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The clinical features and management of 17 cases of detached extraocular muscles are described. They are classified into four groups: (1) the muscle which is cut and lost during squint surgery, (2) the muscle which breaks during squint surgery, (3) the muscle which slips following squint surgery, and (4) the muscle which is damaged during facial or orbital trauma. The prognosis for group 1 is poor whereas groups 2-4 have a good chance of successful muscle relocation.

The measurement of the deviation of strabismus is usually performed by the prism cover test (PCT) and the synoptophore. The corneal reflex test (CRT) (Hirschberg test) has been used as an objective method of determining the angle of deviation. Recent papers (Brodie 1987, Carter & Roth 1978) have re-evaluated the CRT and proposed significantly different ratios (21–22 prism dioptres per millimetre). In strabismus clinics the CRT is frequently used with the patient wearing glasses. However, the corneal reflex test through glasses poses some problems. The reflections from glasses disturb the corneal reflexes. Glasses themselves have prismatic effects. Only one paper has mentioned the CRT through glasses.

This paper is limited to the consideration of acquired ocular palsies attributed to involvement of the cranial nerve pathways, i.e. lower motor neurone lesions. It is not concerned with supranuclear problems, retraction syndromes, myasthenia, dysthyroid eye disease, or blow-out fractures. The words palsy, paresis, and paralysis tend to be used interchangeably, but usually paresis means a mild and paralysis a severe degree of palsy. The cause of an isolated neurogenic ocular palsy is not always established but, in general terms, a IIIrd nerve palsy is often due to an aneurysm, a IVth nerve palsy to trauma, and a VIth nerve palsy to tumour or trauma. Autopsy studies of road accident victims by Heinze (I969) have shown that avulsion of the nerve rootlets from the surface of the brain stem may cause III, IV, or VI palsies. Other IlIrd nerve lesions were due to focal softening in discrete axonal bundles in the proximal segment of that nerve, and intraneural haemorrhage at the superior orbital fissure. VIth nerve lesions were either at the brainstem surface or at its intraorbital termination in the neuro-vascular hilum of the lateral rectus muscle. Only one patient had the VIth nerve damaged by the fractured tip of the petrous temporal bone. When it comes to apportioning significance to minor head trauma as the possible cause of oculomotor palsy, the recent study of Eyster, Hoyt, and Wilson (I 972) has shown that this may be an initial sign of a basal intracranial tumour. In children, a posterior fossa tumour must always be considered in cases of abducent palsy. The associated vestibular upset may lead to a fall and this injury may be accepted as the cause of the palsy without further search. Even Gradenigo's syndrome is not always due to middle ear infection but may be caused by a tumour. Two important causes in young adults are multiple sclerosis, and an unrecongized congenital ocular palsy that is becoming decompensated. Finally, virus infection is often invoked on slender evidence, particularly for recurrent VIth nerve palsies.

Current methods of medical treatment of this difficult condition are briefly reviewed, with comments on the generally unsatisfactory response. Attention is therefore directed to surgical methods and a short history given of the various routes used for orbital decompression. The author's own results of transantral, and more recently ethmoidal, decompression are given, with a detailed description of the technique for the latter approach. An interesting frequent consequence of postoperative A pattern to the ocular movements is discussed in the light of Koornneef's concept of orbital fascial anatomy, and suggestions are made for its avoidance.

31 patients with bilateral fourth nerve palsies are considered in this paper, 25 of the cases being traumatic in origin. Quantitative estimation of the torsional defect is carried out, using special synoptophore slides and a modification of the Lees' screen technique. Inability to prove the patient's retention of fusion in the presence of torsion is discussed. Although many of the traumatic cases had been rendered unconscious for varying periods of time up to several weeks by the initial injury with the known risk of losing fusion, sixteen out of seventeen patients undergoing surgery for their diplopia had postoperative evidence of binocular single vision.

Following reports of a high incidence of chorioretinal scarring related to the Faden Procedure, a retrospective study was carried out at Moorfields Eye Hospital. One hundred unselected Faden procedures were followed up with orthoptic and fundoscopic examination. Our indications and technique for performing this operation are described. A 7% incidence of chorioretinal scarring was noted; this compares well with previously published figures for conventional squint surgery and this operation should therefore be considered safe.

The first 46 patients to undergo surgery for squint with adjustable sutures at Moorfields Eye Hospital, City Road, London, are presented. The indications for surgery were: dysthyroid ophthalmopathy, fourth nerve palsy, monocular aphakia with strabismus and miscellaneous conditions. The technique of surgery is briefly described. The results show a high incidence of alignment, indicating the value of the technique and this is supported by long-term follow-up data where available. Treatment failures are analysed in detail.

I want to make it clear that this paper deals with some forms of squint where certain movements are limited but not because of any ocular muscle paralysis. I have been asked to include specifically dysthyroid ophthalmopathy in this paper and not all ophthalmologists would include such cases under the term ‘paralytic’ strabismus. Reduced ocular rotation may result from decreased innervation input to a muscle or failure of its antagonist to relax and extend normally. Furthermore, changes in orbital connective tissue may prevent normal movement of the eye despite the muscles contracting powerfully.

This rare condition, an oculomotor palsy which is interrupted by spastic contractions of the levator muscle and the pupillary sphincter at fairly regular intervals, had been reported in 54 patients up to 1975. Two patients presented to the authors with apparently complete unilateral ptosis but abnormal pupillary reactions prompted closer examination. Once the diagnosis has been considered only 5 minutes of careful clinical examination are necessary to confirm or reject it. During the past 4 years the authors have found nine new cases of the condition and it is clear that the diagnosis must often be missed. Details of the patients are shown and discussed in the light of Loewenfeld and Thompson's theory of the pathology. The place of surgical treatment is considered.

The indications for and details of the technique of adjustable sutures are fully described. Patients with vertical strabismus and fusion give significantly better results with this method. Illustrative cases of dysthyroid ophthalmopathy and superior oblique palsies are described.