[An immunoelectron microscopic study of distribution and density of nerve fibers innervating the rat iris].

We studied the sympathetic, parasympathetic and sensory nerve fibers in the rat iris using electron microscopic immunohistochemical techniques. Antibodies raised against tyrosine hydroxylase (TH), substance P (SP), and calcitonin gene-related peptide (CGRP) were used alone or combined together to characterize the nerve fibers. The ratios of the TH-positive, SP/CGRP-positive and TH/SP/CGRP-negative fibers were 18%, 37%, and 45% in the anterior half of the dilator stroma, 11%, 3%, and 86% in the posterior half of the dilator stroma, 45%, 26%, and 29% in the sphincter stroma, and 23%, 1%, and 76% in the sphincter muscle layer. These results confirm that the sympathetic and parasympathetic fibers doubly innervate both rat iris sphincter and iris dilator muscles, whereas sensory nerve fibers innervate mainly the stroma.

Ultrastructural analysis of tyrosine hydroxylase-, substance P-, and calcitonin gene-related peptide-immunoreactive nerve fibers in the rat iris.

Different patterns of distribution of chemically different nerve fibers in the rat iris were studied by immunoelectron microscopy. The iris was immunostained either singly for tyrosine hydroxylase (TH), or doubly for substance P (SP) and calcitonin gene-related peptide (CGRP), or triply for TH, SP and CGRP. TH-positive fibers were distributed in the stroma near the iris dilator and within the iris sphincter. SP/CGRP-positive fibers were found mainly in the anterior half of the stroma and partly in the stroma close to the sphincter, but were hardly ever seen in the stroma near the dilator or within the sphincter. Fibers neither positive for TH, SP nor CGRP were observed in the stroma near the dilator and within the sphincter.

[Temporal integration in diseased eyes. I. Exposure duration in visual acuity testing].

Critical duration in visual acuity testing can be viewed as an expression of temporal integration in the human visual system. We examined this phenomenon in 13 eyes with central serous retinopathy (CSR) and 6 eyes with macular edema, by measuring visual acuity at several limited exposure times. The results were then compared with those for 17 normal eyes. The acuity target was a single Landolt ring projected upon a small square screen. The size, direction, and exposure time of the target were computer controlled. The mean critical durations of the CSR and macular edema groups were 1.78 sec. and 2.69 sec. respectively. These values were significantly (p less than 0.01) longer than the mean critical duration of the normal control group (0.62 sec.). Although the mechanism behind the longer critical duration in diseased eyes remains poorly understood, we believe this method provides a possible approach to the study of diseased visual conditions.

[Anomaloscope measurement using the method of constant stimuli].

The range of the normal Rayleigh equation was evaluated using the constant stimuli method which is a psychophysical method with the Neitz anomaloscope OT. Fifteen or 21 settings around the midmatching point established beforehand by the conventional method of adjustment were presented 10 times for each setting respectively. Using a computer, the testing matches were arranged to appear at random. As was expected, the normal Rayleigh match proved to fall within 1 or 2 of the above-mentioned point. Further study is needed as to the choice of the testing points and the number of trials. The result should also be examined in reference to that of the Nagel anomaloscope.