Pseudo‐isochromatic Plates and Artificial Light

Screening of Red‐green Defects of Colour Vision With Pseudoisochromatic Tests

“…Proper use of a combination of the BK I and I1 B series of pseudoisochromatic tests provides an effective preliminary screening of red-green defects of colour vision (Chapanis 1948;Frey 1958;Katavisto 1961). Using this method in the screenings of the present study, a high number (50) of red-green defectives were collected by examining 351 persons.…”

“…There are several reports on effective differentation between normals and red-green defectives obtained with the Ishihara test (Sloan & Habel 1956;Belcher et al 1958;Crone 1961). Allowing 40 per cent of plates misread by normals, effective differentation between normals and red-green defectives was obtained with the fifth (1925), seventh (1936) and ninth (1940) edition (Hardy et al 1945), tenth (1951) edition (Katavisto 1961) and eleventh (1954) edition (Frey 1958). Kettesy (1955), however, found the tenth edition to be less effective.…”

“…I n addition they both misread the plate number 13, and one of them misread the plate number 10. The I1 B test may be somewhat difficult for normal subjects (Kettesy 1955;Frey 1958;Katavisto 1961;Heinsius 1963). In the present study, five normal subjects (5 per cent) failed in this test (only 2 normals failed if plate number 12 is excluded).…”

Screening of Red‐green Defects of Colour Vision With Pseudoisochromatic Tests

“…Proper use of a combination of the BK I and I1 B series of pseudoisochromatic tests provides an effective preliminary screening of red-green defects of colour vision (Chapanis 1948;Frey 1958;Katavisto 1961). Using this method in the screenings of the present study, a high number (50) of red-green defectives were collected by examining 351 persons.…”

“…There are several reports on effective differentation between normals and red-green defectives obtained with the Ishihara test (Sloan & Habel 1956;Belcher et al 1958;Crone 1961). Allowing 40 per cent of plates misread by normals, effective differentation between normals and red-green defectives was obtained with the fifth (1925), seventh (1936) and ninth (1940) edition (Hardy et al 1945), tenth (1951) edition (Katavisto 1961) and eleventh (1954) edition (Frey 1958). Kettesy (1955), however, found the tenth edition to be less effective.…”

“…I n addition they both misread the plate number 13, and one of them misread the plate number 10. The I1 B test may be somewhat difficult for normal subjects (Kettesy 1955;Frey 1958;Katavisto 1961;Heinsius 1963). In the present study, five normal subjects (5 per cent) failed in this test (only 2 normals failed if plate number 12 is excluded).…”

A proposed correction in the weighted method to score the Ishihara test

“…Fluorescent bulbs have pronounced energy in some wavelengths and differ from natural daylight that has similar energy distribution across spectrum [25]. The comparisons between the results of pseudoisochromatic test using natural daylight (or Macbeth easel lamb) and fluorescent daylight lamp have shown variable results [11, 25, 26]. For the present study, some influence of the fluorescent lamp was minimized by the confirmation of the color vision phenotype by other color vision tests.…”

“…As all the examiners had the same training, we expect that this bias would not have had a great impact in the results. The fluorescent illumination is not recommended by the manufacturer, but some investigations have discussed about the use of this kind of illumination during the use of Ishihara test and they have indicated some influences on the results [11, 23]. Ishihara test was designed for natural daylight or CIE standard illuminant C and International standards for colour vision testing have been given [24].…”

Screening of Red‐green Defects of Colour Vision With Pseudoisochromatic Tests

“…Proper use of a combination of the BK I and I1 B series of pseudoisochromatic tests provides an effective preliminary screening of red-green defects of colour vision (Chapanis 1948;Frey 1958;Katavisto 1961). Using this method in the screenings of the present study, a high number (50) of red-green defectives were collected by examining 351 persons.…”

“…There are several reports on effective differentation between normals and red-green defectives obtained with the Ishihara test (Sloan & Habel 1956;Belcher et al 1958;Crone 1961). Allowing 40 per cent of plates misread by normals, effective differentation between normals and red-green defectives was obtained with the fifth (1925), seventh (1936) and ninth (1940) edition (Hardy et al 1945), tenth (1951) edition (Katavisto 1961) and eleventh (1954) edition (Frey 1958). Kettesy (1955), however, found the tenth edition to be less effective.…”

“…I n addition they both misread the plate number 13, and one of them misread the plate number 10. The I1 B test may be somewhat difficult for normal subjects (Kettesy 1955;Frey 1958;Katavisto 1961;Heinsius 1963). In the present study, five normal subjects (5 per cent) failed in this test (only 2 normals failed if plate number 12 is excluded).…”

A proposed correction in the weighted method to score the Ishihara test

“…Fluorescent bulbs have pronounced energy in some wavelengths and differ from natural daylight that has similar energy distribution across spectrum [25]. The comparisons between the results of pseudoisochromatic test using natural daylight (or Macbeth easel lamb) and fluorescent daylight lamp have shown variable results [11, 25, 26]. For the present study, some influence of the fluorescent lamp was minimized by the confirmation of the color vision phenotype by other color vision tests.…”

“…As all the examiners had the same training, we expect that this bias would not have had a great impact in the results. The fluorescent illumination is not recommended by the manufacturer, but some investigations have discussed about the use of this kind of illumination during the use of Ishihara test and they have indicated some influences on the results [11, 23]. Ishihara test was designed for natural daylight or CIE standard illuminant C and International standards for colour vision testing have been given [24].…”

Screening of Red‐green Defects of Colour Vision With Pseudoisochromatic Tests

“…Proper use of a combination of the BK I and I1 B series of pseudoisochromatic tests provides an effective preliminary screening of red-green defects of colour vision (Chapanis 1948;Frey 1958;Katavisto 1961). Using this method in the screenings of the present study, a high number (50) of red-green defectives were collected by examining 351 persons.…”

“…There are several reports on effective differentation between normals and red-green defectives obtained with the Ishihara test (Sloan & Habel 1956;Belcher et al 1958;Crone 1961). Allowing 40 per cent of plates misread by normals, effective differentation between normals and red-green defectives was obtained with the fifth (1925), seventh (1936) and ninth (1940) edition (Hardy et al 1945), tenth (1951) edition (Katavisto 1961) and eleventh (1954) edition (Frey 1958). Kettesy (1955), however, found the tenth edition to be less effective.…”

“…I n addition they both misread the plate number 13, and one of them misread the plate number 10. The I1 B test may be somewhat difficult for normal subjects (Kettesy 1955;Frey 1958;Katavisto 1961;Heinsius 1963). In the present study, five normal subjects (5 per cent) failed in this test (only 2 normals failed if plate number 12 is excluded).…”

A proposed correction in the weighted method to score the Ishihara test

“…Fluorescent bulbs have pronounced energy in some wavelengths and differ from natural daylight that has similar energy distribution across spectrum [25]. The comparisons between the results of pseudoisochromatic test using natural daylight (or Macbeth easel lamb) and fluorescent daylight lamp have shown variable results [11, 25, 26]. For the present study, some influence of the fluorescent lamp was minimized by the confirmation of the color vision phenotype by other color vision tests.…”

“…As all the examiners had the same training, we expect that this bias would not have had a great impact in the results. The fluorescent illumination is not recommended by the manufacturer, but some investigations have discussed about the use of this kind of illumination during the use of Ishihara test and they have indicated some influences on the results [11, 23]. Ishihara test was designed for natural daylight or CIE standard illuminant C and International standards for colour vision testing have been given [24].…”