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Cytidin-5'-diphosphocholine (CDP-choline) has been shown to improve visual acuity (VA), Contrast Sensitivity and Visual Evoked Responses at least temporarily, in amblyopic patients beyond the plastic period of the visual system. In this paper results are presented of a study conducted on forty-five patients with amblyopia in one eye, aged 5-9 years and followed for one year. Of them, 15 (Group A) were treated with CDP-choline (500 mg daily for 10 days every six months); 15 (Group B) were treated with CDP-choline plus one hour of occlusion daily; 15 (Group C) were treated with one hour of occlusion daily. The final VA values were statistically different from the initial ones, for all three groups. Eleven of the Group A patients showed an improvement in VA after the first treatment; a gradual deterioration took place in 6 patients at the end of the fourth month; VA further improved in 9 patients after the second treatment. At the end of the year, VA was higher than at the beginning in 12 of the 15 patients. Group B had an improvement of VA in 13 patients, starting 10 days from the beginning of treatment. This improvement continued throughout the observation period. Group C had an improvement after one month, which continued for 8 months, without deteriorating. In conclusion CDP-choline enhances the effect of part-time occlusion. CDP-choline could be employed also in younger patients. Longer observation periods are still needed and better means of administration have to be found.

Judgement of distances was evaluated in 19 patients with comitant esotropia and without appreciable stereopsis. In nine patients anomalous retinal correspondence (ARC) was present at Bagolini's striated glasses. In the remaining patients there was suppression with the same test. Distance judgement of strabismics with ARC does not differ statistically from that one of normals. Significantly different results were found in strabismics with suppression. It is concluded that ARC is not only an anti-diplopic mechanism, but provides the patients with useful clues in their daily life.

The retinal ganglion cell exhibits two types of functional change. The difference in response appears to depend on whether or not the retrobulbar portion of the optic nerve is actively involved. This may imply differences in the myelinated and non-myelinated portions of the optic nerve and associated structures. In open angle glaucoma, alterations in the sustained- and transient-like functions but not in the flashing repeat static test are found. That is, there are changes in spatial neural interactions, but there is no evidence of a visual fatigue or saturation-like effect. In optic nerve radiation damage without evidence of retinal vascular changes, in optic neuritis secondary to multiple sclerosis, chiasmal lesions, and ischemic optic neuropathy (considered here) varying degrees of visual fatigue or saturation-like effects are demonstrated with little or no change in the sustained- or transient-like functions.

A new provocative test for early diagnosis of Multiple Sclerosis (MS) is presented. It is based on the recording of pattern visual evoked responses (VER) before and after exposing patients to a high luminance background. All 13 patients tested showed a biphasic enlargement of the P100 wave after bleaching even in the absence of an increased P100 latency. This biphasic enlargement can be interpreted as a fatigue or a saturation-like phenomenon as can be seen psychophysically. The saturation-like effect involves probably only affected fibers. No change in the VER was observed in 20 Normal observers examined in the same way. This test can be usefully employed in dubious cases of MS where routine VER do not provide reliable results.

In a series of 562 patients who underwent surgery for retinal detachment, 17 (3.02%) had significant post-operative muscle imbalance. On the basis of the patients histories and clinical examinations, it is possible to classify the disturbances of ocular motility according to the symptoms (type, time of onset) and the pathogenesis (lesion of muscular sheats or bodies, capsulo-conjunctival cicatricial retractions, prolonged muscular compression, decompensation of pre-existing squints). If diplopia does not cease spontaneously, treatment consists of use of temporary prisms, but in some cases surgery is required.

Campos (1982a) reported on his psychophysical studies on the binocularity of patients with comitant strabismus. With binocular visual field techniques, it was possible to show that patients with small-angle eso- and exotropia exhibit a binocular vision, without suppression of the deviated eye. In the present paper visual electrophysiology is used objectively these findings and to provide more insight in the problem. First, the studies on binocularity in normals and strabismics, done by using visual evoked responses (VER) are reviewed. This type of investigation is relatively new and the results of the literature are still conflicting. Then personal results of the authors are reported. It is shown that with VER it is possible to objectively assess the presence of anomalous binocular vision (ABV) sustained by anomalous retinal correspondence (ARC) in small-angle strabismus. In patients with large angle deviations this type of binocularity is absent. A correlation between psychophysical and electrophysiological data is provided. Lastly a simple method is described for differentiating the binocularity of normals from that of Strabismics with ARC. This method is based on the recording of binocular VER with the anteposition in front of the fixing eye of neutral filters of increasing density.

A critical review is made of the literature on binocular perimetry in strabismus. A broad range of results was obtained by various authors, because different testing techniques were used. The concept of sensory testing of strabismic patients in casual seeing condition should be introduced also into binocular perimetry. Therefore a series of experiments is presented in which patients with small-angle comitant strabismus were tested. It was shown that: a) in small-angle esotropia the areas of single vision previously thought to be due to suppression are, instead, areas of binocular vision sustained by anomalous retinal correspondence (ARC); b) this can be seen only when using fusable stimuli as test targets; c) no suppression scotomas were found in patients with small-angle strabismus in the whole visual field; d) appropriate control-marks for binocularity are necessary, i.e. monocularly presented items. They influence the results, as well e) the area of binocular single vision in strabismus (called pseudo-Panum's area) is wider than the Panum's area of normals. Moreover it is easier to disrupt binocular cooperation sustained by ARC causing diplopia than binocular cooperation in normals; f) ARC seems to be more deeply rooted in the center than in the periphery of the visual field; g) superimposable findings were obtained in small-angle constant exotropia; h) in large-angle exotropia wide suppression scotomas were found, which often override the midline. Hemianopic suppression scotomas in exotropia can be found only when 'dissociating' testing techniques are used; i) the same group of patients with small-angle esotropia was examined with the author's technique and with the classical method proposed by Harms. The results were strongly dependent on the method used and the same patient responded differently to the two tests. It is concluded that in small-angle strabismus there is an anomalous type of binocular single vision, which can be tested with binocular visual field techniques. This binocularity can only be found when non-artificial testing conditions are used. The usefulness of this anomalous binocular vision in the every day seeing condition of the patient is discussed.

The visual evoked response transfer function of amblyopic subjects was studied. Strabismic amblyopes showed abnormalities only in the high spatial frequency range. Anisometropic amblyopes on the contrary, showed an abnormal function both in the low and high spatial frequency range. This is an objective correlate of functional differences between strabismic and anisometropic amblyopes.

Patients with optic neuritis describe image fading which is particularly evident at bright light levels. The effect is dependent on adaptation level, and high adaptation levels serve as a provocative test. Kinetic and static perimetry and interferometric acuity tests repeated in time reveal this loss in sensitivity. The latter test, using a large field and a high luminance level, is particularly sensitive to both the residua of pathology and very early phases of disease, often before subjective manifestations of anomalies are present. These effects are large in patients with demyelinating diseases. Here, we show that such changes may be revealed in optic neuritis due to other causes as well. Note, the same form of response may be detected in more central lesions, but usually in more circumscribed areas of field.

Vergence movements induced by base-out prisms were recorded, with an infrared eye movement recording system, in 5 patients with comitant esotropia and anomalous retinal correspondence and in 5 normal volunteers. The findings support the hypothesis that vergence movements in strabismus are induced by disparity, since accommodative as well as proximal vergence had been ruled out. Vergence movements are much slower and with different characteristics in strabismic patients with respect to normals. It may be argued that vergence movements represent the motor fusion component left over in strabismus. They may be considered the objective representation of the well-known phenomenon of prism compensation or adaptation, found in many strabismic patients.

In this paper results are presented of errors in spatial localization found after encircling procedures for retinal detachment both in the operated and in the normal eye. Also changes in spatial localization were found in strabismus patients in which a stretch on the operated muscle was exerted after an adjustable recession. In both groups of patients a manipulation of the eye muscle was performed without inducing an eye muscle imbalance in the retinal detachment patients and without modifying the eye position in the strabismus patients in which a stretch was exerted. These data provide further evidence in favour of the role of proprioceptive information in space perception.

A differentiation of two types of head-turns due to nystagmus, by means of electromyography (EMG) is demonstrated in this paper. The first type is represented by patients who actively block the nystagmus, by means of an increase of discharge of the extraocular muscles who are synergistic and responsible for the head-turn. This block has the same features of the block of nystagmus in convergence and usually exceeds 10-15 degrees from the primary position. The second type is made out of patients whose head-turn is explained with the null-position of Kestenbaum. Here the nystagmus simply disappears in the position of head-turn, which usually is of no more than 10-15 degrees. Both types of patients show the same electronystagmographic features in the position of head-turn. This differentiation is useful from the clinical standpoint. In fact, only the first type of head-turn may require, besides a classical Anderson or Kestenbaum procedure, also a posterior fixation suture according to Cüppers. This operation would be useless in the second type of head-turn. Clinical signs useful for differentiating these two types of head-turn are presented as well.

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.