G. Verriest

A New Assessment of the Normal Ranges of the Farnsworth-Munsell 100-Hue Test Scores

We gave the Farnsworth-Munsell 100-hue color vision test to 232 normal subjects between 10 and 80 years of age. One half the subjects underwent binocular testing followed by monocular testing. In the other half monocular testing preceded binocular testing. Performance was better with both eyes than with either eye alone. The worst performance occurred on monocular tests in subjects without previous experience with the task (that is, those for whom this was the first test). The well-known age trend was apparent (children and elderly have the worst color vision). New data are provided for judging the point at which the total error score may be considered pathologic.

New investigations concerning the relationships between congenital colour vision defects and road traffic security

New extentive experiments demonstrated that: (a) protan observers are more deficient than deutan ones with regard to perception distances of some traffic panels, of vehicle red stop lights, of vehicle red rear-position lights and of white, yellow and red reflectors. Contrarily, deutan observers are more deficient than protan ones for the distinction of differently coloured traffic lights and vehicle rear lights; (b) protan and deutan drivers are nevertheless not responsible for more traffic accidents than drivers with normal colour vision; (c) this apparent contradiction is due to psychological compensation mechanisms. The practical conclusions are: (a) that persons with defective colour vision need not to be excluded from non professional road traffic; (b) that it is nevertheless useful that they should be aware of their handicap; (c) that the red traffic signal has to be larger than the other ones; and (d) that the stop and red position lights of vehicles must be sufficiently intense and that the filters transmitting only pure red should be avoided in them.

Spectral increment thresholds on a white background in different age groups of normal subjects and in acquired ocular diseases.

Energetical achromatic increment thresholds on a white background of 10 cd.m−2 were determined at 5 eccentricities by means of 8 interference filters in corporated to a calibrated Tübingen perimeter.A new study of 3 age groups of normal subjects (10–15, 16–41 and 60–76 years) showed that many of the differences between the means are very significant and that only some of them can be explained by the known prereceptoral changes.The same examination method was applied to 120 pathological eyes. When compared with the normal spreads, taking into account the age factor, the spectral sensitivity curves of the affected retinal areas were found to be unevenly lowered in juvenile macular degeneration and in progressive cone dystrophies (for which scotopic luminosity curves are obtained), in central serous retinopathy (where the sensitivities for the shorter and for some intermediate wavelengths are selectively lowered), in some cases of peripheral pigmentary retinopathy (selective lowering of the sensitivities to the shortest wavelenghts) and in some cases of optic nerve disease (apparant enhancement of the sensitivities to the shorter wavelengths). The spectral sensitivity curves are evenly lowered in other cases and diseases. Moreover, the method proved to be a more sensitive test than static perimetry with white objects and, interestingly, more sensitive than the traditional tests of colour vision (Ishihara, Tritan-Plate, AO H-R-R, Panel D-15 and anomaloscope) when used at the foveal level.An introductory section is devoted to the actual trends in colour perimetry.

Modification of the amplitude of the human electro-oculogram by light and dark adaptation.

WHEN an electrode is placed on the cornea and another near the posterior pole of the eye (or elsewhere on the body) a standing potential is found (Kohlrausch, 1931; Marg, 1951). In vertebrates the cornea is positive in relation to the retina. The axis of this electrical system is approximately the same as the optic axis. If electrodes are placed near the eye and if the eye is turned, the electrode closest to the positive corneal pole will be positive in relation to the others. This recorded electro-oculographic response (EOG) depends on the angle and speed at which the globe rotates; it is independent of the action currents of the eye muscles, which are not recorded. Fig. 1 shows a normal human EOG; the electrodes are placed round the left eye, and when the patient looks to the right (MR) this eye is adducted and electrode (1) on the nasal side becomes nearer to the cornea and positive to electrode (3) on the temporal side; we obtain also an upward deflexion on the derivation 1/3.

Progressive Generalized Cone Dysfunction

The mainly electro-retinographical concept ‘cone dysfunction’, as described by Sloan & Brown (1962), Goodman et al. (1963, 1966), Berson et al. (1968), Krill et al., (1970, 1973), Babel & Stangos (1972, 1973), includes a wide group of clinical pictures.

Results of Colour Vision Tests in Alcoholic and in Mentally Disordered Subjects

The responses at the Ishihara test, the Nagel anomaloscope, the standard Panel D--15 and the 100 hue test (with correction of the age effect) were recorded in 38 alcoholics in deprivation period (successively subdivided according to age, to abstinence duration and to liver condition) and in 32 subjects suffering from mental diseases (successively subdivided according to ethylic past, to age, to duration of the stay in the hospital and to activity). It is shown that alcoholism causes a diminution of the performance at the used colour vision tests and especially at the 100 hue test. The defect can be ascribed to psychical factors (chiefly in the cases of mental disease and in the younger people), but also to an acquired blue-yellow defectiveness of colour vision with a shift of the Rayleigh match to red (such a defectiveness can also be due to a liver damage and to some intoxications) and even to a Type II acquired red-green defectiveness of colour vision (possibly by tobacco or disulfiram intoxication). The defect due to alcohol itself soon disappears during desintoxication. The authors draw some practical conclusions.

ELECTRO-OCULOGRAPHY AS A FUNCTIONAL TEST IN PATHOLOGICAL CONDITIONS OF THE FUNDUS I. FIRST RESULTS

THE modifications of the standing potential in pathological fundus conditions are practically unknown, although electro-oculography (EOG) is a technically simple and clinically very efficient method of obtaining an indirect estimate of its value. Although the EOG is now widely used in order to study ocular motility, it is generally not considered as a functional test: only Riggs (1954) has reported diminished deflections in a case of pigmentary degeneration, and we ourselves have studied the EOG in a few cases of congenital retinal abnormality, such as Oguchis disease (Frangois and Verriest, 1954) and total colour blindness (Fran9ois, Verriest, and De Rouck, 1955b). The present paper deals with the technique, physiological values, and results obtained in a few cases of the more typical diseases of the choroid and the retina.

Electro-oculography as a functional test in pathological conditions of the fundus. II. Base-value and drop during dark adaptation.

IN our first paper (Fran9ois, Verriest, and De Rouck, 1955) we reported upon the modifications of the normal human electro-oculogram (EOG) by light adaptation (2,000 asb for 5 min.) and subsequent dark adaptation; if the former generally gives only a slight decrease in the initial value, the latter is constantly characterized by an initial increase in the recorded deflections (for 1 to 3 min.), followed by a large decrease which lasts about 10 min.; this drop is followed by a slight new increase. In a second contribution (Fran9ois and others, 1956) we studied an arbitrary and standardized base-value M in normal and pathological cases, and recognized that this value was often too low in cases of microphthalmia, primary pigmentary degeneration, cicatricial chorio-retinitis, and retinal detachment. As a third step in the physio-pathological study of the electrical standing potential of the eye, we now refer principally to the drop in the EOG during dark adaptation in pathological cases as compared with normal cases and with the base-values.

NEW ELECTRORETINOGRAPHIC FINDINGS OBTAINED IN CONGENITAL FORMS OF DYSCHROMATOPSIA

INVESTIGATIONS made by Motokawa and Mita (1942), Adrian (1945), Gastaut (1949), Johnson (1949), Schubert and Bornschein (1952), Armington (1952), Armington, Johnson, and Riggs (1952), Bornschein (1953), Burian (1954), and Auerbach and Burian (1955), and by other investigators, have revealed that-under suitable conditions of examination-the human electroretinogram (ERG) normally consists of a photopic wave a,, a scotopic wave a2, a photopic wave b, (or x), and a scotopic wave b2. Investigations made by Wirth (1951), Dodt (1951), Dodt and Wadensten (1954), Heck and Rendahl (1957), Heck (1957), and Rendahl (1958) have shown, among other things, that the bl-wave as such is a complex wave, and that the normal human electroretinogram also comprises other visible components, such as the c-wave, and several off-effects. Absence of the b1-wave in cases of complete achromatopsia has been described by Vukovich (1952), Yonemura and Ishizaka (1952), Dodt (1954), Wadensten (1954, 1956), Goodman and Iser (1956), Iser and Goodman (1956), Bornschein, Goodman, and Gunkel (1957), Heck and Rendahl (1957), Elenius and Heck (1957, 1958) and Schappert-Kimmijser (1958). Armington (1952) and Schubert and Bornschein (1952) have shown that the ERG is virtually normal in deuteranopia and tritanopia, whereas in protanopia it is difficult to demonstrate the bl-wave. Heck and Rendahl (1957) and Rendahl (1958) have demonstrated, among other things, that the b1-wave shows changes, not only in protanopia but also in deuteranomaly and deuteranopia.

Results of a Shortened Lightness Discrimination Test

The Lightness Discrimination Test can be made extending the series of gray caps of Lanthony’s commercially available New Color Test. Despite the greater lightness differences between less numerous caps the meaning of the results remains the same as for the original test.