Mesopic visual acuity requirements for driving licenses in the European Union-Research Report.

In this study different methods for determining the mesopic visual acuity in candidates for driving licenses group 2 are presented (Royal Decree, 1998, European norms). Results of normal subjects are compared. Depending on the method used, visual acuity obtained under mesopic conditions, with an illuminance of 1 lux, showed a mean ranging from 0.5 to 0.65, which is clearly above the legal norm of 0.2. A comparative study of the three published official norms demonstrates that the stringent norms of 1966 do not match those of 1988 and 1998, resulting in a wider margin of acceptability, to the advantage of the candidate.

The luminance fall in anomaloscope examination: clinical examples.

PURPOSE: The evaluation of the anomaloscope slope quotient in patients with acquired colour vision deficiency. METHODS: Two patients with Stargardt's disease in combination with protanomaly and deuteranomaly, respectively, were selected and also 3 patients with a presumed dominant optic atrophy of the protan type. The anomaloscope examination was performed according to the Linksz procedure. The luminance fall was calculated as the slope quotient SQ:Y units luminance fall per X units width of the matching range. RESULTS: The SQ of the 2 Stargardt patients was steeper than the SQ of congenital colour vision defectives, especially at the red end of the anomaloscope green-red mixture scale, indicating pathologic scotopization superimposed on the congenital deficiency. In optic atrophy of the protan type the SQ was flatter than in congenital deficiency, indicating that this deficiency has nothing to do with congenital protan deficiency. CONCLUSION: Calculation of the slope quotient SQ is helpful for the diagnosis of acquired colour vision deficiency, especially when the subject also has a congenital colour vision deficiency or is supposed to have such a deficiency.

A large field Panel D-15 test for low vision patients.

A large surface Panel D-15 Test, specially designed for low vision patients, is presented. The value of the test is compared to the one of other standard colour vision tests in such patients.

The detection of hidden visual loss in optic neuropathy: VISTECH test at variable illuminations.

The sensitivity of the VISTECH chart in the detection of hidden visual loss is debated. We tried to evaluate the diagnostic value of the test by using different illumination levels. Twelve MS-patients with normal acuity but a pathological VEP were examined at 9 different illuminations. We did not identify more abnormalities among patients, using VISTECH test at other illumination levels than the one recommended by the manufacturer.

Muscular activity and perimetric thresholds.

Static and kinetic peripheral luminance thresholds were measured by means of a Goldmann perimeter along oblique meridians in monocular vision. In a main group of 33 young and healthy subjects these measurements and visual reaction time assessments were made successively at rest, when cycling without load, when cycling with load using aerobic energy supply, when cycling with load using anaerobic energy supply and twice again at rest. Another group of subjects did not pedal and served as controls. The results show that peripheral visual sensitivity increases faintly but significantly during muscular exercise. When assessed by static perimetry the sensitivity increase is grossly proportional with load and is thus greatest in anaerobic condition, while kinetic sensitivity differs by a sensitivity decrease when passing from aerobic to anaerobic exercise. The reported modifications in perimetric sensitivity during dynamic muscular exercise seem related to changes in alertness.

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.

In vitro study of lysosomal particles in corneal epithelium cultures after type I herpes virus infection.

The lysosomal cycle has been studied in the primary cultures of corneal epithelium infected with type I herpes virus. Immediately after the infection, the lysosomal system develops. There is a great dispersion in the morphometric analysis of the lysosomal particles. They represent a heterogeneous population with regard to their size. The number of lysosomal particles increases very rapidly during the first hours after the herpetic infection. Finally, many cells become round and die.