Optotypes are signs of different sizes, systematically placed on the visual acuity chart. The human eye has a spatial resolution of 1' of arc (Snellen). Optotypes in the basic row on all charts subtend 5' of arc and their detail 1' of arc, from the testing distance. The disadvantage of all classical charts is the irregular progresssion of optotype sizes in adjacent rows. This was solved by logM...

To the Editor: For some time we have used a clinical visual acuity test (subjective refraction) only for monocular testing. However, we believe that visual acuity measurements need to be performed under binocular open-view conditions as close to natural viewing conditions as possible. Subjective refractions without cycloplegia were examined with the Occlupad (Japan Focus Co., Ltd., Tokyo, Japan...

Eye preference in humans and its correlation with eye dominance, visual acuity and handedness. Eye preference in humans and its correlation with eye dominance, visual acuity and handedness. Handedness is the most obvious expression of lateralized behaviour in humans. However, there is only limited knowledge about other forms of lateralized behaviour, e.g. preferential use of an eye and whether ...

PURPOSE To evaluate the age-related change in contrast sensitivity seen in a middle-aged to elderly Japanese population. METHODS Contrast sensitivity and visual acuity were measured in subjects aged 40 to 79 years randomly recruited from a community in Aichi prefecture near Nagoya, Japan. Contrast sensitivity tests were performed using the Vistech contrast sensitivity test chart (VCTS 6500). ...

Contrast sensitivity (CS) is widely used as a measure of visual function in both basic research and clinical evaluation. There is conflicting evidence on the extent to which measuring the full contrast sensitivity function (CSF) offers more functionally relevant information than a single measurement from an optotype CS test, such as the Pelli-Robson chart. Here we examine the relationship betwe...

BACKGROUND To screen for visual impairment in Malaysian preschool children. METHODS Visual screening was conducted in 400 preschool children aged 4 to 6 years. The screening involved two basic procedures; the distant visual acuity test using the Sheridan Gardiner chart and the depth perception test using the Langs stereoacuity test. Criteria for referral were a visual acuity of 6/12 or less i...

OBJECTIVE We wished to determine the effectiveness of horizontal rectus tenotomy in changing the nystagmus of patients with congenital nystagmus and, secondarily, how their visual function changed. DESIGN This was a prospective, noncomparative, interventional case series. PARTICIPANTS Ten adult patients with varied associated sensory defects and oculographic subtypes of congenital nystagmus...

Visual function abnormalities are common in people living with HIV disease (PLWH) without retinitis, even after improvement in immune status. Abnormalities such as reduced contrast sensitivity, altered color vision, peripheral visual field loss, and electrophysiological changes are related to a combination of retinal dysfunctions, involving inner and outer retinal structures. The standard proto...