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Biomedical subjects

E C Campos

Publications and source records attributed to E C Campos.

15 recordsLinked to original sources
PubMed1992

Epikeratophakia: histopathological and cultural study.

Three epikeratoplasty buttons (one aphakic and two myopic) prepared by the freeze technique were removed two to nineteen months after surgery. A complete morphological and immunohistochemical study was performed on these buttons in order to gain insight into the reasons for epikeratophakia failure. Histopathological studies with light microscopy and scanning and transmission electron microscopy were performed. All three cases showed an anomalous process of re-epithelialization: in the first, the epithelium over the donor cap was almost completely absent, with many abnormalities; in the second, the epithelium was irregular, with a varying number of cell layers and poor adhesion between cells; in the third, the development of an epithelial cyst between the tissue lens and the cornea of the host caused the failure of the epikeratoplasty. The specimens were cultured 'in vitro' and the cells grown typed for HLA antigens. The antigen panel was the same as that of the host. Immunohistochemistry showed CD3- and CD8-positive cells in the stroma, proving the activity of T-suppressor lymphocytes in a cell-mediated immunoreaction.

Adult↗
PubMed1992

Binocularity and photophobia in intermittent exotropia.

The relationship between photophobia and binocular function in intermittent exotropia was examined in 42 subjects (21 patients and 21 controls). In all subjects fusional amplitude and strength of binocular sensory status were tested before and during exposure to bright light. An explanation of photophobia in intermittent exotropia was suggested as impairment in binocular cooperation, since the indicators of binocular function were significantly altered in the patients, particularly during light exposure.

Adolescent↗
PubMed1979

Comparison of visual function studies in two cases of senile macular degeneration.

In this paper two relatively early cases of senile macular degeneration are compared by making use of a number of tests of visual function, some relatively new, coupled with observation of the fundus and analysis by fluorescein angiography. The functional tests include visual acuity, the sustainedlike and transientlike functions which are believed to test inner retinal receptive field properties and to have origin in the inner and outer plexiform layers, the Stiles-Crawford function which reflects the directional sensitivity and orientation of photoreceptors, and increment threshold curves. In one case there was evidence of inner retinal involvement at the time the tests were conducted, but, because the Stiles-Crawford function remained essentially normal, it is assumed that the receptors were not disturbed relative to their orientation. In this case (as in many others), the zone or area exhibiting functional change does not necessarily match the area exhibiting anatomical change as observed by examination of the fundus, fundus photography, and fluorescein angiography. In the second patient there is evidence of both anomalous inner retinal function and disturbance in receptor alignment. The later suggests disorientation of the receptor bed. These findings correlated with the fundus observation and fluorescein angiographic evidence of a leak, resulting in the presence of serous fluid beneath the neurosensory retina. With resolution of this fluid there was a return of the functional tests toward normal. At this time, it is not possible to determine whether, in two cases, the functional changes are proceeding on a parallel course, but are at different stages, or whether they are the expression of somewhat different anomalies.

Aged↗
PubMed1979

Visual resolution in a patient exhibiting a visual fatigue or saturation-like effect: probable multiple sclerosis.

A rapid visual resolution test conducted on available equipment reveals the presence of rapid falloff in acuity in a case of probable multiple sclerosis. Intense large field illumination was used, and grating acuity was tested using laser red light. The effect is so large that minor anomalies (not subjectively appreciated) or the residuum of earlier minor attacks of retrobulbar optic neuritis can be readily detected. A related "visual fatigue or saturation-like syndrome" was described earlier. In bright environments these patients' vision fades. Briefly closing the eyes restores visual sensitivity. Providing filters or lowering the light level tends to maintain vision. This test must be studied intensively. It offers a noninvasive simple means of showing underlying anomalies in neural conduction of the visual signal. Such anomalies can be prognostic and previously have been revealed only with sophisticated electrophysiological techniques.

Adult↗
PubMed1979

Measurement of visual resolution at high luminance levels in patients with possible demyelinating disease.

An interferometric acuity device (Takata) has been used to study visual resolution in individuals with possible demyelinating disease. The instrument employed provides a large field with a continuous range of grid or fringe frequencies and a relatively intense (10(5) mean photopic trolands) stimulus. After a brief period of time with eyes closed, resolution thresholds of patient are repeatedly determined during a five minute period. In all individuals suspected of having a demyelinating disease tested to date, a fall off in resolution capability has been found in time when using this intense stimulus display. This occurs whether eye signs have been present, are present or have not yet been observed. Normal observers do not exhibit comparable decrements. The fall off in resolution capability may or may not occur at lower stimulus levels, and is often not revealed when testing routine Snellen acuity. Outer and inner retinal pathology (division based on vascular support) do not cause a comparable fall off in resolution in time. The interferometric acuity test is a non-invasive, easily applied test.

Adult↗
PubMed1979

Some functional abnormalities in amblyopia.

In discussing the relationship between anomalous retinal correspondence and amblyopia, it is suggested that amblyopia may be due not only to suppression and/or non-use of the deviated eye, but also to a mis-use of this eye. The interaction of the 'focal' and 'ambient' systems in amblyopia and the relationship of the 'ambient' system to the interocular transfer of the motion after-effect are discussed. This effect has been found to be of no clinical significance in predicting the presence or absence of binocular cooperation. It is concluded that in cases of amblyopia there is either no disturbance in the 'ambient' system or an adaptation of the latter to the pathological condition.

Adolescent↗
PubMed1978

Retinal receptive field-like properties and Stiles-Crawford effect in a patient with a traumatic choroidal rupture.

Simple psychophysical techniques were used in order to assess layer-by-layer retinal functions in a patient with sub-retinal fluid due to a choroidal rupture following ocular trauma. A substained-like and a transient-like function believed to reflect retinal receptive-field-like properties, and an indicator of retinal receptor orientation (the Stiles-Crawford effect) have been followed in time. Central visual acuity was also measured. Initially all measured functions provided anomalous responses in affected retinal areas. Of interest here is the nature and order of recovery of the measured response functions. Most notable was the rapid rate of recovery of receptor orientation and the slower rate of recovery of the transient-like function.

Adolescent↗
PubMed1978

[Anomalous fusional movements: the sensorimotor aspect of anomalous binocular vision (author's transl)].

It has been demonstrated that, besides sensory adaptation phenomena, sensorimotor phenoma may also develop in concomitant esotropia. The existence of the latter entity can be shown particularly by means of prisms and is interpreted as fusional in origin. It is therefore defined as 'anomalous fusional movements'. The features of these anomalous fusional movements were studied in a group of 30 patients, mainly in order to investigate their finality. Correlations were evaluated between anomalous fusional movements and entities previously described by different names according to the interpretation given them by various authors.

Accommodation, Ocular↗
PubMed1978

Further evidence for the fusional nature of the compensation (or 'eating up') of prisms in concomitant strabismus.

The fusional nature of the phenomenon of prism compensation in strabismus was studied. At first a general survey was performed on the characteristics of anomalous fusional movements (a.f.m.). The influence of different kinds of stimuli (foveal and peripheral fusionable targets, non-fusionable targets) on a.f.m. was considered, and finally the effect of a sensorial obstacle to fusion was investiaged. It is concluded that 'eating up' the prisms is definitely a phenomenon of fusional nature, although it has special features which are interpreted as a consequence of the initial pathological condition. In this way the puzzling prism compensation also in subjects with normal retinal correspondence may be explained.

Child↗
PubMed1978

Critical flicker-fusion frequency as an indicator of human receptive field-like properties.

A psychophysical function, believed to reflect receptive field-like properties, is described. It is based on the determination of the critical flicker fusion frequency (CFF) of a tiny test target, centered on a round background of fixed luminance, the size of which is varied as the test parameter. Under optimal conditions, the maximal obtained frequency difference is 10 Hz. This function is compared with the so-called sustained-like function, with which it has some common aspects. Additionally, a portion of the flicker-based function apparently derives from a non-sustained-like source.

Flicker Fusion↗