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J T de Faber

Publications and source records attributed to J T de Faber.

13 recordsLinked to original sources
PubMed2000

Neuro-ophthalmologic manifestations of systemic disease and neurologic disease.

Neuro-ophthalmology is a difficult and challenging field for ophthalmologists, orthoptists, and neurologists. Unfortunately, signs and symptoms of these patients can be very subtle and easily overlooked. Although neuro-ophthalmologic cases are rare in the practice of a general ophthalmologist, missing the diagnosis can have severe impact on the patient's health. The authors review last year's publications of neuro-ophthalmologic manifestations of systemic and neurologic disease.

Brain Neoplasms↗
PubMed2000

Retinal nerve fiber layer thickness in human strabismic amblyopia.

BACKGROUND AND PURPOSE: Amblyopia is characterized by histopathological changes in the visual cortex and lateral geniculate nucleus. In the retina, however, no abnormalities have yet been reported. The purpose of this study was to compare the nerve fiber layer (NFL) thickness in the amblyopic eye with that in the sound eye of patients with strabismic amblyopia. As a practical implication, we investigated the validity of comparing Nerve Fiber Analyzer (NFA) measurements obtained in amblyopic eyes to the normative database built into the NFA. METHODS: NFL thickness was measured with a third generation NFA, the GDx (Laser Diagnostic Technologies, San Diego, CA). This is a scanning laser polarimeter, designed for monitoring glaucoma. The following NFL thickness parameters (all in microns) were compared: average thickness, superior maximum, inferior maximum, superior average, inferior average, nasal median and temporal median. Twenty patients with strabismic amblyopia were imaged with the NFA. Patients had no nystagmus, neurological disease or glaucoma. Nine patients had amblyopia in the right eye, and 11 patients in the left eye. RESULTS: In general, the sound eyes yielded higher thickness measures than the amblyopic eyes. These differences, however, were small, averaging only 1.5%, p = 0.6, and therefore not "statistically significant" at the p&le 0.05 level. CONCLUSIONS: Using the standard of "Statistical Significance = p< or =0.05", when amblyopic eyes are measured with the NFA, the built-in normative database may serve as the reference data

Adolescent↗
PubMed1999

Gaze-shift dynamics in subjects with and without symptoms of convergence insufficiency: influence of monocular preference and the effect of training.

We studied gaze-shift dynamics during several gaze-shift tasks and during reading, in five subjects with convergence insufficiency (C.I., a diminished ability to converge), and in ten subjects without C.I. Furthermore, we studied the effect of vergence training in order to verify previous claims that orthoptic exercises can improve vergence performance. We recorded binocular eye movements with the scleral coil technique. Subjects switched fixation between nearby and distant light emitting diodes (LEDs) arranged in isovergence arrays (distances 35 and 130 cm) in a dimly lit room. In both the C.I. and non-C.I. group, two classes of subjects occurred: vergence responders and saccadic responders. During pure vergence tasks, saccadic responders made saccades with no or little vergence; vergence responders made vergence movements with no or small saccadic components. In saccadic responders, fixation of nearby targets was monocular. Subjects with a preferred eye, according to our determination, used the preferred eye. The five C.I. subjects showed idiosyncratic responses with insufficient vergence during most trials. They all had a tendency to alternate fixation between the left and right eye. Vergence-version tasks always elicited larger vergence components than pure vergence tasks. During a reading task, vergence angles were more accurate than during gaze-shifts between LEDs. After the pre-training sessions, nine subjects (one of which had C.I.) practised a pure vergence task three times a day for at least 2 weeks. Vergence amplitudes of four of these subjects were larger after training. We conclude that vergence training can change oculomotor performance. Although C.I. is often associated with abnormal vergence dynamics, there are no typical C.I. vergence dynamics. Unstable monocular preferences may play a role in the aetiology of C.I.

Adult↗
PubMed1999

Comitant strabismus.

This year's review of the literature on comitant strabismus is presented. The main problems in treating strabismus disorders are accurately diagnosing the condition and designing effective treatment plans. A better understanding of the underlying motility disorder facilitates a better treatment outcome. Several of this year's papers address the better detection and identification of comitant strabismus. Some patients with comitant exotropia and esotropia, however, have superimposed incomitant motility patterns such as dissociated vertical deviation. New insights into the possible etiology of dissociated vertical deviation have emerged through use of the sophisticated scleral search coil technique, which permits the discovery of minute motility changes not visible to the clinician's eye. The same technique was used to clarify the traditional clinical experience that convergence insufficiency can improve with convergence exercises.

Eye Movements↗
PubMed1998

Neuro-ophthalmologic manifestations of systemic and neurologic disease.

Neuro-ophthalmology is a difficult and challenging field for both ophthalmologists and neurologists. Unfortunately, signs and symptoms of these patients can be very subtle and easily overlooked. Although neuro-ophthalmologic cases are rare in the practice of a general ophthalmologist, missing the diagnosis can have a severe impact on the patient's health. This paper reviews last year's publications on neuro-ophthalmologic manifestations of systemic and neurologic disease.

Diagnosis, Differential↗
PubMed1997

Neuro-ophthalmologic manifestations of systemic disease and neurologic disease.

Neuro-ophthalmology is a difficult and challenging field for both ophthalmologists and neurologists. Unfortunately, signs and symptoms of these patients can be very subtle and easily overlooked. Although neuro-ophthalmologic cases are rare in the practice of a general ophthalmologist, missing the diagnosis can have a severe impact on the patient's health. This paper reviews the past year's publications of neuro-ophthalmologic manifestations of systemic and neurologic disease.

Brain↗
PubMed1996

Amblyopia.

New knowledge of the pathophysiology of amblyopia has evolved through animal research over the past 30 years. We now know that development and treatment of amblyopia have a critical and sensitive period. After more than a millennium, patching of the dominant eye remains the cornerstone of amblyopia treatment, and compliance plays an important role in its effectiveness. Compliance can now be measured objectively with an occlusion monitoring device. The first successful attempts have been made to pharmacologically influence the plasticity of the human visual system.

Amblyopia↗
PubMed1995

Excess cyclovergence in patients with intermittent exotropia.

Recently, we developed a model of binocular fixation. This model predicts the amount of cyclovergence as a function of target elevation and horizontal target vergence. The prediction derives from the assumption that version and vergence add linearly and that the eye positions are constrained in three respects: (1) the foveae of the two eyes are directed towards the target, (2) the version component follows Listing's law, i.e. cycloversion, and horizontal and vertical version are not independent, (3) the vergence component is restricted to a plane approximately perpendicular to Listing's plane, i.e. horizontal, vertical and torsional vergence are not independent. The version and the vergence components are characterized by a common primary direction for the two eyes. We applied this model to data of patients with intermittent exotropia. In two patients with an amblyopic eye we found that the common primary direction rotates towards the amblyopic eye. In the third patient, not suffering from amblyopia, the common primary direction was practically straight ahead. In all three patients, cyclovergence angles were larger than those found in normal subjects. We found that the increased cyclovergence was compatible with our model for normal subjects if an offset on the horizontal vergence was given. This offset represents the additional convergence effort required in these patients to overcome the exodeviation of the eyes. According to our model the increased horizontal vergence effort results in excess cyclovergence. The relation between horizontal vergence and cyclovergence offers a new method for measuring the angle of exotropia.

Adult↗
PubMed1991

Medial rectus muscle marginal myotomies for persistent esotropia.

We reviewed the records of 18 patients with persistent esotropia after maximal recession of each medial rectus muscle on whom marginal myotomy of both medial recti muscles was subsequently performed. We compared the results in patients with essential infantile esotropia, acquired esotropia, nonaccommodative convergence excess, and nystagmus compensation syndrome. After a follow-up of three years, the mean improvement of esotropia at distance fixation was 9 prism diopters (range, -20 to +41 prism diopters) and was 21 prism diopters at near fixation (range, +4 to +50 prism diopters). The effect of marginal myotomy of previously maximally recessed medial recti muscles is unpredictable. However, we believe it to be an acceptable secondary surgical procedure in selected cases of persistent esotropia. The best results were obtained in essential infantile esotropia.

Adolescent↗
PubMed1989

The effects of reverse monocular deprivation in monkeys. II. Electrophysiological and anatomical studies.

Monkeys had one eye closed at about 30 days of age for 14, 30, 60, or 90 days, then opened, and the fellow eye closed for another 120 days. The animals then had at least 10 months of binocular visual experience before extensive behavioral training and testing were carried out. In terminal experiments concluded more than 18 months later, microelectrode investigations of the striate cortex demonstrated that there was almost a complete absence of binocular neurons in all animals. The initially deprived eyes (IDEs) dominated the majority of cortical neurons, even when soma size measurements of lateral geniculate neurons indicated that the LGN cells driven by the IDE had not regained their normal size. The monkeys which had significant interocular differences in spatial vision also exhibited abnormalities in the distribution of the metabolic enzyme, cytochrome oxidase (CO), within the striate cortex. These results demonstrate that many of the severe alterations in cortical physiology and eye dominance produced by early monocular form deprivation can be reversed, with recovery of normal cortical function, via the reverse-deprivation procedure.

Animals↗