Quantitative visual psychophysics during the period of European enlightenment. The studies of the astronomer and mathematician Tobias Mayer (1723?1762) on visual acuity and colour perception

Daily experience shows that colour of a very distant object cannot be accurately determined. It is assumed that visual acuity (VA) loss is one of the factors at play in this case. The effects of reduced VA as a result of refractive error or optical defocus on colour vision have not been examined. Such study willdictate the need or otherwise for optical correction before assessment of colour vision. The purpose of this study therefore, was to investigate the effects of optical defocus on colour vision in individuals with normal colour vision. Twenty nine young adult subjects (11 male and 18 females) were included in this study. Their ages ranged from 11 to 29 years with a mean of 22.1 ± 3.4 years. All subjects had VA of 6/6 or better and normal colour vision. The colour vision was evaluated with the Farnsworth panel D-15 (desaturated). Each subject was optically defocused to VA of 6/24, 6/60 and 1/60(6/360) at 6 meters respectively and colour vision was assessed at each reduced VA. At VA of 6/24, colour vision was not affected in all subjects. When the VA was reduced to 6/60, however, 15 (51%) of the subjects failed the colour vision test. When the VA was further reduced to 1/60 by optical defocus, 24 (83%) of the subjects failed the colour vision test. It was concluded that optical defocus and reduced VA can adversely affect colour vision test findings. While VA reduction to 6/24 may not affect the colour vision results, VA of 6/60 can. It is therefore, recommended that in clinical colour vision testing and colour vision screening, VA should first be assessed andcompensated, especially if uncorrected VA is 6/24 or worse.

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Optic neuritis as the ocular manifestation of dengue infection: a case report

Malaysian Journal of Ophthalmology ◽

10.35119/myjo.v3i1.152 ◽

2021 ◽

Vol 3 (1) ◽

pp. 46-51

Author(s):

Indra Tri Mahayana ◽

Andreas Surya Anugrah ◽

Ika Kartika ◽

Natalia Christina Angsana ◽

Tatang Talka Gani

Keyword(s):

Visual Acuity ◽

Optic Neuritis ◽

Vision Loss ◽

Early Recognition ◽

Dengue Infection ◽

Young Female ◽

Blurred Vision ◽

Colour Perception ◽

Optic Neuritis Treatment Trial ◽

Optic Discs

Optic neuritis is characterized by decreased vision, impaired colour perception, relative afferent pupillary defects, and scotoma. Optic neuritis following dengue infection is rare and might be underdiagnosed. The pathophysiology of optic neuritis after dengue infection is still unclear and there are only a few reports. We report a case of bilateral simultaneous optic neuritis in a young female adult following dengue haemorrhagic fever. On presentation, she complained of blurred vision, pain around the eyes, central scotoma, and progressively worsening visual acuity to no perception of light in both eyes. The next day, laboratory examination showed leucopoenia (6.74 [4.5–11.5 103/μL]) and lymphocytosis (52.7 [18–42%]), suggesting viral infection with positive anti-dengue IgM and IgG. The patient received intravenous pulse steroid therapy according to the Optic Neuritis Treatment Trial. At 3 months follow-up, best corrected visual acuity improved to 6/6, with pale optic discs but normal perimetry. Although complications of dengue fever in the eye are rare, early recognition must be established to prevent permanent vision loss.

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A STUDY ON THE DIFFERENCES IN VISION BETWEEN THE YOUNG AND THE ELDERLY IN SIGNS

10.25039/x48.2021.op58 ◽

2021 ◽

Author(s):

M. Ishihara ◽

K. Suzuki ◽

J. Heo

Keyword(s):

Visual Acuity ◽

Factor Analysis ◽

Visual Perception ◽

The Elderly ◽

Semantic Differential ◽

Differential Method ◽

Viewing Distance ◽

Colour Perception ◽

Semantic Differential Method ◽

Visual Characteristics

It has been shown that with aging, cataracts become cloudy and colour perception and visual acuity deteriorate. As the world's population ages, there is a need for signage that considers older people's visual characteristics. This study aimed to clarify the effects of sign components on visual perception and identify differences in the effects of age. We conducted a psychological evaluation using the semantic differential method on 20 young and 10 elderly. The results showed that the younger participants gave higher ratings to many questions than the older participants. The factor analysis results showed that the items of the questionnaire consisted of a "visibility factor" and "harmony factor". The elderly were more likely to be affected by the viewing distance than the young invisibility.

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Central Serous Chorioretinopathy – an Overview

Klinische Monatsblätter für Augenheilkunde ◽

10.1055/a-1531-5605 ◽

2021 ◽

Author(s):

Lieselotte Berger ◽

Virginie Bühler ◽

Suzanne Yzer

Keyword(s):

Visual Acuity ◽

Central Serous Chorioretinopathy ◽

Pigment Epithelium ◽

Retinal Pigment ◽

Case Series ◽

Subretinal Fluid ◽

Laser Coagulation ◽

Blurred Vision ◽

Colour Perception ◽

Spontaneous Course

AbstractCentral serous chorioretinopathy (CSCR) is characterised by retinal serous detachment usually localised in the macular region. CSCR predominantly affects men between 30 and 50 years of age. Traditional classification differentiates between acute (duration shorter than 4 to 6 months) and chronic disease (duration longer than 4 to 6 months). The pathogenesis is multifactorial and current thinking assumes the presence of localised choroidal hyperpermeability with subsequent secondary changes in the retinal pigment epithelium (RPE). The symptoms of acute CSCR include central blurred vision, often with deterioration in visual acuity. Optical coherence tomography (OCT) reveals subretinal fluid (SRF) and/or single retinal pigment epithelial detachments. Fluorescein angiography (FA) usually shows a leaking point with absent or only minor RPE changes in the acute phase and indocyanine green angiography (ICG) highlights circumscribed areas of thickened and hyperpermeable choroid. Acute cases may show spontaneous resolution of SRF, but may also recur and/or become chronic. After the initial diagnosis, spontaneous remission is seen in about 70 to 80% of cases, with a recurrence rate of about 50%. Due to the favourable spontaneous course, it is recommended to wait for 4 to 6 months after the first symptoms manifest. Steroid therapy is considered as a major risk factor. Chronic cases are characterised by slow deterioration in visual acuity with reduced contrast and colour perception. There are extensive RPE changes, with secondary degenerative changes of the photoreceptors. The disease can by complicated by choroidal neovascularisation (CNV), especially in elderly patients. The literature lists a number of treatments: The leakage point (visible in the FA) can be treated by focal laser therapy, either micropulse laser or, if sufficiently distant from the fovea, by argon laser coagulation. Randomised trials in chronic CSCR demonstrated good outcomes with photodynamic therapy. With observation periods ranging from 3 to 6 months, several case series reports found improvement after systemic administration of mineralocorticoid receptor antagonists, carbonic anhydrase inhibitors or non-steroidal anti-inflammatory drugs. In the presence of secondary CNV, anti-VEGF treatment should be initiated. It is unclear whether the combination with PDT might be useful.

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