Retinal Correspondence Research Articles

Qualitative and quantitative evaluation of binocular function in accommodative esotropia using pattern reversal visual evoked responses (VER)

Pattern reversal visual evoked responses (PVER) were recorded in 31 children, in order to evaluate binocular functions in an objective manner. Ten cases had normal binocular functions, 21 cases had various degrees of accommodative esotropia and binocular impairment. Monocular and binocular recordings were performed for all the cases. PVER amplitudes of normal and accommodative esotropic children were compared using the dioptic method. Binocular summation was seen in accommodative esotropic children although less than that of the normal group. Thus, the authors thought it possible to assess objectively the presence of anomalous binocular vision sustained by anomalous retinal correspondence in accommodative esotropia by using PVER.

Squint-induced Modification of Visual Receptive Fields in the Lateral Suprasylvian Cortex of the Cat: Binocular Interaction, Vertical Effect and Anomalous Correspondence.

In this study, we investigated the receptive field properties of single cells in the lateral suprasylvian area of strabismic cats. More than three times as many cells could be driven by the non-operated than by the operated eye. Many more cells could be activated by the contralateral than by the ipsilateral eye. In both area 17 and the lateral suprasylvian area, more cells preferred horizontal rather than vertical or oblique orientations ('vertical effect'). In addition, a small percentage of cells in the lateral suprasylvian area showed an adaptive shift of spatial coordinates; this shift could provide the neural basis of anomalous retinal correspondence.

網膜対応： その理論と実際 網膜対応異常症例の経過について

網膜対応： その理論と実際 網膜対応異常症例の経過について

網膜対応： その理論と実際 網膜対応： その理論と実際 イントロダクション

網膜対応： その理論と実際 網膜対応： その理論と実際 イントロダクション

The history of stereoscopy

Ptolemy (127-148 AD) studied physiological diplopia, correspondence and the horopter. He had all the data to build a theory of depth perception through disparity detection, but left that undone. Alhazen (1000 AD) associated depth perception with the sensation of binocular convergence, just as Kepler (1611) and Descartes (1637). With the development of the concept of retinal correspondence and the fusion of the retinal images in the brain (Huygens 1667, Newton 1704) a cerebral mechanism of disparity detection became thinkable. The rise of Empiricism (Molyneux' Premise, the case of Cheselden) postponed the solution of the problem, finally reached by Wheatstone (1838). Physiological proof of Wheatstone's theory came from the experiments of Barlow et al. (1967).

Mechanism of anomalous retinal correspondence: Maintenance of binocularity with alteration of receptive-field position in the lateral suprasylvian (LS) visual area of strabismic cats

We have examined the effects of rearing kittens with a unilateral convergent strabismus, induced surgically at 3 weeks of age, on the binocularity (ocular dominance) and receptive-field position of neurons in the motion-sensitive lateral suprasylvian (LS) area of cat extrastriate cortex. Data were compared to those obtained from area 17 in the same animals, and from the two areas of cortex in normal adult cats. Interocular alignment of the operated cats was assessed in alert adults using corneal reflex photography and during recording from the positions of retinal landmarks under paralysis. The strabismus magnitude in each operated cat was calculated by comparison with equivalent data from the normal animals. Strabismus always caused a major loss of binocularity in area 17. The remaining binocular neurons had receptive-field (RF) pairs arising from positions of normal correspondence in the two retinae and would thus have been responsive to different regions of visual space through the misaligned eyes in the alert animal. In area LS, the effects were dependent on the strabismus magnitude. In the group of four cats with pronounced strabismus (18-30 deg crossed), a loss of binocularity occurred in area LS equivalent in severity to that in area 17. The majority of the remaining binocular LS neurons possessed RF pairs in normal retinal correspondence and would thus, in the alert animal, have received spatially disparate visual input through the two eyes. This also occurred in three other cats with more moderate strabismus (11-15 deg crossed), although only a small breakdown in the binocularity of area LS was apparent. The group of cats with mild strabismus (less than or equal to 10 deg crossed) had normal proportions of binocular neurons in area LS. In three of these cats, the maintenance of binocularity was accompanied by shifts in RF position, with visual inputs arising from anomalous retinal locations. These shifts compensated, in part, for the strabismus angle present in each cat, so that most of the binocular LS neurons would have received inputs from regions of visual correspondence through the misaligned eyes when the animal was alert. Similar mechanisms could afford a basis for the binocular visual compensations that occur in humans with small-angle strabismus of early onset. If so, anomalous retinal correspondence in such individuals would have as a locus areas of extrastriate cortex with a role in motion perception, and would involve alterations to the neural substrate underlying normal binocular vision.

Prism Adaptation Test (PAT) in the Surgical Management of Acquired Esotropia

To the Editor. —I read with great interest the article published by the Prism Adaptation Study Research Group1in the September 1990 issue of theArchives. Patients with fusion and normal retinal correspondence (NRC) were eliminated from the study because they had little or no potential to benefit from prism adaptation. It has been my experience as well as that of other authors2-4that esotropic patients with NRC fusion, even bifoveal fusion (40 seconds of arc stereoacuity), can manifest a substantial angle buildup with prisms. Most, if not all, of these patients do benefit when undergoing surgery for the built-up angle.4If this group of patients had been included, a larger percentage of esotropic patients would have been found to benefit from presurgical prism adaptation test (PAT). If patients with fusion and NRC were eliminated from the study at the start, and the responders were patients who

Changes in Retinal Correspondence after Changes in Ocular Alignment

We studied the changes in retinal correspondence for 32 constant strabismic patients whose ocular alignment was altered either surgically or spontaneously over a period of time. Patients having normal retinal correspondence (N = 10) generally maintained normal correspondence after the change in ocular alignment. Patients with anomalous retinal correspondence (N = 20) behaved differently. Thirteen of these patients maintained anomalous correspondence and seven patients developed normal correspondence after the change in ocular alignment. For the patients who developed normal correspondence, the direction of the strabismus also changed. We conclude that normalization of retinal correspondence is more likely to occur in strabismic deviations that are overcorrected.

Stability of Retinal Correspondence in Normal Binocular Vision

Although many studies have suggested absolute stability of retinal correspondence, perhaps more have concluded that the correspondence of adult subjects with normal binocular vision is capable of small variation, particularly with strong sustained demands upon vergence, in order for binocular vision to be maintained. In this comprehensive review of the literature, the reasons for these differences are critically discussed and areas still to be resolved are pointed out.

Two-dimensional spatial distortions in human strabismic amblyopia

Two-dimensional space perception was measured in the central visual field of amblyopic subjects under special consideration of spatial distortions and spatial uncertainty. The subjects had to construct circles with different radii around a given fixation point. Subjects with deep strabismic amblyopia were showed to exhibit considerable distortion in the amblyopic eye. Each subject exhibited an individual distortion pattern. The dominant eye showed distortions similar to those seen in normal observers. Subjects with mild strabismic amblyopia, strabismic alternators and anisometropic amblyopes did not exhibit any significant spatial distortions. Data from dichoptic localization experiments indicate that anomalous retinal correspondence might contribute to monocular spatial distortions.

Stereopsis and ARC

Abnormal retinal correspondence (ARC) is an adaptive mechanism which occurs in the presence of a manifest deviation. Gross stereopsis is thought to be one of the advantages of ARC. However, this fa...

Vergence Movements in Comitant Strabismus

Vergence movements induced by base-out prisms were recorded, with an infrared eye tracker, for 6 patients with comitant esotropia (i.e., convergent strabismus) and anomalous retinal correspondence and for 6 normal subjects. Vergence movements of strabismic subjects were much slower and showed characteristics different from those of controls. It may be argued that vergence movements are induced by disparity and represent the motor fusion component left over in strabismus. In fact, in this study accommodative as well as proximal vergence had been ruled out. Therefore, the movements recorded can be considered the objective representation of the well-known phenomenon of prism compensation or adaptation, found in many strabismic patients.

Stability of Retinal Correspondence During Divergence: Evaluation with Afterimages and Haidinger Brushes

Retinal correspondence has been described as invariant during normal binocular vision. However, there is substantial evidence that casts doubt on this interpretation and implies that retinal correspondence varies under certain conditions. This article reports the results of two experiments that appraise the stability of correspondence during fusional vergence in persons with normal binocular vision. In the first experiment, afterimages stimulated vertically corresponding retinal meridians prior to divergence. Three of six subjects gave data that indicated a change in the afterimage alignment significantly different from chance. The second experiment determined corresponding retinal areas with Haidinger's brushes. When divergence was maximally maintained, all six subjects who could appreciate the low-contrast Haidinger's brushes on the randomdot background saw two brushes while stereopsis and fusion remained present. Increases in plus lens power increased estimated brush separation.

Changing patterns of binocular visual connections in the intertectal system during development of the frog, Xenopus laevis. I. Normal maturational changes in response to changing binocular geometry.

During metamorphic and post-metamorphic life in the frog. Xenopus laevis, growth-related changes in skull shape produce radical alterations in the spatial relationship between the two eyes. These changes in binocular visual geometry were measured using optical techniques. Between the onset of metamorphic climax at stage 60 and adulthood (2 or more years post-metamorphosis) each eye migrates nasally by 55 degrees and dorsally by 50 degrees with respect to the major body axes of the animal. As a result the nasotemporal extent of the binocular visual field increases from 30 degrees to 162 degrees between these ages. Electrophysiological methods were used to determine changes in the neural representation of the binocular visual field at the paired midbrain optic tecta and in the tectal projection of pairs of corresponding retinal loci at various developmental points between these ages. The proportion of each tectal surface devoted to the representation of the binocular visual field increases from 11% at stage 60 to 77% at adulthood. Retinal correspondence, and hence the tectal projection of corresponding retinal loci, undergoes radical alteration during this period. In normal adults an intertectal system of connections selectively links the tectal projection of corresponding retinal loci and thus provides a neuronal mechanism for integrating binocular visual information in the optic tecta. Electrophysiological methods were used to determine how the intertectal system accommodates the developmental challenge posed by the enlarging binocular visual field and changing retinal correspondence. Between stage 60 and adulthood the ipsilateral visuotectal projection which is the product of the intertectal system, increases in size as the binocular visual field and its tectal representation enlarges. Moreover, throughout this period, it provides a mechanism for integrating binocular visual information in the optic tecta by maintaining its spatial registration with the contralateral visuotectal projection from the other eye. Analysis of the pattern of functional intertectal connections reveals that during the course of normal maturation this system undergoes continuous processes of expansion and of orderly and major remodelling.

Recording of disparity vergence in comitant esotropia.

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.

Acquired Concomitant Esotropia in Pseudotumor Cerebri

Acquired esotropia due to increased intracranial pressure is classically associated with unilateral or bilateral 6th nerve palsy and/or divergence paralysis. We have recently treated a 17 year old black girl with pseudotumor cerebri (benign intracranial hypertension) presenting with headaches, horizontal diplopia, and papilledema. Motility evaluation revealed a concomitant, moderate angle esotropia greater at near, with normal retinal correspondence and good fusional amplitudes. Horizontal saccadic velocities were normal in both eyes, arguing against the presence of 6th cranial nerve palsy. The strabismus resolved following normalization of her intracranial pressure. Acute-onset esotropia may be the presenting sign of increased intracranial pressure in the absence of clinically evident 6th nerve palsy or divergence paralysis.

網膜対応異常の深さの概念について 対応異常のｃｒｉｔｉｃａｌ ｐｅｒｉｏｄについて

網膜対応異常の深さの概念について 対応異常のｃｒｉｔｉｃａｌ ｐｅｒｉｏｄについて

Vertical Abnormal Retinal Correspondence in Three Patients With Congenital Absence of the Superior Oblique Muscle

Three patients with large vertical deviations diagnosed as palsy of the superior oblique muscle were found to have a congenital absence of the muscle during surgery. They also showed large, vertical abnormal retinal correspondence, which caused paradoxical vertical diplopia when the deviations were corrected with Fresnel membrane prisms or surgery. Each patient showed large, long-standing, vertical deviations for which head tilting could not have compensated.

Monocular eye closure in intermittent exotropia.

Monocular eye closure in bright illumination is a common occurrence in intermittent exotropia. In a series of patients with intermittent exotropia with normal retinal correspondence and stereopsis while the eyes were in the straight position, monocular eye closure occurred in 90% of patients with normal retinal correspondence while exotropic and in only 35% of patients with abnormal retinal correspondence while exotropic. Monocular eye closure occurs in people with intermittent exotropia to avoid diplopia and visual confusion even though these are not usual complaints. The cortical adaptation of anomalous retinal correspondence prevents diplopia and visual confusion and obviates the need to close one eye in bright sunlight.

Evaluation of Orthoptic Training

We studied the effects of orthoptic training on binocular vision and aligment after surgery retrospectively in 8 patients of acquired partially accommodative esotropia. Normal retinal correspondence (NRC) was found in 2 cases and anomalous retinal correspondence (ARC) in 6 cases.A kinetic bi-retinal stimulation and chasing training for NRC cases, and a keinetic bi-retinal stimulation and proprioceptive re-orientation training was performed on ARC cases. These trainings were continued for 15 days on an average.Binocular vision improved in 5 cases of ARC and in all cases of NRC. Among those who underwent surgery before orthoptic training, there were some cases whose eye position did not improve to the parallel alignment. However, intended surgical correction was obtained in one patient who underwent surgery during the course of orthoptic training.The present results seem to demonstrate that orthoptic training is effective for the improvement of binocular vision in NRC patients. They also seem to suggest that presurgical orthoptic training for ARC cases may improve the surgical results.