The hypothesis that paranoid and non-paranoid schizophrenics are differentially associated with unilateral hemisphere dysfunction was tested on 12 paranoid and 12 non-paranoid schizophrenics, as well as on 24 affective patients and 24 normal controls. The subjects were presented for 150 ms with series of digit-pairs and open rings to the left or right visual fields. Overall recognition of digits and localization of gaps in the rings were better for the right than for the left visual field. However, performance of the paranoid and non-paranoid schizophrenics was relatively poorer in response to the right and left visual field stimuli, respectively. Since these data do not correspond to the findings obtained in the auditory modality, they were interpreted as indicating modality-specific associations of paranoid schizophrenia with left hemisphere dysfunction, and of non-paranoid schizophrenia with right hemisphere dysfunction.

Objectives: To compare growth patterns of nonfunctioning and prolactin-producing pituitary macroadenomas, and to find whether their specific growth patterns are associated with clinically significant effects on vision. Materials and Methods: From our comprehensive provincial neuropituitary registry, we retrospectively identified 35 randomly selected patients each with nonfunctioning adenomas and prolactinomas >10 mm in any dimension. MRI scans were analyzed to determine the superior and inferior growth, volume, and maximum craniocaudal height of the adenomas. Patients underwent visual field testing at diagnosis. Continuous variables were compared using Student’s t test, the Mann–Whitney U test, and ANOVA. Categorical variables were compared using the chi-square test. Results: The mean height of prolactinomas (23.2±11.3 mm) was similar to nonfunctioning adenomas (22.3±9.3 mm, p=0.8), and so were mean tumor volumes (prolactinoma=5.9±8 ml vs. nonfunctioning adenoma=4.8±5 ml, p=0.47). However, the mean suprasellar growth for prolactinomas was 2.9±5.3 mm and 7.3±4.7 mm for nonfunctioning adenomas (p<0.001), and the mean infrasellar growth was 10.2±8.0 and 5.0±6.6 mm, respectively (p=0.04). The inferior growth pattern of prolactinomas was associated with a significantly lower likelihood of having visual field abnormalities (11.4 vs. 57.1%, p<0.001). Conclusions: Prolactinomas have predominantly inferior growth compared to nonfunctioning adenomas and are less likely to cause vision changes.

The visual abilities of sharks show substantial interspecific variability. In addition, sharks may change their habitat and feeding strategy throughout life. As the eyes of sharks continue to grow throughout the animal’s lifetime, ontogenetic variability in visual ability may also occur. The topographic analysis of the photoreceptor and ganglion cell distributions can identify visual specializations and assess changes in visual abilities that may occur concurrently with eye growth. This study examines an ontogenetic series of whole-mounted retinas in two elasmobranch species, the sandbar shark, Carcharhinus plumbeus, and the shortspine spurdog, Squalus mitsukurii, to identify regional specializations mediating zones for improved spatial resolution. The study examines retinal morphology and presents data on summation ratios between photoreceptor and ganglion cell layers, anatomically determined peak spatial resolving power, and the angular extent of the visual field. Peak densities of photoreceptors and ganglion cells occur in similar retinal locations. The topographic distribution of neurons in the ganglion cell layer does not differ substantially with eye growth. However, predicted peak spatial resolution increases with eye growth from 4.3 to 8.9 cycles/deg in C. plumbeus and from 5.7 to 7.2 cycles/deg in S. mitsukurii. The topographic distribution of different-sized ganglion cells is also mapped in C. plumbeus, and a population of large ganglion cells (soma area 120–350 μm2) form a narrow horizontal streak across the retinal meridian, while the spatial distribution of ordinary-sized ganglion cells (soma area 30–120 μm2) forms an area in the central retina. Species-specific retinal specializations highlight differences in visually mediated behaviors and foraging strategies between C. plumbeus and S. mitsukurii.

This paper presents results from psychophysical experiments on human binocular rivalry in central and peripheral vision. Results show that the incidence of periods of exclusive visibility of a given eye's rival target increased with decreasing target size, and for a given sized target exclusive visibility increased with retinal eccentricity. Control measures confirmed that these results were not attributable solely to reduced peripheral acuity, to Troxler's effect, or to spatial frequency. We computed the minimum-sized stimulus that would lead to a criterion level of exclusive visibility of one or the other eye; this we term the spatial zone of binocular rivalry. The change in estimated size of spatial zones of rivalry with eccentricity compares favorably with estimates of human cortical magnification. We propose a model that assumes concentrically organized zones of rivalry. These zones do not function independently, but instead exhibit a high degree of mutual excitatory cooperativity. The model has multiple solutions for the foveal zone size, but the best fits predict a diameter of 5.3 or 7.3 min of visual angle; these values dovetail nicely with our empirical estimates of the foveal zone size.

The optical alignment of individual cuticular cones in the dioptric array of the lateral eye of Limulus polyphemus was determined with a precision two-circle goniometer constructed and mounted to the stage of a compound microscope and using a new formaldehyde-induced fluorescence procedure. All measurements were made from the corneal surface of the excised eye mounted in seawater through an air/water interface perpendicular to the optic axis of the microscope. Our results revealed two variants of visual field and eye curvature which can actually be discriminated in casual examination of adult animals. We call animals possessing these two variants “morlocks” and “eloi.” Adult male and female morlocks about 25 cm across the carapace have eyes which are relatively elongated, often darker in pigmentation, smaller, and relatively flatter in curvature. Morlocks have a monocular field of view of about 3.13 steradians or 50% of a hemisphere. The coverage averages 115 deg along the vertical axis and 168 deg along the horizontal axis of the eye, with maximum resolution in the anteroventral quadrant. Adult male and female eloi of comparable size have eyes which are relatively more round, often lighter in pigmentation, larger with more ommatidia, and relatively more bulged. Eloi have a monocular field of view of approximately 3.83 steradians or 61% of a hemisphere that covers 145 deg vertically and 185 deg horizontally. Eloi have more uniform resolution than morlocks with best resolution in the posteroventral quadrant. All horseshoe crabs examined, whether morlocks or eloi, have an identical orientation of the margin of the eye relative to the animals’ coordinates.

The population of retinal ganglion cells which project ipsilaterally in the brain was examined in the fat-tailed dunnart, Sminthopsis crassicaudata, following injection of horseradish peroxidase into one optic tract. Retinae were examined as wholemounts and optic nerves as serial sections. In addition, visual fields were measured ophthalmoscopically. Ipsilaterally projecting ganglion cells were located temporal to a line which ran vertically through the middle of the area centralis and extended medially to define a ventrolateral crescent. Temporal to the naso-temporal division, a mean of 77% of ganglion cells projected ipsilaterally; these cells represented 20% of the total ganglion cell population. The magnitude and retinal location of the ipsilateral projection correlated with the extensive binocular field which measured 180 deg in the vertical (from 20 deg below the horizontal axis to 70 deg beyond the zenith) and 140 deg in horizontal meridian. Ipsilaterally projecting axons were restricted to the lateral third of the optic nerve along its length, sharing territory with contralaterally projecting axons.