Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Vision Disparity”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 649 records · Page 36Linked to original sources
PubMed2001

Adaptation of torsional eye alignment in relation to smooth pursuit and saccades.

The long-term fusion of vertical or horizontal disparities by vergence eye movements is known to evoke persistent changes in vertical and horizontal eye alignment. Adaptive changes in response to torsional disparities have not been well studied. Torsional eye position was measured binocularly with a video system before and after 90 min training periods in which subjects attempted to fuse cyclodisparities. Subjects trained with either a single cyclodisparity presented at a single vertical eye position or with cyclodisparities that varied smoothly from an incyclodisparity to an excyclodisparity as a function of either vertical or horizontal eye position. All five subjects showed persistent changes in binocular torsional eye alignment following both types of training. Incyclodisparities were more easily fused during training and the training aftereffect was greater in that direction. The training aftereffect was observed in relation to both saccades and smooth pursuit under both open-loop and closed-loop viewing conditions. During saccades, the dynamics of the cyclovergence training aftereffect more closely resembled the dynamics of cyclofusional movements than the dynamics of the saccades with which they were associated.

Adaptation, Physiological↗
PubMed2001

Are corresponding points fixed?

Several investigators have claimed that the retinal coordinates of corresponding points shift with vergence eye movements. Two kinds of shifts have been reported. First, global shifts that increase with retinal eccentricity; such shifts would cause a flattening of the horopter at all viewing distances and would facilitate fusion of flat surfaces. Second, local shifts that are centered on the fovea; such shifts would cause a dimple in the horopter near fixation and would facilitate fusion of points fixated at extreme viewing distances. Nearly all of the empirical evidence supporting shifts of corresponding points comes from horopter measurements and from comparisons of subjective and objective fixation disparity. In both cases, the experimenter must infer the retinal coordinates of corresponding points from external measurements. We describe four factors that could affect this inference: (1) changes in the projection from object to image points that accompany eye rotation and accommodation, (2) fixation errors during the experimental measurements, (3) non-uniform retinal stretching, and (4) changes in the perceived direction of a monocular point when presented adjacent to a binocular point. We conducted two experiments that eliminated or compensated for these potential errors. In the first experiment, observers aligned dichoptic test lines using an apparatus and procedure that eliminated all but the third error. In the second experiment, observers judged the alignment of dichoptic afterimages, and this technique eliminates all the errors. The results from both experiments show that the retinal coordinates of corresponding points do not change with vergence eye movements. We conclude that corresponding points are in fixed retinal positions for observers with normal retinal correspondence.

Accommodation, Ocular↗
PubMed2006

Flash lag in depth.

The perceived position of a moving target at a particular point in time, indicated by a flash, is often judged to be different from its actual location. Here, we show that the position of a target moving in depth is also systematically mislocalized. We used three types of targets moving in depth at a range of speeds from 2 to 16 cm/s. (i) A target realistically rendered that included concordant looming, disparity, and perspective cues. (ii) A random dot surface whose depth was defined by disparity, without concordant perspective or looming cues. (iii) A surface of dynamic random dots whose depth was defined by disparity with no consistent motion visible monocularly. Subjects viewed the targets moving either towards or away from them and indicated whether the targets appeared to be nearer or farther than a continuously present reference depth at the moment that a flash was presented. A staircase procedure was used to null, and thus measure, any perceptual displacement from the reference depth. A flash lag in depth was found in which the target appeared ahead of its true position, displaced by a constant amount of time depending on the stimulus type and the direction of motion (towards or away). The time displacement varied from 76 ms (for the realistic target moving away from the observer) to 263 ms (for static random dots moving towards). These effects may depend on the confidence with which subjects were able to judge the location of our various targets: greater confidence leading to a smaller temporal displacement.

Cues↗
PubMed2001

Monocular unmasking of noise-embedded patterns.

Binocular disparity cues may help an observer "unmask" a target in a background, thereby enhancing its detectability (e.g., Moraglia & Schneider, 1992). Here, we sought to determine whether similar effects could be produced by monocular displacement cues resulting from a two-frame sequential presentation of a Gabor pattern (a sinusoidal modulation of luminance combined with a Gaussian modulation of local contrast) embedded in an unvarying field of two-dimensional Gaussian noise. The Gabor in the second frame was spatially displaced relative to its location in the first frame; the horizontal displacement corresponded to a phase shift of the peak spatial frequency of the Gabor of 0 degree, 90 degrees, 180 degrees, 360 degrees, or 540 degrees. Monocular detection thresholds for the Gabor were appreciably lower for the 90 degrees, 180 degrees, and 540 degrees shift, than for the 0 degree and 360 degrees values. We explain these findings in terms of a model that constitutes the monocular analog of our summation model of binocular unmasking.

Adult↗
PubMed2005

Stereo-slant adaptation is high level and does not involve disparity coding.

We have investigated the potential stages of visual processing at which adaptation may occur to a slanted surface produced by horizontal magnification. Predictions of three hypotheses were tested utilizing a property of depth from binocular disparity, namely that slant scales with distance. If adaptation occurs at the disparity level, then the after-effect expressed in units of horizontal magnification will be independent of the test distance. If adaptation occurs at either a perceived slant or mapping level, then the after-effect, expressed in units of slant, will be independent of the test distance. If adaptation is contingent on distance, then the after-effect will not transfer over distance. Subjects adapted to a stereo-defined slanted surface at a distance of 57 cm. The after-effect was measured with a test stimulus at a distance of 28, 57, 85, or 114 cm by means of a nulling method. When the after-effect was expressed in units of slant, we found that it was larger at the adapting distance than other test distances, and that the after-effect was constant at test distances different from the adaptation distance. These results suggest that two types of adaptation occurred, namely adaptation on a mapping/perception level and adaptation contingent on distance.

Adaptation, Ocular↗
PubMed1991

Covering one eye in fixation-disparity measurement causes slight movement of fellow eye.

In the subjective measurement of fixation disparity (FD), the subject fuses contours presented in the peripheral macular areas of both eyes (fusion lock). The position of the eyes relative to each other is monitored by means of two haploscopically seen vertical lines presented in the central macular area, one above and one below a binocularly seen horizontal line. The subject is instructed to shift one of the vertical lines horizontally until the two are aligned, while fixating their intersection with the horizontal line. It has recently been questioned whether the foveolae really are pointed towards the perceived intersection. In this study, we monitored the position of one eye while intermittently covering the fellow eye, while the subject maintained fixation of the intersection of the remaining vertical line and the horizontal line. We found slight differences in position of the measured eye, depending on whether the other eye was covered or not, i.e. depending on the presence or absence of fusion in the macular periphery. These differences were more pronounced in the non-dominant eye.

Adult↗
PubMedDate not supplied

A simple model accounts for the response of disparity-tuned V1 neurons to anticorrelated images.

Disparity-tuned cells in primary visual cortex (VI) are thought to play a significant role in the processing of stereoscopic depth. The disparity-specific responses of these neurons have been previously described by an energy model based on local, feedforward interactions. This model fails to predict the response to binocularly anticorrelated stimuli, in which images presented to left and right eyes have opposite contrasts. The original energy model predicts that anticorrelation should invert the disparity tuning curve (phase difference pi), with no change in the amplitude of the response. Experimentally, the amplitude tends to be reduced with anticorrelated stimuli and a spread of phase differences is observed, although phase differences near pi are the most common. These experimental observations could potentially reflect a modulation of the V1 signals by feedback from higher visual areas (because anticorrelated stimuli create a weaker or nonexistent stereoscopic depth sensation). This hypothesis could explain the effects on amplitude, but the spread of phase differences is harder to understand. Here, we demonstrate that changes in both amplitude and phase can be explained by a straightforward modification of the energy model that involves only local processing. Input from each eye is passed through a monocular simple cell, incorporating a threshold, before being combined at a binocular simple cell that feeds into the energy computation. Since this local feedforward model can explain the responses of complex cells to both correlated and anticorrelated stimuli, there is no need to invoke any influence of global stereoscopic matching.

Animals↗
PubMed2002

Dynamics of attention in depth: evidence from multi-element tracking.

We examined the allocation of attention in depth using a multi-element tracking paradigm. Observers were required to track a predefined subset of from two to eight elements in displays containing up to sixteen identical moving elements. We first show that depth cues, such as binocular disparity and occlusion through T-junctions, improve performance in a multi-element tracking task in the case where element boundaries are allowed to intersect in the depiction of motion in a single frontoparallel plane. We also show that the allocation of attention across two perceptually distinguishable planar surfaces, either frontoparallel or receding at a slanting angle and defined by coplanar elements, is easier than allocation of attention within a single surface. The same result was not found when attention was required to be deployed across items of two-color populations rather than across items of a single color. Our results suggest that, when surface information does not suffice to distinguish between targets and distractors that are embedded in these surfaces, division of attention across two surfaces aids in tracking moving targets. A final experiment with populations of elements moving within distinct volumes produced similar results, suggesting that spatial separation in three dimensions, rather than confinement to surfaces as such, may explain the improved performance for the two-surface case.

Analysis of Variance↗
PubMed2002

[Do prisms according to Hans-Joachim Haase influence ocular prevalence?].

BACKGROUND: Ocular prevalence is defined as an unequal weighting of the eyes in the directional perception of stereo objects. Opinions differ as to the cause and relevance of ocular prevalence. Hans-Joachim Haase suggested that ocular prevalence is due to fixation disparity, brought about by incomplete compensation of heterophoria. He further suggested that prismatic spectacles determined by his "measuring and correcting methodology" (MKH) could restore bicentral fixation and thus establish a perceptual balance between both eyes. METHODS: We examined 10 non-strabismic subjects with a visual acuity of > or = 1.0 in both eyes. It turned out that all 10 had a "fixation disparity type II", characterised according to Haase by a "disparate retinal correspondence". All subjects underwent the automatic Freiburg Ocular Prevalence Test, without and with MKH prisms. In addition we examined ocular prevalence under forced vergence and compared ocular prevalence with stereoacuity. RESULTS: Spontaneous ocular prevalence ranged between 1 and 69 %. Averaged over all 10 subjects, ocular prevalence without and with the MKH prisms were not significantly different. Statistical evaluation of single subjects revealed only in one of the 10 a significant difference (Bonferroni-corrected p = 0.001). In the subgroup of 5 subjects who underwent forced vergence, ocular prevalence remained unaltered between 0 and 18 Delta base out. The stereoscopic threshold of all 10 subjects ranged between 1.5 and 14.5 arcsec. There was no correlation between ocular prevalence and stereoscopic threshold (r = - 0.2, p = 0.5). CONCLUSION: Our results indicate that ocular prevalence is largely independent of phoria correction and vergence stress. The excellent stereoacuity of all subjects suggests that ocular prevalence is abandoned for the sake of optimal resolution when very small differences in depth have to be judged.

Adult↗
PubMed1991

[Unusual perceptions with the Pola Test in a case of esotropia with anomalous correspondence].

That the Pola test figures of heterophoric subjects with fixation disparities are described as deformed at times, was published by H. J. Haase two decades ago. The main subject in this publication is a 13-year-old boy with early childhood convergent strabismus, in which the "squint therapy" which was used at that time, did not change the angle of squint and the anomalous correspondence to any extent. The corrected visual acuity was the same bilaterally, 1.0 to 1.1. If the esotropic eye position was corrected as well as possible with prisms to the objective angle, a change between diplopia and binocular fusion occurred; occasionally even to "normal corresponding" fusion with correct stereopsis. In the transition phases the test level appeared to be more or less drawn out in width, and the half figures underwent all kinds of "somersaults". Binocular macropsia and monocular micropsia and macropsia, and also polyopia and unusual depth effects were described. Confusion did not occur; all pictures had form. These rare phenomena were interpreted as a competition between established anomalous and latent normal correspondence. This communication should stimulate further observations of this type and, should the occasion arise, lead to experimental research.

Adolescent↗
PubMed2002

Crossed and uncrossed stereoacuity at distance and the effect from heterophoria.

BACKGROUND: Previous studies have found that crossed disparities give better stereoacuity than uncrossed. When near phoria is considered, exophores had a better crossed stereoacuity and esophores had a better uncrossed stereoacuity. The current study investigated the effect of heterophoria on distant crossed and uncrossed stereoacuity. METHODS: Seventy-two subjects were recruited and their distant heterophoria measured. Heterophoria within two prism dioptres was considered as orthophoric. Esophoric group had esophoria greater than two prism dioptres. Exophoric group had exophoria greater than two prism dioptres. There were 40 orthophores, 23 exophores and nine esophores. Their stereoacuity was measured with a three-rod apparatus at 6 m. RESULTS: The mean crossed stereoacuity was 4.8" and uncrossed stereoacuity was 7.2" (t = -3.03, p < 0.01). The mean stereoacuity for orthophoric subjects was 5.31", 6.02" for exophores and 8.91" for esophores. The distant crossed stereoacuity is better than uncrossed stereoacuity in all three groups but the difference is only significant for the exophores. Exophoric subjects demonstrated a significant difference between crossed (4.10") and uncrossed (7.95") stereoacuity. CONCLUSIONS: Orthophores have the best stereoacuity, followed by exophores and esophores. Exophoric subjects have a better crossed than uncrossed stereoacuity. More esophoric subjects should be recruited to confirm the difference between crossed and uncrossed stereoacuity.

Adolescent↗
PubMed2002

Adaptive modification of disparity vergence components: an independent component analysis study.

PURPOSE: Although a disparity vergence stimulus produces a smooth exponential-like response, considerable experimental evidence indicates that it is the product of at least two motor components: a pulselike transient component and a steplike sustained component. Recently, a new application of independent component analysis (ICA) has been used to decompose the vergence step response into these underlying components. Other recent experiments have shown that the vergence system is capable of rapidly modifying its dynamic characteristics (short-term adaptation) when exposed to specially designed "adapting" stimuli. Adapted responses were characterized by faster dynamics, often featuring large overshoots. In this study, ICA was used to examine changes in the underlying components produced by dynamic adaptation. METHODS: Disparity vergence eye movements in response to identical step stimuli were obtained from four subjects both in normal (baseline) conditions and after modification by adaptive training stimuli. ICA-based component decomposition was applied to vergence step-response data sets in both normal and adapted conditions to estimate, and compare activation patterns of the two underlying components. RESULTS: An eigenvector analysis indicated that both normal and adapted vergence responses contained two major components. ICA analysis showed that the enhanced dynamics seen in adapted responses was due to an increase in pulse component amplitude. In addition, the step component of adapted responses often showed double-step behavior in the later portion of the response. Finally, the magnitude of adaptation appeared to be related to the unadapted response dynamics. CONCLUSIONS: The adaptive process does not evoke additional components, but modifies the two components that are present under normal conditions. Double steps seen in the step component were attributed to an interaction between pulse and step neural mechanisms. The generation of an enhanced pulse component interfered with the production of the step component. Under this scenario, the reduced initial-step component was then compensated by the generation of a second-step component, probably mediated by an internal feedback mechanism.

Adaptation, Ocular↗
PubMed1989

Evaluation of a new criterion of binocularity.

The purpose of this study was to assess a new criterion for binocular comfort analogous to the classical Sheard's criterion. Instead of equating the fusional demand with the monocular phoria as is done when Sheard's criterion is applied, the new criterion uses a calculated binocular fusional demand. The binocular demand was derived using a clinical measurement of the convergence accommodation per convergence (CA/C) ratio. Sheard's criterion was also evaluated. Other commonly used indicators of binocularity (heterophoria, vergences, accommodative amplitude, facility and response, fixation disparity, and the associated phoria) were measured. One hundred subjects (52 males, 48 females; mean age 26 years) were classified as either symptomatic or asymptomatic by an interviewing clinician. The examining clinician was intentionally masked as to the classification of the subjects. We hypothesized that the new criterion would best discriminate between the two groups of patients inasmuch as it is based on currently accepted dual-interaction models of accommodation and vergence. Our analysis confirmed that the CA/C ratio corresponded closely to those published previously (mean = 0.06 D/delta). Significant differences (p less than 0.05) were determined between the symptomatic and asymptomatic groups for gender, near phoria through a +2.00 D add, accommodative amplitude, positive vergences at near, and both the classical Sheard's and the new criterion. The new criterion was the best discriminator between the groups, identifying 72% correctly, an improvement of 6% over the classical Sheard's. However, various stepwise discriminant analysis procedures consistently failed to demonstrate that the calculated binocular fusional demand or the new criterion was superior to the near phoria or the classical Sheard's value. These results suggest potential clinical utility for new procedures based on recently described models of accommodation and vergence, but further development appears necessary.

Accommodation, Ocular↗
PubMed1999

Vertical fusional vergence: the key to dissociated vertical deviation.

OBJECTIVES: To test the previous findings of Enright that disparity-induced vertical vergence is mediated primarily by the oblique muscles, and to relate this normal eye movement pattern to the eye movement pattern seen in subjects with dissociated vertical deviation. METHODS: Sixteen normal volunteers underwent 55 measurements of the cycloversion associated with prism-induced vertical vergence using an afterimage apparatus. A Vernier scale measured the direction and magnitude of the torsional shift that occurred with recovery of fusion on removal of a 3- or 4-prism diopter prism. RESULTS: Of the 55 trials, the directions of torsional shift were consistent with the oblique muscles being the primary mediators of vertical fusional vergence in 51 (93%) (P = .03 using a binomial distribution). The mean +/- SD value of torsional shift was 1.15 degrees+/-0.76 degrees in the expected direction. CONCLUSIONS: Vertical fusional vergences in this study were produced primarily by the oblique extraocular muscles. The eye movement patterns of these vertical vergences in normal subjects are qualitatively similar to those seen in recordings of patients with dissociated vertical deviation. Dissociated vertical deviation thus seems to be an exaggeration of a normally occurring eye movement pattern. The cyclovertical component of dissociated vertical deviation may help stabilize the fixing eye by damping vertical nystagmus, while the accompanying hypertropia is an incidental and undesirable side effect.

Adolescent↗
PubMed2006

[Associated heterophoria and the asymmetry of ocular prevalence for stereo images in front of or behind a reference plane].

BACKGROUND: An unequal weighting of the eyes in the directional perception of stereodisparate objects, is referred to as ocular prevalence of the right or left eye, respectively. Between 1962 and 1964 H.-J. Haase developed a valence test for the prismatic correction of heterophoria. He suggested that there would be less prevalence for stereo images presented in front of or behind a reference plane, and that this asymmetry of prevalence may be related to the direction of the associated heterophoria (eso- or exophoria). According to H.-J. Haase, the asymmetry may indicate a fixation disparity with a corresponding shift in retinal correspondence. Hence, the valence test could be an indicator for the prismatic correction of heterophoria. METHODS: Prevalence was tested in 37 subjects, using three methods: The subjects were asked to describe their perception (1), to make a paper drawing of their perception (2), and to align the position of the stereo images to the central fusion target with a computer-controlled device (3). METHODS 2 and 3 were used to reduce a possible suggestive influence on part of the investigator. The associated heterophoria was determined with the cross test by H.-J. Haase. RESULTS: Depending on whether the triangular stereo images were presented behind or in front of the reference plane, more or less prevalence was measured (mean values) in the group with exophoria than in the group with esophoria. These results were confirmed with all three methods. The asymmetry of prevalence was correlated with the direction of the associated heterophoria with r = 0.5. CONCLUSION: Statistically, these results confirm Haase's hypothesis of a relation between the asymmetry of ocular prevalence and the direction (eso- or exophoria) of the associated heterophoria. Since this relation holds true only for the group mean value, but not for each individual, the valence test cannot be generally recommended as an adjunct for the prismatic correction of heterophoria.

Adult↗
PubMed1996

Cyclopean discrimination thresholds for the direction and speed of motion in depth.

We measured just-noticeable differences in the direction and speed of motion in depth of cyclopean and monocularly visible targets. Our stimulus set comprised different combinations of (d phi/dt)/(d delta/ dt), d delta/dt, d phi/dt and delta delta, where d phi/dt was the angular frontal plane speed of the binocularly-fused target, d delta/dt was its rate of change of disparity and delta delta was its disparity displacement. Our three subjects based their direction discriminations entirely on the task-relevant variable (d phi/dt)/(d delta/dt), and based their speed discriminations entirely on the task-relevant variable d delta/dt. They ignored all task-irrelevant variables in both tasks. Performance on both tasks was the same for motion within the horizontal and vertical meridians. Direction discrimination threshold rose significantly as the reference direction grew more oblique with respect to a line passing midway between the eyes and perpendicular to the frontal plane. Performance on the direction discrimination task was significantly better for the noncyclopean than for the cyclopean target, but the difference was not great. For the cyclopean target, the lowest value of the direction discrimination threshold was 0.70 deg (mean of three observers and two meridians). The Weber fraction for discriminating speed was not significantly different for the cyclopean and monocularly visible targets, and did not depend on the direction of motion in depth. The lowest values (mean of three observers and two meridians) were 0.12 (cyclopean) and 0.10 (noncyclopean). Findings did not scale for viewing distance. We propose that the human visual pathway contains: (a) a cyclopean mechanism sensitive to variations in the ratio (d phi/dt)/(d delta/dt) that is comparatively insensitive to both d phi/dt and d delta/dt; and (b) a speed-sensitive cyclopean mechanism that responds to variations in the value of d delta/dt, but is comparatively insensitive to d phi/dt. We also propose that a single speed-sensitive mechanism determines speed discrimination thresholds for both cyclopean and monocularly visible targets.

Adult↗
PubMed2006

Aging does not affect the accuracy of vertical saccades nor the quality of their binocular coordination: a study of a special elderly group.

Fine binocular coordination of vertical saccades is a complex process requiring appropriate distribution of innervations to all six extraocular muscles. Loss of such coordination causes vertical binocular disparities that are particularly bothersome. We studied the quality of binocular control of vertical saccades in healthy subjects, 11 young adults (20-28 years) and 11 elderly adults (63-75 years). We used LED targets at 7.5 degrees or 15 degrees from the center (fixation), up or down in four conditions: gap and overlap tasks, each done at two distances--near (40 cm) and far (150 cm). Vertical eye movements were recorded with video-oculography (CHRONOS). The results showed: aged subjects performed vertical saccades as accurately as young subjects. Importantly, the binocular coordination of vertical saccades was well preserved in the elderly; the mean difference of vertical saccades between the two eyes was 0.10 degrees and 0.09 degrees in young and elderly subjects, respectively. Upward saccades were associated with divergence, downward ones with convergence. This secondary phenomenon was also the same and of the similar amplitude for young (1.30 degrees ) and elderly (1.25 degrees) subjects. Thus, despite its complexity, the quality of binocular coordination of vertical saccades remains intact with age. The other observations are mostly dependent of several aspects on the direction (up/down), viewing distances and eccentricities; the horizontal vergence during or after vertical saccades was found to be larger for downward saccades than for upward saccades, for saccades at far distance than at close, and for the more eccentric targets (15 degrees versus 7.5 degrees). All these phenomena are the same for both young and elderly subjects. We conclude that the accuracy and the binocular coordination of vertical saccades, at least for target steps less than 15 degrees , are preserved in elderly subjects <75 years who maintain good physical and intellectual form. The data are consistent with the idea of the existence of non-aging system function in the human CNS.

Adult↗
PubMed1999

Binocular depth-from-motion in infantile and late-onset esotropia patients with poor stereopsis.

PURPOSE: There are at least two possible ways to detect motion-in-depth binocular without monocular cues: the binocular disparities at different times and a mechanism that detects interocular velocity differences. The perception of interocular velocity differences (Binocular depth-from-motion [BDFM]) depends on the relative velocity of the images on the retina of the left and right eyes, and this information can be experienced by normal and some strabismic patients. The purpose of this study was to determine the characteristics of esotropic patients who have BDFM but have poor stereopsis. METHODS: Forty-one infantile and 28 late-onset esotropia patients with poor stereopsis were studied. Dynamic stereopsis and BDFM were tested with computer-generated random dot stereograms and kinematograms. The correlations between BDFM and other binocular functional tests were determined. RESULTS: A total of 31 (44.9%) patients, 15 (36.5%) of the infantile and 16 (57.1%) of the late-onset esotropia group, passed the BDFM test. None of these patients passed the random dot stereo test under static or dynamic conditions. Fusion of the Worth four dot test at near 0.3 m was correlated with the presence of BDFM. Three of the 15 infantile and 10 of the 16 late-onset esotropic patients with positive BDFM showed gross stereopsis as measured by the Titmus Fly. The angle of strabismus was significantly smaller in the patients with positive BDFM for the infantile and the late-onset esotropia groups. CONCLUSIONS: BDFM was present in about half of the esotropic patients who do not have fine stereopsis. Ocular alignment within 10 to 15 prism diopters is an important factor in obtaining BDFM. Strabismus surgery still provides some binocular benefit for infantile esotropia patients who were bypassed for early surgery. Separate mechanisms may underlie static stereopsis and BDFM.

Adolescent↗