hildebrand
Our study has all the limitations of retrospective reviews: namely reliance on existing case records and absence of standardization of initial assessment at presentation. Many of the children did not have a formal orthoptic review until after their initial decompression surgery. Therefore, it is difficult to conclude at exactly what point children developed strabismus. Although we report 33 patients had non-paralytic strabismus during follow up, we suspect that many of these patients had resolved paralytic strabismus which has been previously reported.34 There was only one case in which a child presented with non-paralytic strabismus which was an exotropia in the context of very reduced vision in one eye. One child also had a longstanding esotropia that had previously been operated on and so was incidental.
Acquired monocular elevation deficit in a case of Parry–Romberg syndrome
Published in Strabismus, 2019
Xuhong Zuo, Lusheng Ma, Xvying Zhuo, Yuanbin Li
A variety of ocular motility disorders have been reported in Parry–Romberg syndrome (progressive hemifacial atrophy), an idiopathic craniofacial disorder characterized by slowly progressive atrophy of soft tissues of one side of the face.1 Various ocular motor defects have been described in these cases, some of which are explained by mechanical restriction from fibrosis, others are thought to be caused by nerve paresis.1–3 This report describes a rare case of acquired monocular elevation deficit (MED) in a child without any restrictive component. The paralytic nature of strabismus and its surgical management in this syndrome was documented. This study was approved by the ethics committee of the Yantai Yuhuangding Hospital. Written informed consent forms were obtained from the patient and her parents.
Related Knowledge Centers
- Amblyopia
- Diplopia
- Esotropia
- Exotropia
- Depth Perception
- Preterm Birth
- Cerebral Palsy
- Vision Disorder
- Far-Sightedness
- Hypertropia