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J Leid

Publications and source records attributed to J Leid.

15 recordsLinked to original sources
PubMed2006

[Neurophysiological basis and clinical tests for assessment of X-linked color vision deficiencies in school children].

Vision screening of school children at 5-6 years of age must include color vision screening. X-linked dyschromatopsia is the most frequent disorder affecting 8% of boys and 0.4% of girls. This paper presents the physiology of these deficiencies caused by an alteration of the spectral absorption properties of one of the cone pigments (protanomalous or deuteranomalous trichromats) or the absence of one of the pigments (protanopia or deuteranopia), the most frequent. Absence of two of the pigments (blue cone monochromacy) is very rare and differs from achromatopsia. The physiological basis of the main tests for easy clinical screening are presented. Testing methods designed for children are reviewed. The Ishihara test is the most widely used screening test specific for congenital color defects. If the plates are correctly read, the child has normal color vision. If not, arrangement tests such as Panel D 15 and desaturated Panel D 15 tests can be used to diagnose the type of the defect (protan or deutan) and grade the degree of color deficiency according to a strategy adapted to children. Examples of results are presented for each axis along which caps are confused, providing a quick and easy preliminary diagnosis. Early detection of color vision malfunction in children allows parents and teachers to make necessary adjustments to the teaching methods for appropriate learning.

Adolescent↗
PubMed2004

[Up-dated ophthalmological screening and follow-up management for long-term antimalarial treatment].

The early detection of macular toxicity linked to long-term antimalarial treatment requires regular ophthalmological screening based on patients'classification based on their results compared to successive controls. Patients are classified as "low risk" with screening every 18 months if all of the following criteria are met: age under 65 years, no associated renal, hepatic or retinal disease, treatment for less than 5 years, dose less than or equal to 6,5mg/kg/d for hydroxychloroquine and 3mg/kg/d for chloroquine (for a lean patient's weight); "at risk, without fundus findings" with screening every 12 months if one of the following criteria is met: age over 65 years (at the start of or during treatment), antimalarial treatment for more than 5 years, daily dose higher than recommended, presence of renal and/or hepatic disease; "at risk, with fundus findings" with screening every 6 months if a retinal dysfunction has been detected and even if treatment is established or followed. Screening consists of an in-depth clinical examination and at least two complementary tests of macular function: color vision (desaturated-Panel-D15 test) and/or static macular perimetry (central 10 degrees) and/or macular electroretinography (pattern ERG/multifocal ERG). If any changes or anomalies are found between two successive check-ups, the state of the retina can be assessed by angiography and global retinal function by full-field-ERG and electro-oculogram (EOG). The progression from one check-up to the next decides whether a course of treatment will be followed.

Antimalarials↗
PubMed2001

Colour vision at very high altitude.

The goal of our study was to evaluate colour vision during high-altitude mountain climbing without supplemental oxygen. Two Himalayan expeditions were invited to test their colour perception at both the highest possible altitude and on the largest possible number of subjects. The panel desaturated D15 was used, because only a simple test could be transported to those altitudes. There were 2 evaluations (i.e., 4 eyes) at 7,000 m during the first expedition in 1997, and 3 evaluations (i.e., 6 eyes) at 6,500 m during the second expedition in 1998. The results were in perfect agreement and can be considered practically normal for all 5 mountain climbers.

Altitude↗
PubMed1991

[Value of very low voltage halogen lighting of desaturated panel D 15 test in established glaucoma].

The colour vision of a first group of glaucomatous patients was tested with the desaturated Panel D 15 test, first illuminated by a 300 lux Macbeth lamp, then with a very low voltage 1000 lux halogen lamp. In addition to the recording of 80% cases of dyschromatopsia, in line with previously published data, we demonstrated a great number (33.3%) of red-green axis anomalies under Macbeth light and, paradoxically, even more under halogen light (53.3%). To explain this high percentage of red-green axes under halogen light, we discuss the influence of luminance and emission spectrum of the light source. We conclude that the use of high luminance halogen light is capable of revealing concealed Verriest type II dyschromatopsias probably due to a specific fragilisation of the red-green channels induced by the glaucoma disease. This original colour vision testing procedure applied on established glaucomatous patients enabled us to easily obtain a factor of severity in the course of the disease.

Adult↗
PubMed1983

[Age and photopic and mesopic visual acuity].

Visual acuity at high luminance (100 cdm2) and at low luminance (0.8 cdm2) was measured in normal subjects aged between 20 and 50 years. A decrease of visual acuity at Low luminance was noted with increasing age whereas high luminance acuity remained unchanged (20/20). At thirty years of age, low luminance visual acuity was an average of 20/30 decreasing at 40 years to 20/40. Results were confirmed by statistical analysis. A short study with interference fringes, formed by a coherent light (neon-helium laser) produced directly on the retina and thus by-passing optical effects on the eye, suggested that the retina-brain system was responsible for decreased mesopic visual acuity, night myopia or right presbyopia not playing any part in this decrease as suggested by some authors. Consequences of these findings, concerning particularly workers at low luminance such as pilots or drivers, are discussed.

Adult↗