[Management of unilateral traumatic bulb luxation with disruption of the optic nerve]

Luxation of the eyeball, which means that the eye protrudes between the eyelids,may occur spontaneously or as a rare sequel to major trauma to the orbital wall. It can be accompanied by a disruption of the optic nerve, which is called optic nerve avulsion. In most cases primary enucleation is performed as therapeutic treatment. In our case of a 1 1/2-year-old child bulb luxation with disruption of the optic nerve followed a relatively slight trauma,presumably a fall onto a toy. An irreversible amaurosis was diagnosed. To guarantee symmetrical growth of the orbita and face, the eyeball was replaced into the orbit under microscopic and endoscopic vision via a transnasal and transethmoidal approach.Postoperative examinations showed an exotropy with unrestricted motility of the globe and amaurosis. Five years after the trauma we found symmetrical facial development with uniform orbital cavities. The clinical features and management of globe luxation are discussed, importance of a rapid reposition of the eyeball in contrast to primary enucleation for functional, cosmetic and psychological reasons is emphasized.

[The function of Tenon's capsule revisited]

Tenon's capsule is at the forefront of today's strabismus news. Its function as a muscle pulley was recognized by Tenon himself in 1806. Neiger, then Koornneef, and more recently Demer gave a more modern description of Tenon's capsule. The anterior or muscular part is made up of collagen, elastic, and smooth muscle fibers. It forms a sleeve around extraocular muscles from the Tenon foramen to their scleral insertion. Directly in front of the foramen, it includes a zone of strong capsular-muscular adherence, which is also solidly suspended by ocular suspension system to the periosteum of the orbit; the intermuscular membrane consolidates the adherence zones of the rectus muscles. The posterior part is simply a condensation of collagenous fibers. The function of Tenon's capsule is essential. At the place where it adheres to the muscles, the sleeve that it forms around the muscles plays the role of a pulley diverting the muscle's path, with the pulley representing the proximal functional insertion of the muscle. The position of a rectus muscle's pulley is stable during ocular movements perpendicular to the axis of this muscle because of the transversal and radial fastening of the capsular-muscular adherence zone. During movements along the muscle axis, the pulley moves with the ocular globe. In fact, it is positioned actively to accompany the ocular globe's movements. The anomalies of these pulleys can contribute to or be responsible for an extraocular muscle imbalance: a position anomaly, an instability, a displacement, or a pathological adherence of one pulley can be the cause. Surgery of Tenon's pulley has always been an integral part of extraocular muscle surgery. Any intervention on the muscular level involves, to a lesser or greater extent, the operated muscle's pulley. Different examples demonstrate this.

[Differentiation between dyslexia and ocular causes of reading disorders]

BACKGROUND

Dyslexia is defined as a reading and/or writing disability persisting after exclusion of organic causes. Studies show that ocular disorders, especially small refraction errors, hypoaccommodation and symptomatic heterophoria, are often not detected or treated in cases of reading and/or writing problems which were otherwise diagnosed as dyslexia.

METHODS

We evaluated the data of patients referred to our department from December 1997 to March 2000 with the diagnosis of dyslexia.

RESULTS

We found ocular disturbances in 28 (84.8%) out of 33 children, 26 (78.8%) showed improved reading after therapy. They had mostly accommodative problems: uncorrected hyperopia, hypoaccommodation and/or exophoria compensated by accommodative convergence (pathophoria).

CONCLUSIONS

Our results underline the importance of the correction of even small refraction and/or motility errors in the presence of reading and writing difficulties.

Frequency of reading disability caused by ocular problems in 9- and 10-year-old children in a small town

INTRODUCTION AND PURPOSE

In most children referred to our department with a diagnosis of dyslexia, we have found an ocular disorder that had not been detected during previous ophthalmologic examinations. Exophoria and/or hypoaccommodation were the most common cause. Some of these children needed eye muscle surgery to improve the reading problems. However, these patients represent a selection. Therefore, we performed a field study to determine the percentage of children with reading disability caused by ocular disorders and the percentage of children with real dyslexia in a normal population. This was made possible by an examination of most pupils in the 4th grade of the three primary schools in a small German town. The co-author and a very experienced orthoptist performed all of the examinations.

RESULTS

Eighty-nine out of 127 children were examined. Of these, 16 (18%) had reading problems (2 girls and 14 boys). Most of them had accommodation problems: six (6.7%) suffered from an uncorrected hypoaccommodation, three children did not wear their prescribed glasses, one child had not been prescribed any glasses yet and one child had the wrong glasses. Two children suffered from pathophoria: one from eso- and the other from exophoria compensated by accommodative convergence. In 3 (3.4%) children no ocular cause could be found. These children may have true dyslexia.

CONCLUSION

Of the 89 children examined, 16 (18%) had reading problems and only 3/16 had no detectable ophthalmologic explanation. Hypoaccommodation was the most common cause of reading problems (in 6 of 16). In most of the cases it had not been diagnosed before. In all of these children the reading ability improved markedly with the proper refractive correction, bifocals or prisms.

Ondansetron, droperidol and their combination for the prevention of post-operative vomiting in children

In this study the antiemetic effects of droperidol, ondansetron and their combination were evaluated in 160 ASA Grade I and II children undergoing surgery for strabismus, who were randomly assigned to one of four groups: Group D received droperidol 75 micrograms kg-1, group O ondansetron 0.1 mg kg-1, group D+O received both droperidol 75 micrograms kg-1 and ondansetron 0.1 mg kg-1, and group N NaCl as placebo. Emesis within the first 24 h occurred in 95.0% of the children with placebo medication, compared with 32.5% (D), 40.0% (O) and 45.0% (D+O) in the groups with antiemetic prophylaxis. The differences between group N and all other groups were significant (P < 0.001). However, there were no statistically significant differences between the groups D, O and D+O. It is concluded that droperidol (75 micrograms kg-1) and ondansetron (0.1 mg kg-1) both significantly reduce PONV in children undergoing surgery for strabismus. Neither ondansetron, nor the combination D+O were superior to droperidol alone.

[The effect of the laryngeal mask airway on the postoperative incidence of vomiting and sore throat in children]

100 ASA I and II children, aged 4 to 14 years, and scheduled for strabismus surgery, were randomly assigned to one of the following groups: group 1 (n = 50): endotracheal tube, group 2 (n = 50): laryngeal mask airway. Apart from airway management, the anaesthesiological procedures were identical in both groups: induction with 2-3 mg/kg propofol, 0.02 mg/kg alfentanil, 0.05 mg/kg vecuronium, and 0.01 mg/kg atropine. After endotracheal intubation or insertion of the laryngeal mask, anaesthesia was continued with 6-15 mg/kg.h propofol and 10-30 micrograms/kg.h alfentanil. All patients were ventilated with N2O/O2 (2:1). No antiemetics were given, gastric contents were not aspirated. Postoperative nausea and vomiting (PONV) were recorded by 24 h, the incidence of sore throats was recorded 8, 12, and 24 h post-operatively.

RESULTS

The incidence of PONV was higher in group 1 (vomiting 48% vs 32%), nausea 28% vs 16% n.s.). Group 1 children had a higher incidence of sore throats (20% vs. 12%, n.s.), of a "lump in the throat" (10% vs 4%, n.s.), hoarseness (24% vs 0%, p < 0.001) and dysarthria (10% vs 4%, n.s.).

CONCLUSIONS

In children undergoing strabismus surgery, the laryngeal mask airway was superior to the endotracheal tube in terms of PONV and was associated with fewer local complications such as sore throat.

[Voluntary control of unilateral strabismus sursoadductorius]

BACKGROUND

Strabismus with unilateral elevation in adduction is an upward deviation of the adducting eye of unknown, not necessarily paretic origin. The term "old trochlear palsy" may be erroneous since the hypertropia is not necessarily larger in downward gaze and a causative lesion can usually not be identified. We describe here a marked voluntary influence on unilateral elevation in adduction, in situations that exclude binocular fusion.

PATIENTS

Two patients with an elevation in adduction of the right eye and a positive head-tilt phenomenon, a 21-year-old and a 28-year-old man, were able to vary their vertical angle of squint at will. Even under artificial conditions that exclude binocular fusion (alternate cover test, dark-red glass test) could they change their right-over-left deviation, Patient 1 between 4 and 20 degrees and Patient 2 between 0 and 15 degrees. Under natural viewing conditions both patients had binocular vision with stereopsis that decompensated only when they looked to the left.

CONCLUSIONS

We assume that our two patients had a "motor memory" that stores the muscle innervation for parallel eyes, i.e. the innervation suitable for binocular vision, and that the patients made use of or neglected this memory at will. In general, our observations suggest that a variable recourse to such a motor memory explains why, in patients with unilateral elevation in adduction, the angle of squint often changes. A voluntary access to this memory may, however, be exceptional.

[Jaensch-Brown syndrome--etiology and surgical procedure]

BACKGROUND

The classical clinical picture of inferior oblique pseudopalsy can be caused by (1) a tight connection between the superior oblique insertion and the trochlea and (2) a thickening of the tendon restricting the passage of the tendon through the trochlea. The entity may be congenital or acquired and constant or intermittend. A spontaneous cure is possible.

QUESTION AND RESULTS

We looked for the cause of the inferior oblique pseudopalsy in 41 patients operated on during the last 15 years. 31 patients had a congenital and 10 an acquired inferior oblique pseudopalsy. None of these cases had an alteration of the sheath of the superior oblique tendon. Instead we found a tight band at the posterior border of the tendon between the trochlea and the sclera in all patients with a congenital inferior oblique pseudopalsy. Resection of this band, either in toto or soley of the portion near the sclera resulted in a normalisation of the active and passive elevation in adduction. In some patients a second operation was necessary. The 'V-pattern' existing preoperatively regressed in part or completely during the 1.5 postoperatives years. A consecutive superior oblique palsy was seen in one case only.

CONCLUSION

A tight band at the posterior border of the tendon between the trochlea and the sclera explains the congenital variety of the inferior oblique pseudopalsy in many cases. A thickening of the tendon restricting the passage of the tendon through the trochlea may play a role in some cases, particularly in those with a spontaneous cure, but the surgical approach used in this series of patients was not suited to verify this mechanism.

NAME OF THE SYNDROME

The pathognomonic signs of the inferior oblique pseudopalsy, restriction of active and passive elevation in adduction, were first described by Jaensch in 1928 in an acquired case, and Jaensch already suggested a tight band between the trochlea and the sclera as the mechanism. Brown, in 1950, only added the congenital variety. Since we owe the first description of the inferior oblique pseudopalsy to Jaensch, his name should be included in the designation of the syndrome, i.e., it should be called "Jaensch-Brown syndrome" rather than "Brown's syndrome". The name suggested by Brown, "superior oblique tendon sheath syndrome", is no longer appropriate since the tissue surrounding the superior oblique tendon is normal.

Symptomatology, surgical therapy and postoperative results of sphenoorbital, intraorbital-intracanalicular and optic sheath meningiomas

A series of 7 patients with optic sheath meningiomas, 3 intracanalicular and intraorbital, 2 intraosseus meningiomas of the sphenoid wing involving the optic canal, and 4 sphenoorbital meningiomas were reported. The choice of a surgical approach to the orbit was appropriate to the location and size of the tumour relative to the optic nerve. The most common complaints were proptosis, reduction of visual acuity and paresis of eye muscles. Patients with optic sheath meningiomas are threatened postoperatively by visual loss whereas the high recurrence rate has to be taken into consideration in cases of sphenoorbital meningiomas.

[The effect of propofol on vomiting after strabismus surgery in children]

Strabismus surgery in children is associated with a high incidence of postoperative nausea and vomiting (PONV). METHODS. Ninety ASA class I and II children aged 6 to 16 years and scheduled for strabismus surgery were randomly assigned to one of the following groups: Group 1 (n=30):thiopentone 4-6 mg/kg i.v., halothane 0.8-1.5%, N2O--O2 2:1, no opioids, droperidol 75 micrograms/kg i.v.; Group 2 (n=30):propofol 2-3 mg/kg i.v., propofol 6-9 mg/kg.h, alfentanil 30 micrgrams/kg.h, N2O-O2 2:1, no antiemetics; Group 3 (n=30):similar to group 2, but ventilation with air and O2 2:1. All patients were mechanically ventilated during anaesthesia and gastric contents were aspirated. Recovery scores were calculated for 2 h, emetic scores for 24 h postoperatively.

[Indications and methods of surgical treatment in congenital nystagmus]

The authors present methods of operation performed in different types of congenital nystagmus in which the amplitude and frequency of nystagmus vary in different positions of gaze. In many cases, a "neutral zone" exists in which the nystagmus is less pronounced or may even be absent. If the "neutral zone" is in the primary position of gaze, then the head position may be normal. If the neutral zone is in another position of gaze, then the patient may assume compensatory head position (CHP) to achieve optimal visual acuity. Methods of surgical treatment in these case are presented. The indications are based on measurement of compensatory head position or on amplitude of convergence in nystagmus blockage syndrome. The elimination of CHP is possible by the Anderson procedure or, in more advanced cases, by the Kestenbaum procedure and/or the artificial divergence procedure of Cüppers. Sometimes Cüppers procedure alone or in combination with recession of the muscles is indicated. Our own material and results of surgical treatment are presented in the next paper.

Surgical dampening of nystagmus in patients with achromatopsia

Lack of cone function is one and nystagmus is the other cause of low vision in patients with rod monochromatism. The nystagmus has been assumed to be a consequence of the increased light sensitivity due to the predominance of rods. However, symptoms of patients with cone dystrophy are not very different from those observed in patients with congenital nystagmus. For example, they occasionally have a dampening of the nystagmus on fixation at near. Therefore, like in congenital nystagmus, we can elicit convergence innervation during fixation at distance with prisms base-out or with a surgically induced divergence ('artificial divergence'). This approach only works in patients with binocular function, necessary to keep the eyes aligned. The authors report on three patients with complete rod monochromatism in whom they performed an artificial divergence operation (OAD) by recessing the medial rectus muscle and resecting the lateral muscle of one eye. After surgery, the measured visual acuity was the same but the nystagmus of these patients had been considerably reduced. The patients themselves considered the effect of surgery a great improvement.

[Emesis and the oculocardiac reflex. Drug prophylaxis with droperidol and atropine in children undergoing strabismus surgery]

Although droperidol is often used to prevent emesis, vomiting is still common in children undergoing strabismus surgery. METHODS. One hundred children aged 3 to 12 years admitted for strabismus surgery were enrolled in a randomised, double-blind study to investigate the influence of the timing of the administration of droperidol (75 micrograms/kg i.v.) and the effect of atropine (10 micrograms/kg i.v.) on postoperative vomiting and the occurrence of the oculocardiac reflex (OCR). Each child was prospectively assigned to one of the following groups: Group A: atropine and droperidol before the beginning of surgery (n = 25); Group B: atropine before the beginning, droperidol after completion of surgery (n = 25); Group C: no atropine, droperidol before the beginning of surgery (n = 25); Group D: no atropine, droperidol after completion of surgery (n = 25). After oral premedication with 0.4 mg/kg midazolam, anaesthesia was induced via a face mask by inhalation of halothane, nitrous oxide, and oxygen and 1 mg/kg succinylcholine was given to facilitate tracheal intubation. Gastric contents were aspirated by a gastric tube at the end of the operation. Vomiting and retching were recorded for 24 h; recovery from anaesthesia was assessed by a modified Steward score. RESULTS. The four groups were comparable regarding age, sex, body weight, duration of anaesthesia, and number of repaired eye muscles. Patients receiving droperidol before and after the end of surgery had a similar incidence of vomiting (groups A and C 60% vs. groups B and D 50%). There was no significant difference in the number of patients vomiting between groups A and B (58%) and groups C and D (52%). The incidence of the OCR was lower in the patients premedicated with atropine (18% vs. 60%, P < 0.01). There was no statistical relationship between the occurrence of the OCR and post-operative emesis. Younger children (3 to 6 years) vomited more often than older ones (7 to 12 years). The incidence of the OCR was higher in patients with more than two eye muscles repaired than in others. Recovery scores were slightly lower in patients with droperidol after completion of surgery; postoperative recovery times did not differ significantly between the study groups. CONCLUSIONS. The timing of the administration of droperidol (75 micrograms/kg) had no influence on postoperative vomiting. The application of atropine (10 micrograms/kg) prior to surgery did not influence vomiting after strabismus surgery. Atropine (10 micrograms/kg) reduced the incidence of the OCR significantly. There was no statistical relationship between the occurrence of the OCR and postoperative vomiting.

Is there a cholinergic and an adrenergic phase of the oculocardiac reflex during strabismus surgery?

We investigated the counterregulatory effect of the oculocardiac reflex (OCR) in 25 infants and children during strabismus surgery under three experimental conditions. In group 1, a series of measurements were recorded when the OCR was elicited by traction. The beat-to-beat heart rate reduction ranged from -26 to -64 beats/min (median: -46 beats/min). Constant traction increased heart rate in all patients from +23 to +50 beats/min (median: +30.5; P < 0.001). After a sudden release of the stimulation, heart rate rose further from +6 to +40 beats/min (median: +15; P < 0.001). In group 2, atropine (0.01 mg/kg) was administered 3-4 min prior to the same manipulations as in group 1. Constant traction changed heart rate from -1 to +20 beats/min (median: +4.5; P < 0.01). In group 3, a retrobulbar blockade suppressed the OCR and the counterregulation completely. These findings indicate that there is an active counterregulatory process which maintains heart rate during traction at the extraocular muscles after the bradycardic reflex has been initiated. The bradycardia and the counterregulation may be referred to as cholinergic and adrenergic phrases of the OCR. Atropine eliminates the cholinergic phase. Our study indicates that there may be receptors and afferent fibres for both phases, which can be blocked by local anaesthetics.

[The 4-prism diopter base-in test in diagnosis of exophoria with asthenopia and compensation by accommodative convergence]

About 30% of our patients suffering from purely binocular asthenopia showed lower binocular than monocular visual acuity. Cover test examination revealed exophoria at near fixation, which could be regarded to be physiological. Furthermore, the Pola test as well as Graefe's prism diplopia test showed no pathological findings. When given 4 prism base-in, a better binocular acuity was achieved and exophoria at for distance fixation was revealed. Often the prisms base-in had to be increased slowly and an operative treatment was indicated in 80%. The test is described in detail and examples from typical case studies are demonstrated. The importance of the test for understanding asthenopia in cases with heterophoria is discussed.

Normal square wave jerks in differing age groups

This report details the characteristics of normal square wave jerks (SWJ) over a broad age range. Sixty normally sighted subjects, categorized into three age groups (35-49 yr, 50-64 yr, and 65-89 yr) underwent electrooculographic (EOG) examination to investigate the characteristics of normal SWJ. The frequency, duration, and amplitude of SWJ per minute were calculated in three clinically used test conditions: 1) with a fixation point in a lighted room; 2) with eyes closed and 3) in darkness without a fixation point. Results were compared over age and conditions as well as with the scores of 50 normal young subjects (20-37 yr). SWJ were recorded in all conditions, with the highest number found with closed eyes and in darkness for all age groups. Contrary to earlier findings, no statistical differences in frequency of SWJ per minute due to age were observed. These findings describe a range of normalcy for these three EOG conditions from which pathology can be inferred.

[Frontobasal osteoplastic orbitotomy in surgical treatment of intraorbital processes]

A modified frontobasal osteoplastic orbitotomy with reconstruction of the orbital roof for operative approach to intraorbital processes of any localization and of different origin (tumors, foreign bodies etc.) will be presented. After a small trapezium-shaped frontal craniotomy, the superior orbital rim and the orbital roof are resected in one piece by means of an oscillating saw. This "orbital flap" has a triangular shape, its long tip pointing to the canal of the optic nerve. There is no significant retraction of the frontal lobe by using microscope. The orbital flap is replaced and fixed by two miniplates of Luhr. This technique facilitates a significantly better exposure of all intraorbital structures than other surgical approaches, reduces operative trauma, and has better postoperative functional results. In the last 4 years we have operated upon 16 cases by means of this method, which will be presented. Although in many cases the frontal sinus was involved there was only one infection. Most common postoperative complication (50%) has been lesion of the levator palpebrae muscle followed by ptosis, which usually improved after 4-6 weeks.

A reexamination of end-point and rebound nystagmus in normals

In order to detail the characteristics of end-point (EPN) and rebound nystagmus (RN), two series of experiments were performed with infrared oculography for measurement of horizontal eye movements. Experiment 1 consisted of EPN recordings during sustained lateral gaze (40 degrees and 50 degrees) in 20 normal subjects. Experiment 2 consisted of recordings of RN in 5 normal subjects. Nine of 20 subjects demonstrated a jerk EPN. EPN almost always appeared immediately and was sustained for 15-25 sec. In Experiment 2, RN occurred in 5 of the 5 subjects who demonstrated EPN. The mean amplitude of RN was always less than that of EPN, and decayed over a 5-10-sec time period. The experiment demonstrated that RN can be evoked in normals even when a fixation target, in a fully lit room, is present.

Morphometric comparison between human and rat abducens and oculomotor nerves

A morphologic and morphometric comparison between normal human and rat extraocular muscle nerves was performed using a computer-assisted method to obtain scatter diagrams of relative sheath thickness (g ratio = quotient axon diameter/fiber diameter). Human and rat extraocular muscle nerves (nervus abducens and ramus medialis n. oculomotorii) were excised immediately before the nerve branching at the entering point into the muscle. There was no difference in the absolute number of myelinated fibers between the oculomotor and abducens nerves in both species. The distribution of myelinated fibers was classified according to their g ratios into a two-stage density cluster analysis. Two main populations of nerve fibers for human oculomotor and rat oculomotor and abducens nerves and three main populations for human abducens nerve were differentiated morphometrically and mathematically, differing in their relative sheath thicknesses. There are distinct differences between scatter diagrams of human and rat extraocular muscle nerves, in correlation with the basically different oculomotor functions of these two species. The morphometric differences between human and rat extraocular muscle nerves suggest a difference in the myelination process and the presence of functionally different nerve fibers, strongly indicated by the populations and subpopulations of myelinating nerve fibers peculiar to extraocular muscle. The existence of more than two different types of myelinated fibers in the human nerves implies that the traditional classification based on fiber caliber must be reviewed and a comparison of different classes of nerve and muscle fibers should be performed.

[Optic nerve damage following craniocerebral trauma. A critical analysis of trans-ethmoid decompression of the optic nerve]

Over a period of 10 years 39 patients who suffered an optic nerve compression after a craniocerebral trauma underwent transethmoidal decompression surgery. The operation was performed bilaterally on 5 patients. Fifty per cent of the patients involved suffered a blunt head or brain injury, the others a brain concussion or space-occupying haemorrhage. At the side of optic nerve compression we found specific signs and symptoms, such as negative or sluggish direct light reaction of the pupil, a wound on the lateral side of the eyebrow, bleeding from the nose, eyelid haematoma, maximum of skull fractures and intracranial haematomas. Since the coincidence of radiological and intraoperative findings was only 67%, the ophthalmological findings such as lack of direct pupil reaction with preserved consensual light reaction or progressive loss of vision after a corresponding traumatic incident are our guideline for performing transethmoidal decompression of the optic nerve. In comparison with the results of conservative therapy as published in the literature, we achieved restitution of the visual function in about 10% more of the cases.

How normal are "normal" square wave jerks?

Fifty normally sighted young subjects underwent horizontal electro-oculographic (EOG) examination to investigate fixation stability of the saccadic system. The number of square wave jerks (SWJ) and saccades per minute were calculated in three clinically used test conditions: (1) with a fixation point; (2) in darkness; and (3) with eyes closed. SWJ were recorded in all conditions. The highest number of SWJ per minute were found in darkness and with closed eyes. The analysis of the findings shows a range of normalcy for these three clinically used EOG conditions from which pathology can be inferred.

Distribution of axial combinations in astigmatism patients

A total of 527 astigmatic patients were examined for their axial distribution. The values taken for all eyes together confirmed the preponderance of "+" cylinder at an axis of 90 degrees. However, only a small percentage of patients demonstrated a 90 degree axis for each eye separately. Mirroring and parallel axes were more common and an asymmetric axial distribution was found most frequently. The influence of lid pressure on the development of astigmatism thus seems, according to our findings, unlikely. Genetic factors are more probable.

Fast-phase instabilities in normally sighted relatives of congenital nystagmus patients--autosomal dominant and x-chromosome recessive modes of inheritance

Verification of inheritance in congenital nystagmus (CN) is only possible through the identification of more than one affected member in a family since in a single case there are no accurate clinical differentiations between "spontaneous" and inherited CN. We performed electronystagmographic examinations (ENG) to search for abnormal involuntary eye movements as a sign of heredity in seemingly unaffected members of CN families. ENG registrations were performed under three test conditions: (1) with the subject fixating a target, (2) with the room lights off and (3) with closed eyes. Fifty normally sighted individuals (group (a] underwent the test procedure to provide a baseline of normality. Five CN families (three dominant, two sex-linked recessive) were tested as group (b). The eye movement recordings were analysed in terms of nystagmus intensity (amplitude x frequency of the involuntary saccade). In every one of the five families, abnormalities in seemingly non-affected members could be demonstrated: in four families, fast-phase instabilities, in the fifth family a true (CN) (slow-phase instability). All certain gene carriers were diagnosed correctly by the ENG. These findings indicate a method for detecting slightly affected members in dominant pedigrees and female gene carriers in sex-linked mode of transmission.

Transethmoidal decompression of the optic nerve in the case of craniocerebral trauma

Over a period of ten years, 39 patients who had suffered optic nerve compression after a craniocerebral trauma underwent transethmoidal decompression surgery. The operation was performed bilaterally on 5 patients. Fifty percent of patients involved suffered a blunt head or brain injury, the others brain compression or contusion. On the side of optic nerve compression, we found specific signs and symptoms of the compression such as negative or sluggish direct light reaction of the pupil, wounds on the lateral side of the eyebrow, bleeding from the nose, eyelid hematoma, skull fractures and intracranial hematomas. Since radiological and intraoperative findings were the same in only 67% of cases ophthalmological findings such as lack of direct pupil reaction occurring together with preserved consensual light reaction and progressive loss of vision after a traumatic incident are used as guideline for performing transethmoidal decompression of the optic nerve. Surgery produced restitution of visual function in about 10% more cases than conservative therapy reported in the literature.

[Analysis of motility disturbances due to a combination of different orbital lesions by means of the synoptometer (author's transl)]

There is no clear cut symptomatology of the ocular motility in blow-out fractures. It is essentially dependant on the number of muscles involved, what muscle in particular and where the muscle in incarcerated. Besides the blow-out fracture an additional impairment of motility can occur, for example central nerve palsy or Brown's syndrome of traumatic origin. For the exact analysis of the deviation measurement from 10 to 10 degrees is essential which can best be achieved with the synoptometer of Cüppers.

[Age-dependent changes in transverse sections of muscle fibres from the exterior eye muscles in man]

Muscle fibers of extraocular muscles (M. rectus internus, M. rectus externus and M. rectus inferior) from 27 patients ranging in age from birth to 83 years were measured planimetrically in cross sections between the origin-, insertion-, and middle-thirds of the muscle length. In all the muscles the middle third of the muscle possessed fibers with an average thickness greater than in the third of the muscle at either end (origin or insertion). This observation was, however, dependent on the age of the patients. This difference in muscle fiber thickness was most constant in patients in the age groups 20 to 30 and 40 to 50 years. On patients 60 years and older, the muscle fibers in all portions of the muscle were thicker; however, the M. rectus externus and especially the M. rectus internus also possessed a larger number of thinner fibers. The percent of thin fibers in the M. rectus internus was even greater than that found in one year-old patients. These observations are most likely explained by a decrease in the accomodation capacity in older patients and a correlative reduced convergence activity of the muscle fibers that are only active during convergence, resulting in decreased demand on the muscle fibers and their consequent atrophy.

Histological and ultrastructural studies on the ringbands in human extraocular muscles

Ringbands are a typical finding in the extraocular muscles of individuals of twenty years and older. The number of these structures increases distinctly after the 60th year of life. In optimally fixed muscles the ringbands are separated from the sarcolemma by a space containing the so-called sarcoplasmic masses. These masses were composed of vaculated mitochondria, dilated tubules of the sarcoplasmic system and, in some fibers, of fragments of myofibrils. Structures from which a neoformation of myofibrils as the origin of the ringbands could be concluded (as proposed by Jonecko, 1967), were never observed in this hypolemmal area. In contrast, the formation of the ringbands seems to be correlated to the ultrastructural alterations of the myofilaments and the looser arrangement of the myofibrils which can first be observed in extraocular muscles of 10-year-old patients and increasingly in older patients (Mühlendyck, 1977). These alterations lead to continous and repeated changes in the orientation of the myofibrils during the extension and contraction processes of the muscle fiber. Thus, the myofibrils undergo a constant mechanical stress which they cannot resist indefinetly, leading to disruption of some of the fibrils. The disrupted free end contracts, deviates almost at a right angle from its former course and, while the sarcolemma forms thread-like folds during the contraction of the muscle fiber, it is coiled around the longitudinal undisrupted fibrillar core. This leads to a disfunction of the muscle fiber and aids in explaining the steady decrease of the excursion of the eye after about 30 years of age.

[Blepharoachalasis (Fuchs) and the Laffer-Ascher syndrome]

The case report of a 20 year old woman illustrates the course of blepharochalasis. This disease was defined as an entity by E. Fuchs in 1896. It is characterized by relapsong edematous tumefaction and increasing relaxation of the eye lids with atrophy of the skin, blepharophimosis and emergence of a pseudoepicanthus. Folding of the oral mucosa in the upper lip, the so-called double lip, euthyroid struma, and, in later stages, orbital fat hernia and prolapse of the lacrimal gland, are further facultative symptoms. Partially, late stages of the disease had been described as Ascher- or Laffer-Ascher-Syndrome. This syndrome is no separate entity.

[The "synoptometer" as basis for surgical indication and postoperative follow-up study in cases with complicated extraocular muscle diseases (author's transl)]

Determinating the objective angle of squint with the usual diagnosis procedures false results are not uncommon. On the other hand muscle-function cannot be estimated in the extreme direction of gaze because of interference with the patient's nose and orbital margin. The newly developed "Synoptometer" (Oculus-Dutenhofen, W-Germany) provides the possibilities of determination the objective angle of squint in the extreme direction of gaze; false results can be prevented. This new instrument offers wide range of diagnostic possibilities for the evaluation of extraocular muscle paresis and for surgical indications; typical cases are demonstrated.

[The operative treatment of nystagmus-caused variable squint angles with Cüppers "Fadenoperation" (author's transl)]

THE "Fadenoperation" developed by Cüppers is described. With this, the arc of contact is changed with retension of the anatomical insertion. It is indicated when an innervational factor is to be influenced, especially by the treatment of an instable squint angle caused by nystagmus. A differentiation between a static and dynamic angle must be made. Only the static angle can be corrected by common recession and resection. The dynamic angle can be corrected by the "Fadenoperation" described by Cüppers. The difficulty in recognizing the nystagmus and determining the width of the static and dynamic angle is described in detail. Satisfying results were attained, following these criteria, shown by 19 (76%) of the operated convergent squinters with an instable angle.