Joseph Bauer

Characteristics of moving visual scenes influencing spatial orientation

Abstract A visual display rotating in a frontal plane induces effects equivalent to a change in the apparent direction of gravity. Magnitude of visual tilt was measured as a function of time from onset of rotation, velocity of rotation, and area and retinal location of the stimulating field. The major part of the tilt occurs within 30 sec from onset of stimulation. It increases with angular velocity, but independently of area and location of field, up to about 30 to 40° of rotation per sec and then levels off. Tilt increases with field size but the effect of thin ring-fields increases with retinal eccentricity. The interaction of visual and non-visual determinants of the induced effects is discussed.

A Dynamic Relationship between Myopia and Blur-driven Accommodation in School-aged Children

Previously we reported that recently myopic children accommodated insufficiently to blur induced by negative lenses. The purpose of the present study was to relate changes in blur-driven accommodation to myopia development in children. Refractive errors and the accommodation response function (ARF) were measured in 23 myopic and 40 emmetropic children on two occasions separated by periods ranging from 6 to 12 months. Repeated measures of accommodation were made with a Canon R-1 autorefractor while negative lenses of increasing power were placed in front of the childs right eye viewing 20/100 letters at 4 m. Concomitant changes in refractive error and in accommodative function over periods of 6-12 months were found to be highly correlated in myopes (r = 0.77) but not in emmetropes (r = 0.09).

Visually Guided Reaching in Infant Monkeys after Restricted Rearing

Infant macaques were reared from birth in an apparatus which pre cluded sight of their body parts. At 35 days postpartum one hand was exposed to view. Visual fixation of this hand was insistent and prolonged; visually guided reaching was poor, but it improved during ten succeeding hours of exposure. Little concomitant improvement occurred in the reaching of the unexposed hand.

Visual acuity and its meridional variations in children aged 7–60 months

A new operant procedure was used to assess grating acuity in children aged 7-60 months. The procedure was successful for 95% of the children sampled and had high test-retest reliability. Visual acuity for main axis (horizontal and vertical) gratings improved from 6/15 at 12 months to 6/6 at 60 months. For the 7-16 month age group, preferential-looking estimates of acuity agreed well with operant estimates. Acuity for oblique gratings was approximately 1/4 octave lower than main axis acuity throughout the age range. The results suggest that the human visual system continues to develop throughout the first 5 years of life.

Pre-stereoptic binocular vision in infants

In a preferential looking experiment, identical patterns (vertical stripes) were presented to both eyes on one of two screens while orthogonal patterns (vertical stripes in one eye and horizontal stripes in the other) were presented on the other screen. Most infants younger than 3.5 months of age originally showed a preference for the dichoptic (interocularly orthogonal) pattern. At an average age of 3.5 months, however, they showed a sudden shift of preference from this pattern to the interocularly identical pattern. The full shift from a preference for one stimulus to the other (both statistically significant) occurred within a few weeks in most cases. The onset age of the shift in preference agreed with the onset age of fusion-rivalry discrimination found in a previous study (Birch et al., 1985). The original preference for the bincularly orthogonal patterns may be interpreted as a preference for a grid (interocularly emergent intersections) over a grating, judging from results of two control experiments. These data suggest that the pre-stereoptic system non-selectively combines information from the two eyes without regard to edge orientation because it loses eye-of-origin information at a relatively early stage of binocular visual processing. Thus, the pre-stereoptic system does not have the capability of interocular suppression. The theoretical and clinical significance of the new findings are discussed along with a neuronal model of cortical development of ocular segregation and binocular pathways.

Development of spatial contrast sensitivity from infancy to adulthood : Psychophysical data

Purpose. This study examined changes in contrast sensitivity, the location of the peak of the contrast sensitivity function (CSF), and the shape of the function from infancy to adulthood. Methods. Contrast thresholds were obtained using behavioral methods, preferential looking for infants, and operant techniques for older children and adults, with the same stimuli for all ages. Results. Contrast sensitivity at the peak improved almost two log units from infancy to adulthood. Much of the shift in the peak to higher spatial frequencies occurred in infancy. Sensitivity decreased by almost one octave at 0.38 c/deg between 2 and 4 months of age. Sensitivity was not yet at adult levels at 8 years of age. Conclusions. The reduction in contrast sensitivity at the lowest frequency between 2 and 4 months of age suggests an increase in lateral inhibition during early infancy. Contrast sensitivity at the peak increased by two log units from then until adulthood.

Shifts in tonic accommodation after near work are related to refractive errors in children.

A link between changes in tonic accommodation (TA) produced by sustained near work and the development of adult‐onset myopia has been suggested in studies of young adults. Measures of TA before and after near work have been lacking in children of school age, which is the most susceptible period for the development and progression of juvenile‐onset myopia. In the present study accommodation was measured in 87 children, aged 7 to 16 years, before and after 15 minutes of video game playing. All children were refracted before testing and wore optical correction during measures of accommodation with a Canon R1 autorefractor. Most children showed initial values of TA (far focus minus dark focus) between 0.0 and 1.0D, with a mean of 0.68D. Grouped by refractive status, the myopic children initially showed 0.30D of TA, while the emmetropic children showed 0.75D and the hyperopic children showed 0.94D. After playing the video game, TA of the myopes increased by 1.15D, compared to smaller increases for the emmetropes (0.68D) and hyperopes (0.24D). Comparable values have been obtained from young adults. These results indicate that the smallest initial values of TA and the largest inward shifts in TA are found during the period of acquisition and progression of myopia, regardless of age.

Binocular Function in Human Infants: Correlation of Stereoptic and Fusion-Rivalry Discriminations

Studies of stereopsis in infants have shown that the average age of onset is 3.5 months. This is the same age at which infants first show evidence of another binocular function, namely, preference for binocularly fusible patterns over rivalrous ones. We tracked the development, using two-alternative forced-choice preferential looking, of the two forms of binocular function in 17 infants, 11 male and six female. They were tested at regular intervals until they showed preferences for 1) a fusible pattern (vertical stripes presented to each eye) over a rivalrous one (vertical stripes presented to one eye, horizontal stripes to the other), and 2) a line stereogram of 32 min crossed disparity over a comparable stereogram with zero disparity. The correlation between the age of onset of the fusion preference (mean 12.4 weeks) and the age of onset of stereopsis (mean 11.0 weeks) was r = 0.79. Female infants showed a preference for the fusible stimulus at a mean age of 9.9 weeks, significantly earlier than the males at a mean age of 13.8 weeks. Similarly, females also showed evidence of stereopsis at an earlier age (9.1 weeks compared with 12.1 weeks for males).

Monkeys Show an Oblique Effect

Monkeys aligned a cursor bar with high-contrast square-wave gratings presented in a variety of orientations. Alignment time increased with increasing spatial frequency from 6 to 24 cycles deg−1 regardless of the orientation of the grating. At higher spatial frequencies, alignment tasks took longer for obliquely oriented gratings than for horizontal and vertical ones. Reducing grating contrast by blurring the image of the 24 cycle deg−1 grating also produced longer alignment times for the obliques. These data indicate that monkeys have an oblique effect similar to that found in humans, implying that the monkey is a useful animal model for investigating the development of meridional anisotropies.

A device for rapid recording of positioning responses in two dimensions

A device for rapid recording of positioning responses is described. It utilizes an extremely simple, low-cost position transducer and two digital voltmeters or their equivalent. The device has the advantages of rapid, accurate measurement, reliability, ease of reading, and the potential for automatic recording of positional data in two dimensions.