A simulated field test was designed to determine whether the Holmes-Wright A lantern (HWA) is a valid color vision test for the rail industry. The simulation replicated viewing rail signal lights at 0.8 km distance under daylight conditions. Using the worst-normal as the maximum number of allowable errors on the simulation, 94% of the color-defectives failed both tests on the first trial and 92...

The results are given of a questionnaire study to determine the range of difficulties that doctors notice in their work due to congenital colour vision deficiency (CCVD). The study is primarily qualitative. A questionnaire was sent to 40 self-selected doctors, 35 of whom were general practitioners (GPs). All were administered a number of colour vision tests to assess the type and severity of th...

This study examines the equivalence of the City University color vision test (CUT) to the Farnsworth Munsell D-15 (D-15). This information is important because a number of occupations require individuals to pass either the D-15 of the CUT. Using two or more major crossings on the D-15 as failure, our results indicate that agreement between tests can be improved if the failing criterion for the ...

Clinicians usually do not have access to a lantern test when making an occupational assessment of the ability of a person with defective colour vision to recognise signal light colours: they must rely on the results of ordinary clinical tests. While all colour vision defectives fail the Holmes Wright Type B lantern test and most fail the Holmes Wright Type A lantern, 35% of colour vision defect...

BACKGROUND An experiment on the relationship between aeromedical color vision screening test performance and performance on color-dependent tasks of Air Traffic Control Specialists (ATCS) was replicated to expand the database supporting the job-related validity of 13 FAA-accepted screening tests. METHODS The original experiment (10) (n = 108), and the replication (n = 136) involved a total of...

R Vision therapy, also known as vision training, is a term used to define highly specific, sequential, sensory-motorperceptual stimulation paradigms and regimens that are used to improve vision skills, such as eye movement control and eye coordination.1 This training procedure can be performed in both home and office settings, but always under the professional supervision of an optometrist or a...

Knowledge of measurability of vision and its impact on safe driving have been proven to be important to secure a safe traffic system. Several different approaches to measuring visual function in order to improve road safety have been identified around the world. A trend seen in the literature is that traditional vision tests are increasingly supplemented by cognitive tests. The purpose of this ...

Visual agnosia is a neuropsychological impairment of visual object recognition despite near-normal acuity and visual fields. A century of research has provided only a rudimentary account of the functional damage underlying this deficit. We find that the object-recognition ability of agnosic patients viewing an object directly is like that of normally-sighted observers viewing it indirectly, wit...

Teaching color vision testing can be challenging when all (or nearly all) of the students in the class have normal color vision. Colored filters or computer simulation can be used to simulate color vision deficiencies, but both have some drawbacks. As an alternative, we used a blue compact fluorescent lamp to illuminate various clinical color vision tests. The results from 20 students showed th...

OBJECTIVE In this article, we review the impact of vision on older people's night driving abilities. Driving is the preferred and primary mode of transport for older people. It is a complex activity where intact vision is seminal for road safety. Night driving requires mesopic rather than scotopic vision, because there is always some light available when driving at night. Scotopic refers to nig...